[Numpy-discussion] numpy.reshape() bug?

Neil Martinsen-Burrell nmb@wartburg....
Mon Sep 28 15:50:32 CDT 2009


On 2009-09-28 15:39 , Chris wrote:
> I am trying to "collapse" two dimensions of a 3-D array, using reshape:
>
> (Pdb) dims = np.shape(trace)
> (Pdb) dims
> Out[2]: (1000, 4, 3)
> (Pdb) newdims = (dims[0], sum(dims[1:]))
> (Pdb) newdims
> Out[2]: (1000, 7)
>
> However, reshape seems to think I am missing something:
>
> (Pdb) np.reshape(trace, newdims)
> *** ValueError: total size of new array must be unchanged
>
> Clearly the total size of the new array *is* unchanged.

I think you meant prod(dims[1:]).  A 4 x 3 sub-array has 12 elements, 
not 7.  (Whence the curse of dimensionality...)

-Neil


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