[SciPy-user] Re: [SciPy-dev] matrixmultiply()

David Grant david.grant at telus.net
Sat Apr 9 13:23:29 CDT 2005


Robert Kern wrote:

> David Grant wrote:
>
>> Can anyone tell me why the * operation on matrices is for element-wise
>> multiplcation and not matrix multiplication for Numeric/numpy arrays?
>
>
> Not everyone is using Numeric for linear algebra on matrices.
> Element-wise multiplication is the most consistent interpretation for
> * in this general-purpose context.
>
> Sine you *are* doing linear algebra on matrices, you can use Matrix
> objects, which do define the * operator to be matrix multiplication.
>
>
Cool, I found the Matrix object you talk about hidden in the Numeric
documentation.

What if I start by declaring my arrays using zeros() and ones(), do I
have to pass it through mat()? That seems like a rather annoying second
step.

-- 
David J. Grant
http://www.davidandnasha.ca



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