Multiply one dimension of a 3D Matrix by a vector

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James Brown on 18 Dec 2020
Commented: James Brown on 18 Dec 2020
I wish to element multiply the third dimension of Matrix A by vector B by for all xy points. The following operation takes 329 seconds.
Is there an operation that avoids the for loops?
My Code:
Matrix A has dimensions A(2048,200,513)
Vector B has dimension(513)
C = zeros(numx,numy,numz);
for j = 1:numy
for i = 1:numx
Az = squeeze(A(i,j,:));
C(i,j,:) = squeeze(B.*Az);
end
end

James Tursa on 18 Dec 2020
Edited: James Tursa on 18 Dec 2020
C = A .* reshape(B,1,1,[]);
For earlier versions of MATLAB that do not have implicit expansion it would be this:
C = bsxfun(@times,A,reshape(B,1,1,[]));
James Brown on 18 Dec 2020
Excellent. Thank you.

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