Multiply a 3D matrix with a 2D matrix

matlab matrix vectorization matrix-multiplication
Jacob picture Jacob · Nov 16, 2009 · Viewed 23.1k times · Source

Suppose I have an AxBxC matrix X and a BxD matrix Y.

Is there a non-loop method by which I can multiply each of the C AxB matrices with Y?

Answer

Zaid picture Zaid · Nov 17, 2009

As a personal preference, I like my code to be as succinct and readable as possible.

Here's what I would have done, though it doesn't meet your 'no-loops' requirement:

for m = 1:C

    Z(:,:,m) = X(:,:,m)*Y;

end

This results in an A x D x C matrix Z.

And of course, you can always pre-allocate Z to speed things up by using Z = zeros(A,D,C);.

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