MATLAB: Fast function application

Question

Hi,

Let a be n-dimensional vector, B n-by-n dimensional matrix, f(a, b) – binary function that operates on two vectors, and returns scalar as a result. Is there fast way (no-loops) to implement application of this function to vector a and every column of matrix B? More precisely forall_j r(j) = f(a, B(:, j))?

Answer 1

These days, "no loops" is not necessary any faster.

You can use

arrayfun(@(K) f(a,B(:,K)), 1:size(B,2))

but that will probably not be any faster than a loop.