For the storing the point coordinates you might look at either cell-arrays:
r1 = [1,2,3];
r2 = [3,2,5];
r3 = [4.5,pi,1,5]; % if some of your point-coordinates are of different sizes
Point_array = {r1,r2,r3} ; % and so on
or simply a higherdimensional array:
r1 = [1,2,3];
r2 = [3,2,5];
r3 = [4.5,pi,1]; % if some of your point-coordinates are of different sizes
Point_array(:,3) = r3;
Point_array(:,2) = r2;
Point_array(:,1) = r1; % and so on
For the selection of n points out of that one, have a look at the file exchange for: nextchoose and nextperm. They solve most of my problems with tasks like that.
HTH
