I was hoping for help with vectorizing the following:
say I have a matrix A and a function F: (i,j) -> j'. I would like to create a new matrix B with the rule: B(i,j) = A(i,F(i, j)).
This can be done with a forloop, but F is very quick to compute and the overhead in running this forloop appears to be a massive bottleneck for me. Is there a better way to write it than the following? I tried arrayfun but this seems to have an even worse overhead?
B = zeros(size(A));
for i = 1:size(A,1)
for j = 1:size(A,2)
B(i,j) = A(i, F(i,j));