[Numpy-discussion] Possible conversion bug with record array

eat e.antero.tammi at gmail.com
Wed May 22 14:15:59 EDT 2013


Hi,

FWIW, apparently bug related to dtype of np.eye(.)


On Wed, May 22, 2013 at 8:07 PM, Nicolas Rougier
<Nicolas.Rougier at inria.fr>wrote:

>
>
> Hi all,
>
> I got a weird output from the following script:
>
> import numpy as np
>
> 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]],)
>
> U[0] = np.eye(4, dtype=np.float32)
> print U[0]
> # output:  ([[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]],)
>
>
> The first output is obviously wrong. Can anyone confirm ?
> (using numpy 1.7.1 on osx 10.8.3)
>
In []: sys.version
Out[]: '2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)]'
In []: np.__version__
Out[]: '1.6.0'
In []: U= np.zeros(1, dtype= [('x', np.float32, (4, 4))])

In []: U[0]= np.eye(4)
In []: U
Out[]:
array([ ([[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]],)],
      dtype=[('x', '<f4', (4, 4))])

In []: U[0]= np.eye(4, dtype= np.float32)
In []: U
Out[]:
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))])

and
In []: sys.version
Out[]: '3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 10:57:17) [MSC v.1600 64
bit (AMD64)]'
In []: np.__version__
Out[]: '1.7.0rc1'
In []: U= np.zeros(1, dtype= [('x', np.float32, (4, 4))])

In []: U[0]= np.eye(4)
In []: U
Out[17]:
array([ ([[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]],)],
      dtype=[('x', '<f4', (4, 4))])

U[0]= np.eye(4, dtype= np.float32)

In []: U
Out[]:
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))])


My 2 cents,
-eat

>
>
> Nicolas
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