title: Tensorflow,assign value to variable
body: <p>I am total newbie to tensorflow, I am learning from </p>
  
  <pre><code>https://www.tensorflow.org/get_started/get_started
  
  fixW = tf.assign(W, [-1.])
  </code></pre>
  
  <p>works fine,but</p>
  
  <pre><code>fixb = tf.assign(b, [1.])
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/milenko/anaconda3/lib/python3.6/site-packages/tensorflow/python/ops/state_ops.py", line 272, in assign
      return ref.assign(value)
  AttributeError: 'Tensor' object has no attribute 'assign'
  </code></pre>
  
  <p>One other example</p>
  
  <pre><code>zero_tsr = tf.zeros([1.,2.])
  zero_tsr
  &lt;tf.Tensor 'zeros:0' shape=(1, 2) dtype=float32&gt;
  </code></pre>
  
  <p>If I try to change zero_tsr</p>
  
  <pre><code>fixz = tf.assign(zero_tsr, [2.,2.])
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/milenko/anaconda3/lib/python3.6/site-packages/tensorflow/python/ops/state_ops.py", line 272, in assign
      return ref.assign(value)
  AttributeError: 'Tensor' object has no attribute 'assign'
  </code></pre>
  
  <p>Again,the same problem.</p>
  
  <p>I have not changed shell,everything is the same.Why do I have problem here?</p>