[SciPy-user] Interaction of sparse and dense matrices in scipy

Ed Schofield schofield at ftw.at
Tue Feb 21 05:33:20 CST 2006

Nils Wagner wrote:

>Hi Ed,
>Thank you for your valuable comments.
>The multiplication a*b, where a is dense a b is sparse, is certainly of
>For example Block Krylov methods make heavily use of such products.
>Anyway, it would be nice if scipy can handle such products :-)
It does work now where 'a' is an *array*, but not when 'a' is a (dense)
matrix.  For now, just use a dense array :)

The reason is that the matrix object overrides the * operator and calls
dot(a, b).  I'll think about this problem when I have time and make some
proposals on scipy-dev and/or numpy-discussion for how to solve it...

-- Ed

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