"""Adds docstrings to functions defined in the torch._C"""

import re

import torch._C
from torch._C import _add_docstr as add_docstr


def parse_kwargs(desc):
    """Maps a description of args to a dictionary of {argname: description}.
    Input:
        ('    weight (Tensor): a weight tensor\n' +
         '        Some optional description')
    Output: {
        'weight': \
        'weight (Tensor): a weight tensor\n        Some optional description'
    }
    """
    # Split on exactly 4 spaces after a newline
    regx = re.compile(r"\n\s{4}(?!\s)")
    kwargs = [section.strip() for section in regx.split(desc)]
    kwargs = [section for section in kwargs if len(section) > 0]
    return {desc.split(' ')[0]: desc for desc in kwargs}


reduceops_common_args = parse_kwargs("""
    dtype (:class:`torch.dtype`, optional): the desired data type of returned tensor.
        If specified, the input tensor is casted to :attr:`dtype` before the operation
        is performed. This is useful for preventing data type overflows. Default: None.
""")

factory_common_args = parse_kwargs("""
    out (Tensor, optional): the output tensor
    dtype (:class:`torch.dtype`, optional): the desired data type of returned tensor.
        Default: if ``None``, uses a global default (see :func:`torch.set_default_tensor_type`).
    layout (:class:`torch.layout`, optional): the desired layout of returned Tensor.
        Default: ``torch.strided``.
    device (:class:`torch.device`, optional): the desired device of returned tensor.
        Default: if ``None``, uses the current device for the default tensor type
        (see :func:`torch.set_default_tensor_type`). :attr:`device` will be the CPU
        for CPU tensor types and the current CUDA device for CUDA tensor types.
    requires_grad (bool, optional): If autograd should record operations on the
        returned tensor. Default: ``False``.
""")

factory_like_common_args = parse_kwargs("""
    input (Tensor): the size of :attr:`input` will determine size of the output tensor
    layout (:class:`torch.layout`, optional): the desired layout of returned tensor.
        Default: if ``None``, defaults to the layout of :attr:`input`.
    dtype (:class:`torch.dtype`, optional): the desired data type of returned Tensor.
        Default: if ``None``, defaults to the dtype of :attr:`input`.
    device (:class:`torch.device`, optional): the desired device of returned tensor.
        Default: if ``None``, defaults to the device of :attr:`input`.
    requires_grad (bool, optional): If autograd should record operations on the
        returned tensor. Default: ``False``.
""")

factory_data_common_args = parse_kwargs("""
    data (array_like): Initial data for the tensor. Can be a list, tuple,
        NumPy ``ndarray``, scalar, and other types.
    dtype (:class:`torch.dtype`, optional): the desired data type of returned tensor.
        Default: if ``None``, infers data type from :attr:`data`.
    device (:class:`torch.device`, optional): the desired device of returned tensor.
        Default: if ``None``, uses the current device for the default tensor type
        (see :func:`torch.set_default_tensor_type`). :attr:`device` will be the CPU
        for CPU tensor types and the current CUDA device for CUDA tensor types.
    requires_grad (bool, optional): If autograd should record operations on the
        returned tensor. Default: ``False``.
""")

add_docstr(torch.abs,
           r"""
abs(input, out=None) -> Tensor

Computes the element-wise absolute value of the given :attr:`input` tensor.

.. math::
    \text{out}_{i} = |\text{input}_{i}|

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> torch.abs(torch.tensor([-1, -2, 3]))
    tensor([ 1,  2,  3])
""")

add_docstr(torch.acos,
           r"""
acos(input, out=None) -> Tensor

Returns a new tensor with the arccosine  of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \cos^{-1}(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.3348, -0.5889,  0.2005, -0.1584])
    >>> torch.acos(a)
    tensor([ 1.2294,  2.2004,  1.3690,  1.7298])
""")

add_docstr(torch.add,
           r"""
.. function:: add(input, value, out=None)

Adds the scalar :attr:`value` to each element of the input :attr:`input`
and returns a new resulting tensor.

.. math::
    \text{out} = \text{input} + \text{value}

If :attr:`input` is of type FloatTensor or DoubleTensor, :attr:`value` must be
a real number, otherwise it should be an integer.

Args:
    input (Tensor): the input tensor
    value (Number): the number to be added to each element of :attr:`input`

Keyword arguments:
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.0202,  1.0985,  1.3506, -0.6056])
    >>> torch.add(a, 20)
    tensor([ 20.0202,  21.0985,  21.3506,  19.3944])

.. function:: add(input, value=1, other, out=None)

Each element of the tensor :attr:`other` is multiplied by the scalar
:attr:`value` and added to each element of the tensor :attr:`input`.
The resulting tensor is returned.

The shapes of :attr:`input` and :attr:`other` must be
:ref:`broadcastable <broadcasting-semantics>`.

.. math::
    \text{out} = \text{input} + \text{value} \times \text{other}

If :attr:`other` is of type FloatTensor or DoubleTensor, :attr:`value` must be
a real number, otherwise it should be an integer.

Args:
    input (Tensor): the first input tensor
    value (Number): the scalar multiplier for :attr:`other`
    other (Tensor): the second input tensor

Keyword arguments:
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.9732, -0.3497,  0.6245,  0.4022])
    >>> b = torch.randn(4, 1)
    >>> b
    tensor([[ 0.3743],
            [-1.7724],
            [-0.5811],
            [-0.8017]])
    >>> torch.add(a, 10, b)
    tensor([[  2.7695,   3.3930,   4.3672,   4.1450],
            [-18.6971, -18.0736, -17.0994, -17.3216],
            [ -6.7845,  -6.1610,  -5.1868,  -5.4090],
            [ -8.9902,  -8.3667,  -7.3925,  -7.6147]])
""")

add_docstr(torch.addbmm,
           r"""
addbmm(beta=1, mat, alpha=1, batch1, batch2, out=None) -> Tensor

Performs a batch matrix-matrix product of matrices stored
in :attr:`batch1` and :attr:`batch2`,
with a reduced add step (all matrix multiplications get accumulated
along the first dimension).
:attr:`mat` is added to the final result.

:attr:`batch1` and :attr:`batch2` must be 3-D tensors each containing the
same number of matrices.

If :attr:`batch1` is a :math:`(b \times n \times m)` tensor, :attr:`batch2` is a
:math:`(b \times m \times p)` tensor, :attr:`mat` must be
:ref:`broadcastable <broadcasting-semantics>` with a :math:`(n \times p)` tensor
and :attr:`out` will be a :math:`(n \times p)` tensor.

.. math::
    out = \beta\ \text{mat} + \alpha\ (\sum_{i=0}^{b} \text{batch1}_i \mathbin{@} \text{batch2}_i)

For inputs of type `FloatTensor` or `DoubleTensor`, arguments :attr:`beta` and :attr:`alpha`
must be real numbers, otherwise they should be integers.

Args:
    beta (Number, optional): multiplier for :attr:`mat` (:math:`\beta`)
    mat (Tensor): matrix to be added
    alpha (Number, optional): multiplier for `batch1 @ batch2` (:math:`\alpha`)
    batch1 (Tensor): the first batch of matrices to be multiplied
    batch2 (Tensor): the second batch of matrices to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> M = torch.randn(3, 5)
    >>> batch1 = torch.randn(10, 3, 4)
    >>> batch2 = torch.randn(10, 4, 5)
    >>> torch.addbmm(M, batch1, batch2)
    tensor([[  6.6311,   0.0503,   6.9768, -12.0362,  -2.1653],
            [ -4.8185,  -1.4255,  -6.6760,   8.9453,   2.5743],
            [ -3.8202,   4.3691,   1.0943,  -1.1109,   5.4730]])
""")

add_docstr(torch.addcdiv,
           r"""
addcdiv(tensor, value=1, tensor1, tensor2, out=None) -> Tensor

Performs the element-wise division of :attr:`tensor1` by :attr:`tensor2`,
multiply the result by the scalar :attr:`value` and add it to :attr:`tensor`.

.. math::
    \text{out}_i = \text{tensor}_i + \text{value} \times \frac{\text{tensor1}_i}{\text{tensor2}_i}

The shapes of :attr:`tensor`, :attr:`tensor1`, and :attr:`tensor2` must be
:ref:`broadcastable <broadcasting-semantics>`.

For inputs of type `FloatTensor` or `DoubleTensor`, :attr:`value` must be
a real number, otherwise an integer.

Args:
    tensor (Tensor): the tensor to be added
    value (Number, optional): multiplier for :math:`\text{tensor1} / \text{tensor2}`
    tensor1 (Tensor): the numerator tensor
    tensor2 (Tensor): the denominator tensor
    out (Tensor, optional): the output tensor

Example::

    >>> t = torch.randn(1, 3)
    >>> t1 = torch.randn(3, 1)
    >>> t2 = torch.randn(1, 3)
    >>> torch.addcdiv(t, 0.1, t1, t2)
    tensor([[-0.2312, -3.6496,  0.1312],
            [-1.0428,  3.4292, -0.1030],
            [-0.5369, -0.9829,  0.0430]])
""")

add_docstr(torch.addcmul,
           r"""
addcmul(tensor, value=1, tensor1, tensor2, out=None) -> Tensor

Performs the element-wise multiplication of :attr:`tensor1`
by :attr:`tensor2`, multiply the result by the scalar :attr:`value`
and add it to :attr:`tensor`.

.. math::
    \text{out}_i = \text{tensor}_i + \text{value} \times \text{tensor1}_i \times \text{tensor2}_i

The shapes of :attr:`tensor`, :attr:`tensor1`, and :attr:`tensor2` must be
:ref:`broadcastable <broadcasting-semantics>`.

For inputs of type `FloatTensor` or `DoubleTensor`, :attr:`value` must be
a real number, otherwise an integer.

Args:
    tensor (Tensor): the tensor to be added
    value (Number, optional): multiplier for :math:`tensor1 .* tensor2`
    tensor1 (Tensor): the tensor to be multiplied
    tensor2 (Tensor): the tensor to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> t = torch.randn(1, 3)
    >>> t1 = torch.randn(3, 1)
    >>> t2 = torch.randn(1, 3)
    >>> torch.addcmul(t, 0.1, t1, t2)
    tensor([[-0.8635, -0.6391,  1.6174],
            [-0.7617, -0.5879,  1.7388],
            [-0.8353, -0.6249,  1.6511]])
""")

add_docstr(torch.addmm,
           r"""
addmm(beta=1, mat, alpha=1, mat1, mat2, out=None) -> Tensor

Performs a matrix multiplication of the matrices :attr:`mat1` and :attr:`mat2`.
The matrix :attr:`mat` is added to the final result.

If :attr:`mat1` is a :math:`(n \times m)` tensor, :attr:`mat2` is a
:math:`(m \times p)` tensor, then :attr:`mat` must be
:ref:`broadcastable <broadcasting-semantics>` with a :math:`(n \times p)` tensor
and :attr:`out` will be a :math:`(n \times p)` tensor.

:attr:`alpha` and :attr:`beta` are scaling factors on matrix-vector product between
:attr:`mat1` and :attr`mat2` and the added matrix :attr:`mat` respectively.

.. math::
    \text{out} = \beta\ \text{mat} + \alpha\ (\text{mat1}_i \mathbin{@} \text{mat2}_i)

For inputs of type `FloatTensor` or `DoubleTensor`, arguments :attr:`beta` and
:attr:`alpha` must be real numbers, otherwise they should be integers.

Args:
    beta (Number, optional): multiplier for :attr:`mat` (:math:`\beta`)
    mat (Tensor): matrix to be added
    alpha (Number, optional): multiplier for :math:`mat1 @ mat2` (:math:`\alpha`)
    mat1 (Tensor): the first matrix to be multiplied
    mat2 (Tensor): the second matrix to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> M = torch.randn(2, 3)
    >>> mat1 = torch.randn(2, 3)
    >>> mat2 = torch.randn(3, 3)
    >>> torch.addmm(M, mat1, mat2)
    tensor([[-4.8716,  1.4671, -1.3746],
            [ 0.7573, -3.9555, -2.8681]])
""")

add_docstr(torch.addmv,
           r"""
addmv(beta=1, tensor, alpha=1, mat, vec, out=None) -> Tensor

Performs a matrix-vector product of the matrix :attr:`mat` and
the vector :attr:`vec`.
The vector :attr:`tensor` is added to the final result.

If :attr:`mat` is a :math:`(n \times m)` tensor, :attr:`vec` is a 1-D tensor of
size `m`, then :attr:`tensor` must be
:ref:`broadcastable <broadcasting-semantics>` with a 1-D tensor of size `n` and
:attr:`out` will be 1-D tensor of size `n`.

:attr:`alpha` and :attr:`beta` are scaling factors on matrix-vector product between
:attr:`mat` and :attr:`vec` and the added tensor :attr:`tensor` respectively.

.. math::
    \text{out} = \beta\ \text{tensor} + \alpha\ (\text{mat} \mathbin{@} \text{vec})

For inputs of type `FloatTensor` or `DoubleTensor`, arguments :attr:`beta` and
:attr:`alpha` must be real numbers, otherwise they should be integers

Args:
    beta (Number, optional): multiplier for :attr:`tensor` (:math:`\beta`)
    tensor (Tensor): vector to be added
    alpha (Number, optional): multiplier for :math:`mat @ vec` (:math:`\alpha`)
    mat (Tensor): matrix to be multiplied
    vec (Tensor): vector to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> M = torch.randn(2)
    >>> mat = torch.randn(2, 3)
    >>> vec = torch.randn(3)
    >>> torch.addmv(M, mat, vec)
    tensor([-0.3768, -5.5565])
""")

add_docstr(torch.addr,
           r"""
addr(beta=1, mat, alpha=1, vec1, vec2, out=None) -> Tensor

Performs the outer-product of vectors :attr:`vec1` and :attr:`vec2`
and adds it to the matrix :attr:`mat`.

Optional values :attr:`beta` and :attr:`alpha` are scaling factors on the
outer product between :attr:`vec1` and :attr:`vec2` and the added matrix
:attr:`mat` respectively.

.. math::
    \text{out} = \beta\ \text{mat} + \alpha\ (\text{vec1} \otimes \text{vec2})

If :attr:`vec1` is a vector of size `n` and :attr:`vec2` is a vector
of size `m`, then :attr:`mat` must be
:ref:`broadcastable <broadcasting-semantics>` with a matrix of size
:math:`(n \times m)` and :attr:`out` will be a matrix of size
:math:`(n \times m)`.

For inputs of type `FloatTensor` or `DoubleTensor`, arguments :attr:`beta` and
:attr:`alpha` must be real numbers, otherwise they should be integers

Args:
    beta (Number, optional): multiplier for :attr:`mat` (:math:`\beta`)
    mat (Tensor): matrix to be added
    alpha (Number, optional): multiplier for :math:`\text{vec1} \otimes \text{vec2}` (:math:`\alpha`)
    vec1 (Tensor): the first vector of the outer product
    vec2 (Tensor): the second vector of the outer product
    out (Tensor, optional): the output tensor

Example::

    >>> vec1 = torch.arange(1., 4.)
    >>> vec2 = torch.arange(1., 3.)
    >>> M = torch.zeros(3, 2)
    >>> torch.addr(M, vec1, vec2)
    tensor([[ 1.,  2.],
            [ 2.,  4.],
            [ 3.,  6.]])
""")

add_docstr(torch.allclose,
           r"""
allclose(self, other, rtol=1e-05, atol=1e-08, equal_nan=False) -> bool

This function checks if all :attr:`self` and :attr:`other` satisfy the condition:

.. math::
    \lvert \text{self} - \text{other} \rvert \leq \texttt{atol} + \texttt{rtol} \times \lvert \text{other} \rvert

elementwise, for all elements of :attr:`self` and :attr:`other`. The behaviour of this function is analogous to
`numpy.allclose <https://docs.scipy.org/doc/numpy/reference/generated/numpy.allclose.html>`_

Args:
    self (Tensor): first tensor to compare
    other (Tensor): second tensor to compare
    atol (float, optional): absolute tolerance. Default: 1e-08
    rtol (float, optional): relative tolerance. Default: 1e-05
    equal_nan (float, optional): if ``True``, then two ``NaN`` s will be compared as equal. Default: ``False``

Example::

    >>> torch.allclose(torch.tensor([10000., 1e-07]), torch.tensor([10000.1, 1e-08]))
    False
    >>> torch.allclose(torch.tensor([10000., 1e-08]), torch.tensor([10000.1, 1e-09]))
    True
    >>> torch.allclose(torch.tensor([1.0, float('nan')]), torch.tensor([1.0, float('nan')]))
    False
    >>> torch.allclose(torch.tensor([1.0, float('nan')]), torch.tensor([1.0, float('nan')]), equal_nan=True)
    True
""")

add_docstr(torch.as_tensor,
           r"""
as_tensor(data, dtype=None, device=None) -> Tensor

Convert the data into a `torch.Tensor`. If the data is already a `Tensor` with the same `dtype` and `device`,
no copy will be performed, otherwise a new `Tensor` will be returned with computational graph retained if data
`Tensor` has ``requires_grad=True``. Similarly, if the data is an ``ndarray`` of the corresponding `dtype` and
the `device` is the cpu, no copy will be performed.

Args:
    {data}
    {dtype}
    {device}

Example::

    >>> a = numpy.array([1, 2, 3])
    >>> t = torch.as_tensor(a)
    >>> t
    tensor([ 1,  2,  3])
    >>> t[0] = -1
    >>> a
    array([-1,  2,  3])

    >>> a = numpy.array([1, 2, 3])
    >>> t = torch.as_tensor(a, device=torch.device('cuda'))
    >>> t
    tensor([ 1,  2,  3])
    >>> t[0] = -1
    >>> a
    array([1,  2,  3])
""".format(**factory_data_common_args))

add_docstr(torch.asin,
           r"""
asin(input, out=None) -> Tensor

Returns a new tensor with the arcsine  of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \sin^{-1}(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.5962,  1.4985, -0.4396,  1.4525])
    >>> torch.asin(a)
    tensor([-0.6387,     nan, -0.4552,     nan])
""")

add_docstr(torch.atan,
           r"""
atan(input, out=None) -> Tensor

Returns a new tensor with the arctangent  of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \tan^{-1}(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.2341,  0.2539, -0.6256, -0.6448])
    >>> torch.atan(a)
    tensor([ 0.2299,  0.2487, -0.5591, -0.5727])
""")

add_docstr(torch.atan2,
           r"""
atan2(input1, input2, out=None) -> Tensor

Returns a new tensor with the arctangent of the elements of :attr:`input1`
and :attr:`input2`.

The shapes of :attr:`input1` and :attr:`input2` must be
:ref:`broadcastable <broadcasting-semantics>`.

Args:
    input1 (Tensor): the first input tensor
    input2 (Tensor): the second input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.9041,  0.0196, -0.3108, -2.4423])
    >>> torch.atan2(a, torch.randn(4))
    tensor([ 0.9833,  0.0811, -1.9743, -1.4151])
""")

add_docstr(torch.baddbmm,
           r"""
baddbmm(beta=1, mat, alpha=1, batch1, batch2, out=None) -> Tensor

Performs a batch matrix-matrix product of matrices in :attr:`batch1`
and :attr:`batch2`.
:attr:`mat` is added to the final result.

:attr:`batch1` and :attr:`batch2` must be 3-D tensors each containing the same
number of matrices.

If :attr:`batch1` is a :math:`(b \times n \times m)` tensor, :attr:`batch2` is a
:math:`(b \times m \times p)` tensor, then :attr:`mat` must be
:ref:`broadcastable <broadcasting-semantics>` with a
:math:`(b \times n \times p)` tensor and :attr:`out` will be a
:math:`(b \times n \times p)` tensor. Both :attr:`alpha` and :attr:`beta` mean the
same as the scaling factors used in :meth:`torch.addbmm`.

.. math::
    \text{out}_i = \beta\ \text{mat}_i + \alpha\ (\text{batch1}_i \mathbin{@} \text{batch2}_i)

For inputs of type `FloatTensor` or `DoubleTensor`, arguments :attr:`beta` and
:attr:`alpha` must be real numbers, otherwise they should be integers.

Args:
    beta (Number, optional): multiplier for :attr:`mat` (:math:`\beta`)
    mat (Tensor): the tensor to be added
    alpha (Number, optional): multiplier for :math:`\text{batch1} \mathbin{@} \text{batch2}` (:math:`\alpha`)
    batch1 (Tensor): the first batch of matrices to be multiplied
    batch2 (Tensor): the second batch of matrices to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> M = torch.randn(10, 3, 5)
    >>> batch1 = torch.randn(10, 3, 4)
    >>> batch2 = torch.randn(10, 4, 5)
    >>> torch.baddbmm(M, batch1, batch2).size()
    torch.Size([10, 3, 5])
""")

add_docstr(torch.bernoulli,
           r"""
bernoulli(input, *, generator=None, out=None) -> Tensor

Draws binary random numbers (0 or 1) from a Bernoulli distribution.

The :attr:`input` tensor should be a tensor containing probabilities
to be used for drawing the binary random number.
Hence, all values in :attr:`input` have to be in the range:
:math:`0 \leq \text{input}_i \leq 1`.

The :math:`\text{i}^{th}` element of the output tensor will draw a
value :math:`1` according to the :math:`\text{i}^{th}` probability value given
in :attr:`input`.

.. math::
    \text{out}_{i} \sim \mathrm{Bernoulli}(p = \text{input}_{i})

The returned :attr:`out` tensor only has values 0 or 1 and is of the same
shape as :attr:`input`.

:attr:`out` can have integral ``dtype``, but :attr`input` must have floating
point ``dtype``.

Args:
    input (Tensor): the input tensor of probability values for the Bernoulli distribution
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.empty(3, 3).uniform_(0, 1)  # generate a uniform random matrix with range [0, 1]
    >>> a
    tensor([[ 0.1737,  0.0950,  0.3609],
            [ 0.7148,  0.0289,  0.2676],
            [ 0.9456,  0.8937,  0.7202]])
    >>> torch.bernoulli(a)
    tensor([[ 1.,  0.,  0.],
            [ 0.,  0.,  0.],
            [ 1.,  1.,  1.]])

    >>> a = torch.ones(3, 3) # probability of drawing "1" is 1
    >>> torch.bernoulli(a)
    tensor([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])
    >>> a = torch.zeros(3, 3) # probability of drawing "1" is 0
    >>> torch.bernoulli(a)
    tensor([[ 0.,  0.,  0.],
            [ 0.,  0.,  0.],
            [ 0.,  0.,  0.]])
""")

add_docstr(torch.bincount,
           r"""
bincount(self, weights=None, minlength=0) -> Tensor

Count the frequency of each value in an array of non-negative ints.

The number of bins (size 1) is one larger than the largest value in
:attr:`input` unless :attr:`input` is empty, in which case the result is a
tensor of size 0. If :attr:`minlength` is specified, the number of bins is at least
:attr:`minlength` and if :attr:`input` is empty, then the result is tensor of size
:attr:`minlength` filled with zeros. If ``n`` is the value at position ``i``,
``out[n] += weights[i]`` if :attr:`weights` is specified else
``out[n] += 1``.

.. include:: cuda_deterministic.rst

Arguments:
    input (Tensor): 1-d int tensor
    weights (Tensor): optional, weight for each value in the input tensor.
        Should be of same size as input tensor.
    minlength (int): optional, minimum number of bins. Should be non-negative.

Returns:
    output (Tensor): a tensor of shape ``Size([max(input) + 1])`` if
    :attr:`input` is non-empty, else ``Size(0)``

Example::

    >>> input = torch.randint(0, 8, (5,), dtype=torch.int64)
    >>> weights = torch.linspace(0, 1, steps=5)
    >>> input, weights
    (tensor([4, 3, 6, 3, 4]),
     tensor([ 0.0000,  0.2500,  0.5000,  0.7500,  1.0000])

    >>> torch.bincount(input)
    tensor([0, 0, 0, 2, 2, 0, 1])

    >>> input.bincount(weights)
    tensor([0.0000, 0.0000, 0.0000, 1.0000, 1.0000, 0.0000, 0.5000])
""")

add_docstr(torch.bmm,
           r"""
bmm(batch1, batch2, out=None) -> Tensor

Performs a batch matrix-matrix product of matrices stored in :attr:`batch1`
and :attr:`batch2`.

