title: Converting np-array from float to complex
body: <p>I have an numpy-array with a float data type, but an extern function needs it with a complex data type. When I use <code>a.view(np.complex)</code>, the real values are also used for the complex values, messing up my further calculations, i.e.:</p>
  
  <pre><code>a = [1, 2, 3]
  b = a.view(np.complex)
  &gt; b = [1+1i, 2+2i, 3+3i]
  </code></pre>
  
  <p>Is there a command such that I get</p>
  
  <pre><code>&gt; b = [1+0i, 2+0i, 3+0i]
  </code></pre>
  
  <p>?</p>