title: Check if two scipy.sparse.csr_matrix are equal
body: <p>I want to check if two <a href="http://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.sparse.csr_matrix.html" rel="noreferrer">csr_matrix</a> are equal.</p>
  
  <p>If I do:</p>
  
  <pre><code>x.__eq__(y)
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>raise ValueError("The truth value of an array with more than one "
  ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all().
  </code></pre>
  
  <p>This, However, works well:</p>
  
  <pre><code>assert (z in x for z in y)
  </code></pre>
  
  <p>Is there a better way to do it? maybe using some <code>scipy</code> optimized function instead? </p>
  
  <p>Thanks so much</p>