:attr:`batch1` and :attr:`batch2` must be 3-D tensors each containing
the same number of matrices.

If :attr:`batch1` is a :math:`(b \times n \times m)` tensor, :attr:`batch2` is a
:math:`(b \times m \times p)` tensor, :attr:`out` will be a
:math:`(b \times n \times p)` tensor.

.. math::
    \text{out}_i = \text{batch1}_i \mathbin{@} \text{batch2}_i

.. note:: This function does not :ref:`broadcast <broadcasting-semantics>`.
          For broadcasting matrix products, see :func:`torch.matmul`.

Args:
    batch1 (Tensor): the first batch of matrices to be multiplied
    batch2 (Tensor): the second batch of matrices to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> batch1 = torch.randn(10, 3, 4)
    >>> batch2 = torch.randn(10, 4, 5)
    >>> res = torch.bmm(batch1, batch2)
    >>> res.size()
    torch.Size([10, 3, 5])
""")

add_docstr(torch.stack,
           r"""
stack(seq, dim=0, out=None) -> Tensor

Concatenates sequence of tensors along a new dimension.

All tensors need to be of the same size.

Arguments:
    seq (sequence of Tensors): sequence of tensors to concatenate
    dim (int): dimension to insert. Has to be between 0 and the number
        of dimensions of concatenated tensors (inclusive)
    out (Tensor, optional): the output tensor
""")

add_docstr(torch.chunk,
           r"""
chunk(tensor, chunks, dim=0) -> List of Tensors

Splits a tensor into a specific number of chunks.

Last chunk will be smaller if the tensor size along the given dimension
:attr:`dim` is not divisible by :attr:`chunks`.

Arguments:
    tensor (Tensor): the tensor to split
    chunks (int): number of chunks to return
    dim (int): dimension along which to split the tensor
""")

add_docstr(torch.cat,
           r"""
cat(tensors, dim=0, out=None) -> Tensor

Concatenates the given sequence of :attr:`seq` tensors in the given dimension.
All tensors must either have the same shape (except in the concatenating
dimension) or be empty.

:func:`torch.cat` can be seen as an inverse operation for :func:`torch.split`
and :func:`torch.chunk`.

:func:`torch.cat` can be best understood via examples.

Args:
    tensors (sequence of Tensors): any python sequence of tensors of the same type.
        Non-empty tensors provided must have the same shape, except in the
        cat dimension.
    dim (int, optional): the dimension over which the tensors are concatenated
    out (Tensor, optional): the output tensor

Example::

    >>> x = torch.randn(2, 3)
    >>> x
    tensor([[ 0.6580, -1.0969, -0.4614],
            [-0.1034, -0.5790,  0.1497]])
    >>> torch.cat((x, x, x), 0)
    tensor([[ 0.6580, -1.0969, -0.4614],
            [-0.1034, -0.5790,  0.1497],
            [ 0.6580, -1.0969, -0.4614],
            [-0.1034, -0.5790,  0.1497],
            [ 0.6580, -1.0969, -0.4614],
            [-0.1034, -0.5790,  0.1497]])
    >>> torch.cat((x, x, x), 1)
    tensor([[ 0.6580, -1.0969, -0.4614,  0.6580, -1.0969, -0.4614,  0.6580,
             -1.0969, -0.4614],
            [-0.1034, -0.5790,  0.1497, -0.1034, -0.5790,  0.1497, -0.1034,
             -0.5790,  0.1497]])
""")

add_docstr(torch.ceil,
           r"""
ceil(input, out=None) -> Tensor

Returns a new tensor with the ceil of the elements of :attr:`input`,
the smallest integer greater than or equal to each element.

.. math::
    \text{out}_{i} = \left\lceil \text{input}_{i} \right\rceil = \left\lfloor \text{input}_{i} \right\rfloor + 1

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.6341, -1.4208, -1.0900,  0.5826])
    >>> torch.ceil(a)
    tensor([-0., -1., -1.,  1.])
""")

add_docstr(torch.reciprocal,
           r"""
reciprocal(input, out=None) -> Tensor

Returns a new tensor with the reciprocal of the elements of :attr:`input`

.. math::
    \text{out}_{i} = \frac{1}{\text{input}_{i}}

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.4595, -2.1219, -1.4314,  0.7298])
    >>> torch.reciprocal(a)
    tensor([-2.1763, -0.4713, -0.6986,  1.3702])
""")

add_docstr(torch.clamp,
           r"""
clamp(input, min, max, out=None) -> Tensor

Clamp all elements in :attr:`input` into the range `[` :attr:`min`, :attr:`max` `]` and return
a resulting tensor:

.. math::
    y_i = \begin{cases}
        \text{min} & \text{if } x_i < \text{min} \\
        x_i & \text{if } \text{min} \leq x_i \leq \text{max} \\
        \text{max} & \text{if } x_i > \text{max}
    \end{cases}

If :attr:`input` is of type `FloatTensor` or `DoubleTensor`, args :attr:`min`
and :attr:`max` must be real numbers, otherwise they should be integers.

Args:
    input (Tensor): the input tensor
    min (Number): lower-bound of the range to be clamped to
    max (Number): upper-bound of the range to be clamped to
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-1.7120,  0.1734, -0.0478, -0.0922])
    >>> torch.clamp(a, min=-0.5, max=0.5)
    tensor([-0.5000,  0.1734, -0.0478, -0.0922])

.. function:: clamp(input, *, min, out=None) -> Tensor

Clamps all elements in :attr:`input` to be larger or equal :attr:`min`.

If :attr:`input` is of type `FloatTensor` or `DoubleTensor`, :attr:`value`
should be a real number, otherwise it should be an integer.

Args:
    input (Tensor): the input tensor
    value (Number): minimal value of each element in the output
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.0299, -2.3184,  2.1593, -0.8883])
    >>> torch.clamp(a, min=0.5)
    tensor([ 0.5000,  0.5000,  2.1593,  0.5000])

.. function:: clamp(input, *, max, out=None) -> Tensor

Clamps all elements in :attr:`input` to be smaller or equal :attr:`max`.

If :attr:`input` is of type `FloatTensor` or `DoubleTensor`, :attr:`value`
should be a real number, otherwise it should be an integer.

Args:
    input (Tensor): the input tensor
    value (Number): maximal value of each element in the output
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.7753, -0.4702, -0.4599,  1.1899])
    >>> torch.clamp(a, max=0.5)
    tensor([ 0.5000, -0.4702, -0.4599,  0.5000])
""")

add_docstr(torch.cos,
           r"""
cos(input, out=None) -> Tensor

Returns a new tensor with the cosine  of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \cos(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 1.4309,  1.2706, -0.8562,  0.9796])
    >>> torch.cos(a)
    tensor([ 0.1395,  0.2957,  0.6553,  0.5574])
""")

add_docstr(torch.cosh,
           r"""
cosh(input, out=None) -> Tensor

Returns a new tensor with the hyperbolic cosine  of the elements of
:attr:`input`.

.. math::
    \text{out}_{i} = \cosh(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.1632,  1.1835, -0.6979, -0.7325])
    >>> torch.cosh(a)
    tensor([ 1.0133,  1.7860,  1.2536,  1.2805])
""")

add_docstr(torch.cross,
           r"""
cross(input, other, dim=-1, out=None) -> Tensor


Returns the cross product of vectors in dimension :attr:`dim` of :attr:`input`
and :attr:`other`.

:attr:`input` and :attr:`other` must have the same size, and the size of their
:attr:`dim` dimension should be 3.

If :attr:`dim` is not given, it defaults to the first dimension found with the
size 3.

Args:
    input (Tensor): the input tensor
    other (Tensor): the second input tensor
    dim  (int, optional): the dimension to take the cross-product in.
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4, 3)
    >>> a
    tensor([[-0.3956,  1.1455,  1.6895],
            [-0.5849,  1.3672,  0.3599],
            [-1.1626,  0.7180, -0.0521],
            [-0.1339,  0.9902, -2.0225]])
    >>> b = torch.randn(4, 3)
    >>> b
    tensor([[-0.0257, -1.4725, -1.2251],
            [-1.1479, -0.7005, -1.9757],
            [-1.3904,  0.3726, -1.1836],
            [-0.9688, -0.7153,  0.2159]])
    >>> torch.cross(a, b, dim=1)
    tensor([[ 1.0844, -0.5281,  0.6120],
            [-2.4490, -1.5687,  1.9792],
            [-0.8304, -1.3037,  0.5650],
            [-1.2329,  1.9883,  1.0551]])
    >>> torch.cross(a, b)
    tensor([[ 1.0844, -0.5281,  0.6120],
            [-2.4490, -1.5687,  1.9792],
            [-0.8304, -1.3037,  0.5650],
            [-1.2329,  1.9883,  1.0551]])
""")

add_docstr(torch.cumprod,
           r"""
cumprod(input, dim, dtype=None) -> Tensor

Returns the cumulative product of elements of :attr:`input` in the dimension
:attr:`dim`.

For example, if :attr:`input` is a vector of size N, the result will also be
a vector of size N, with elements.

.. math::
    y_i = x_1 \times x_2\times x_3\times \dots \times x_i

Args:
    input (Tensor): the input tensor
    dim  (int): the dimension to do the operation over
    {dtype}

Example::

    >>> a = torch.randn(10)
    >>> a
    tensor([ 0.6001,  0.2069, -0.1919,  0.9792,  0.6727,  1.0062,  0.4126,
            -0.2129, -0.4206,  0.1968])
    >>> torch.cumprod(a, dim=0)
    tensor([ 0.6001,  0.1241, -0.0238, -0.0233, -0.0157, -0.0158, -0.0065,
             0.0014, -0.0006, -0.0001])

    >>> a[5] = 0.0
    >>> torch.cumprod(a, dim=0)
    tensor([ 0.6001,  0.1241, -0.0238, -0.0233, -0.0157, -0.0000, -0.0000,
             0.0000, -0.0000, -0.0000])
""".format(**reduceops_common_args))

add_docstr(torch.cumsum,
           r"""
cumsum(input, dim, out=None, dtype=None) -> Tensor

Returns the cumulative sum of elements of :attr:`input` in the dimension
:attr:`dim`.

For example, if :attr:`input` is a vector of size N, the result will also be
a vector of size N, with elements.

.. math::
    y_i = x_1 + x_2 + x_3 + \dots + x_i

Args:
    input (Tensor): the input tensor
    dim  (int): the dimension to do the operation over
    {dtype}

Example::

    >>> a = torch.randn(10)
    >>> a
    tensor([-0.8286, -0.4890,  0.5155,  0.8443,  0.1865, -0.1752, -2.0595,
             0.1850, -1.1571, -0.4243])
    >>> torch.cumsum(a, dim=0)
    tensor([-0.8286, -1.3175, -0.8020,  0.0423,  0.2289,  0.0537, -2.0058,
            -1.8209, -2.9780, -3.4022])
""".format(**reduceops_common_args))

add_docstr(torch.diag,
           r"""
diag(input, diagonal=0, out=None) -> Tensor

- If :attr:`input` is a vector (1-D tensor), then returns a 2-D square tensor
  with the elements of :attr:`input` as the diagonal.
- If :attr:`input` is a matrix (2-D tensor), then returns a 1-D tensor with
  the diagonal elements of :attr:`input`.

The argument :attr:`diagonal` controls which diagonal to consider:

- If :attr:`diagonal` = 0, it is the main diagonal.
- If :attr:`diagonal` > 0, it is above the main diagonal.
- If :attr:`diagonal` < 0, it is below the main diagonal.

Args:
    input (Tensor): the input tensor
    diagonal (int, optional): the diagonal to consider
    out (Tensor, optional): the output tensor

.. seealso::

        :func:`torch.diagonal` always returns the diagonal of its input.

        :func:`torch.diagflat` always constructs a tensor with diagonal elements
        specified by the input.

Examples:

Get the square matrix where the input vector is the diagonal::

    >>> a = torch.randn(3)
    >>> a
    tensor([ 0.5950,-0.0872, 2.3298])
    >>> torch.diag(a)
    tensor([[ 0.5950, 0.0000, 0.0000],
            [ 0.0000,-0.0872, 0.0000],
            [ 0.0000, 0.0000, 2.3298]])
    >>> torch.diag(a, 1)
    tensor([[ 0.0000, 0.5950, 0.0000, 0.0000],
            [ 0.0000, 0.0000,-0.0872, 0.0000],
            [ 0.0000, 0.0000, 0.0000, 2.3298],
            [ 0.0000, 0.0000, 0.0000, 0.0000]])

Get the k-th diagonal of a given matrix::

    >>> a = torch.randn(3, 3)
    >>> a
    tensor([[-0.4264, 0.0255,-0.1064],
            [ 0.8795,-0.2429, 0.1374],
            [ 0.1029,-0.6482,-1.6300]])
    >>> torch.diag(a, 0)
    tensor([-0.4264,-0.2429,-1.6300])
    >>> torch.diag(a, 1)
    tensor([ 0.0255, 0.1374])
""")

add_docstr(torch.diagflat,
           r"""
diagflat(input, diagonal=0) -> Tensor

- If :attr:`input` is a vector (1-D tensor), then returns a 2-D square tensor
  with the elements of :attr:`input` as the diagonal.
- If :attr:`input` is a tensor with more than one dimension, then returns a
  2-D tensor with diagonal elements equal to a flattened :attr:`input`.

The argument :attr:`offset` controls which diagonal to consider:

- If :attr:`offset` = 0, it is the main diagonal.
- If :attr:`offset` > 0, it is above the main diagonal.
- If :attr:`offset` < 0, it is below the main diagonal.

Args:
    input (Tensor): the input tensor
    offset (int, optional): the diagonal to consider. Default: 0 (main
        diagonal).

Examples::

    >>> a = torch.randn(3)
    >>> a
    tensor([-0.2956, -0.9068,  0.1695])
    >>> torch.diagflat(a)
    tensor([[-0.2956,  0.0000,  0.0000],
            [ 0.0000, -0.9068,  0.0000],
            [ 0.0000,  0.0000,  0.1695]])
    >>> torch.diagflat(a, 1)
    tensor([[ 0.0000, -0.2956,  0.0000,  0.0000],
            [ 0.0000,  0.0000, -0.9068,  0.0000],
            [ 0.0000,  0.0000,  0.0000,  0.1695],
            [ 0.0000,  0.0000,  0.0000,  0.0000]])

    >>> a = torch.randn(2, 2)
    >>> a
    tensor([[ 0.2094, -0.3018],
            [-0.1516,  1.9342]])
    >>> torch.diagflat(a)
    tensor([[ 0.2094,  0.0000,  0.0000,  0.0000],
            [ 0.0000, -0.3018,  0.0000,  0.0000],
            [ 0.0000,  0.0000, -0.1516,  0.0000],
            [ 0.0000,  0.0000,  0.0000,  1.9342]])
""")

add_docstr(torch.diagonal,
           r"""
diagonal(input, offset=0, dim1=0, dim2=1) -> Tensor

Returns a partial view of :attr:`input` with the its diagonal elements
with respect to :attr:`dim1` and :attr:`dim2` appended as a dimension
at the end of the shape.

The argument :attr:`offset` controls which diagonal to consider:

- If :attr:`offset` = 0, it is the main diagonal.
- If :attr:`offset` > 0, it is above the main diagonal.
- If :attr:`offset` < 0, it is below the main diagonal.

Args:
    input (Tensor): the input tensor. Must be at least 2-dimensional.
    offset (int, optional): which diagonal to consider. Default: 0
        (main diagonal).
    dim1 (int, optional): first dimension with respect to which to
        take diagonal. Default: 0.
    dim2 (int, optional): second dimension with respect to which to
        take diagonal. Default: 1.

.. note::  To take a batch diagonal, pass in dim1=-2, dim2=-1.

Examples::

    >>> a = torch.randn(3, 3)
    >>> a
    tensor([[-1.0854,  1.1431, -0.1752],
            [ 0.8536, -0.0905,  0.0360],
            [ 0.6927, -0.3735, -0.4945]])


    >>> torch.diagonal(a, 0)
    tensor([-1.0854, -0.0905, -0.4945])


    >>> torch.diagonal(a, 1)
    tensor([ 1.1431,  0.0360])


    >>> x = torch.randn(2, 5, 4, 2)
    >>> torch.diagonal(x, offset=-1, dim1=1, dim2=2)
    tensor([[[-1.2631,  0.3755, -1.5977, -1.8172],
             [-1.1065,  1.0401, -0.2235, -0.7938]],

            [[-1.7325, -0.3081,  0.6166,  0.2335],
             [ 1.0500,  0.7336, -0.3836, -1.1015]]])
""")

add_docstr(torch.digamma,
           r"""
digamma(input) -> Tensor

Computes the logarithmic derivative of the gamma function on `input`.

.. math::
    \psi(x) = \frac{d}{dx} \ln\left(\Gamma\left(x\right)\right) = \frac{\Gamma'(x)}{\Gamma(x)}

Args:
    input (Tensor): the tensor to compute the digamma function on

Example::

    >>> a = torch.tensor([1, 0.5])
    >>> torch.digamma(a)
    tensor([-0.5772, -1.9635])
""")


add_docstr(torch.dist,
           r"""
dist(input, other, p=2) -> Tensor

Returns the p-norm of (:attr:`input` - :attr:`other`)

The shapes of :attr:`input` and :attr:`other` must be
:ref:`broadcastable <broadcasting-semantics>`.

Args:
    input (Tensor): the input tensor
    other (Tensor): the Right-hand-side input tensor
    p (float, optional): the norm to be computed

Example::

    >>> x = torch.randn(4)
    >>> x
    tensor([-1.5393, -0.8675,  0.5916,  1.6321])
    >>> y = torch.randn(4)
    >>> y
    tensor([ 0.0967, -1.0511,  0.6295,  0.8360])
    >>> torch.dist(x, y, 3.5)
    tensor(1.6727)
    >>> torch.dist(x, y, 3)
    tensor(1.6973)
    >>> torch.dist(x, y, 0)
    tensor(inf)
    >>> torch.dist(x, y, 1)
    tensor(2.6537)
""")

add_docstr(torch.div,
           r"""
.. function:: div(input, value, out=None) -> Tensor

Divides each element of the input :attr:`input` with the scalar :attr:`value`
and returns a new resulting tensor.

.. math::
    \text{out}_i = \frac{\text{input}_i}{\text{value}}

If :attr:`input` is of type `FloatTensor` or `DoubleTensor`, :attr:`value`
should be a real number, otherwise it should be an integer

Args:
    input (Tensor): the input tensor
    value (Number): the number to be divided to each element of :attr:`input`
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(5)
    >>> a
    tensor([ 0.3810,  1.2774, -0.2972, -0.3719,  0.4637])
    >>> torch.div(a, 0.5)
    tensor([ 0.7620,  2.5548, -0.5944, -0.7439,  0.9275])

.. function:: div(input, other, out=None) -> Tensor

Each element of the tensor :attr:`input` is divided by each element
of the tensor :attr:`other`. The resulting tensor is returned. The shapes of
:attr:`input` and :attr:`other` must be
:ref:`broadcastable <broadcasting-semantics>`.

.. math::
    \text{out}_i = \frac{\text{input}_i}{\text{other}_i}

Args:
    input (Tensor): the numerator tensor
    other (Tensor): the denominator tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[-0.3711, -1.9353, -0.4605, -0.2917],
            [ 0.1815, -1.0111,  0.9805, -1.5923],
            [ 0.1062,  1.4581,  0.7759, -1.2344],
            [-0.1830, -0.0313,  1.1908, -1.4757]])
    >>> b = torch.randn(4)
    >>> b
    tensor([ 0.8032,  0.2930, -0.8113, -0.2308])
    >>> torch.div(a, b)
    tensor([[-0.4620, -6.6051,  0.5676,  1.2637],
            [ 0.2260, -3.4507, -1.2086,  6.8988],
            [ 0.1322,  4.9764, -0.9564,  5.3480],
            [-0.2278, -0.1068, -1.4678,  6.3936]])
""")

add_docstr(torch.dot,
           r"""
dot(tensor1, tensor2) -> Tensor

Computes the dot product (inner product) of two tensors.

.. note:: This function does not :ref:`broadcast <broadcasting-semantics>`.

Example::

    >>> torch.dot(torch.tensor([2, 3]), torch.tensor([2, 1]))
    tensor(7)
""")

add_docstr(torch.eig,
           r"""
eig(a, eigenvectors=False, out=None) -> (Tensor, Tensor)

Computes the eigenvalues and eigenvectors of a real square matrix.

Args:
    a (Tensor): the square matrix of shape :math:`(n \times n)` for which the eigenvalues and eigenvectors
        will be computed
    eigenvectors (bool): ``True`` to compute both eigenvalues and eigenvectors;
        otherwise, only eigenvalues will be computed
    out (tuple, optional): the output tensors

Returns:
    (Tensor, Tensor): A tuple containing

        - **e** (*Tensor*): Shape :math:`(n \times 2)`. Each row is an eigenvalue of ``a``,
          where the first element is the real part and the second element is the imaginary part.
          The eigenvalues are not necessarily ordered.
        - **v** (*Tensor*): If ``eigenvectors=False``, it's an empty tensor.
          Otherwise, this tensor of shape :math:`(n \times n)` can be used to compute normalized (unit length)
          eigenvectors of corresponding eigenvalues ``e`` as follows.
          If the corresponding e[j] is a real number, column v[:, j] is the eigenvector corresponding to
          eigenvalue e[j].
          If the corresponding e[j] and e[j + 1] eigenvalues form a complex conjugate pair, then the true eigenvectors
          can be computed as
          :math:`\text{eigenvector}[j] = v[:, j] + i \times v[:, j + 1]`,
          :math:`\text{eigenvector}[j + 1] = v[:, j] - i \times v[:, j + 1]`.
""")

add_docstr(torch.eq,
           r"""
eq(input, other, out=None) -> Tensor

Computes element-wise equality

The second argument can be a number or a tensor whose shape is
:ref:`broadcastable <broadcasting-semantics>` with the first argument.

Args:
    input (Tensor): the tensor to compare
    other (Tensor or float): the tensor or value to compare
    out (Tensor, optional): the output tensor. Must be a `ByteTensor`

Returns:
    Tensor: A ``torch.ByteTensor`` containing a 1 at each location where comparison is true

Example::

    >>> torch.eq(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
    tensor([[ 1,  0],
            [ 0,  1]], dtype=torch.uint8)
""")

add_docstr(torch.equal,
           r"""
equal(tensor1, tensor2) -> bool

``True`` if two tensors have the same size and elements, ``False`` otherwise.

Example::

    >>> torch.equal(torch.tensor([1, 2]), torch.tensor([1, 2]))
    True
""")

add_docstr(torch.erf,
           r"""
erf(tensor, out=None) -> Tensor

Computes the error function of each element. The error function is defined as follows:

.. math::
    \mathrm{erf}(x) = \frac{2}{\sqrt{\pi}} \int_{0}^{x} e^{-t^2} dt

Args:
    tensor (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> torch.erf(torch.tensor([0, -1., 10.]))
    tensor([ 0.0000, -0.8427,  1.0000])
""")

add_docstr(torch.erfc,
           r"""
erfc(tensor, out=None) -> Tensor

Computes the complementary error function of each element. The complementary error function is defined as follows:

.. math::
    \mathrm{erfc}(x) = 1 - \frac{2}{\sqrt{\pi}} \int_{0}^{x} e^{-t^2} dt

Args:
    tensor (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> torch.erfc(torch.tensor([0, -1., 10.]))
    tensor([ 1.0000, 1.8427,  0.0000])
""")

add_docstr(torch.erfinv,
           r"""
erfinv(tensor, out=None) -> Tensor

Computes the inverse error function of each element. The inverse error function is defined
in the range :math:`(-1, 1)` as:

.. math::
    \mathrm{erfinv}(\mathrm{erf}(x)) = x

Args:
    tensor (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> torch.erfinv(torch.tensor([0, 0.5, -1.]))
    tensor([ 0.0000,  0.4769,    -inf])
""")

add_docstr(torch.exp,
           r"""
exp(tensor, out=None) -> Tensor

Returns a new tensor with the exponential of the elements
of :attr:`input`.

.. math::
    y_{i} = e^{x_{i}}

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Args:
    tensor (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> torch.exp(torch.tensor([0, math.log(2.)]))
    tensor([ 1.,  2.])
""")

add_docstr(torch.expm1,
           r"""
expm1(tensor, out=None) -> Tensor

Returns a new tensor with the exponential of the elements minus 1
of :attr:`input`.

