[Numpy-discussion] Possible conversion bug with record array

[Chris Barker - NOAA Federal]

On Wed, May 22, 2013 at 10:07 AM, Nicolas Rougier
> U = np.zeros(1, dtype=[('x', np.float32, (4,4))])
>
> U[0] = np.eye(4)
> print U[0]
> # output:  ([[0.0, 1.875, 0.0, 0.0], [0.0, 0.0, 0.0, 0.0], [0.0, 0.0, 0.0, 1.875], [0.0, 0.0, 0.0, 0.0]],)

I get the same thing. Note:

In [86]: U[0].shape
Out[86]: ()

it's a rank-zero array, not a 4X4 array -- some odd tings can happen there...

This works:

In [94]: U = np.zeros(1, dtype=[('x', np.float32, (4,4))])

In [95]: U['x'][0] = np.eye(4)

In [96]: U
Out[96]:
array([ ([[1.0, 0.0, 0.0, 0.0], [0.0, 1.0, 0.0, 0.0], [0.0, 0.0, 1.0,
0.0], [0.0, 0.0, 0.0, 1.0]],)],
      dtype=[('x', '<f4', (4, 4))])

Not that the first version isn't a bug!


-- 

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
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Chris.Barker at noaa.gov