CODEWITHSUNDEEP
c++matlabmatrixblas
zergylord
zergylord

Reputation: 4436

Element wise multiplication between matrices in BLAS?

I'm starting to use BLAS functions in c++ (specifically Intel MKL) to create faster versions of some of my old Matlab code.

It's been working out well so far, but I can't figure out how to perform elementwise multiplication on 2 matrices (A .* B in Matlab).

I know gemv does something similar between a matrix and a vector, so should I just break one of my matrices into vectors and call gemv repeatedly? I think this would work, but I feel like there should be something built in for this operation.

Upvotes: 5

Views: 3885

Answers (1)

Adam Kosiorek
Adam Kosiorek

Reputation: 1528

Use the Hadamard product. In MKL it's v?MUL. E.g. for doubles:

vdMul( n, a, b, y );

in Matlab notation it performs:

y[1:n] = a[1:n] .* b[1:n]

In your case you can treat matrices as vectors.

Upvotes: 3

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