MATLAB: Add each row in a matrix with corresponding element in a vector

matrixvector

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

bsxfun(@plus,M,V)
bsxfun(@times,M,V)

M(:,2:end) = M(:,2:end)+1

V = ones(1,size(M,2));
V(1) = 0;
M = bsxfun(@plus,M,V)

Use bsxfun:

m  = rand(10,5);
v = rand(10,1);
vm = bsxfun(@times, v, m);

Here, ‘m’ is the matrix, ‘v’ is the vector, and ‘vm’ is the element-by-element product of the columns of ‘m’ and column vector ‘v’.