I posted this question in another place. 

in case you dont see it ...

Given a matrix A, say

A = rand(5);

together with two index arrays of the same length, e.g.

I = [1,2];

J = [3,4];

  here is the question: How to shorten the following script into one line? i.e. how to vectorize the performance …

%start

vec =[];

for i=1:length(I)

vec = [vec, A(I(i),J(i))];

end

%end

Any suggestion is greatly appreciated!