[Numpy-discussion] matrix multiplication A x, x has some zeros

dmitrey dmitrey.kroshko@scipy....
Fri Dec 14 03:44:04 CST 2007


I guess it doesn't matter, but typical n are 1...1000.
However, I need to call the operation hundreds or thousands times (while 
running NLP solver ralg, so 4..5 * nIter times).
Number of zeros can be 0...n-1

Charles R Harris wrote:
> How big is n?
>
> On Dec 14, 2007 1:24 AM, dmitrey <dmitrey.kroshko@scipy.org 
> <mailto:dmitrey.kroshko@scipy.org>> wrote:
>
>     Hi all,
>     I have to get Ax, A  is n x n matrix, x is vector of length n.
>     Some coords of x are zeros, so I want to economy time/cputime somehow
>     w/o connecting sparse module from scipy.
>     What's the easiest way to do so?
>
>     Thx, D.
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