[Numpy-discussion] element wise help
Thu May 7 12:04:46 CDT 2009
unfortunately, the actual function being processes is not so simple, and
involves evaluating user functions input from the prompt as strings. So i
have no idea how to do it in Cython.
Let me look into this broadcasting.
On Thu, May 7, 2009 at 12:56 PM, <firstname.lastname@example.org> wrote:
> On Thu, May 7, 2009 at 12:39 PM, Chris Colbert <email@example.com>
> > suppose i have two arrays: n and t, both are 1-D arrays.
> > for each value in t, I need to use it to perform an element wise scalar
> > operation on every value in n and then sum the results into a single
> > to be stored in the output array.
> > Is there any way to do this without the for loop like below:
> > for val in t_array:
> > out = (n / val).sum() # not the actual function being done,
> > you get the idea
> broad casting should work, e.g.
> (n[:,np.newaxis] / val[np.newaxis,:]).sum()
> but it constructs the full product array, which is memory intensive
> for a reduce operation, if the 1d arrays are large.
> another candidate for a cython loop if the arrays are large?
> Numpy-discussion mailing list
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