[Numpy-discussion] could anyone check on a 32bit system?

[Bradley M. Froehle]

On Tue, Apr 30, 2013 at 8:08 PM, Yaroslav Halchenko <lists at onerussian.com>wrote:

> could anyone on 32bit system with fresh numpy (1.7.1) test following:
>
> > wget -nc http://www.onerussian.com/tmp/data.npy ; python -c 'import
> numpy as np; data1 = np.load("/tmp/data.npy"); print
>  np.sum(data1[1,:,0,1]) - np.sum(data1, axis=1)[1,0,1]'
>
> 0.0
>
> because unfortunately it seems on fresh ubuntu raring (in 32bit build only,
> seems ok in 64 bit... also never ran into it on older numpy releases):
>
> > python -c 'import numpy as np; data1 = np.load("/tmp/data.npy"); print
>  np.sum(data1[1,:,0,1]) - np.sum(data1, axis=1)[1,0,1]'
> -1.11022302463e-16
>

Perhaps on the 32-bit system one call is using the 80-bit extended
precision register for the summation and the other one is not?

-Brad
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