This solved one problem. But now in runtime, when called
torch::jit::script::Module module = torch::jit::load(filename);
where filename is a traced torchscript model. I get a new error.:
Unknown builtin op: aten::mul.
Could not find any similar ops to aten::mul. This op may not exist or may not be currently supported in TorchScript.
:
  File "<string>", line 3

def mul(a : float, b : Tensor) -> Tensor:
  return b * a
         ~~~~~ <--- HERE
def add(a : float, b : Tensor) -> Tensor:
  return b + a
'mul' is being compiled since it was called from 'Conv2d.forward'
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\nn\modules\conv.py(346): _conv_forward
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\nn\modules\conv.py(349): forward
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\nn\modules\module.py(534): _slow_forward
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\nn\modules\module.py(548): __call__
C:/Users/PycharmProjects/caffe2_to_pytorch/pytorch.py(58): forward
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\nn\modules\module.py(534): _slow_forward
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\nn\modules\module.py(548): __call__
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\jit\__init__.py(1027): trace_module
D:\Soft\Miniconda3\envs\caffe2_to_pytorch\lib\site-packages\torch\jit\__init__.py(875): trace
C:/Users/PycharmProjects/caffe2_to_pytorch/pytorch.py(201): <module>
C:\Program Files\JetBrains\PyCharm Community Edition 2019.2\helpers\pydev\_pydev_imps\_pydev_execfile.py(18): execfile
C:\Program Files\JetBrains\PyCharm Community Edition 2019.2\helpers\pydev\pydevd.py(1412): _exec
C:\Program Files\JetBrains\PyCharm Community Edition 2019.2\helpers\pydev\pydevd.py(1405): run
C:\Program Files\JetBrains\PyCharm Community Edition 2019.2\helpers\pydev\pydevd.py(2054): main
C:\Program Files\JetBrains\PyCharm Community Edition 2019.2\helpers\pydev\pydevd.py(2060): <module>
Serialized   File "code/__torch__/torch/nn/modules/conv.py", line 9
    x: Tensor) -> Tensor:
    _0 = self.bias
    input = torch._convolution(x, self.weight, _0, [1, 1], [0, 0], [1, 1], False, [0, 0], 1, False, False, True)
                                                                                                           ~~~~ <--- HERE
    return input

or where file is the same scripted model:
Couldn't find an operator for aten::dropout(Tensor input, float p, bool train) -> Tensor. Do you have to update a set of hardcoded JIT ops? 
(lookupByLiteral at C:\...\torch\csrc\jit\runtime\operator.cpp:72)

Dynamic build is working fine.