title: How to change float64 to double in numpy
body: <p>The objective is to convert from <code>float64</code> to double.</p>
  <p>However, using the <code>astype(np.double)</code> does not changed the array type.</p>
  <pre><code>numpy.random.seed(0)
  arr=np.random.rand(32,30,30)
  arr1=arr.astype(np.double)
  print(f'arr:{arr.dtype} and arr1: {arr1.dtype}')
  </code></pre>
  <blockquote>
  <p>arr:float64 and arr1: float64</p>
  </blockquote>