.. math::
    y_{i} = e^{x_{i}} - 1

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Args:
    tensor (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> torch.expm1(torch.tensor([0, math.log(2.)]))
    tensor([ 0.,  1.])
""")

add_docstr(torch.eye,
           r"""
eye(n, m=None, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a 2-D tensor with ones on the diagonal and zeros elsewhere.

Args:
    n (int): the number of rows
    m (int, optional): the number of columns with default being :attr:`n`
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Returns:
    Tensor: A 2-D tensor with ones on the diagonal and zeros elsewhere

Example::

    >>> torch.eye(3)
    tensor([[ 1.,  0.,  0.],
            [ 0.,  1.,  0.],
            [ 0.,  0.,  1.]])
""".format(**factory_common_args))

add_docstr(torch.floor,
           r"""
floor(input, out=None) -> Tensor

Returns a new tensor with the floor of the elements of :attr:`input`,
the largest integer less than or equal to each element.

.. math::
    \text{out}_{i} = \left\lfloor \text{input}_{i} \right\rfloor

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.8166,  1.5308, -0.2530, -0.2091])
    >>> torch.floor(a)
    tensor([-1.,  1., -1., -1.])
""")

add_docstr(torch.fmod,
           r"""
fmod(input, divisor, out=None) -> Tensor

Computes the element-wise remainder of division.

The dividend and divisor may contain both for integer and floating point
numbers. The remainder has the same sign as the dividend :attr:`input`.

When :attr:`divisor` is a tensor, the shapes of :attr:`input` and
:attr:`divisor` must be :ref:`broadcastable <broadcasting-semantics>`.

Args:
    input (Tensor): the dividend
    divisor (Tensor or float): the divisor, which may be either a number or a tensor of the same shape as the dividend
    out (Tensor, optional): the output tensor

Example::

    >>> torch.fmod(torch.tensor([-3., -2, -1, 1, 2, 3]), 2)
    tensor([-1., -0., -1.,  1.,  0.,  1.])
    >>> torch.fmod(torch.tensor([1., 2, 3, 4, 5]), 1.5)
    tensor([ 1.0000,  0.5000,  0.0000,  1.0000,  0.5000])


""")

add_docstr(torch.frac,
           r"""
frac(tensor, out=None) -> Tensor

Computes the fractional portion of each element in :attr:`tensor`.

.. math::
    \text{out}_{i} = \text{input}_{i} - \left\lfloor \text{input}_{i} \right\rfloor

Example::

    >>> torch.frac(torch.tensor([1, 2.5, -3.2]))
    tensor([ 0.0000,  0.5000, -0.2000])
""")

add_docstr(torch.from_numpy,
           r"""
from_numpy(ndarray) -> Tensor

Creates a :class:`Tensor` from a :class:`numpy.ndarray`.

The returned tensor and :attr:`ndarray` share the same memory. Modifications to
the tensor will be reflected in the :attr:`ndarray` and vice versa. The returned
tensor is not resizable.

Example::

    >>> a = numpy.array([1, 2, 3])
    >>> t = torch.from_numpy(a)
    >>> t
    tensor([ 1,  2,  3])
    >>> t[0] = -1
    >>> a
    array([-1,  2,  3])
""")

add_docstr(torch.flatten,
           r"""
flatten(input, start_dim=0, end_dim=-1) -> Tensor

Flattens a contiguous range of dims in a tensor.

Args:
    input (Tensor): the input tensor
    start_dim (int): the first dim to flatten
    end_dim (int): the last dim to flatten

Example::

    >>> t = torch.tensor([[[1, 2],
                           [3, 4]],
                          [[5, 6],
                           [7, 8]]])
    >>> torch.flatten(t)
    tensor([1, 2, 3, 4, 5, 6, 7, 8])
    >>> torch.flatten(t, start_dim=1)
    tensor([[1, 2, 3, 4],
            [5, 6, 7, 8]])
""")

add_docstr(torch.gather,
           r"""
gather(input, dim, index, out=None) -> Tensor

Gathers values along an axis specified by `dim`.

For a 3-D tensor the output is specified by::

    out[i][j][k] = input[index[i][j][k]][j][k]  # if dim == 0
    out[i][j][k] = input[i][index[i][j][k]][k]  # if dim == 1
    out[i][j][k] = input[i][j][index[i][j][k]]  # if dim == 2

If :attr:`input` is an n-dimensional tensor with size
:math:`(x_0, x_1..., x_{i-1}, x_i, x_{i+1}, ..., x_{n-1})`
and ``dim = i``, then :attr:`index` must be an :math:`n`-dimensional tensor with
size :math:`(x_0, x_1, ..., x_{i-1}, y, x_{i+1}, ..., x_{n-1})` where :math:`y \geq 1`
and :attr:`out` will have the same size as :attr:`index`.

Args:
    input (Tensor): the source tensor
    dim (int): the axis along which to index
    index (LongTensor): the indices of elements to gather
    out (Tensor, optional): the destination tensor

Example::

    >>> t = torch.tensor([[1,2],[3,4]])
    >>> torch.gather(t, 1, torch.tensor([[0,0],[1,0]]))
    tensor([[ 1,  1],
            [ 4,  3]])
""")

add_docstr(torch.ge,
           r"""
ge(input, other, out=None) -> Tensor

Computes :math:`\text{input} \geq \text{other}` element-wise.

The second argument can be a number or a tensor whose shape is
:ref:`broadcastable <broadcasting-semantics>` with the first argument.

Args:
    input (Tensor): the tensor to compare
    other (Tensor or float): the tensor or value to compare
    out (Tensor, optional): the output tensor that must be a `ByteTensor`

Returns:
    Tensor: A ``torch.ByteTensor`` containing a 1 at each location where comparison is true

Example::

    >>> torch.ge(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
    tensor([[ 1,  1],
            [ 0,  1]], dtype=torch.uint8)
""")

add_docstr(torch.gels,
           r"""
gels(B, A, out=None) -> Tensor

Computes the solution to the least squares and least norm problems for a full
rank matrix :math:`A` of size :math:`(m \times n)` and a matrix :math:`B` of
size :math:`(m \times k)`.

If :math:`m \geq n`, :func:`gels` solves the least-squares problem:

.. math::

   \begin{array}{ll}
   \min_X & \|AX-B\|_2.
   \end{array}

If :math:`m < n`, :func:`gels` solves the least-norm problem:

.. math::

   \begin{array}{ll}
   \min_X & \|X\|_2 & \text{subject to} & AX = B.
   \end{array}

Returned tensor :math:`X` has shape :math:`(\max(m, n) \times k)`. The first :math:`n`
rows of :math:`X` contains the solution. If :math:`m \geq n`, the residual sum of squares
for the solution in each column is given by the sum of squares of elements in the
remaining :math:`m - n` rows of that column.

Args:
    B (Tensor): the matrix :math:`B`
    A (Tensor): the :math:`m` by :math:`n` matrix :math:`A`
    out (tuple, optional): the optional destination tensor

Returns:
    (Tensor, Tensor): A tuple containing:

        - **X** (*Tensor*): the least squares solution
        - **qr** (*Tensor*): the details of the QR factorization

.. note::

    The returned matrices will always be transposed, irrespective of the strides
    of the input matrices. That is, they will have stride `(1, m)` instead of
    `(m, 1)`.

Example::

    >>> A = torch.tensor([[1., 1, 1],
                          [2, 3, 4],
                          [3, 5, 2],
                          [4, 2, 5],
                          [5, 4, 3]])
    >>> B = torch.tensor([[-10., -3],
                          [ 12, 14],
                          [ 14, 12],
                          [ 16, 16],
                          [ 18, 16]])
    >>> X, _ = torch.gels(B, A)
    >>> X
    tensor([[  2.0000,   1.0000],
            [  1.0000,   1.0000],
            [  1.0000,   2.0000],
            [ 10.9635,   4.8501],
            [  8.9332,   5.2418]])
""")

add_docstr(torch.geqrf,
           r"""
geqrf(input, out=None) -> (Tensor, Tensor)

This is a low-level function for calling LAPACK directly.

You'll generally want to use :func:`torch.qr` instead.

Computes a QR decomposition of :attr:`input`, but without constructing
:math:`Q` and :math:`R` as explicit separate matrices.

Rather, this directly calls the underlying LAPACK function `?geqrf`
which produces a sequence of 'elementary reflectors'.

See `LAPACK documentation for geqrf`_ for further details.

Args:
    input (Tensor): the input matrix
    out (tuple, optional): the output tuple of (Tensor, Tensor)

.. _LAPACK documentation for geqrf:
    https://software.intel.com/en-us/node/521004

""")

add_docstr(torch.ger,
           r"""
ger(vec1, vec2, out=None) -> Tensor

Outer product of :attr:`vec1` and :attr:`vec2`.
If :attr:`vec1` is a vector of size :math:`n` and :attr:`vec2` is a vector of
size :math:`m`, then :attr:`out` must be a matrix of size :math:`(n \times m)`.

.. note:: This function does not :ref:`broadcast <broadcasting-semantics>`.

Args:
    vec1 (Tensor): 1-D input vector
    vec2 (Tensor): 1-D input vector
    out (Tensor, optional): optional output matrix

Example::

    >>> v1 = torch.arange(1., 5.)
    >>> v2 = torch.arange(1., 4.)
    >>> torch.ger(v1, v2)
    tensor([[  1.,   2.,   3.],
            [  2.,   4.,   6.],
            [  3.,   6.,   9.],
            [  4.,   8.,  12.]])
""")

add_docstr(torch.gesv,
           r"""
torch.gesv(B, A) -> (Tensor, Tensor)

This function returns the solution to the system of linear
equations represented by :math:`AX = B` and the LU factorization of
A, in order as a tuple `X, LU`.

`LU` contains `L` and `U` factors for LU factorization of `A`.

`torch.gesv(B, A)` can take in 2D inputs `B, A` or inputs that are
batches of 2D matrices. If the inputs are batches, then returns
batched outputs `X, LU`.

.. note::

    The :attr:`out` keyword only supports 2D matrix inputs, that is,
    `B, A` must be 2D matrices.

.. note::

    Irrespective of the original strides, the returned matrices
    `X` and `LU` will be transposed, i.e. with strides like
    `B.contiguous().transpose(-1, -2).strides()` and
    `A.contiguous().transpose(-1, -2).strides()` respectively.

Args:
    B (Tensor): input matrix of size :math:`(*, m, k)` , where :math:`*`
                is zero or more batch dimensions.
    A (Tensor): input square matrix of size :math:`(*, m, m)`, where
                :math:`*` is zero or more batch dimensions.
    out ((Tensor, Tensor), optional): optional output tuple.

Example::

    >>> A = torch.tensor([[6.80, -2.11,  5.66,  5.97,  8.23],
                          [-6.05, -3.30,  5.36, -4.44,  1.08],
                          [-0.45,  2.58, -2.70,  0.27,  9.04],
                          [8.32,  2.71,  4.35,  -7.17,  2.14],
                          [-9.67, -5.14, -7.26,  6.08, -6.87]]).t()
    >>> B = torch.tensor([[4.02,  6.19, -8.22, -7.57, -3.03],
                          [-1.56,  4.00, -8.67,  1.75,  2.86],
                          [9.81, -4.09, -4.57, -8.61,  8.99]]).t()
    >>> X, LU = torch.gesv(B, A)
    >>> torch.dist(B, torch.mm(A, X))
    tensor(1.00000e-06 *
           7.0977)

    >>> # Batched solver example
    >>> A = torch.randn(2, 3, 1, 4, 4)
    >>> B = torch.randn(2, 3, 1, 4, 6)
    >>> X, LU = torch.gesv(B, A)
    >>> torch.dist(B, A.matmul(X))
    tensor(1.00000e-06 *
       3.6386)

""")

add_docstr(torch.get_default_dtype,
           r"""
get_default_dtype() -> :class:`torch.dtype`

Get the current default floating point :class:`torch.dtype`.

Example::

    >>> torch.get_default_dtype()  # initial default for floating point is torch.float32
    torch.float32
    >>> torch.set_default_dtype(torch.float64)
    >>> torch.get_default_dtype()  # default is now changed to torch.float64
    torch.float64
    >>> torch.set_default_tensor_type(torch.FloatTensor)  # setting tensor type also affects this
    >>> torch.get_default_dtype()  # changed to torch.float32, the dtype for torch.FloatTensor
    torch.float32

""")

add_docstr(torch.get_num_threads,
           r"""
get_num_threads() -> int

Gets the number of OpenMP threads used for parallelizing CPU operations
""")

add_docstr(torch.gt,
           r"""
gt(input, other, out=None) -> Tensor

Computes :math:`\text{input} > \text{other}` element-wise.

The second argument can be a number or a tensor whose shape is
:ref:`broadcastable <broadcasting-semantics>` with the first argument.

Args:
    input (Tensor): the tensor to compare
    other (Tensor or float): the tensor or value to compare
    out (Tensor, optional): the output tensor that must be a `ByteTensor`

Returns:
    Tensor: A ``torch.ByteTensor`` containing a 1 at each location where comparison is true

Example::

    >>> torch.gt(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
    tensor([[ 0,  1],
            [ 0,  0]], dtype=torch.uint8)
""")

add_docstr(torch.histc,
           r"""
histc(input, bins=100, min=0, max=0, out=None) -> Tensor

Computes the histogram of a tensor.

The elements are sorted into equal width bins between :attr:`min` and
:attr:`max`. If :attr:`min` and :attr:`max` are both zero, the minimum and
maximum values of the data are used.

Args:
    input (Tensor): the input tensor
    bins (int): number of histogram bins
    min (int): lower end of the range (inclusive)
    max (int): upper end of the range (inclusive)
    out (Tensor, optional): the output tensor

Returns:
    Tensor: Histogram represented as a tensor

Example::

    >>> torch.histc(torch.tensor([1., 2, 1]), bins=4, min=0, max=3)
    tensor([ 0.,  2.,  1.,  0.])
""")

add_docstr(torch.index_select,
           r"""
index_select(input, dim, index, out=None) -> Tensor

Returns a new tensor which indexes the :attr:`input` tensor along dimension
:attr:`dim` using the entries in :attr:`index` which is a `LongTensor`.

The returned tensor has the same number of dimensions as the original tensor
(:attr:`input`).  The :attr:`dim`\ th dimension has the same size as the length
of :attr:`index`; other dimensions have the same size as in the original tensor.

.. note:: The returned tensor does **not** use the same storage as the original
          tensor.  If :attr:`out` has a different shape than expected, we
          silently change it to the correct shape, reallocating the underlying
          storage if necessary.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension in which we index
    index (LongTensor): the 1-D tensor containing the indices to index
    out (Tensor, optional): the output tensor

Example::

    >>> x = torch.randn(3, 4)
    >>> x
    tensor([[ 0.1427,  0.0231, -0.5414, -1.0009],
            [-0.4664,  0.2647, -0.1228, -1.1068],
            [-1.1734, -0.6571,  0.7230, -0.6004]])
    >>> indices = torch.tensor([0, 2])
    >>> torch.index_select(x, 0, indices)
    tensor([[ 0.1427,  0.0231, -0.5414, -1.0009],
            [-1.1734, -0.6571,  0.7230, -0.6004]])
    >>> torch.index_select(x, 1, indices)
    tensor([[ 0.1427, -0.5414],
            [-0.4664, -0.1228],
            [-1.1734,  0.7230]])
""")

add_docstr(torch.inverse,
           r"""
inverse(input, out=None) -> Tensor

Takes the inverse of the square matrix :attr:`input`. :attr:`input` can be batches
of 2D square tensors, in which case this function would return a tensor composed of
individual inverses.

.. note::

    Irrespective of the original strides, the returned tensors will be
    transposed, i.e. with strides like `input.contiguous().transpose(-2, -1).strides()`

Args:
    input (Tensor): the input tensor of size (*, n, n) where `*` is zero or more
                    batch dimensions
    out (Tensor, optional): the optional output tensor

Example::

    >>> x = torch.rand(4, 4)
    >>> y = torch.inverse(x)
    >>> z = torch.mm(x, y)
    >>> z
    tensor([[ 1.0000, -0.0000, -0.0000,  0.0000],
            [ 0.0000,  1.0000,  0.0000,  0.0000],
            [ 0.0000,  0.0000,  1.0000,  0.0000],
            [ 0.0000, -0.0000, -0.0000,  1.0000]])
    >>> torch.max(torch.abs(z - torch.eye(4))) # Max non-zero
    tensor(1.1921e-07)
    >>> # Batched inverse example
    >>> x = torch.randn(2, 3, 4, 4)
    >>> y = torch.inverse(x)
    >>> z = torch.matmul(x, y)
    >>> torch.max(torch.abs(z - torch.eye(4).expand_as(x))) # Max non-zero
    tensor(1.9073e-06)
""")

add_docstr(torch.kthvalue,
           r"""
kthvalue(input, k, dim=None, keepdim=False, out=None) -> (Tensor, LongTensor)

Returns the :attr:`k` th smallest element of the given :attr:`input` tensor
along a given dimension.

If :attr:`dim` is not given, the last dimension of the `input` is chosen.

A tuple of `(values, indices)` is returned, where the `indices` is the indices
of the kth-smallest element in the original `input` tensor in dimension `dim`.

If :attr:`keepdim` is ``True``, both the :attr:`values` and :attr:`indices` tensors
are the same size as :attr:`input`, except in the dimension :attr:`dim` where
they are of size 1. Otherwise, :attr:`dim` is squeezed
(see :func:`torch.squeeze`), resulting in both the :attr:`values` and
:attr:`indices` tensors having 1 fewer dimension than the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor
    k (int): k for the k-th smallest element
    dim (int, optional): the dimension to find the kth value along
    keepdim (bool): whether the output tensors have :attr:`dim` retained or not
    out (tuple, optional): the output tuple of (Tensor, LongTensor)
                           can be optionally given to be used as output buffers

Example::

    >>> x = torch.arange(1., 6.)
    >>> x
    tensor([ 1.,  2.,  3.,  4.,  5.])
    >>> torch.kthvalue(x, 4)
    (tensor(4.), tensor(3))

    >>> x=torch.arange(1.,7.).resize_(2,3)
    >>> x
    tensor([[ 1.,  2.,  3.],
            [ 4.,  5.,  6.]])
    >>> torch.kthvalue(x,2,0,True)
    (tensor([[ 4.,  5.,  6.]]), tensor([[ 1,  1,  1]]))
""")

add_docstr(torch.le,
           r"""
le(input, other, out=None) -> Tensor

Computes :math:`\text{input} \leq \text{other}` element-wise.

The second argument can be a number or a tensor whose shape is
:ref:`broadcastable <broadcasting-semantics>` with the first argument.

Args:
    input (Tensor): the tensor to compare
    other (Tensor or float): the tensor or value to compare
    out (Tensor, optional): the output tensor that must be a `ByteTensor`

Returns:
    Tensor: A ``torch.ByteTensor`` containing a 1 at each location where comparison is true

Example::

    >>> torch.le(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
    tensor([[ 1,  0],
            [ 1,  1]], dtype=torch.uint8)
""")

add_docstr(torch.lerp,
           r"""
lerp(start, end, weight, out=None)

Does a linear interpolation of two tensors :attr:`start` and :attr:`end` based
on a scalar :attr:`weight` and returns the resulting :attr:`out` tensor.

.. math::
    \text{out}_i = \text{start}_i + \text{weight} \times (\text{end}_i - \text{start}_i)

The shapes of :attr:`start` and :attr:`end` must be
:ref:`broadcastable <broadcasting-semantics>`.

Args:
    start (Tensor): the tensor with the starting points
    end (Tensor): the tensor with the ending points
    weight (float): the weight for the interpolation formula
    out (Tensor, optional): the output tensor

Example::

    >>> start = torch.arange(1., 5.)
    >>> end = torch.empty(4).fill_(10)
    >>> start
    tensor([ 1.,  2.,  3.,  4.])
    >>> end
    tensor([ 10.,  10.,  10.,  10.])
    >>> torch.lerp(start, end, 0.5)
    tensor([ 5.5000,  6.0000,  6.5000,  7.0000])
""")

add_docstr(torch.linspace,
           r"""
linspace(start, end, steps=100, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a one-dimensional tensor of :attr:`steps`
equally spaced points between :attr:`start` and :attr:`end`.

The output tensor is 1-D of size :attr:`steps`.

Args:
    start (float): the starting value for the set of points
    end (float): the ending value for the set of points
    steps (int): number of points to sample between :attr:`start`
        and :attr:`end`. Default: ``100``.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}


Example::

    >>> torch.linspace(3, 10, steps=5)
    tensor([  3.0000,   4.7500,   6.5000,   8.2500,  10.0000])
    >>> torch.linspace(-10, 10, steps=5)
    tensor([-10.,  -5.,   0.,   5.,  10.])
    >>> torch.linspace(start=-10, end=10, steps=5)
    tensor([-10.,  -5.,   0.,   5.,  10.])
""".format(**factory_common_args))

add_docstr(torch.log,
           r"""
log(input, out=None) -> Tensor

Returns a new tensor with the natural logarithm of the elements
of :attr:`input`.

.. math::
    y_{i} = \log_{e} (x_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(5)
    >>> a
    tensor([-0.7168, -0.5471, -0.8933, -1.4428, -0.1190])
    >>> torch.log(a)
    tensor([ nan,  nan,  nan,  nan,  nan])
""")

add_docstr(torch.log10,
           r"""
log10(input, out=None) -> Tensor

Returns a new tensor with the logarithm to the base 10 of the elements
of :attr:`input`.

.. math::
    y_{i} = \log_{10} (x_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.rand(5)
    >>> a
    tensor([ 0.5224,  0.9354,  0.7257,  0.1301,  0.2251])


    >>> torch.log10(a)
    tensor([-0.2820, -0.0290, -0.1392, -0.8857, -0.6476])

""")

add_docstr(torch.log1p,
           r"""
log1p(input, out=None) -> Tensor

Returns a new tensor with the natural logarithm of (1 + :attr:`input`).

.. math::
    y_i = \log_{e} (x_i + 1)

.. note:: This function is more accurate than :func:`torch.log` for small
          values of :attr:`input`

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(5)
    >>> a
    tensor([-1.0090, -0.9923,  1.0249, -0.5372,  0.2492])
    >>> torch.log1p(a)
    tensor([    nan, -4.8653,  0.7055, -0.7705,  0.2225])
""")

add_docstr(torch.log2,
           r"""
log2(input, out=None) -> Tensor

Returns a new tensor with the logarithm to the base 2 of the elements
of :attr:`input`.

.. math::
    y_{i} = \log_{2} (x_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.rand(5)
    >>> a
    tensor([ 0.8419,  0.8003,  0.9971,  0.5287,  0.0490])


    >>> torch.log2(a)
    tensor([-0.2483, -0.3213, -0.0042, -0.9196, -4.3504])

""")

add_docstr(torch.logspace,
           r"""
logspace(start, end, steps=100, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a one-dimensional tensor of :attr:`steps` points
logarithmically spaced between :math:`10^{{\text{{start}}}}` and :math:`10^{{\text{{end}}}}`.

The output tensor is 1-D of size :attr:`steps`.

Args:
    start (float): the starting value for the set of points
    end (float): the ending value for the set of points
    steps (int): number of points to sample between :attr:`start`
        and :attr:`end`. Default: ``100``.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.logspace(start=-10, end=10, steps=5)
    tensor([ 1.0000e-10,  1.0000e-05,  1.0000e+00,  1.0000e+05,  1.0000e+10])
    >>> torch.logspace(start=0.1, end=1.0, steps=5)
    tensor([  1.2589,   2.1135,   3.5481,   5.9566,  10.0000])
""".format(**factory_common_args))

add_docstr(torch.logsumexp,
           r"""
logsumexp(input, dim, keepdim=False, out=None)

Returns the log of summed exponentials of each row of the :attr:`input`
tensor in the given dimension :attr:`dim`. The computation is numerically
stabilized.

For summation index :math:`j` given by `dim` and other indices :math:`i`, the result is

    .. math::
        \text{logsumexp}(x)_{i} = \log \sum_j \exp(x_{ij})

If :attr:`keepdim` is ``True``, the output tensor is of the same size
as :attr:`input` except in the dimension :attr:`dim` where it is of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting in
the output tensor having 1 fewer dimension than :attr:`input`.

