We don't have data to check your code. Note that, You need not to run a loop...simply use, s(1).r(Lia,:) to get the common elements.
As you have two sets and you want to pick the common elements, you can find intersection of both the arrays. Intersection gives you common elements. doc intersect.
Sometimes depending on the floating point numbers, ismember/ intersect may not work. That case, you need to fix a tolerance value and use ismemebrtol. doc ismembertol.
