title: Theano - Compute element wise sum of list of theano matrix
body: <p>I have a list of theano matrices(using in a neural network implementation). I need to perform element wise sum on the corresponding elements. </p>
  
  <p>Eg Input :<code>x1 = [&lt;TensorType(float64, matrix)&gt;, &lt;TensorType(float64, matrix)&gt; , &lt;TensorType(float64, matrix)&gt;]</code></p>
  
  <pre><code>Output : &lt;TensorType(float64, matrix)&gt; -&gt; which is the element wise sum of the 3 matrices.
  </code></pre>
  
  <p>Looked at a few posts but unable to figure out how to proceed. Please advice. Thanks in advance.</p>