Args:
    input (Tensor): the input tensor
    dim (int or tuple of ints): the dimension or dimensions to reduce
    keepdim (bool): whether the output tensor has :attr:`dim` retained or not
    out (Tensor, optional): the output tensor


Example::
    >>> a = torch.randn(3, 3)
    >>> torch.logsumexp(a, 1)
    tensor([ 0.8442,  1.4322,  0.8711])
""")

add_docstr(torch.lt,
           r"""
lt(input, other, out=None) -> Tensor

Computes :math:`\text{input} < \text{other}` element-wise.

The second argument can be a number or a tensor whose shape is
:ref:`broadcastable <broadcasting-semantics>` with the first argument.

Args:
    input (Tensor): the tensor to compare
    other (Tensor or float): the tensor or value to compare
    out (Tensor, optional): the output tensor that must be a `ByteTensor`

Returns:
    Tensor: A `torch.ByteTensor` containing a 1 at each location where comparison is true

Example::

    >>> torch.lt(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
    tensor([[ 0,  0],
            [ 1,  0]], dtype=torch.uint8)
""")

add_docstr(torch.masked_select,
           r"""
masked_select(input, mask, out=None) -> Tensor

Returns a new 1-D tensor which indexes the :attr:`input` tensor according to
the binary mask :attr:`mask` which is a `ByteTensor`.

The shapes of the :attr:`mask` tensor and the :attr:`input` tensor don't need
to match, but they must be :ref:`broadcastable <broadcasting-semantics>`.

.. note:: The returned tensor does **not** use the same storage
          as the original tensor

Args:
    input (Tensor): the input data
    mask  (ByteTensor): the tensor containing the binary mask to index with
    out (Tensor, optional): the output tensor

Example::

    >>> x = torch.randn(3, 4)
    >>> x
    tensor([[ 0.3552, -2.3825, -0.8297,  0.3477],
            [-1.2035,  1.2252,  0.5002,  0.6248],
            [ 0.1307, -2.0608,  0.1244,  2.0139]])
    >>> mask = x.ge(0.5)
    >>> mask
    tensor([[ 0,  0,  0,  0],
            [ 0,  1,  1,  1],
            [ 0,  0,  0,  1]], dtype=torch.uint8)
    >>> torch.masked_select(x, mask)
    tensor([ 1.2252,  0.5002,  0.6248,  2.0139])
""")

add_docstr(torch.matrix_rank,
           r"""
matrix_rank(input, tol=None, bool symmetric=False) -> Tensor

Returns the numerical rank of a 2-D tensor. The method to compute the
matrix rank is done using SVD by default. If :attr:`symmetric` is ``True``,
then :attr:`input` is assumed to be symmetric, and the computation of the
rank is done by obtaining the eigenvalues.

:attr:`tol` is the threshold below which the singular values (or the eigenvalues
when :attr:`symmetric` is ``True``) are considered to be 0. If :attr:`tol` is not
specified, :attr:`tol` is set to ``S.max() * max(S.size()) * eps`` where `S` is the
singular values (or the eigenvalues when :attr:`symmetric` is ``True``), and ``eps``
is the epsilon value for the datatype of :attr:`input`.

Args:
    input (Tensor): the input 2-D tensor
    tol (float, optional): the tolerance value. Default: ``None``
    symmetric(bool, optional): indicates whether :attr:`input` is symmetric.
                               Default: ``False``

Example::

    >>> a = torch.eye(10)
    >>> torch.matrix_rank(a)
    tensor(10)
    >>> b = torch.eye(10)
    >>> b[0, 0] = 0
    >>> torch.matrix_rank(b)
    tensor(9)
""")

add_docstr(torch.matrix_power,
           r"""
matrix_power(input, n) -> Tensor

Returns the matrix raised to the power :attr:`n` for square matrices.
For batch of matrices, each individual matrix is raised to the power :attr:`n`.

If :attr:`n` is negative, then the inverse of the matrix (if invertible) is
raised to the power :attr:`n`.  For a batch of matrices, the batched inverse
(if invertible) is raised to the power :attr:`n`. If :attr:`n` is 0, then an identity matrix
is returned.

Args:
    input (Tensor): the input tensor
    n (int): the power to raise the matrix to

Example::

    >>> a = torch.randn(2, 2, 2)
    >>> a
    tensor([[[-1.9975, -1.9610],
             [ 0.9592, -2.3364]],

            [[-1.2534, -1.3429],
             [ 0.4153, -1.4664]]])
    >>> torch.matrix_power(a, 3)
    tensor([[[  3.9392, -23.9916],
             [ 11.7357,  -0.2070]],

            [[  0.2468,  -6.7168],
             [  2.0774,  -0.8187]]])
""")

add_docstr(torch.max,
           r"""
.. function:: max(input) -> Tensor

Returns the maximum value of all elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[ 0.6763,  0.7445, -2.2369]])
    >>> torch.max(a)
    tensor(0.7445)

.. function:: max(input, dim, keepdim=False, out=None) -> (Tensor, LongTensor)

Returns the maximum value of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`. The second return value is the index location of each
maximum value found (argmax).

If :attr:`keepdim` is ``True``, the output tensors are of the same size
as :attr:`input` except in the dimension :attr:`dim` where they are of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting
in the output tensors having 1 fewer dimension than :attr:`input`.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensors have :attr:`dim` retained or not
    out (tuple, optional): the result tuple of two output tensors (max, max_indices)

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[-1.2360, -0.2942, -0.1222,  0.8475],
            [ 1.1949, -1.1127, -2.2379, -0.6702],
            [ 1.5717, -0.9207,  0.1297, -1.8768],
            [-0.6172,  1.0036, -0.6060, -0.2432]])
    >>> torch.max(a, 1)
    (tensor([ 0.8475,  1.1949,  1.5717,  1.0036]), tensor([ 3,  0,  0,  1]))

.. function:: max(input, other, out=None) -> Tensor

Each element of the tensor :attr:`input` is compared with the corresponding
element of the tensor :attr:`other` and an element-wise maximum is taken.

The shapes of :attr:`input` and :attr:`other` don't need to match,
but they must be :ref:`broadcastable <broadcasting-semantics>`.

.. math::
    \text{out}_i = \max(\text{tensor}_i, \text{other}_i)

.. note:: When the shapes do not match, the shape of the returned output tensor
          follows the :ref:`broadcasting rules <broadcasting-semantics>`.

Args:
    input (Tensor): the input tensor
    other (Tensor): the second input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.2942, -0.7416,  0.2653, -0.1584])
    >>> b = torch.randn(4)
    >>> b
    tensor([ 0.8722, -1.7421, -0.4141, -0.5055])
    >>> torch.max(a, b)
    tensor([ 0.8722, -0.7416,  0.2653, -0.1584])
""")

add_docstr(torch.mean,
           r"""
.. function:: mean(input) -> Tensor

Returns the mean value of all elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[ 0.2294, -0.5481,  1.3288]])
    >>> torch.mean(a)
    tensor(0.3367)

.. function:: mean(input, dim, keepdim=False, out=None) -> Tensor

Returns the mean value of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`.

If :attr:`keepdim` is ``True``, the output tensor is of the same size
as :attr:`input` except in the dimension :attr:`dim` where it is of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting in the
output tensor having 1 fewer dimension.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool, optional): whether the output tensor has :attr:`dim` retained or not
    out (Tensor): the output tensor

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[-0.3841,  0.6320,  0.4254, -0.7384],
            [-0.9644,  1.0131, -0.6549, -1.4279],
            [-0.2951, -1.3350, -0.7694,  0.5600],
            [ 1.0842, -0.9580,  0.3623,  0.2343]])
    >>> torch.mean(a, 1)
    tensor([-0.0163, -0.5085, -0.4599,  0.1807])
    >>> torch.mean(a, 1, True)
    tensor([[-0.0163],
            [-0.5085],
            [-0.4599],
            [ 0.1807]])
""")

add_docstr(torch.median,
           r"""
.. function:: median(input) -> Tensor

Returns the median value of all elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[ 1.5219, -1.5212,  0.2202]])
    >>> torch.median(a)
    tensor(0.2202)

.. function:: median(input, dim=-1, keepdim=False, values=None, indices=None) -> (Tensor, LongTensor)

Returns the median value of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`. Also returns the index location of the median value
as a `LongTensor`.

By default, :attr:`dim` is the last dimension of the :attr:`input` tensor.

If :attr:`keepdim` is ``True``, the output tensors are of the same size
as :attr:`input` except in the dimension :attr:`dim` where they are of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting in
the outputs tensor having 1 fewer dimension than :attr:`input`.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensors have :attr:`dim` retained or not
    values (Tensor, optional): the output tensor
    indices (Tensor, optional): the output index tensor

Example::

    >>> a = torch.randn(4, 5)
    >>> a
    tensor([[ 0.2505, -0.3982, -0.9948,  0.3518, -1.3131],
            [ 0.3180, -0.6993,  1.0436,  0.0438,  0.2270],
            [-0.2751,  0.7303,  0.2192,  0.3321,  0.2488],
            [ 1.0778, -1.9510,  0.7048,  0.4742, -0.7125]])
    >>> torch.median(a, 1)
    (tensor([-0.3982,  0.2270,  0.2488,  0.4742]), tensor([ 1,  4,  4,  3]))
""")

add_docstr(torch.min,
           r"""
.. function:: min(input) -> Tensor

Returns the minimum value of all elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[ 0.6750,  1.0857,  1.7197]])
    >>> torch.min(a)
    tensor(0.6750)

.. function:: min(input, dim, keepdim=False, out=None) -> (Tensor, LongTensor)

Returns the minimum value of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`. The second return value is the index location of each
minimum value found (argmin).

If :attr:`keepdim` is ``True``, the output tensors are of the same size as
:attr:`input` except in the dimension :attr:`dim` where they are of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting in
the output tensors having 1 fewer dimension than :attr:`input`.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensors have :attr:`dim` retained or not
    out (tuple, optional): the tuple of two output tensors (min, min_indices)

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[-0.6248,  1.1334, -1.1899, -0.2803],
            [-1.4644, -0.2635, -0.3651,  0.6134],
            [ 0.2457,  0.0384,  1.0128,  0.7015],
            [-0.1153,  2.9849,  2.1458,  0.5788]])
    >>> torch.min(a, 1)
    (tensor([-1.1899, -1.4644,  0.0384, -0.1153]), tensor([ 2,  0,  1,  0]))

.. function:: min(input, other, out=None) -> Tensor

Each element of the tensor :attr:`input` is compared with the corresponding
element of the tensor :attr:`other` and an element-wise minimum is taken.
The resulting tensor is returned.

The shapes of :attr:`input` and :attr:`other` don't need to match,
but they must be :ref:`broadcastable <broadcasting-semantics>`.

.. math::
    \text{out}_i = \min(\text{tensor}_i, \text{other}_i)

.. note:: When the shapes do not match, the shape of the returned output tensor
          follows the :ref:`broadcasting rules <broadcasting-semantics>`.

Args:
    input (Tensor): the input tensor
    other (Tensor): the second input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.8137, -1.1740, -0.6460,  0.6308])
    >>> b = torch.randn(4)
    >>> b
    tensor([-0.1369,  0.1555,  0.4019, -0.1929])
    >>> torch.min(a, b)
    tensor([-0.1369, -1.1740, -0.6460, -0.1929])
""")

add_docstr(torch.mm,
           r"""
mm(mat1, mat2, out=None) -> Tensor

Performs a matrix multiplication of the matrices :attr:`mat1` and :attr:`mat2`.

If :attr:`mat1` is a :math:`(n \times m)` tensor, :attr:`mat2` is a
:math:`(m \times p)` tensor, :attr:`out` will be a :math:`(n \times p)` tensor.

.. note:: This function does not :ref:`broadcast <broadcasting-semantics>`.
          For broadcasting matrix products, see :func:`torch.matmul`.

Args:
    mat1 (Tensor): the first matrix to be multiplied
    mat2 (Tensor): the second matrix to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> mat1 = torch.randn(2, 3)
    >>> mat2 = torch.randn(3, 3)
    >>> torch.mm(mat1, mat2)
    tensor([[ 0.4851,  0.5037, -0.3633],
            [-0.0760, -3.6705,  2.4784]])
""")

add_docstr(torch.matmul,
           r"""
matmul(tensor1, tensor2, out=None) -> Tensor

Matrix product of two tensors.

The behavior depends on the dimensionality of the tensors as follows:

- If both tensors are 1-dimensional, the dot product (scalar) is returned.
- If both arguments are 2-dimensional, the matrix-matrix product is returned.
- If the first argument is 1-dimensional and the second argument is 2-dimensional,
  a 1 is prepended to its dimension for the purpose of the matrix multiply.
  After the matrix multiply, the prepended dimension is removed.
- If the first argument is 2-dimensional and the second argument is 1-dimensional,
  the matrix-vector product is returned.
- If both arguments are at least 1-dimensional and at least one argument is
  N-dimensional (where N > 2), then a batched matrix multiply is returned.  If the first
  argument is 1-dimensional, a 1 is prepended to its dimension for the purpose of the
  batched matrix multiply and removed after.  If the second argument is 1-dimensional, a
  1 is appended to its dimension for the purpose of the batched matrix multiple and removed after.
  The non-matrix (i.e. batch) dimensions are :ref:`broadcasted <broadcasting-semantics>` (and thus
  must be broadcastable).  For example, if :attr:`tensor1` is a
  :math:`(j \times 1 \times n \times m)` tensor and :attr:`tensor2` is a :math:`(k \times m \times p)`
  tensor, :attr:`out` will be an :math:`(j \times k \times n \times p)` tensor.

.. note::

    The 1-dimensional dot product version of this function does not support an :attr:`out` parameter.

Arguments:
    tensor1 (Tensor): the first tensor to be multiplied
    tensor2 (Tensor): the second tensor to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> # vector x vector
    >>> tensor1 = torch.randn(3)
    >>> tensor2 = torch.randn(3)
    >>> torch.matmul(tensor1, tensor2).size()
    torch.Size([])
    >>> # matrix x vector
    >>> tensor1 = torch.randn(3, 4)
    >>> tensor2 = torch.randn(4)
    >>> torch.matmul(tensor1, tensor2).size()
    torch.Size([3])
    >>> # batched matrix x broadcasted vector
    >>> tensor1 = torch.randn(10, 3, 4)
    >>> tensor2 = torch.randn(4)
    >>> torch.matmul(tensor1, tensor2).size()
    torch.Size([10, 3])
    >>> # batched matrix x batched matrix
    >>> tensor1 = torch.randn(10, 3, 4)
    >>> tensor2 = torch.randn(10, 4, 5)
    >>> torch.matmul(tensor1, tensor2).size()
    torch.Size([10, 3, 5])
    >>> # batched matrix x broadcasted matrix
    >>> tensor1 = torch.randn(10, 3, 4)
    >>> tensor2 = torch.randn(4, 5)
    >>> torch.matmul(tensor1, tensor2).size()
    torch.Size([10, 3, 5])

""")

add_docstr(torch.mode,
           r"""
mode(input, dim=-1, keepdim=False, values=None, indices=None) -> (Tensor, LongTensor)

Returns the mode value of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`. Also returns the index location of the mode value
as a `LongTensor`.

By default, :attr:`dim` is the last dimension of the :attr:`input` tensor.

If :attr:`keepdim` is ``True``, the output tensors are of the same size as
:attr:`input` except in the dimension :attr:`dim` where they are of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting
in the output tensors having 1 fewer dimension than :attr:`input`.

.. note:: This function is not defined for ``torch.cuda.Tensor`` yet.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensors have :attr:`dim` retained or not
    values (Tensor, optional): the output tensor
    indices (Tensor, optional): the output index tensor

Example::

    >>> a = torch.randn(4, 5)
    >>> a
    tensor([[-1.2808, -1.0966, -1.5946, -0.1148,  0.3631],
            [ 1.1395,  1.1452, -0.6383,  0.3667,  0.4545],
            [-0.4061, -0.3074,  0.4579, -1.3514,  1.2729],
            [-1.0130,  0.3546, -1.4689, -0.1254,  0.0473]])
    >>> torch.mode(a, 1)
    (tensor([-1.5946, -0.6383, -1.3514, -1.4689]), tensor([ 2,  2,  3,  2]))
""")

add_docstr(torch.mul,
           r"""
.. function:: mul(input, value, out=None)

Multiplies each element of the input :attr:`input` with the scalar
:attr:`value` and returns a new resulting tensor.

.. math::
    \text{out}_i = \text{value} \times \text{input}_i

If :attr:`input` is of type `FloatTensor` or `DoubleTensor`, :attr:`value`
should be a real number, otherwise it should be an integer

Args:
    input (Tensor): the input tensor
    value (Number): the number to be multiplied to each element of :attr:`input`
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(3)
    >>> a
    tensor([ 0.2015, -0.4255,  2.6087])
    >>> torch.mul(a, 100)
    tensor([  20.1494,  -42.5491,  260.8663])

.. function:: mul(input, other, out=None)

Each element of the tensor :attr:`input` is multiplied by each element of the
Tensor :attr:`other`. The resulting tensor is returned.

The shapes of :attr:`input` and :attr:`other` must be
:ref:`broadcastable <broadcasting-semantics>`.

.. math::
    \text{out}_i = \text{input}_i \times \text{other}_i

Args:
    input (Tensor): the first multiplicand tensor
    other (Tensor): the second multiplicand tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4, 1)
    >>> a
    tensor([[ 1.1207],
            [-0.3137],
            [ 0.0700],
            [ 0.8378]])
    >>> b = torch.randn(1, 4)
    >>> b
    tensor([[ 0.5146,  0.1216, -0.5244,  2.2382]])
    >>> torch.mul(a, b)
    tensor([[ 0.5767,  0.1363, -0.5877,  2.5083],
            [-0.1614, -0.0382,  0.1645, -0.7021],
            [ 0.0360,  0.0085, -0.0367,  0.1567],
            [ 0.4312,  0.1019, -0.4394,  1.8753]])
""")

add_docstr(torch.multinomial,
           r"""
multinomial(input, num_samples, replacement=False, out=None) -> LongTensor

Returns a tensor where each row contains :attr:`num_samples` indices sampled
from the multinomial probability distribution located in the corresponding row
of tensor :attr:`input`.

.. note::
    The rows of :attr:`input` do not need to sum to one (in which case we use
    the values as weights), but must be non-negative, finite and have
    a non-zero sum.

Indices are ordered from left to right according to when each was sampled
(first samples are placed in first column).

If :attr:`input` is a vector, :attr:`out` is a vector of size :attr:`num_samples`.

If :attr:`input` is a matrix with `m` rows, :attr:`out` is an matrix of shape
:math:`(m \times \text{num\_samples})`.

If replacement is ``True``, samples are drawn with replacement.

If not, they are drawn without replacement, which means that when a
sample index is drawn for a row, it cannot be drawn again for that row.

This implies the constraint that :attr:`num_samples` must be lower than
:attr:`input` length (or number of columns of :attr:`input` if it is a matrix).

Args:
    input (Tensor): the input tensor containing probabilities
    num_samples (int): number of samples to draw
    replacement (bool, optional): whether to draw with replacement or not
    out (Tensor, optional): the output tensor

Example::

    >>> weights = torch.tensor([0, 10, 3, 0], dtype=torch.float) # create a tensor of weights
    >>> torch.multinomial(weights, 4)
    tensor([ 1,  2,  0,  0])
    >>> torch.multinomial(weights, 4, replacement=True)
    tensor([ 2,  1,  1,  1])
""")

add_docstr(torch.mv,
           r"""
mv(mat, vec, out=None) -> Tensor

Performs a matrix-vector product of the matrix :attr:`mat` and the vector
:attr:`vec`.

If :attr:`mat` is a :math:`(n \times m)` tensor, :attr:`vec` is a 1-D tensor of
size :math:`m`, :attr:`out` will be 1-D of size :math:`n`.

.. note:: This function does not :ref:`broadcast <broadcasting-semantics>`.

Args:
    mat (Tensor): matrix to be multiplied
    vec (Tensor): vector to be multiplied
    out (Tensor, optional): the output tensor

Example::

    >>> mat = torch.randn(2, 3)
    >>> vec = torch.randn(3)
    >>> torch.mv(mat, vec)
    tensor([ 1.0404, -0.6361])
""")

add_docstr(torch.mvlgamma,
           r"""
mvlgamma(input, p) -> Tensor

Computes the multivariate log-gamma function with dimension :math:`p` element-wise, given by

.. math::
    \log(\Gamma_{p}(a)) = C + \displaystyle \sum_{i=1}^{p} \log\left(\Gamma\left(a - \frac{i - 1}{2}\right)\right)

where :math:`C = \log(\pi) \times \frac{p (p - 1)}{2}` and :math:`\Gamma(\cdot)` is the Gamma function.

If any of the elements are less than or equal to :math:`\frac{p - 1}{2}`, then an error
is thrown.

Args:
    input (Tensor): the tensor to compute the multivariate log-gamma function
    p (int): the number of dimensions

Example::

    >>> a = torch.empty(2, 3).uniform_(1, 2)
    >>> a
    tensor([[1.6835, 1.8474, 1.1929],
            [1.0475, 1.7162, 1.4180]])
    >>> torch.mvlgamma(a, 2)
    tensor([[0.3928, 0.4007, 0.7586],
            [1.0311, 0.3901, 0.5049]])
""")

add_docstr(torch.narrow,
           r"""
narrow(input, dimension, start, length) -> Tensor

Returns a new tensor that is a narrowed version of :attr:`input` tensor. The
dimension :attr:`dim` is input from :attr:`start` to :attr:`start + length`. The
returned tensor and :attr:`self` tensor share the same underlying storage.

Args:
    input (Tensor): the tensor to narrow
    dimension (int): the dimension along which to narrow
    start (int): the starting dimension
    length (int): the distance to the ending dimension

Example::

    >>> x = torch.tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
    >>> torch.narrow(x, 0, 0, 2)
    tensor([[ 1,  2,  3],
            [ 4,  5,  6]])
    >>> torch.narrow(x, 1, 1, 2)
    tensor([[ 2,  3],
            [ 5,  6],
            [ 8,  9]])
""")

add_docstr(torch.ne,
           r"""
ne(input, other, out=None) -> Tensor

Computes :math:`input \neq other` element-wise.

The second argument can be a number or a tensor whose shape is
:ref:`broadcastable <broadcasting-semantics>` with the first argument.

Args:
    input (Tensor): the tensor to compare
    other (Tensor or float): the tensor or value to compare
    out (Tensor, optional): the output tensor that must be a `ByteTensor`

Returns:
    Tensor: A ``torch.ByteTensor`` containing a 1 at each location where comparison is true.

Example::

    >>> torch.ne(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
    tensor([[ 0,  1],
            [ 1,  0]], dtype=torch.uint8)
""")

add_docstr(torch.neg,
           r"""
neg(input, out=None) -> Tensor

Returns a new tensor with the negative of the elements of :attr:`input`.

.. math::
    \text{out} = -1 \times \text{input}

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(5)
    >>> a
    tensor([ 0.0090, -0.2262, -0.0682, -0.2866,  0.3940])
    >>> torch.neg(a)
    tensor([-0.0090,  0.2262,  0.0682,  0.2866, -0.3940])
""")

add_docstr(torch.nonzero,
           r"""
nonzero(input, out=None) -> LongTensor

Returns a tensor containing the indices of all non-zero elements of
:attr:`input`.  Each row in the result contains the indices of a non-zero
element in :attr:`input`.

If :attr:`input` has `n` dimensions, then the resulting indices tensor
:attr:`out` is of size :math:`(z \times n)`, where :math:`z` is the total number of
non-zero elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor
    out (LongTensor, optional): the output tensor containing indices

Example::

    >>> torch.nonzero(torch.tensor([1, 1, 1, 0, 1]))
    tensor([[ 0],
            [ 1],
            [ 2],
            [ 4]])
    >>> torch.nonzero(torch.tensor([[0.6, 0.0, 0.0, 0.0],
                                    [0.0, 0.4, 0.0, 0.0],
                                    [0.0, 0.0, 1.2, 0.0],
                                    [0.0, 0.0, 0.0,-0.4]]))
    tensor([[ 0,  0],
            [ 1,  1],
            [ 2,  2],
            [ 3,  3]])
""")

add_docstr(torch.normal,
           r"""
.. function:: normal(mean, std, out=None) -> Tensor

Returns a tensor of random numbers drawn from separate normal distributions
whose mean and standard deviation are given.

