[Numpy-discussion] Numpy performance vs Matlab.
Fri Jan 9 13:13:36 CST 2009
Nicolas ROUX wrote:
> -2- Now with the code below I have strange result.
> With w=h=400:
> With w=400 and h=300:
> - Using "numpy.ogrid", => broadcast ERROR !
> The last broadcast error is:
> "ValueError: shape mismatch: objects cannot be broadcast to a single shape"
This is probably a broadcasting error, which means your result with w=h
is probably wrong.
Always test with non-square arrays, to make sure you are broadcasting as
Don't test with "zeros" or "ones" for your test data -- so you can look
at the results and see if you are getting what you expect. I often use
a = numpy.arange(w*h).reshape((h,w))
I also test with very small dimensions so that I can easily print the
results of each step as I develop the code
With this approach you will probably figure out what's going on.
Christopher Barker, Ph.D.
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