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Topic: Help vectorize this matrix multiplication
Replies: 3   Last Post: Jun 25, 2011 3:26 AM

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Jim Rockford

Posts: 164
Registered: 6/30/06
Help vectorize this matrix multiplication
Posted: Jun 24, 2011 11:59 PM
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I have a matrix M for which I want to multiply each row by a scalar,
which can be different for each row.

One way to do it is as follows. Suppose the set of scalars are put
into a vector v. Then

diag(v) * M

effects this multiplication.

In my case, the problem is that constructing the diagonal matrix
diag(v) will exceed my computer memory. Obviously I could resort to a
loop, but I'm wondering if there is a different way to vectorize this


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