The :attr:`mean` is a tensor with the mean of
each output element's normal distribution

The :attr:`std` is a tensor with the standard deviation of
each output element's normal distribution

The shapes of :attr:`mean` and :attr:`std` don't need to match, but the
total number of elements in each tensor need to be the same.

.. note:: When the shapes do not match, the shape of :attr:`mean`
          is used as the shape for the returned output tensor

Args:
    mean (Tensor): the tensor of per-element means
    std (Tensor): the tensor of per-element standard deviations
    out (Tensor, optional): the output tensor

Example::

    >>> torch.normal(mean=torch.arange(1., 11.), std=torch.arange(1, 0, -0.1))
    tensor([  1.0425,   3.5672,   2.7969,   4.2925,   4.7229,   6.2134,
              8.0505,   8.1408,   9.0563,  10.0566])

.. function:: normal(mean=0.0, std, out=None) -> Tensor

Similar to the function above, but the means are shared among all drawn
elements.

Args:
    mean (float, optional): the mean for all distributions
    std (Tensor): the tensor of per-element standard deviations
    out (Tensor, optional): the output tensor

Example::

    >>> torch.normal(mean=0.5, std=torch.arange(1., 6.))
    tensor([-1.2793, -1.0732, -2.0687,  5.1177, -1.2303])

.. function:: normal(mean, std=1.0, out=None) -> Tensor

Similar to the function above, but the standard-deviations are shared among
all drawn elements.

Args:
    mean (Tensor): the tensor of per-element means
    std (float, optional): the standard deviation for all distributions
    out (Tensor, optional): the output tensor

Example::

    >>> torch.normal(mean=torch.arange(1., 6.))
    tensor([ 1.1552,  2.6148,  2.6535,  5.8318,  4.2361])
""")

add_docstr(torch.numel,
           r"""
numel(input) -> int

Returns the total number of elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor

Example::

    >>> a = torch.randn(1, 2, 3, 4, 5)
    >>> torch.numel(a)
    120
    >>> a = torch.zeros(4,4)
    >>> torch.numel(a)
    16

""")

add_docstr(torch.ones,
           r"""
ones(*sizes, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with the scalar value `1`, with the shape defined
by the variable argument :attr:`sizes`.

Args:
    sizes (int...): a sequence of integers defining the shape of the output tensor.
        Can be a variable number of arguments or a collection like a list or tuple.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.ones(2, 3)
    tensor([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])

    >>> torch.ones(5)
    tensor([ 1.,  1.,  1.,  1.,  1.])

""".format(**factory_common_args))

add_docstr(torch.ones_like,
           r"""
ones_like(input, dtype=None, layout=None, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with the scalar value `1`, with the same size as
:attr:`input`. ``torch.ones_like(input)`` is equivalent to
``torch.ones(input.size(), dtype=input.dtype, layout=input.layout, device=input.device)``.

.. warning::
    As of 0.4, this function does not support an :attr:`out` keyword. As an alternative,
    the old ``torch.ones_like(input, out=output)`` is equivalent to
    ``torch.ones(input.size(), out=output)``.

Args:
    {input}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> input = torch.empty(2, 3)
    >>> torch.ones_like(input)
    tensor([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])
""".format(**factory_like_common_args))

add_docstr(torch.orgqr,
           r"""
orgqr(a, tau) -> Tensor

Computes the orthogonal matrix `Q` of a QR factorization, from the `(a, tau)`
tuple returned by :func:`torch.geqrf`.

This directly calls the underlying LAPACK function `?orgqr`.
See `LAPACK documentation for orgqr`_ for further details.

Args:
    a (Tensor): the `a` from :func:`torch.geqrf`.
    tau (Tensor): the `tau` from :func:`torch.geqrf`.

.. _LAPACK documentation for orgqr:
    https://software.intel.com/en-us/mkl-developer-reference-c-orgqr

""")

add_docstr(torch.ormqr,
           r"""
ormqr(a, tau, mat, left=True, transpose=False) -> (Tensor, Tensor)

Multiplies `mat` by the orthogonal `Q` matrix of the QR factorization
formed by :func:`torch.geqrf` that is represented by `(a, tau)`.

This directly calls the underlying LAPACK function `?ormqr`.
See `LAPACK documentation for ormqr`_ for further details.

Args:
    a (Tensor): the `a` from :func:`torch.geqrf`.
    tau (Tensor): the `tau` from :func:`torch.geqrf`.
    mat (Tensor): the matrix to be multiplied.

.. _LAPACK documentation for ormqr:
    https://software.intel.com/en-us/mkl-developer-reference-c-ormqr

""")

add_docstr(torch.potrf, r"""
potrf(a, upper=True, out=None) -> Tensor

Computes the Cholesky decomposition of a symmetric positive-definite
matrix :math:`A`.

If :attr:`upper` is ``True``, the returned matrix `U` is upper-triangular, and
the decomposition has the form:

.. math::

  A = U^TU

If :attr:`upper` is ``False``, the returned matrix `L` is lower-triangular, and
the decomposition has the form:

.. math::

    A = LL^T

Args:
    a (Tensor): the input 2-D tensor, a symmetric positive-definite matrix
    upper (bool, optional): flag that indicates whether to return the
                            upper or lower triangular matrix
    out (Tensor, optional): the output matrix

Example::

    >>> a = torch.randn(3, 3)
    >>> a = torch.mm(a, a.t()) # make symmetric positive definite
    >>> u = torch.potrf(a)
    >>> a
    tensor([[ 2.4112, -0.7486,  1.4551],
            [-0.7486,  1.3544,  0.1294],
            [ 1.4551,  0.1294,  1.6724]])
    >>> u
    tensor([[ 1.5528, -0.4821,  0.9371],
            [ 0.0000,  1.0592,  0.5486],
            [ 0.0000,  0.0000,  0.7023]])
    >>> torch.mm(u.t(), u)
    tensor([[ 2.4112, -0.7486,  1.4551],
            [-0.7486,  1.3544,  0.1294],
            [ 1.4551,  0.1294,  1.6724]])
""")

add_docstr(torch.potri, r"""
potri(u, upper=True, out=None) -> Tensor

Computes the inverse of a positive semidefinite matrix given its
Cholesky factor :attr:`u`: returns matrix `inv`

If :attr:`upper` is ``True`` or not provided, :attr:`u` is upper
triangular such that the returned tensor is

.. math::
    inv = (u^T u)^{-1}

If :attr:`upper` is ``False``, :attr:`u` is lower triangular
such that the returned tensor is

.. math::
    inv = (uu^{T})^{-1}

Args:
    u (Tensor): the input 2-D tensor, a upper or lower triangular
           Cholesky factor
    upper (bool, optional): whether to return a upper (default) or lower triangular matrix
    out (Tensor, optional): the output tensor for `inv`

Example::

    >>> a = torch.randn(3, 3)
    >>> a = torch.mm(a, a.t()) # make symmetric positive definite
    >>> u = torch.potrf(a)
    >>> a
    tensor([[  0.9935,  -0.6353,   1.5806],
            [ -0.6353,   0.8769,  -1.7183],
            [  1.5806,  -1.7183,  10.6618]])
    >>> torch.potri(u)
    tensor([[ 1.9314,  1.2251, -0.0889],
            [ 1.2251,  2.4439,  0.2122],
            [-0.0889,  0.2122,  0.1412]])
    >>> a.inverse()
    tensor([[ 1.9314,  1.2251, -0.0889],
            [ 1.2251,  2.4439,  0.2122],
            [-0.0889,  0.2122,  0.1412]])
""")

add_docstr(torch.potrs, r"""
potrs(b, u, upper=True, out=None) -> Tensor

Solves a linear system of equations with a positive semidefinite
matrix to be inverted given its Cholesky factor matrix :attr:`u`.

If :attr:`upper` is ``True`` or not provided, :attr:`u` is upper triangular
and `c` is returned such that:

.. math::
    c = (u^T u)^{-1} b

If :attr:`upper` is ``False``, :attr:`u` is and lower triangular and `c` is
returned such that:

.. math::
    c = (u u^T)^{-1} b

.. note:: :attr:`b` is always a 2-D tensor, use `b.unsqueeze(1)` to convert a vector.

Args:
    b (Tensor): the right hand side 2-D tensor
    u (Tensor): the input 2-D tensor, a upper or lower triangular Cholesky factor
    upper (bool, optional): whether to return a upper (default) or lower triangular matrix
    out (Tensor, optional): the output tensor for `c`

Example::

    >>> a = torch.randn(3, 3)
    >>> a = torch.mm(a, a.t()) # make symmetric positive definite
    >>> u = torch.potrf(a)
    >>> a
    tensor([[ 0.7747, -1.9549,  1.3086],
            [-1.9549,  6.7546, -5.4114],
            [ 1.3086, -5.4114,  4.8733]])
    >>> b = torch.randn(3, 2)
    >>> b
    tensor([[-0.6355,  0.9891],
            [ 0.1974,  1.4706],
            [-0.4115, -0.6225]])
    >>> torch.potrs(b,u)
    tensor([[ -8.1625,  19.6097],
            [ -5.8398,  14.2387],
            [ -4.3771,  10.4173]])
    >>> torch.mm(a.inverse(),b)
    tensor([[ -8.1626,  19.6097],
            [ -5.8398,  14.2387],
            [ -4.3771,  10.4173]])
""")

add_docstr(torch.pow,
           r"""
.. function:: pow(input, exponent, out=None) -> Tensor

Takes the power of each element in :attr:`input` with :attr:`exponent` and
returns a tensor with the result.

:attr:`exponent` can be either a single ``float`` number or a `Tensor`
with the same number of elements as :attr:`input`.

When :attr:`exponent` is a scalar value, the operation applied is:

.. math::
    \text{out}_i = x_i ^ \text{exponent}

When :attr:`exponent` is a tensor, the operation applied is:

.. math::
    \text{out}_i = x_i ^ {\text{exponent}_i}

When :attr:`exponent` is a tensor, the shapes of :attr:`input`
and :attr:`exponent` must be :ref:`broadcastable <broadcasting-semantics>`.

Args:
    input (Tensor): the input tensor
    exponent (float or tensor): the exponent value
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.4331,  1.2475,  0.6834, -0.2791])
    >>> torch.pow(a, 2)
    tensor([ 0.1875,  1.5561,  0.4670,  0.0779])
    >>> exp = torch.arange(1., 5.)

    >>> a = torch.arange(1., 5.)
    >>> a
    tensor([ 1.,  2.,  3.,  4.])
    >>> exp
    tensor([ 1.,  2.,  3.,  4.])
    >>> torch.pow(a, exp)
    tensor([   1.,    4.,   27.,  256.])

.. function:: pow(base, input, out=None) -> Tensor

:attr:`base` is a scalar ``float`` value, and :attr:`input` is a tensor.
The returned tensor :attr:`out` is of the same shape as :attr:`input`

The operation applied is:

.. math::
    out_i = base ^ {input_i}

Args:
    base (float): the scalar base value for the power operation
    input (Tensor): the exponent tensor
    out (Tensor, optional): the output tensor

Example::

    >>> exp = torch.arange(1., 5.)
    >>> base = 2
    >>> torch.pow(base, exp)
    tensor([  2.,   4.,   8.,  16.])
""")

add_docstr(torch.prod,
           r"""
.. function:: prod(input, dtype=None) -> Tensor

Returns the product of all elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor
    {dtype}

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[-0.8020,  0.5428, -1.5854]])
    >>> torch.prod(a)
    tensor(0.6902)

.. function:: prod(input, dim, keepdim=False, dtype=None) -> Tensor

Returns the product of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`.

If :attr:`keepdim` is ``True``, the output tensor is of the same size as
:attr:`input` except in the dimension :attr:`dim` where it is of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting
in the output tensor having 1 fewer dimension than :attr:`input`.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensor has :attr:`dim` retained or not
    {dtype}

Example::

    >>> a = torch.randn(4, 2)
    >>> a
    tensor([[ 0.5261, -0.3837],
            [ 1.1857, -0.2498],
            [-1.1646,  0.0705],
            [ 1.1131, -1.0629]])
    >>> torch.prod(a, 1)
    tensor([-0.2018, -0.2962, -0.0821, -1.1831])
""".format(**reduceops_common_args))

add_docstr(torch.pstrf, r"""
pstrf(a, upper=True, out=None) -> (Tensor, Tensor)

Computes the pivoted Cholesky decomposition of a positive semidefinite
matrix :attr:`a`. returns matrices `u` and `piv`.

If :attr:`upper` is ``True`` or not provided, `u` is upper triangular
such that :math:`a = p^T u^T u p`, with `p` the permutation given by `piv`.

If :attr:`upper` is ``False``, `u` is lower triangular such that
:math:`a = p^T u u^T p`.

Args:
    a (Tensor): the input 2-D tensor
    upper (bool, optional): whether to return a upper (default) or lower triangular matrix
    out (tuple, optional): tuple of `u` and `piv` tensors

Example::

    >>> a = torch.randn(3, 3)
    >>> a = torch.mm(a, a.t()) # make symmetric positive definite
    >>> a
    tensor([[ 3.5405, -0.4577,  0.8342],
            [-0.4577,  1.8244, -0.1996],
            [ 0.8342, -0.1996,  3.7493]])
    >>> u,piv = torch.pstrf(a)
    >>> u
    tensor([[ 1.9363,  0.4308, -0.1031],
            [ 0.0000,  1.8316, -0.2256],
            [ 0.0000,  0.0000,  1.3277]])
    >>> piv
    tensor([ 2,  0,  1], dtype=torch.int32)
    >>> p = torch.eye(3).index_select(0,piv.long()).index_select(0,piv.long()).t() # make pivot permutation
    >>> torch.mm(torch.mm(p.t(),torch.mm(u.t(),u)),p) # reconstruct
    tensor([[ 3.5405, -0.4577,  0.8342],
            [-0.4577,  1.8244, -0.1996],
            [ 0.8342, -0.1996,  3.7493]])
""")

add_docstr(torch.qr,
           r"""
qr(input, out=None) -> (Tensor, Tensor)

Computes the QR decomposition of a matrix :attr:`input`, and returns matrices
`Q` and `R` such that :math:`\text{input} = Q R`, with :math:`Q` being an
orthogonal matrix and :math:`R` being an upper triangular matrix.

This returns the thin (reduced) QR factorization.

.. note:: precision may be lost if the magnitudes of the elements of :attr:`input`
          are large

.. note:: While it should always give you a valid decomposition, it may not
          give you the same one across platforms - it will depend on your
          LAPACK implementation.

.. note:: Irrespective of the original strides, the returned matrix :math:`Q` will be
          transposed, i.e. with strides `(1, m)` instead of `(m, 1)`.

Args:
    input (Tensor): the input 2-D tensor
    out (tuple, optional): tuple of `Q` and `R` tensors

Example::

    >>> a = torch.tensor([[12., -51, 4], [6, 167, -68], [-4, 24, -41]])
    >>> q, r = torch.qr(a)
    >>> q
    tensor([[-0.8571,  0.3943,  0.3314],
            [-0.4286, -0.9029, -0.0343],
            [ 0.2857, -0.1714,  0.9429]])
    >>> r
    tensor([[ -14.0000,  -21.0000,   14.0000],
            [   0.0000, -175.0000,   70.0000],
            [   0.0000,    0.0000,  -35.0000]])
    >>> torch.mm(q, r).round()
    tensor([[  12.,  -51.,    4.],
            [   6.,  167.,  -68.],
            [  -4.,   24.,  -41.]])
    >>> torch.mm(q.t(), q).round()
    tensor([[ 1.,  0.,  0.],
            [ 0.,  1., -0.],
            [ 0., -0.,  1.]])
""")

add_docstr(torch.rand,
           r"""
rand(*sizes, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with random numbers from a uniform distribution
on the interval :math:`[0, 1)`

The shape of the tensor is defined by the variable argument :attr:`sizes`.

Args:
    sizes (int...): a sequence of integers defining the shape of the output tensor.
        Can be a variable number of arguments or a collection like a list or tuple.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.rand(4)
    tensor([ 0.5204,  0.2503,  0.3525,  0.5673])
    >>> torch.rand(2, 3)
    tensor([[ 0.8237,  0.5781,  0.6879],
            [ 0.3816,  0.7249,  0.0998]])
""".format(**factory_common_args))

add_docstr(torch.rand_like,
           r"""
rand_like(input, dtype=None, layout=None, device=None, requires_grad=False) -> Tensor

Returns a tensor with the same size as :attr:`input` that is filled with
random numbers from a uniform distribution on the interval :math:`[0, 1)`.
``torch.rand_like(input)`` is equivalent to
``torch.rand(input.size(), dtype=input.dtype, layout=input.layout, device=input.device)``.

Args:
    {input}
    {dtype}
    {layout}
    {device}
    {requires_grad}

""".format(**factory_like_common_args))

add_docstr(torch.randint,
           r"""
randint(low=0, high, size, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with random integers generated uniformly
between :attr:`low` (inclusive) and :attr:`high` (exclusive).

The shape of the tensor is defined by the variable argument :attr:`size`.

.. note:
    With the global dtype default (`torch.float32`), this function returns
    a tensor with dtype `torch.float32`, NOT an integer dtype.

Args:
    low (int, optional): Lowest integer to be drawn from the distribution. Default: 0.
    high (int): One above the highest integer to be drawn from the distribution.
    size (tuple): a tuple defining the shape of the output tensor.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.randint(3, 5, (3,))
    tensor([ 4.,  3.,  4.])


    >>> torch.randint(10, (2,2))
    tensor([[ 0.,  2.],
            [ 5.,  5.]])


    >>> torch.randint(3, 10, (2,2))
    tensor([[ 4.,  5.],
            [ 6.,  7.]])


""".format(**factory_common_args))

add_docstr(torch.randint_like,
           r"""
randint_like(input, low=0, high, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor with the same shape as Tensor :attr:`input` filled with
random integers generated uniformly between :attr:`low` (inclusive) and
:attr:`high` (exclusive).

.. note:
    With the global dtype default (`torch.float32`), this function returns
    a tensor with dtype `torch.float32`, NOT an integer dtype.

Args:
    {input}
    low (int, optional): Lowest integer to be drawn from the distribution. Default: 0.
    high (int): One above the highest integer to be drawn from the distribution.
    {dtype}
    {layout}
    {device}
    {requires_grad}

""".format(**factory_like_common_args))

add_docstr(torch.randn,
           r"""
randn(*sizes, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with random numbers from a normal distribution
with mean `0` and variance `1` (also called the standard normal
distribution).

.. math::
    \text{{out}}_{{i}} \sim \mathcal{{N}}(0, 1)

The shape of the tensor is defined by the variable argument :attr:`sizes`.

Args:
    sizes (int...): a sequence of integers defining the shape of the output tensor.
        Can be a variable number of arguments or a collection like a list or tuple.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.randn(4)
    tensor([-2.1436,  0.9966,  2.3426, -0.6366])
    >>> torch.randn(2, 3)
    tensor([[ 1.5954,  2.8929, -1.0923],
            [ 1.1719, -0.4709, -0.1996]])
""".format(**factory_common_args))

add_docstr(torch.randn_like,
           r"""
randn_like(input, dtype=None, layout=None, device=None, requires_grad=False) -> Tensor

Returns a tensor with the same size as :attr:`input` that is filled with
random numbers from a normal distribution with mean 0 and variance 1.
``torch.randn_like(input)`` is equivalent to
``torch.randn(input.size(), dtype=input.dtype, layout=input.layout, device=input.device)``.

Args:
    {input}
    {dtype}
    {layout}
    {device}
    {requires_grad}

""".format(**factory_like_common_args))

add_docstr(torch.randperm,
           r"""
randperm(n, out=None, dtype=torch.int64, layout=torch.strided, device=None, requires_grad=False) -> LongTensor

Returns a random permutation of integers from ``0`` to ``n - 1``.

Args:
    n (int): the upper bound (exclusive)
    {out}
    dtype (:class:`torch.dtype`, optional): the desired data type of returned tensor.
        Default: ``torch.int64``.
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.randperm(4)
    tensor([ 2,  1,  0,  3])
""".format(**factory_common_args))

add_docstr(torch.tensor,
           r"""
tensor(data, dtype=None, device=None, requires_grad=False) -> Tensor

Constructs a tensor with :attr:`data`.

.. warning::

    :func:`torch.tensor` always copies :attr:`data`. If you have a Tensor
    ``data`` and want to avoid a copy, use :func:`torch.Tensor.requires_grad_`
    or :func:`torch.Tensor.detach`.
    If you have a NumPy ``ndarray`` and want to avoid a copy, use
    :func:`torch.from_numpy`.

.. warning::

    When data is a tensor `x`, :func:`torch.tensor` reads out 'the data' from whatever it is passed,
    and constructs a leaf variable. Therefore ``torch.tensor(x)`` is equivalent to ``x.clone().detach()``
    and ``torch.tensor(x, requires_grad=True)`` is equivalent to ``x.clone().detach().requires_grad_(True)``.
    The equivalents using ``clone()`` and ``detach()`` are recommended.

Args:
    {data}
    {dtype}
    {device}
    {requires_grad}


Example::

    >>> torch.tensor([[0.1, 1.2], [2.2, 3.1], [4.9, 5.2]])
    tensor([[ 0.1000,  1.2000],
            [ 2.2000,  3.1000],
            [ 4.9000,  5.2000]])

    >>> torch.tensor([0, 1])  # Type inference on data
    tensor([ 0,  1])

    >>> torch.tensor([[0.11111, 0.222222, 0.3333333]],
                     dtype=torch.float64,
                     device=torch.device('cuda:0'))  # creates a torch.cuda.DoubleTensor
    tensor([[ 0.1111,  0.2222,  0.3333]], dtype=torch.float64, device='cuda:0')

    >>> torch.tensor(3.14159)  # Create a scalar (zero-dimensional tensor)
    tensor(3.1416)

    >>> torch.tensor([])  # Create an empty tensor (of size (0,))
    tensor([])
""".format(**factory_data_common_args))

add_docstr(torch.range,
           r"""
range(start=0, end, step=1, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a 1-D tensor of size :math:`\left\lfloor \frac{\text{end} - \text{start}}{\text{step}} \right\rfloor + 1`
with values from :attr:`start` to :attr:`end` with step :attr:`step`. Step is
the gap between two values in the tensor.

.. math::
    \text{out}_{i+1} = \text{out}_i + \text{step}.
""" + r"""
.. warning::
    This function is deprecated in favor of :func:`torch.arange`.

Args:
    start (float): the starting value for the set of points. Default: ``0``.
    end (float): the ending value for the set of points
    step (float): the gap between each pair of adjacent points. Default: ``1``.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.range(1, 4)
    tensor([ 1.,  2.,  3.,  4.])
    >>> torch.range(1, 4, 0.5)
    tensor([ 1.0000,  1.5000,  2.0000,  2.5000,  3.0000,  3.5000,  4.0000])
""".format(**factory_common_args))

add_docstr(torch.arange,
           r"""
arange(start=0, end, step=1, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a 1-D tensor of size :math:`\left\lfloor \frac{\text{end} - \text{start}}{\text{step}} \right\rfloor`
with values from the interval ``[start, end)`` taken with common difference
:attr:`step` beginning from `start`.

Note that non-integer :attr:`step` is subject to floating point rounding errors when
comparing against :attr:`end`; to avoid inconsistency, we advise adding a small epsilon to :attr:`end`
in such cases.

.. math::
    \text{out}_{{i+1}} = \text{out}_{i} + \text{step}
""" + r"""
Args:
    start (Number): the starting value for the set of points. Default: ``0``.
    end (Number): the ending value for the set of points
    step (Number): the gap between each pair of adjacent points. Default: ``1``.
    {out}
    {dtype} If `dtype` is not given, infer the data type from the other input
        arguments. If any of `start`, `end`, or `stop` are floating-point, the
        `dtype` is inferred to be the default dtype, see
        :meth:`~torch.get_default_dtype`. Otherwise, the `dtype` is inferred to
        be `torch.int64`.
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.arange(5)
    tensor([ 0,  1,  2,  3,  4])
    >>> torch.arange(1, 4)
    tensor([ 1,  2,  3])
    >>> torch.arange(1, 2.5, 0.5)
    tensor([ 1.0000,  1.5000,  2.0000])
""".format(**factory_common_args))

add_docstr(torch.remainder,
           r"""
remainder(input, divisor, out=None) -> Tensor

Computes the element-wise remainder of division.

