Index value intersection query in matlab

I'm trying to calculate the intersection value of x,y from a matrix.

The loop seems correct but the values that I get seems wrong,when I try to run it alone it gives me right values ?

Lets assume a be some double with 32 points and b too same 32 points ,I'm trying to intersect both in rms(279x249 double)

This below one works but when I try to put the same in loop it doesn't why ?

ex (1,:) = rms(b(1),a(1));

ex (2,:) = rms(b(2),a(2));

a = round (x);
b = round (y);

for k = 1:length(a)
    for l = 1:length(b)
       index (k,:)  = rms(b(l),a(k));
      
  end
    end

index = index';

return

Answer 1

[KSSV]

a = round (x);
b = round (y);

for k = 1:length(a)
    index (k,:)  = rms(b(k),a(k));     
end

index = index';

[Ramesh Bala]

Yes I've figured it out,but thank you for quick answer KSSV.