title: numpy.where on structured array with object dtype of tuples
body: <pre><code>import numpy as np
  rec=np.recarray((10,),names=('x'),formats=('object'))
  for i in rec:
      i.x=(0,0)
  print np.where(rec.x==(0,0))
  </code></pre>
  
  <p>The result is <code>(array([], dtype=int32),)</code>, not 0 to 9 that I expected. why? Can anybody explain for me and how should I get the index of this kind of structured array?</p>