How do I calculate differences in one column for specific pairs of rows (whose index are listed in another matrix)?

I've got a matrix A with two columns (mx2). Each row is a pair of row indices for another matrix B.

e.g. A = [1 3 ; 5 8 ; 11 15 ; ... ] means that row 1 and 3 of matrix B are one pair.

I need to calculate the difference in column 11 of matrix B for all pairs of rows given in A. Any ideas?

Answer 1

[dpb]

"Deadahead" solution...

for i=1:size(A,1)
  D(i)=B(A(i,2),11)-B(A(i,1),11);
end