The divisor and dividend may contain both for integer and floating point
numbers. The remainder has the same sign as the divisor.

When :attr:`divisor` is a tensor, the shapes of :attr:`input` and
:attr:`divisor` must be :ref:`broadcastable <broadcasting-semantics>`.

Args:
    input (Tensor): the dividend
    divisor (Tensor or float): the divisor that may be either a number or a
                               Tensor of the same shape as the dividend
    out (Tensor, optional): the output tensor

Example::

    >>> torch.remainder(torch.tensor([-3., -2, -1, 1, 2, 3]), 2)
    tensor([ 1.,  0.,  1.,  1.,  0.,  1.])
    >>> torch.remainder(torch.tensor([1., 2, 3, 4, 5]), 1.5)
    tensor([ 1.0000,  0.5000,  0.0000,  1.0000,  0.5000])

.. seealso::

        :func:`torch.fmod`, which computes the element-wise remainder of
        division equivalently to the C library function ``fmod()``.
""")

add_docstr(torch.renorm,
           r"""
renorm(input, p, dim, maxnorm, out=None) -> Tensor

Returns a tensor where each sub-tensor of :attr:`input` along dimension
:attr:`dim` is normalized such that the `p`-norm of the sub-tensor is lower
than the value :attr:`maxnorm`

.. note:: If the norm of a row is lower than `maxnorm`, the row is unchanged

Args:
    input (Tensor): the input tensor
    p (float): the power for the norm computation
    dim (int): the dimension to slice over to get the sub-tensors
    maxnorm (float): the maximum norm to keep each sub-tensor under
    out (Tensor, optional): the output tensor

Example::

    >>> x = torch.ones(3, 3)
    >>> x[1].fill_(2)
    tensor([ 2.,  2.,  2.])
    >>> x[2].fill_(3)
    tensor([ 3.,  3.,  3.])
    >>> x
    tensor([[ 1.,  1.,  1.],
            [ 2.,  2.,  2.],
            [ 3.,  3.,  3.]])
    >>> torch.renorm(x, 1, 0, 5)
    tensor([[ 1.0000,  1.0000,  1.0000],
            [ 1.6667,  1.6667,  1.6667],
            [ 1.6667,  1.6667,  1.6667]])
""")

add_docstr(torch.reshape,
           r"""
reshape(input, shape) -> Tensor

Returns a tensor with the same data and number of elements as :attr:`input`,
but with the specified shape. When possible, the returned tensor will be a view
of :attr:`input`. Otherwise, it will be a copy. Contiguous inputs and inputs
with compatible strides can be reshaped without copying, but you should not
depend on the copying vs. viewing behavior.

See :meth:`torch.Tensor.view` on when it is possible to return a view.

A single dimension may be -1, in which case it's inferred from the remaining
dimensions and the number of elements in :attr:`input`.

Args:
    input (Tensor): the tensor to be reshaped
    shape (tuple of ints): the new shape

Example::

    >>> a = torch.arange(4.)
    >>> torch.reshape(a, (2, 2))
    tensor([[ 0.,  1.],
            [ 2.,  3.]])
    >>> b = torch.tensor([[0, 1], [2, 3]])
    >>> torch.reshape(b, (-1,))
    tensor([ 0,  1,  2,  3])
""")


add_docstr(torch.round,
           r"""
round(input, out=None) -> Tensor

Returns a new tensor with each of the elements of :attr:`input` rounded
to the closest integer.

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.9920,  0.6077,  0.9734, -1.0362])
    >>> torch.round(a)
    tensor([ 1.,  1.,  1., -1.])
""")

add_docstr(torch.rsqrt,
           r"""
rsqrt(input, out=None) -> Tensor

Returns a new tensor with the reciprocal of the square-root of each of
the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \frac{1}{\sqrt{\text{input}_{i}}}

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.0370,  0.2970,  1.5420, -0.9105])
    >>> torch.rsqrt(a)
    tensor([    nan,  1.8351,  0.8053,     nan])
""")

add_docstr(torch.set_flush_denormal,
           r"""
set_flush_denormal(mode) -> bool

Disables denormal floating numbers on CPU.

Returns ``True`` if your system supports flushing denormal numbers and it
successfully configures flush denormal mode.  :meth:`~torch.set_flush_denormal`
is only supported on x86 architectures supporting SSE3.

Args:
    mode (bool): Controls whether to enable flush denormal mode or not

Example::

    >>> torch.set_flush_denormal(True)
    True
    >>> torch.tensor([1e-323], dtype=torch.float64)
    tensor([ 0.], dtype=torch.float64)
    >>> torch.set_flush_denormal(False)
    True
    >>> torch.tensor([1e-323], dtype=torch.float64)
    tensor(9.88131e-324 *
           [ 1.0000], dtype=torch.float64)
""")

add_docstr(torch.set_num_threads,
           r"""
set_num_threads(int)

Sets the number of OpenMP threads used for parallelizing CPU operations
""")

add_docstr(torch.sigmoid,
           r"""
sigmoid(input, out=None) -> Tensor

Returns a new tensor with the sigmoid of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \frac{1}{1 + e^{-\text{input}_{i}}}

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.9213,  1.0887, -0.8858, -1.7683])
    >>> torch.sigmoid(a)
    tensor([ 0.7153,  0.7481,  0.2920,  0.1458])
""")

add_docstr(torch.sign,
           r"""
sign(input, out=None) -> Tensor

Returns a new tensor with the sign of the elements of :attr:`input`.

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 1.0382, -1.4526, -0.9709,  0.4542])
    >>> torch.sign(a)
    tensor([ 1., -1., -1.,  1.])
""")

add_docstr(torch.sin,
           r"""
sin(input, out=None) -> Tensor

Returns a new tensor with the sine of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \sin(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-0.5461,  0.1347, -2.7266, -0.2746])
    >>> torch.sin(a)
    tensor([-0.5194,  0.1343, -0.4032, -0.2711])
""")

add_docstr(torch.sinh,
           r"""
sinh(input, out=None) -> Tensor

Returns a new tensor with the hyperbolic sine of the elements of
:attr:`input`.

.. math::
    \text{out}_{i} = \sinh(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.5380, -0.8632, -0.1265,  0.9399])
    >>> torch.sinh(a)
    tensor([ 0.5644, -0.9744, -0.1268,  1.0845])
""")

add_docstr(torch.sort,
           r"""
sort(input, dim=None, descending=False, out=None) -> (Tensor, LongTensor)

Sorts the elements of the :attr:`input` tensor along a given dimension
in ascending order by value.

If :attr:`dim` is not given, the last dimension of the `input` is chosen.

If :attr:`descending` is ``True`` then the elements are sorted in descending
order by value.

A tuple of (sorted_tensor, sorted_indices) is returned, where the
sorted_indices are the indices of the elements in the original `input` tensor.

Args:
    input (Tensor): the input tensor
    dim (int, optional): the dimension to sort along
    descending (bool, optional): controls the sorting order (ascending or descending)
    out (tuple, optional): the output tuple of (`Tensor`, `LongTensor`) that can
        be optionally given to be used as output buffers

Example::

    >>> x = torch.randn(3, 4)
    >>> sorted, indices = torch.sort(x)
    >>> sorted
    tensor([[-0.2162,  0.0608,  0.6719,  2.3332],
            [-0.5793,  0.0061,  0.6058,  0.9497],
            [-0.5071,  0.3343,  0.9553,  1.0960]])
    >>> indices
    tensor([[ 1,  0,  2,  3],
            [ 3,  1,  0,  2],
            [ 0,  3,  1,  2]])

    >>> sorted, indices = torch.sort(x, 0)
    >>> sorted
    tensor([[-0.5071, -0.2162,  0.6719, -0.5793],
            [ 0.0608,  0.0061,  0.9497,  0.3343],
            [ 0.6058,  0.9553,  1.0960,  2.3332]])
    >>> indices
    tensor([[ 2,  0,  0,  1],
            [ 0,  1,  1,  2],
            [ 1,  2,  2,  0]])
""")

add_docstr(torch.sparse_coo_tensor,
           r"""
sparse_coo_tensor(indices, values, size=None, dtype=None, device=None, requires_grad=False) -> Tensor

Constructs a sparse tensors in COO(rdinate) format with non-zero elements at the given :attr:`indices`
with the given :attr:`values`. A sparse tensor can be `uncoalesced`, in that case, there are duplicate
coordinates in the indices, and the value at that index is the sum of all duplicate value entries:
`torch.sparse`_.

Args:
    indices (array_like): Initial data for the tensor. Can be a list, tuple,
        NumPy ``ndarray``, scalar, and other types. Will be cast to a :class:`torch.LongTensor`
        internally. The indices are the coordinates of the non-zero values in the matrix, and thus
        should be two-dimensional where the first dimension is the number of tensor dimensions and
        the second dimension is the number of non-zero values.
    values (array_like): Initial values for the tensor. Can be a list, tuple,
        NumPy ``ndarray``, scalar, and other types.
    size (list, tuple, or :class:`torch.Size`, optional): Size of the sparse tensor. If not
        provided the size will be inferred as the minimum size big enough to hold all non-zero
        elements.
    dtype (:class:`torch.dtype`, optional): the desired data type of returned tensor.
        Default: if None, infers data type from :attr:`values`.
    device (:class:`torch.device`, optional): the desired device of returned tensor.
        Default: if None, uses the current device for the default tensor type
        (see :func:`torch.set_default_tensor_type`). :attr:`device` will be the CPU
        for CPU tensor types and the current CUDA device for CUDA tensor types.
    requires_grad (bool, optional): If autograd should record operations on the
        returned tensor. Default: ``False``.


Example::

    >>> i = torch.tensor([[0, 1, 1],
                          [2, 0, 2]])
    >>> v = torch.tensor([3, 4, 5], dtype=torch.float32)
    >>> torch.sparse_coo_tensor(i, v, [2, 4])
    tensor(indices=tensor([[0, 1, 1],
                           [2, 0, 2]]),
           values=tensor([3., 4., 5.]),
           size=(2, 4), nnz=3, layout=torch.sparse_coo)

    >>> torch.sparse_coo_tensor(i, v)  # Shape inference
    tensor(indices=tensor([[0, 1, 1],
                           [2, 0, 2]]),
           values=tensor([3., 4., 5.]),
           size=(2, 3), nnz=3, layout=torch.sparse_coo)

    >>> torch.sparse_coo_tensor(i, v, [2, 4],
                                dtype=torch.float64,
                                device=torch.device('cuda:0'))
    tensor(indices=tensor([[0, 1, 1],
                           [2, 0, 2]]),
           values=tensor([3., 4., 5.]),
           device='cuda:0', size=(2, 4), nnz=3, dtype=torch.float64,
           layout=torch.sparse_coo)

    # Create an empty sparse tensor with the following invariants:
    #   1. sparse_dim + dense_dim = len(SparseTensor.shape)
    #   2. SparseTensor._indices().shape = (sparse_dim, nnz)
    #   3. SparseTensor._values().shape = (nnz, SparseTensor.shape[sparse_dim:])
    #
    # For instance, to create an empty sparse tensor with nnz = 0, dense_dim = 0 and
    # sparse_dim = 1 (hence indices is a 2D tensor of shape = (1, 0))
    >>> S = torch.sparse_coo_tensor(torch.empty([1, 0]), [], [1])
    tensor(indices=tensor([], size=(1, 0)),
           values=tensor([], size=(0,)),
           size=(1,), nnz=0, layout=torch.sparse_coo)

    # and to create an empty sparse tensor with nnz = 0, dense_dim = 1 and
    # sparse_dim = 1
    >>> S = torch.sparse_coo_tensor(torch.empty([1, 0]), torch.empty([0, 2]), [1, 2])
    tensor(indices=tensor([], size=(1, 0)),
           values=tensor([], size=(0, 2)),
           size=(1, 2), nnz=0, layout=torch.sparse_coo)

.. _torch.sparse: https://pytorch.org/docs/stable/sparse.html
""")

add_docstr(torch.sqrt,
           r"""
sqrt(input, out=None) -> Tensor

Returns a new tensor with the square-root of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \sqrt{\text{input}_{i}}

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-2.0755,  1.0226,  0.0831,  0.4806])
    >>> torch.sqrt(a)
    tensor([    nan,  1.0112,  0.2883,  0.6933])
""")

add_docstr(torch.squeeze,
           r"""
squeeze(input, dim=None, out=None) -> Tensor

Returns a tensor with all the dimensions of :attr:`input` of size `1` removed.

For example, if `input` is of shape:
:math:`(A \times 1 \times B \times C \times 1 \times D)` then the `out` tensor
will be of shape: :math:`(A \times B \times C \times D)`.

When :attr:`dim` is given, a squeeze operation is done only in the given
dimension. If `input` is of shape: :math:`(A \times 1 \times B)`,
``squeeze(input, 0)`` leaves the tensor unchanged, but ``squeeze(input, 1)``
will squeeze the tensor to the shape :math:`(A \times B)`.

.. note:: The returned tensor shares the storage with the input tensor,
          so changing the contents of one will change the contents of the other.

Args:
    input (Tensor): the input tensor
    dim (int, optional): if given, the input will be squeezed only in
           this dimension
    out (Tensor, optional): the output tensor

Example::

    >>> x = torch.zeros(2, 1, 2, 1, 2)
    >>> x.size()
    torch.Size([2, 1, 2, 1, 2])
    >>> y = torch.squeeze(x)
    >>> y.size()
    torch.Size([2, 2, 2])
    >>> y = torch.squeeze(x, 0)
    >>> y.size()
    torch.Size([2, 1, 2, 1, 2])
    >>> y = torch.squeeze(x, 1)
    >>> y.size()
    torch.Size([2, 2, 1, 2])
""")

add_docstr(torch.std,
           r"""
.. function:: std(input, unbiased=True) -> Tensor

Returns the standard-deviation of all elements in the :attr:`input` tensor.

If :attr:`unbiased` is ``False``, then the standard-deviation will be calculated
via the biased estimator. Otherwise, Bessel's correction will be used.

Args:
    input (Tensor): the input tensor
    unbiased (bool): whether to use the unbiased estimation or not

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[-0.8166, -1.3802, -0.3560]])
    >>> torch.std(a)
    tensor(0.5130)

.. function:: std(input, dim, keepdim=False, unbiased=True, out=None) -> Tensor

Returns the standard-deviation of each row of the :attr:`input` tensor in the
given dimension :attr:`dim`.

If :attr:`keepdim` is ``True``, the output tensor is of the same size as
:attr:`input` except in the dimension :attr:`dim` where it is of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting
in the output tensor having 1 fewer dimension than :attr:`input`.

If :attr:`unbiased` is ``False``, then the standard-deviation will be calculated
via the biased estimator. Otherwise, Bessel's correction will be used.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensor has :attr:`dim` retained or not
    unbiased (bool): whether to use the unbiased estimation or not
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[ 0.2035,  1.2959,  1.8101, -0.4644],
            [ 1.5027, -0.3270,  0.5905,  0.6538],
            [-1.5745,  1.3330, -0.5596, -0.6548],
            [ 0.1264, -0.5080,  1.6420,  0.1992]])
    >>> torch.std(a, dim=1)
    tensor([ 1.0311,  0.7477,  1.2204,  0.9087])
""")

add_docstr(torch.sum,
           r"""
.. function:: sum(input, dtype=None) -> Tensor

Returns the sum of all elements in the :attr:`input` tensor.

Args:
    input (Tensor): the input tensor
    {dtype}

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[ 0.1133, -0.9567,  0.2958]])
    >>> torch.sum(a)
    tensor(-0.5475)

.. function:: sum(input, dim, keepdim=False, dtype=None) -> Tensor

Returns the sum of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`. If :attr::`dim` is a list of dimensions,
reduce over all of them.

If :attr:`keepdim` is ``True``, the output tensor is of the same size
as :attr:`input` except in the dimension :attr:`dim` where it is of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting in
the output tensor having 1 fewer dimension than :attr:`input`.

Args:
    input (Tensor): the input tensor
    dim (int or tuple of ints): the dimension or dimensions to reduce
    keepdim (bool): whether the output tensor has :attr:`dim` retained or not
    {dtype}

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[ 0.0569, -0.2475,  0.0737, -0.3429],
            [-0.2993,  0.9138,  0.9337, -1.6864],
            [ 0.1132,  0.7892, -0.1003,  0.5688],
            [ 0.3637, -0.9906, -0.4752, -1.5197]])
    >>> torch.sum(a, 1)
    tensor([-0.4598, -0.1381,  1.3708, -2.6217])
    >>> b = torch.arange(4 * 5 * 6).view(4, 5, 6)
    >>> torch.sum(b, (2, 1))
    tensor([  435.,  1335.,  2235.,  3135.])
""".format(**reduceops_common_args))

add_docstr(torch.svd,
           r"""
svd(input, some=True, compute_uv=True, out=None) -> (Tensor, Tensor, Tensor)

`U, S, V = torch.svd(A)` returns the singular value decomposition of a
real matrix `A` of size `(n x m)` such that :math:`A = USV^T`.

`U` is of shape :math:`(n \times n)`.

`S` is a diagonal matrix of shape :math:`(n \times m)`, represented as a vector
of size :math:`\min(n, m)` containing the non-negative diagonal entries.

`V` is of shape :math:`(m \times m)`.

If :attr:`some` is ``True`` (default), the returned `U` and `V` matrices will
contain only :math:`min(n, m)` orthonormal columns.

If :attr:`compute_uv` is ``False``, the returned `U` and `V` matrices will be zero matrices
of shape :math:`(n \times n)` and :math:`(m \times m)` respectively. :attr:`some` will be ignored here.

.. note:: The implementation of SVD on CPU uses the LAPACK routine `?gesdd` (a divide-and-conquer
          algorithm) instead of `?gesvd` for speed. Analogously, the SVD on GPU uses the MAGMA routine
          `gesdd` as well.

.. note:: Irrespective of the original strides, the returned matrix `U`
          will be transposed, i.e. with strides `(1, n)` instead of `(n, 1)`.

.. note:: Extra care needs to be taken when backward through `U` and `V`
          outputs. Such operation is really only stable when :attr:`input` is
          full rank with all distinct singular values. Otherwise, ``NaN`` can
          appear as the gradients are not properly defined. Also, notice that
          double backward will usually do an additional backward through `U` and
          `V` even if the original backward is only on `S`.

.. note:: When :attr:`some` = ``False``, the gradients on ``U[:, min(n, m):]``
          and ``V[:, min(n, m):]`` will be ignored in backward as those vectors
          can be arbitrary bases of the subspaces.

.. note:: When :attr:`compute_uv` = ``False``, backward cannot be performed since ``U`` and ``V``
          from the forward pass is required for the backward operation.

Args:
    input (Tensor): the input 2-D tensor
    some (bool, optional): controls the shape of returned `U` and `V`
    out (tuple, optional): the output tuple of tensors

Example::

    >>> a = torch.tensor([[8.79,  6.11, -9.15,  9.57, -3.49,  9.84],
                          [9.93,  6.91, -7.93,  1.64,  4.02,  0.15],
                          [9.83,  5.04,  4.86,  8.83,  9.80, -8.99],
                          [5.45, -0.27,  4.85,  0.74, 10.00, -6.02],
                          [3.16,  7.98,  3.01,  5.80,  4.27, -5.31]]).t()

    >>> u, s, v = torch.svd(a)
    >>> u
    tensor([[-0.5911,  0.2632,  0.3554,  0.3143,  0.2299],
            [-0.3976,  0.2438, -0.2224, -0.7535, -0.3636],
            [-0.0335, -0.6003, -0.4508,  0.2334, -0.3055],
            [-0.4297,  0.2362, -0.6859,  0.3319,  0.1649],
            [-0.4697, -0.3509,  0.3874,  0.1587, -0.5183],
            [ 0.2934,  0.5763, -0.0209,  0.3791, -0.6526]])
    >>> s
    tensor([ 27.4687,  22.6432,   8.5584,   5.9857,   2.0149])
    >>> v
    tensor([[-0.2514,  0.8148, -0.2606,  0.3967, -0.2180],
            [-0.3968,  0.3587,  0.7008, -0.4507,  0.1402],
            [-0.6922, -0.2489, -0.2208,  0.2513,  0.5891],
            [-0.3662, -0.3686,  0.3859,  0.4342, -0.6265],
            [-0.4076, -0.0980, -0.4933, -0.6227, -0.4396]])
    >>> torch.dist(a, torch.mm(torch.mm(u, torch.diag(s)), v.t()))
    tensor(1.00000e-06 *
           9.3738)
""")

add_docstr(torch.symeig,
           r"""
symeig(input, eigenvectors=False, upper=True, out=None) -> (Tensor, Tensor)

This function returns eigenvalues and eigenvectors
of a real symmetric matrix :attr:`input`, represented by a tuple :math:`(e, V)`.

:attr:`input` and :math:`V` are :math:`(m \times m)` matrices and :math:`e` is a
:math:`m` dimensional vector.

This function calculates all eigenvalues (and vectors) of :attr:`input`
such that :math:`\text{input} = V \text{diag}(e) V^T`.

The boolean argument :attr:`eigenvectors` defines computation of
eigenvectors or eigenvalues only.

If it is ``False``, only eigenvalues are computed. If it is ``True``,
both eigenvalues and eigenvectors are computed.

Since the input matrix :attr:`input` is supposed to be symmetric,
only the upper triangular portion is used by default.

If :attr:`upper` is ``False``, then lower triangular portion is used.

Note: Irrespective of the original strides, the returned matrix `V` will
be transposed, i.e. with strides `(1, m)` instead of `(m, 1)`.

Args:
    input (Tensor): the input symmetric matrix
    eigenvectors(boolean, optional): controls whether eigenvectors have to be computed
    upper(boolean, optional): controls whether to consider upper-triangular or lower-triangular region
    out (tuple, optional): the output tuple of (Tensor, Tensor)

Returns:
    (Tensor, Tensor): A tuple containing

        - **e** (*Tensor*): Shape :math:`(m)`. Each element is an eigenvalue of ``input``,
          The eigenvalues are in ascending order.
        - **V** (*Tensor*): Shape :math:`(m \times m)`.
          If ``eigenvectors=False``, it's a tensor filled with zeros.
          Otherwise, this tensor contains the orthonormal eigenvectors of the ``input``.

Examples::


    >>> a = torch.tensor([[ 1.96,  0.00,  0.00,  0.00,  0.00],
                          [-6.49,  3.80,  0.00,  0.00,  0.00],
                          [-0.47, -6.39,  4.17,  0.00,  0.00],
                          [-7.20,  1.50, -1.51,  5.70,  0.00],
                          [-0.65, -6.34,  2.67,  1.80, -7.10]]).t()
    >>> e, v = torch.symeig(a, eigenvectors=True)
    >>> e
    tensor([-11.0656,  -6.2287,   0.8640,   8.8655,  16.0948])
    >>> v
    tensor([[-0.2981, -0.6075,  0.4026, -0.3745,  0.4896],
            [-0.5078, -0.2880, -0.4066, -0.3572, -0.6053],
            [-0.0816, -0.3843, -0.6600,  0.5008,  0.3991],
            [-0.0036, -0.4467,  0.4553,  0.6204, -0.4564],
            [-0.8041,  0.4480,  0.1725,  0.3108,  0.1622]])
""")

add_docstr(torch.t,
           r"""
t(input) -> Tensor

Expects :attr:`input` to be a matrix (2-D tensor) and transposes dimensions 0
and 1.

Can be seen as a short-hand function for ``transpose(input, 0, 1)``.

Args:
    input (Tensor): the input tensor

Example::

    >>> x = torch.randn(2, 3)
    >>> x
    tensor([[ 0.4875,  0.9158, -0.5872],
            [ 0.3938, -0.6929,  0.6932]])
    >>> torch.t(x)
    tensor([[ 0.4875,  0.3938],
            [ 0.9158, -0.6929],
            [-0.5872,  0.6932]])
""")

add_docstr(torch.flip,
           r"""
flip(input, dims) -> Tensor

Reverse the order of a n-D tensor along given axis in dims.

