Pareto/Efficient frontier?

I'm trying to find the non-dominated points in two vectors of random numbers so I can plot the Pareto front of those points. Here's my code so far, but I'm very stuck:

x=rand(113,1)
y=rand(113,1)
x=sort(x, 'descend')
v=[x,y]
for i=1:113
   m=max(v(i,2))
        if v(i,2) > m
            n=max(v(i,2))
        end 

end

Any suggestions on where to go next would be greatly appreciated.