title: How to get value from a theano tensor variable backed by a shared variable?
body: <p>I have a theano tensor variable created from casting a shared variable. How can I extract the original or casted values? (I need that so I don't have to carry the original shared/numpy values around.)</p>
  
  <pre><code>&gt;&gt;&gt; x = theano.shared(numpy.asarray([1, 2, 3], dtype='float'))
  &gt;&gt;&gt; y = theano.tensor.cast(x, 'int32')
  &gt;&gt;&gt; y.get_value(borrow=True)
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  AttributeError: 'TensorVariable' object has no attribute 'get_value'
  # whereas I can do this against the original shared variable
  &gt;&gt;&gt; x.get_value(borrow=True)
  array([ 1.,  2.,  3.])
  </code></pre>