Args:
    input (Tensor): the input tensor
    dims (a list or tuple): axis to flip on

Example::

    >>> x = torch.arange(8).view(2, 2, 2)
    >>> x
    tensor([[[ 0,  1],
             [ 2,  3]],

            [[ 4,  5],
             [ 6,  7]]])
    >>> torch.flip(x, [0, 1])
    tensor([[[ 6,  7],
             [ 4,  5]],

            [[ 2,  3],
             [ 0,  1]]])
""")

add_docstr(torch.rot90,
           r"""
rot90(input, k, dims) -> Tensor

Rotate a n-D tensor by 90 degrees in the plane specified by dims axis.
Rotation direction is from the first towards the second axis if k > 0, and from the second towards the first for k < 0.

Args:
    input (Tensor): the input tensor
    k (int): number of times to rotate
    dims (a list or tuple): axis to rotate

Example::

    >>> x = torch.arange(4).view(2, 2)
    >>> x
    tensor([[0, 1],
            [2, 3]])
    >>> torch.rot90(x, 1, [0, 1])
    tensor([[1, 3],
            [0, 2]])

    >>> x = torch.arange(8).view(2, 2, 2)
    >>> x
    tensor([[[0, 1],
             [2, 3]],

            [[4, 5],
             [6, 7]]])
    >>> torch.rot90(x, 1, [1, 2])
    tensor([[[1, 3],
             [0, 2]],

            [[5, 7],
             [4, 6]]])
""")

add_docstr(torch.take,
           r"""
take(input, indices) -> Tensor

Returns a new tensor with the elements of :attr:`input` at the given indices.
The input tensor is treated as if it were viewed as a 1-D tensor. The result
takes the same shape as the indices.

Args:
    input (Tensor): the input tensor
    indices (LongTensor): the indices into tensor

Example::

    >>> src = torch.tensor([[4, 3, 5],
                            [6, 7, 8]])
    >>> torch.take(src, torch.tensor([0, 2, 5]))
    tensor([ 4,  5,  8])
""")

add_docstr(torch.tan,
           r"""
tan(input, out=None) -> Tensor

Returns a new tensor with the tangent of the elements of :attr:`input`.

.. math::
    \text{out}_{i} = \tan(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([-1.2027, -1.7687,  0.4412, -1.3856])
    >>> torch.tan(a)
    tensor([-2.5930,  4.9859,  0.4722, -5.3366])
""")

add_docstr(torch.tanh,
           r"""
tanh(input, out=None) -> Tensor

Returns a new tensor with the hyperbolic tangent of the elements
of :attr:`input`.

.. math::
    \text{out}_{i} = \tanh(\text{input}_{i})

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 0.8986, -0.7279,  1.1745,  0.2611])
    >>> torch.tanh(a)
    tensor([ 0.7156, -0.6218,  0.8257,  0.2553])
""")

add_docstr(torch.topk,
           r"""
topk(input, k, dim=None, largest=True, sorted=True, out=None) -> (Tensor, LongTensor)

Returns the :attr:`k` largest elements of the given :attr:`input` tensor along
a given dimension.

If :attr:`dim` is not given, the last dimension of the `input` is chosen.

If :attr:`largest` is ``False`` then the `k` smallest elements are returned.

A tuple of `(values, indices)` is returned, where the `indices` are the indices
of the elements in the original `input` tensor.

The boolean option :attr:`sorted` if ``True``, will make sure that the returned
`k` elements are themselves sorted

Args:
    input (Tensor): the input tensor
    k (int): the k in "top-k"
    dim (int, optional): the dimension to sort along
    largest (bool, optional): controls whether to return largest or
           smallest elements
    sorted (bool, optional): controls whether to return the elements
           in sorted order
    out (tuple, optional): the output tuple of (Tensor, LongTensor) that can be
        optionally given to be used as output buffers

Example::

    >>> x = torch.arange(1., 6.)
    >>> x
    tensor([ 1.,  2.,  3.,  4.,  5.])
    >>> torch.topk(x, 3)
    (tensor([ 5.,  4.,  3.]), tensor([ 4,  3,  2]))
""")

add_docstr(torch.trace,
           r"""
trace(input) -> Tensor

Returns the sum of the elements of the diagonal of the input 2-D matrix.

Example::

    >>> x = torch.arange(1., 10.).view(3, 3)
    >>> x
    tensor([[ 1.,  2.,  3.],
            [ 4.,  5.,  6.],
            [ 7.,  8.,  9.]])
    >>> torch.trace(x)
    tensor(15.)
""")

add_docstr(torch.transpose,
           r"""
transpose(input, dim0, dim1) -> Tensor

Returns a tensor that is a transposed version of :attr:`input`.
The given dimensions :attr:`dim0` and :attr:`dim1` are swapped.

The resulting :attr:`out` tensor shares it's underlying storage with the
:attr:`input` tensor, so changing the content of one would change the content
of the other.

Args:
    input (Tensor): the input tensor
    dim0 (int): the first dimension to be transposed
    dim1 (int): the second dimension to be transposed

Example::

    >>> x = torch.randn(2, 3)
    >>> x
    tensor([[ 1.0028, -0.9893,  0.5809],
            [-0.1669,  0.7299,  0.4942]])
    >>> torch.transpose(x, 0, 1)
    tensor([[ 1.0028, -0.1669],
            [-0.9893,  0.7299],
            [ 0.5809,  0.4942]])
""")

add_docstr(torch.tril,
           r"""
tril(input, diagonal=0, out=None) -> Tensor

Returns the lower triangular part of the matrix (2-D tensor) :attr:`input`,
the other elements of the result tensor :attr:`out` are set to 0.

The lower triangular part of the matrix is defined as the elements on and
below the diagonal.

The argument :attr:`diagonal` controls which diagonal to consider. If
:attr:`diagonal` = 0, all elements on and below the main diagonal are
retained. A positive value includes just as many diagonals above the main
diagonal, and similarly a negative value excludes just as many diagonals below
the main diagonal. The main diagonal are the set of indices
:math:`\lbrace (i, i) \rbrace` for :math:`i \in [0, \min\{d_{1}, d_{2}\} - 1]` where
:math:`d_{1}, d_{2}` are the dimensions of the matrix.

Args:
    input (Tensor): the input tensor
    diagonal (int, optional): the diagonal to consider
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(3, 3)
    >>> a
    tensor([[-1.0813, -0.8619,  0.7105],
            [ 0.0935,  0.1380,  2.2112],
            [-0.3409, -0.9828,  0.0289]])
    >>> torch.tril(a)
    tensor([[-1.0813,  0.0000,  0.0000],
            [ 0.0935,  0.1380,  0.0000],
            [-0.3409, -0.9828,  0.0289]])

    >>> b = torch.randn(4, 6)
    >>> b
    tensor([[ 1.2219,  0.5653, -0.2521, -0.2345,  1.2544,  0.3461],
            [ 0.4785, -0.4477,  0.6049,  0.6368,  0.8775,  0.7145],
            [ 1.1502,  3.2716, -1.1243, -0.5413,  0.3615,  0.6864],
            [-0.0614, -0.7344, -1.3164, -0.7648, -1.4024,  0.0978]])
    >>> torch.tril(b, diagonal=1)
    tensor([[ 1.2219,  0.5653,  0.0000,  0.0000,  0.0000,  0.0000],
            [ 0.4785, -0.4477,  0.6049,  0.0000,  0.0000,  0.0000],
            [ 1.1502,  3.2716, -1.1243, -0.5413,  0.0000,  0.0000],
            [-0.0614, -0.7344, -1.3164, -0.7648, -1.4024,  0.0000]])
    >>> torch.tril(b, diagonal=-1)
    tensor([[ 0.0000,  0.0000,  0.0000,  0.0000,  0.0000,  0.0000],
            [ 0.4785,  0.0000,  0.0000,  0.0000,  0.0000,  0.0000],
            [ 1.1502,  3.2716,  0.0000,  0.0000,  0.0000,  0.0000],
            [-0.0614, -0.7344, -1.3164,  0.0000,  0.0000,  0.0000]])
""")

add_docstr(torch.triu,
           r"""
triu(input, diagonal=0, out=None) -> Tensor

Returns the upper triangular part of the matrix (2-D tensor) :attr:`input`,
the other elements of the result tensor :attr:`out` are set to 0.

The upper triangular part of the matrix is defined as the elements on and
above the diagonal.

The argument :attr:`diagonal` controls which diagonal to consider. If
:attr:`diagonal` = 0, all elements on and below the main diagonal are
retained. A positive value excludes just as many diagonals above the main
diagonal, and similarly a negative value includes just as many diagonals below
the main diagonal. The main diagonal are the set of indices
:math:`\lbrace (i, i) \rbrace` for :math:`i \in [0, \min\{d_{1}, d_{2}\} - 1]` where
:math:`d_{1}, d_{2}` are the dimensions of the matrix.

Args:
    input (Tensor): the input tensor
    diagonal (int, optional): the diagonal to consider
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(3, 3)
    >>> a
    tensor([[ 0.2309,  0.5207,  2.0049],
            [ 0.2072, -1.0680,  0.6602],
            [ 0.3480, -0.5211, -0.4573]])
    >>> torch.triu(a)
    tensor([[ 0.2309,  0.5207,  2.0049],
            [ 0.0000, -1.0680,  0.6602],
            [ 0.0000,  0.0000, -0.4573]])
    >>> torch.triu(a, diagonal=1)
    tensor([[ 0.0000,  0.5207,  2.0049],
            [ 0.0000,  0.0000,  0.6602],
            [ 0.0000,  0.0000,  0.0000]])
    >>> torch.triu(a, diagonal=-1)
    tensor([[ 0.2309,  0.5207,  2.0049],
            [ 0.2072, -1.0680,  0.6602],
            [ 0.0000, -0.5211, -0.4573]])

    >>> b = torch.randn(4, 6)
    >>> b
    tensor([[ 0.5876, -0.0794, -1.8373,  0.6654,  0.2604,  1.5235],
            [-0.2447,  0.9556, -1.2919,  1.3378, -0.1768, -1.0857],
            [ 0.4333,  0.3146,  0.6576, -1.0432,  0.9348, -0.4410],
            [-0.9888,  1.0679, -1.3337, -1.6556,  0.4798,  0.2830]])
    >>> torch.tril(b, diagonal=1)
    tensor([[ 0.5876, -0.0794,  0.0000,  0.0000,  0.0000,  0.0000],
            [-0.2447,  0.9556, -1.2919,  0.0000,  0.0000,  0.0000],
            [ 0.4333,  0.3146,  0.6576, -1.0432,  0.0000,  0.0000],
            [-0.9888,  1.0679, -1.3337, -1.6556,  0.4798,  0.0000]])
    >>> torch.tril(b, diagonal=-1)
    tensor([[ 0.0000,  0.0000,  0.0000,  0.0000,  0.0000,  0.0000],
            [-0.2447,  0.0000,  0.0000,  0.0000,  0.0000,  0.0000],
            [ 0.4333,  0.3146,  0.0000,  0.0000,  0.0000,  0.0000],
            [-0.9888,  1.0679, -1.3337,  0.0000,  0.0000,  0.0000]])
""")

add_docstr(torch.trtrs,
           r"""
trtrs(b, A, upper=True, transpose=False, unitriangular=False) -> (Tensor, Tensor)

Solves a system of equations with a triangular coefficient matrix :math:`A`
and multiple right-hand sides :attr:`b`.

In particular, solves :math:`AX = b` and assumes :math:`A` is upper-triangular
with the default keyword arguments.

Args:
    A (Tensor): the input triangular coefficient matrix
    b (Tensor): multiple right-hand sides. Each column of :math:`b` is a
        right-hand side for the system of equations.
    upper (bool, optional): whether to solve the upper-triangular system
        of equations (default) or the lower-triangular system of equations. Default: True.
    transpose (bool, optional): whether :math:`A` should be transposed before
        being sent into the solver. Default: False.
    unitriangular (bool, optional): whether :math:`A` is unit triangular.
        If True, the diagonal elements of :math:`A` are assumed to be
        1 and not referenced from :math:`A`. Default: False.

Returns:
    A tuple :math:`(X, M)` where :math:`M` is a clone of :math:`A` and :math:`X`
    is the solution to :math:`AX = b` (or whatever variant of the system of
    equations, depending on the keyword arguments.)

Shape:
    - A: :math:`(N, N)`
    - b: :math:`(N, C)`
    - output[0]: :math:`(N, C)`
    - output[1]: :math:`(N, N)`

Examples::

    >>> A = torch.randn(2, 2).triu()
    >>> A
    tensor([[ 1.1527, -1.0753],
            [ 0.0000,  0.7986]])
    >>> b = torch.randn(2, 3)
    >>> b
    tensor([[-0.0210,  2.3513, -1.5492],
            [ 1.5429,  0.7403, -1.0243]])
    >>> torch.trtrs(b, A)
    (tensor([[ 1.7840,  2.9045, -2.5405],
            [ 1.9319,  0.9269, -1.2826]]), tensor([[ 1.1527, -1.0753],
            [ 0.0000,  0.7986]]))
""")

add_docstr(torch.trunc,
           r"""
trunc(input, out=None) -> Tensor

Returns a new tensor with the truncated integer values of
the elements of :attr:`input`.

Args:
    input (Tensor): the input tensor
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4)
    >>> a
    tensor([ 3.4742,  0.5466, -0.8008, -0.9079])
    >>> torch.trunc(a)
    tensor([ 3.,  0., -0., -0.])
""")

add_docstr(torch.unsqueeze,
           r"""
unsqueeze(input, dim, out=None) -> Tensor

Returns a new tensor with a dimension of size one inserted at the
specified position.

The returned tensor shares the same underlying data with this tensor.

A :attr:`dim` value within the range ``[-input.dim() - 1, input.dim() + 1)``
can be used. Negative :attr:`dim` will correspond to :meth:`unsqueeze`
applied at :attr:`dim` = ``dim + input.dim() + 1``.

Args:
    input (Tensor): the input tensor
    dim (int): the index at which to insert the singleton dimension
    out (Tensor, optional): the output tensor

Example::

    >>> x = torch.tensor([1, 2, 3, 4])
    >>> torch.unsqueeze(x, 0)
    tensor([[ 1,  2,  3,  4]])
    >>> torch.unsqueeze(x, 1)
    tensor([[ 1],
            [ 2],
            [ 3],
            [ 4]])
""")

add_docstr(torch.var,
           r"""
.. function:: var(input, unbiased=True) -> Tensor

Returns the variance of all elements in the :attr:`input` tensor.

If :attr:`unbiased` is ``False``, then the variance will be calculated via the
biased estimator. Otherwise, Bessel's correction will be used.

Args:
    input (Tensor): the input tensor
    unbiased (bool): whether to use the unbiased estimation or not

Example::

    >>> a = torch.randn(1, 3)
    >>> a
    tensor([[-0.3425, -1.2636, -0.4864]])
    >>> torch.var(a)
    tensor(0.2455)


.. function:: var(input, dim, keepdim=False, unbiased=True, out=None) -> Tensor

Returns the variance of each row of the :attr:`input` tensor in the given
dimension :attr:`dim`.

If :attr:`keepdim` is ``True``, the output tensors are of the same size
as :attr:`input` except in the dimension :attr:`dim` where they are of size 1.
Otherwise, :attr:`dim` is squeezed (see :func:`torch.squeeze`), resulting in
the outputs tensor having 1 fewer dimension than :attr:`input`.

If :attr:`unbiased` is ``False``, then the variance will be calculated via the
biased estimator. Otherwise, Bessel's correction will be used.

Args:
    input (Tensor): the input tensor
    dim (int): the dimension to reduce
    keepdim (bool): whether the output tensor has :attr:`dim` retained or not
    unbiased (bool): whether to use the unbiased estimation or not
    out (Tensor, optional): the output tensor

Example::

    >>> a = torch.randn(4, 4)
    >>> a
    tensor([[-0.3567,  1.7385, -1.3042,  0.7423],
            [ 1.3436, -0.1015, -0.9834, -0.8438],
            [ 0.6056,  0.1089, -0.3112, -1.4085],
            [-0.7700,  0.6074, -0.1469,  0.7777]])
    >>> torch.var(a, 1)
    tensor([ 1.7444,  1.1363,  0.7356,  0.5112])
""")

add_docstr(torch.zeros,
           r"""
zeros(*sizes, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with the scalar value `0`, with the shape defined
by the variable argument :attr:`sizes`.

Args:
    sizes (int...): a sequence of integers defining the shape of the output tensor.
        Can be a variable number of arguments or a collection like a list or tuple.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.zeros(2, 3)
    tensor([[ 0.,  0.,  0.],
            [ 0.,  0.,  0.]])

    >>> torch.zeros(5)
    tensor([ 0.,  0.,  0.,  0.,  0.])
""".format(**factory_common_args))

add_docstr(torch.zeros_like,
           r"""
zeros_like(input, dtype=None, layout=None, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with the scalar value `0`, with the same size as
:attr:`input`. ``torch.zeros_like(input)`` is equivalent to
``torch.zeros(input.size(), dtype=input.dtype, layout=input.layout, device=input.device)``.

.. warning::
    As of 0.4, this function does not support an :attr:`out` keyword. As an alternative,
    the old ``torch.zeros_like(input, out=output)`` is equivalent to
    ``torch.zeros(input.size(), out=output)``.

Args:
    {input}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> input = torch.empty(2, 3)
    >>> torch.zeros_like(input)
    tensor([[ 0.,  0.,  0.],
            [ 0.,  0.,  0.]])
""".format(**factory_like_common_args))

add_docstr(torch.btrifact_with_info,
           r"""
btrifact_with_info(A, pivot=True) -> (Tensor, IntTensor, IntTensor)

Batch LU factorization with additional error information.

This is a version of :meth:`torch.btrifact` that always creates an info
`IntTensor`, and returns it as the third return value.

Arguments:
    A (Tensor): the tensor to factor
    pivot (bool, optional): controls whether pivoting is done

Returns:
    A tuple containing factorization, pivots, and an `IntTensor` where non-zero
    values indicate whether factorization for each minibatch sample succeeds.

Example::

    >>> A = torch.randn(2, 3, 3)
    >>> A_LU, pivots, info = A.btrifact_with_info()
    >>> if info.nonzero().size(0) == 0:
    >>>   print('LU factorization succeeded for all samples!')
    LU factorization succeeded for all samples!
""")

add_docstr(torch.btrisolve,
           r"""
btrisolve(b, LU_data, LU_pivots) -> Tensor

Batch LU solve.

Returns the LU solve of the linear system :math:`Ax = b`.

Arguments:
    b (Tensor): the RHS tensor
    LU_data (Tensor): the pivoted LU factorization of A from :meth:`btrifact`.
    LU_pivots (IntTensor): the pivots of the LU factorization

Example::

    >>> A = torch.randn(2, 3, 3)
    >>> b = torch.randn(2, 3)
    >>> A_LU = torch.btrifact(A)
    >>> x = torch.btrisolve(b, *A_LU)
    >>> torch.norm(torch.bmm(A, x.unsqueeze(2)) - b.unsqueeze(2))
    tensor(1.00000e-07 *
           2.8312)
""")

add_docstr(torch.empty,
           r"""
empty(*sizes, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor filled with uninitialized data. The shape of the tensor is
defined by the variable argument :attr:`sizes`.

Args:
    sizes (int...): a sequence of integers defining the shape of the output tensor.
        Can be a variable number of arguments or a collection like a list or tuple.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.empty(2, 3)
    tensor(1.00000e-08 *
           [[ 6.3984,  0.0000,  0.0000],
            [ 0.0000,  0.0000,  0.0000]])

""".format(**factory_common_args))

add_docstr(torch.empty_like,
           r"""
empty_like(input, dtype=None, layout=None, device=None, requires_grad=False) -> Tensor

Returns an uninitialized tensor with the same size as :attr:`input`.
``torch.empty_like(input)`` is equivalent to
``torch.empty(input.size(), dtype=input.dtype, layout=input.layout, device=input.device)``.

Args:
    {input}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.empty((2,3), dtype=torch.int64)
    tensor([[ 9.4064e+13,  2.8000e+01,  9.3493e+13],
            [ 7.5751e+18,  7.1428e+18,  7.5955e+18]])
""".format(**factory_like_common_args))

add_docstr(torch.full,
           r"""
full(size, fill_value, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor of size :attr:`size` filled with :attr:`fill_value`.

Args:
    size (int...): a list, tuple, or :class:`torch.Size` of integers defining the
        shape of the output tensor.
    fill_value: the number to fill the output tensor with.
    {out}
    {dtype}
    {layout}
    {device}
    {requires_grad}

Example::

    >>> torch.full((2, 3), 3.141592)
    tensor([[ 3.1416,  3.1416,  3.1416],
            [ 3.1416,  3.1416,  3.1416]])

""".format(**factory_common_args))

add_docstr(torch.full_like,
           r"""
full_like(input, fill_value, out=None, dtype=None, layout=torch.strided, device=None, requires_grad=False) -> Tensor

Returns a tensor with the same size as :attr:`input` filled with :attr:`fill_value`.
``torch.full_like(input, fill_value)`` is equivalent to
``torch.full_like(input.size(), fill_value, dtype=input.dtype, layout=input.layout, device=input.device)``.

Args:
    {input}
    fill_value: the number to fill the output tensor with.
    {dtype}
    {layout}
    {device}
    {requires_grad}
""".format(**factory_like_common_args))

add_docstr(torch.det,
           r"""
det(A) -> Tensor

Calculates determinant of a 2D square tensor.

.. note::
    Backward through :meth:`det` internally uses SVD results when :attr:`A` is
    not invertible. In this case, double backward through :meth:`det` will be
    unstable in when :attr:`A` doesn't have distinct singular values. See
    :meth:`~torch.svd` for details.

Arguments:
    A (Tensor): The input 2D square tensor

Example::

    >>> A = torch.randn(3, 3)
    >>> torch.det(A)
    tensor(3.7641)
""")

add_docstr(torch.where,
           r"""
where(condition, x, y) -> Tensor

Return a tensor of elements selected from either :attr:`x` or :attr:`y`, depending on :attr:`condition`.

The operation is defined as:

.. math::
    out_i = \begin{cases}
        x_i & \text{if } \text{condition}_i \\
        y_i & \text{otherwise} \\
    \end{cases}

.. note::
    The tensors :attr:`condition`, :attr:`x`, :attr:`y` must be :ref:`broadcastable <broadcasting-semantics>`.

Arguments:
    condition (ByteTensor): When True (nonzero), yield x, otherwise yield y
    x (Tensor): values selected at indices where :attr:`condition` is ``True``
    y (Tensor): values selected at indices where :attr:`condition` is ``False``

Returns:
    Tensor: A tensor of shape equal to the broadcasted shape of :attr:`condition`, :attr:`x`, :attr:`y`

Example::

    >>> x = torch.randn(3, 2)
    >>> y = torch.ones(3, 2)
    >>> x
    tensor([[-0.4620,  0.3139],
            [ 0.3898, -0.7197],
            [ 0.0478, -0.1657]])
    >>> torch.where(x > 0, x, y)
    tensor([[ 1.0000,  0.3139],
            [ 0.3898,  1.0000],
            [ 0.0478,  1.0000]])
""")

add_docstr(torch.logdet,
           r"""
logdet(A) -> Tensor

Calculates log determinant of a 2D square tensor.

.. note::
    Result is ``-inf`` if :attr:`A` has zero log determinant, and is ``nan`` if
    :attr:`A` has negative determinant.

.. note::
    Backward through :meth:`logdet` internally uses SVD results when :attr:`A`
    is not invertible. In this case, double backward through :meth:`logdet` will
    be unstable in when :attr:`A` doesn't have distinct singular values. See
    :meth:`~torch.svd` for details.

Arguments:
    A (Tensor): The input 2D square tensor

Example::

    >>> A = torch.randn(3, 3)
    >>> torch.det(A)
    tensor(0.2611)
    >>> torch.logdet(A)
    tensor(-1.3430)
""")

add_docstr(torch.slogdet,
           r"""
slogdet(A) -> (Tensor, Tensor)

Calculates the sign and log value of a 2D square tensor's determinant.

.. note::
    If ``A`` has zero determinant, this returns ``(0, -inf)``.

