Creating pairs of vector elements

I have 3 vectors, each containing 9 elements. I want to create all the possible pairs (729) of the vector elements in a random order. What would be an efficient way to do it?

Thanks a million! N.

Answer 1

[Azzi Abdelmalek]

% Example
a=randi(9,9,1);
b=randi(9,9,1);
c=randi(9,9,1);
%-----------------------------------
[ii2,jj2]=ndgrid(a,b);
[ii3,jj3]=ndgrid(1:numel(ii2),c);
v2=[a(ii2(:)) b(jj2(:))];
v3=[v2(ii3(:),:)  c(jj3(:))];
n=size(v3,1);
v3=v3(randperm(n),:)

Answer 2

[Andrei Bobrov]

a = (1:9)';
b = a;
c = a;

[ii,jj,k] = ndgrid(a,b,c);
out = [ii(:),jj(:),k(:)];