Add each row in a matrix with corresponding element in a vector?

Hi,

I have a matrix, say M = [ 1 1; 2 2; 3 3] and a vector V = [1;2;3], where V(1) adds to M(1,:) and V(2) adds to M(2,:), etc. The way I calculate it is

sum = M + ( V * ones(1,size(M,2)) )

same question for scaling a matrix with a vector.

Answer = M .* ( V * ones(1,size(M,2)) )

I can also use a for loop but I guess it's even slower. I wonder if there is an easier way to get this done?

Thanks

Answer 1

[James Tursa]

bsxfun(@plus,M,V)

bsxfun(@times,M,V)

[Yue]

Exactly! thanks

Answer 2

[Jan]

bsxfun is nicer and faster, but for completeness:

S = M +  V(:, ones(1, size(M,2));
A = M .* V(:, ones(1, size(M,2));

PS. Do not use sum as name of a variable, because this shadows tzhe builtin function with the same name.