Given a vector V, I can define an element-wise multiplication on another vector W as V.*W. I'd like to be able to likewise multiply the rows or columns of a matrix by a vector V in the same sense. In other words, given a vector with components V(i) and a matrix with components M(i,j), I'd like to output a new matrix W(i,j) whose elements are W(i,j)= V(j) M(i,j).
One way to achieve that, just to demonstrate what I mean, is by using a loop:
But, it would be nicer to vectorize that -- I have to use this type of operation many times and the multiple nested loops slow the code down. Attempting something like
does not work, though it really should if you think about both sides as a collection of vectors parametrized by the index 1:N. Any way to accomplish that with a valid Matlab syntax?
This is an example of more general issue, of attempting to vectorize nested loops. A single iterator is usually fairly easy to replace by an index of a matrix, harder to replace nested loops by multiple indices. General advice would be appreciated.