.. note::
    Backward through :meth:`slogdet` internally uses SVD results when :attr:`A`
    is not invertible. In this case, double backward through :meth:`slogdet`
    will be unstable in when :attr:`A` doesn't have distinct singular values.
    See :meth:`~torch.svd` for details.

Arguments:
    A (Tensor): The input 2D square tensor

Returns:
    A tuple containing the sign of the determinant, and the log value of the
    absolute determinant.

Example::

    >>> A = torch.randn(3, 3)
    >>> torch.det(A)
    tensor(-4.8215)
    >>> torch.logdet(A)
    tensor(nan)
    >>> torch.slogdet(A)
    (tensor(-1.), tensor(1.5731))
""")

add_docstr(torch.pinverse,
           r"""
pinverse(input, rcond=1e-15) -> Tensor

Calculates the pseudo-inverse (also known as the Moore-Penrose inverse) of a 2D tensor.
Please look at `Moore-Penrose inverse`_ for more details

.. note::
    This method is implemented using the Singular Value Decomposition.

.. note::
    The pseudo-inverse is not necessarily a continuous function in the elements of the matrix `[1]`_.
    Therefore, derivatives are not always existent, and exist for a constant rank only `[2]`_.
    However, this method is backprop-able due to the implementation by using SVD results, and
    could be unstable. Double-backward will also be unstable due to the usage of SVD internally.
    See :meth:`~torch.svd` for more details.

Arguments:
    input (Tensor): The input 2D tensor of dimensions :math:`m \times n`
    rcond (float): A floating point value to determine the cutoff for small singular values.
                   Default: 1e-15

Returns:
    The pseudo-inverse of :attr:`input` of dimensions :math:`n \times m`

Example::

    >>> input = torch.randn(3, 5)
    >>> input
    tensor([[ 0.5495,  0.0979, -1.4092, -0.1128,  0.4132],
            [-1.1143, -0.3662,  0.3042,  1.6374, -0.9294],
            [-0.3269, -0.5745, -0.0382, -0.5922, -0.6759]])
    >>> torch.pinverse(input)
    tensor([[ 0.0600, -0.1933, -0.2090],
            [-0.0903, -0.0817, -0.4752],
            [-0.7124, -0.1631, -0.2272],
            [ 0.1356,  0.3933, -0.5023],
            [-0.0308, -0.1725, -0.5216]])

.. _Moore-Penrose inverse: https://en.wikipedia.org/wiki/Moore%E2%80%93Penrose_inverse

.. _[1]: https://epubs.siam.org/doi/10.1137/0117004

.. _[2]: https://www.jstor.org/stable/2156365
""")

add_docstr(torch.fft,
           r"""
fft(input, signal_ndim, normalized=False) -> Tensor

Complex-to-complex Discrete Fourier Transform

This method computes the complex-to-complex discrete Fourier transform.
Ignoring the batch dimensions, it computes the following expression:

.. math::
    X[\omega_1, \dots, \omega_d] =
        \sum_{n_1=0}^{N_1} \dots \sum_{n_d=0}^{N_d} x[n_1, \dots, n_d]
         e^{-j\ 2 \pi \sum_{i=0}^d \frac{\omega_i n_i}{N_i}},

where :math:`d` = :attr:`signal_ndim` is number of dimensions for the
signal, and :math:`N_i` is the size of signal dimension :math:`i`.

This method supports 1D, 2D and 3D complex-to-complex transforms, indicated
by :attr:`signal_ndim`. :attr:`input` must be a tensor with last dimension
of size 2, representing the real and imaginary components of complex
numbers, and should have at least ``signal_ndim + 1`` dimensions with optionally
arbitrary number of leading batch dimensions. If :attr:`normalized` is set to
``True``, this normalizes the result by dividing it with
:math:`\sqrt{\prod_{i=1}^K N_i}` so that the operator is unitary.

Returns the real and the imaginary parts together as one tensor of the same
shape of :attr:`input`.

The inverse of this function is :func:`~torch.ifft`.

.. note::
    For CUDA tensors, an LRU cache is used for cuFFT plans to speed up
    repeatedly running FFT methods on tensors of same geometry with same
    same configuration.

    Changing ``torch.backends.cuda.cufft_plan_cache.max_size`` (default is
    4096 on CUDA 10 and newer, and 1023 on older CUDA versions) controls the
    capacity of this cache. Some cuFFT plans may allocate GPU memory. You can
    use ``torch.backends.cuda.cufft_plan_cache.size`` to query the number of
    plans currently in cache, and
    ``torch.backends.cuda.cufft_plan_cache.clear()`` to clear the cache.

.. warning::
    For CPU tensors, this method is currently only available with MKL. Use
    :func:`torch.backends.mkl.is_available` to check if MKL is installed.

Arguments:
    input (Tensor): the input tensor of at least :attr:`signal_ndim` ``+ 1``
        dimensions
    signal_ndim (int): the number of dimensions in each signal.
        :attr:`signal_ndim` can only be 1, 2 or 3
    normalized (bool, optional): controls whether to return normalized results.
        Default: ``False``

Returns:
    Tensor: A tensor containing the complex-to-complex Fourier transform result

Example::

    >>> # unbatched 2D FFT
    >>> x = torch.randn(4, 3, 2)
    >>> torch.fft(x, 2)
    tensor([[[-0.0876,  1.7835],
             [-2.0399, -2.9754],
             [ 4.4773, -5.0119]],

            [[-1.5716,  2.7631],
             [-3.8846,  5.2652],
             [ 0.2046, -0.7088]],

            [[ 1.9938, -0.5901],
             [ 6.5637,  6.4556],
             [ 2.9865,  4.9318]],

            [[ 7.0193,  1.1742],
             [-1.3717, -2.1084],
             [ 2.0289,  2.9357]]])
    >>> # batched 1D FFT
    >>> torch.fft(x, 1)
    tensor([[[ 1.8385,  1.2827],
             [-0.1831,  1.6593],
             [ 2.4243,  0.5367]],

            [[-0.9176, -1.5543],
             [-3.9943, -2.9860],
             [ 1.2838, -2.9420]],

            [[-0.8854, -0.6860],
             [ 2.4450,  0.0808],
             [ 1.3076, -0.5768]],

            [[-0.1231,  2.7411],
             [-0.3075, -1.7295],
             [-0.5384, -2.0299]]])
    >>> # arbitrary number of batch dimensions, 2D FFT
    >>> x = torch.randn(3, 3, 5, 5, 2)
    >>> y = torch.fft(x, 2)
    >>> y.shape
    torch.Size([3, 3, 5, 5, 2])

""")

add_docstr(torch.ifft,
           r"""
ifft(input, signal_ndim, normalized=False) -> Tensor

Complex-to-complex Inverse Discrete Fourier Transform

This method computes the complex-to-complex inverse discrete Fourier
transform. Ignoring the batch dimensions, it computes the following
expression:

.. math::
    X[\omega_1, \dots, \omega_d] =
        \frac{1}{\prod_{i=1}^d N_i} \sum_{n_1=0}^{N_1} \dots \sum_{n_d=0}^{N_d} x[n_1, \dots, n_d]
         e^{\ j\ 2 \pi \sum_{i=0}^d \frac{\omega_i n_i}{N_i}},

where :math:`d` = :attr:`signal_ndim` is number of dimensions for the
signal, and :math:`N_i` is the size of signal dimension :math:`i`.

The argument specifications are almost identical with :func:`~torch.fft`.
However, if :attr:`normalized` is set to ``True``, this instead returns the
results multiplied by :math:`\sqrt{\prod_{i=1}^d N_i}`, to become a unitary
operator. Therefore, to invert a :func:`~torch.fft`, the :attr:`normalized`
argument should be set identically for :func:`~torch.fft`.

Returns the real and the imaginary parts together as one tensor of the same
shape of :attr:`input`.

The inverse of this function is :func:`~torch.fft`.

.. note::
    For CUDA tensors, an LRU cache is used for cuFFT plans to speed up
    repeatedly running FFT methods on tensors of same geometry with same
    same configuration.

    Changing ``torch.backends.cuda.cufft_plan_cache.max_size`` (default is
    4096 on CUDA 10 and newer, and 1023 on older CUDA versions) controls the
    capacity of this cache. Some cuFFT plans may allocate GPU memory. You can
    use ``torch.backends.cuda.cufft_plan_cache.size`` to query the number of
    plans currently in cache, and
    ``torch.backends.cuda.cufft_plan_cache.clear()`` to clear the cache.

.. warning::
    For CPU tensors, this method is currently only available with MKL. Use
    :func:`torch.backends.mkl.is_available` to check if MKL is installed.

Arguments:
    input (Tensor): the input tensor of at least :attr:`signal_ndim` ``+ 1``
        dimensions
    signal_ndim (int): the number of dimensions in each signal.
        :attr:`signal_ndim` can only be 1, 2 or 3
    normalized (bool, optional): controls whether to return normalized results.
        Default: ``False``

Returns:
    Tensor: A tensor containing the complex-to-complex inverse Fourier transform result

Example::

    >>> x = torch.randn(3, 3, 2)
    >>> x
    tensor([[[ 1.2766,  1.3680],
             [-0.8337,  2.0251],
             [ 0.9465, -1.4390]],

            [[-0.1890,  1.6010],
             [ 1.1034, -1.9230],
             [-0.9482,  1.0775]],

            [[-0.7708, -0.8176],
             [-0.1843, -0.2287],
             [-1.9034, -0.2196]]])
    >>> y = torch.fft(x, 2)
    >>> torch.ifft(y, 2)  # recover x
    tensor([[[ 1.2766,  1.3680],
             [-0.8337,  2.0251],
             [ 0.9465, -1.4390]],

            [[-0.1890,  1.6010],
             [ 1.1034, -1.9230],
             [-0.9482,  1.0775]],

            [[-0.7708, -0.8176],
             [-0.1843, -0.2287],
             [-1.9034, -0.2196]]])

""")

add_docstr(torch.rfft,
           r"""
rfft(input, signal_ndim, normalized=False, onesided=True) -> Tensor

Real-to-complex Discrete Fourier Transform

This method computes the real-to-complex discrete Fourier transform. It is
mathematically equivalent with :func:`~torch.fft` with differences only in
formats of the input and output.

This method supports 1D, 2D and 3D real-to-complex transforms, indicated
by :attr:`signal_ndim`. :attr:`input` must be a tensor with at least
``signal_ndim`` dimensions with optionally arbitrary number of leading batch
dimensions. If :attr:`normalized` is set to ``True``, this normalizes the result
by dividing it with :math:`\sqrt{\prod_{i=1}^K N_i}` so that the operator is
unitary, where :math:`N_i` is the size of signal dimension :math:`i`.

The real-to-complex Fourier transform results follow conjugate symmetry:

.. math::
    X[\omega_1, \dots, \omega_d] = X^*[N_1 - \omega_1, \dots, N_d - \omega_d],

where the index arithmetic is computed modulus the size of the corresponding
dimension, :math:`\ ^*` is the conjugate operator, and
:math:`d` = :attr:`signal_ndim`. :attr:`onesided` flag controls whether to avoid
redundancy in the output results. If set to ``True`` (default), the output will
not be full complex result of shape :math:`(*, 2)`, where :math:`*` is the shape
of :attr:`input`, but instead the last dimension will be halfed as of size
:math:`\lfloor \frac{N_d}{2} \rfloor + 1`.

The inverse of this function is :func:`~torch.irfft`.

.. note::
    For CUDA tensors, an LRU cache is used for cuFFT plans to speed up
    repeatedly running FFT methods on tensors of same geometry with same
    same configuration.

    Changing ``torch.backends.cuda.cufft_plan_cache.max_size`` (default is
    4096 on CUDA 10 and newer, and 1023 on older CUDA versions) controls the
    capacity of this cache. Some cuFFT plans may allocate GPU memory. You can
    use ``torch.backends.cuda.cufft_plan_cache.size`` to query the number of
    plans currently in cache, and
    ``torch.backends.cuda.cufft_plan_cache.clear()`` to clear the cache.

.. warning::
    For CPU tensors, this method is currently only available with MKL. Use
    :func:`torch.backends.mkl.is_available` to check if MKL is installed.

Arguments:
    input (Tensor): the input tensor of at least :attr:`signal_ndim` dimensions
    signal_ndim (int): the number of dimensions in each signal.
        :attr:`signal_ndim` can only be 1, 2 or 3
    normalized (bool, optional): controls whether to return normalized results.
        Default: ``False``
    onesided (bool, optional): controls whether to return half of results to
        avoid redundancy. Default: ``True``

Returns:
    Tensor: A tensor containing the real-to-complex Fourier transform result

Example::

    >>> x = torch.randn(5, 5)
    >>> torch.rfft(x, 2).shape
    torch.Size([5, 3, 2])
    >>> torch.rfft(x, 2, onesided=False).shape
    torch.Size([5, 5, 2])

""")


add_docstr(torch.irfft,
           r"""
irfft(input, signal_ndim, normalized=False, onesided=True, signal_sizes=None) -> Tensor

Complex-to-real Inverse Discrete Fourier Transform

This method computes the complex-to-real inverse discrete Fourier transform.
It is mathematically equivalent with :func:`ifft` with differences only in
formats of the input and output.

The argument specifications are almost identical with :func:`~torch.ifft`.
Similar to :func:`~torch.ifft`, if :attr:`normalized` is set to ``True``,
this normalizes the result by multiplying it with
:math:`\sqrt{\prod_{i=1}^K N_i}` so that the operator is unitary, where
:math:`N_i` is the size of signal dimension :math:`i`.

Due to the conjugate symmetry, :attr:`input` do not need to contain the full
complex frequency values. Roughly half of the values will be sufficient, as
is the case when :attr:`input` is given by :func:`~torch.rfft` with
``rfft(signal, onesided=True)``. In such case, set the :attr:`onesided`
argument of this method to ``True``. Moreover, the original signal shape
information can sometimes be lost, optionally set :attr:`signal_sizes` to be
the size of the original signal (without the batch dimensions if in batched
mode) to recover it with correct shape.

Therefore, to invert an :func:`~torch.rfft`, the :attr:`normalized` and
:attr:`onesided` arguments should be set identically for :func:`~torch.irfft`,
and preferrably a :attr:`signal_sizes` is given to avoid size mismatch. See the
example below for a case of size mismatch.

See :func:`~torch.rfft` for details on conjugate symmetry.

The inverse of this function is :func:`~torch.rfft`.

.. warning::
    Generally speaking, the input of this function should contain values
    following conjugate symmetry. Note that even if :attr:`onesided` is
    ``True``, often symmetry on some part is still needed. When this
    requirement is not satisfied, the behavior of :func:`~torch.irfft` is
    undefined. Since :func:`torch.autograd.gradcheck` estimates numerical
    Jacobian with point perturbations, :func:`~torch.irfft` will almost
    certainly fail the check.

.. note::
    For CUDA tensors, an LRU cache is used for cuFFT plans to speed up
    repeatedly running FFT methods on tensors of same geometry with same
    same configuration.

    Changing ``torch.backends.cuda.cufft_plan_cache.max_size`` (default is
    4096 on CUDA 10 and newer, and 1023 on older CUDA versions) controls the
    capacity of this cache. Some cuFFT plans may allocate GPU memory. You can
    use ``torch.backends.cuda.cufft_plan_cache.size`` to query the number of
    plans currently in cache, and
    ``torch.backends.cuda.cufft_plan_cache.clear()`` to clear the cache.

.. warning::
    For CPU tensors, this method is currently only available with MKL. Use
    :func:`torch.backends.mkl.is_available` to check if MKL is installed.

Arguments:
    input (Tensor): the input tensor of at least :attr:`signal_ndim` ``+ 1``
        dimensions
    signal_ndim (int): the number of dimensions in each signal.
        :attr:`signal_ndim` can only be 1, 2 or 3
    normalized (bool, optional): controls whether to return normalized results.
        Default: ``False``
    onesided (bool, optional): controls whether :attr:`input` was halfed to avoid
        redundancy, e.g., by :func:`rfft`. Default: ``True``
    signal_sizes (list or :class:`torch.Size`, optional): the size of the original
        signal (without batch dimension). Default: ``None``

Returns:
    Tensor: A tensor containing the complex-to-real inverse Fourier transform result

Example::

    >>> x = torch.randn(4, 4)
    >>> torch.rfft(x, 2, onesided=True).shape
    torch.Size([4, 3, 2])
    >>>
    >>> # notice that with onesided=True, output size does not determine the original signal size
    >>> x = torch.randn(4, 5)

    >>> torch.rfft(x, 2, onesided=True).shape
    torch.Size([4, 3, 2])
    >>>
    >>> # now we use the original shape to recover x
    >>> x
    tensor([[-0.8992,  0.6117, -1.6091, -0.4155, -0.8346],
            [-2.1596, -0.0853,  0.7232,  0.1941, -0.0789],
            [-2.0329,  1.1031,  0.6869, -0.5042,  0.9895],
            [-0.1884,  0.2858, -1.5831,  0.9917, -0.8356]])
    >>> y = torch.rfft(x, 2, onesided=True)
    >>> torch.irfft(y, 2, onesided=True, signal_sizes=x.shape)  # recover x
    tensor([[-0.8992,  0.6117, -1.6091, -0.4155, -0.8346],
            [-2.1596, -0.0853,  0.7232,  0.1941, -0.0789],
            [-2.0329,  1.1031,  0.6869, -0.5042,  0.9895],
            [-0.1884,  0.2858, -1.5831,  0.9917, -0.8356]])

""")


add_docstr(torch.hann_window,
           """
hann_window(window_length, periodic=True, dtype=None, \
layout=torch.strided, device=None, requires_grad=False) -> Tensor
""" + r"""
Hann window function.

.. math::
    w[n] = \frac{1}{2}\ \left[1 - \cos \left( \frac{2 \pi n}{N - 1} \right)\right] =
            \sin^2 \left( \frac{\pi n}{N - 1} \right),

where :math:`N` is the full window size.

The input :attr:`window_length` is a positive integer controlling the
returned window size. :attr:`periodic` flag determines whether the returned
window trims off the last duplicate value from the symmetric window and is
ready to be used as a periodic window with functions like
:meth:`torch.stft`. Therefore, if :attr:`periodic` is true, the :math:`N` in
above formula is in fact :math:`\text{window\_length} + 1`. Also, we always have
``torch.hann_window(L, periodic=True)`` equal to
``torch.hann_window(L + 1, periodic=False)[:-1])``.

.. note::
    If :attr:`window_length` :math:`=1`, the returned window contains a single value 1.
""" + r"""
Arguments:
    window_length (int): the size of returned window
    periodic (bool, optional): If True, returns a window to be used as periodic
        function. If False, return a symmetric window.
    {dtype} Only floating point types are supported.
    layout (:class:`torch.layout`, optional): the desired layout of returned window tensor. Only
          ``torch.strided`` (dense layout) is supported.
    {device}
    {requires_grad}

Returns:
    Tensor: A 1-D tensor of size :math:`(\text{{window\_length}},)` containing the window

""".format(**factory_common_args))


add_docstr(torch.hamming_window,
           """
hamming_window(window_length, periodic=True, alpha=0.54, beta=0.46, dtype=None, \
layout=torch.strided, device=None, requires_grad=False) -> Tensor
""" + r"""
Hamming window function.

.. math::
    w[n] = \alpha - \beta\ \cos \left( \frac{2 \pi n}{N - 1} \right),

where :math:`N` is the full window size.

The input :attr:`window_length` is a positive integer controlling the
returned window size. :attr:`periodic` flag determines whether the returned
window trims off the last duplicate value from the symmetric window and is
ready to be used as a periodic window with functions like
:meth:`torch.stft`. Therefore, if :attr:`periodic` is true, the :math:`N` in
above formula is in fact :math:`\text{window\_length} + 1`. Also, we always have
``torch.hamming_window(L, periodic=True)`` equal to
``torch.hamming_window(L + 1, periodic=False)[:-1])``.

.. note::
    If :attr:`window_length` :math:`=1`, the returned window contains a single value 1.

.. note::
    This is a generalized version of :meth:`torch.hann_window`.
""" + r"""
Arguments:
    window_length (int): the size of returned window
    periodic (bool, optional): If True, returns a window to be used as periodic
        function. If False, return a symmetric window.
    {dtype} Only floating point types are supported.
    layout (:class:`torch.layout`, optional): the desired layout of returned window tensor. Only
          ``torch.strided`` (dense layout) is supported.
    {device}
    {requires_grad}

Returns:
    Tensor: A 1-D tensor of size :math:`(\text{{window\_length}},)` containing the window

""".format(**factory_common_args))


add_docstr(torch.bartlett_window,
           """
bartlett_window(window_length, periodic=True, dtype=None, \
layout=torch.strided, device=None, requires_grad=False) -> Tensor
""" + r"""
Bartlett window function.

.. math::
    w[n] = 1 - \left| \frac{2n}{N-1} - 1 \right| = \begin{cases}
        \frac{2n}{N - 1} & \text{if } 0 \leq n \leq \frac{N - 1}{2} \\
        2 - \frac{2n}{N - 1} & \text{if } \frac{N - 1}{2} < n < N \\
    \end{cases},

where :math:`N` is the full window size.

The input :attr:`window_length` is a positive integer controlling the
returned window size. :attr:`periodic` flag determines whether the returned
window trims off the last duplicate value from the symmetric window and is
ready to be used as a periodic window with functions like
:meth:`torch.stft`. Therefore, if :attr:`periodic` is true, the :math:`N` in
above formula is in fact :math:`\text{window\_length} + 1`. Also, we always have
``torch.bartlett_window(L, periodic=True)`` equal to
``torch.bartlett_window(L + 1, periodic=False)[:-1])``.

.. note::
    If :attr:`window_length` :math:`=1`, the returned window contains a single value 1.
""" + r"""
Arguments:
    window_length (int): the size of returned window
    periodic (bool, optional): If True, returns a window to be used as periodic
        function. If False, return a symmetric window.
    {dtype} Only floating point types are supported.
    layout (:class:`torch.layout`, optional): the desired layout of returned window tensor. Only
          ``torch.strided`` (dense layout) is supported.
    {device}
    {requires_grad}

Returns:
    Tensor: A 1-D tensor of size :math:`(\text{{window\_length}},)` containing the window

""".format(**factory_common_args))


add_docstr(torch.blackman_window,
           """
blackman_window(window_length, periodic=True, dtype=None, \
layout=torch.strided, device=None, requires_grad=False) -> Tensor
""" + r"""
Blackman window function.

.. math::
    w[n] = 0.42 - 0.5 \cos \left( \frac{2 \pi n}{N - 1} \right) + 0.08 \cos \left( \frac{4 \pi n}{N - 1} \right)

where :math:`N` is the full window size.

The input :attr:`window_length` is a positive integer controlling the
returned window size. :attr:`periodic` flag determines whether the returned
window trims off the last duplicate value from the symmetric window and is
ready to be used as a periodic window with functions like
:meth:`torch.stft`. Therefore, if :attr:`periodic` is true, the :math:`N` in
above formula is in fact :math:`\text{window\_length} + 1`. Also, we always have
``torch.blackman_window(L, periodic=True)`` equal to
``torch.blackman_window(L + 1, periodic=False)[:-1])``.

.. note::
    If :attr:`window_length` :math:`=1`, the returned window contains a single value 1.
""" + r"""
Arguments:
    window_length (int): the size of returned window
    periodic (bool, optional): If True, returns a window to be used as periodic
        function. If False, return a symmetric window.
    {dtype} Only floating point types are supported.
    layout (:class:`torch.layout`, optional): the desired layout of returned window tensor. Only
          ``torch.strided`` (dense layout) is supported.
    {device}
    {requires_grad}

Returns:
    Tensor: A 1-D tensor of size :math:`(\text{{window\_length}},)` containing the window

""".format(**factory_common_args))


add_docstr(torch.unbind,
           r"""
unbind(tensor, dim=0) -> seq

Removes a tensor dimension.

Returns a tuple of all slices along a given dimension, already without it.

Arguments:
    tensor (Tensor): the tensor to unbind
    dim (int): dimension to remove

Example::

    >>> torch.unbind(torch.tensor([[1, 2, 3],
    >>>                            [4, 5, 6],
    >>>                            [7, 8, 9]]))
    (tensor([1, 2, 3]), tensor([4, 5, 6]), tensor([7, 8, 9]))
""")
