title: Eigen::Tensor, how to access matrix from Tensor
body: <p>I have the following Eigen Tensor:</p>
  
  <pre><code>Eigen::Tensor&lt;float, 3&gt; m(3,10,10);
  </code></pre>
  
  <p>I want to access the 1st matrix. In numpy I would do it as such</p>
  
  <pre><code>m(0,:,:)
  </code></pre>
  
  <p>How would I do this in Eigen</p>