expanding matrix

Hi all

I want to expand matrix.for example if x=[x1;x2] then the new matrix will be:

xx = [x1 x1 x1;x1 x1 x2;x1 x2 x1;x1 x2 x2;x2 x1 x1;x2 x1 x2;x2 x2 x1;x2 x2 x2]

How can I do that

Answer 1

[Andrei Bobrov]

[j k i]=meshgrid([x1,x2]);
xx = [i(:) j(:) k(:)];

Answer 2

[Matt Fig]

Here is a general purpose file for doing the same thing. What you are basically doing is finding the permutations of the set [x1 x2] taken three at a time with replacement. For example:

x1 = 7;x2 = 9;  % Sample data
xx = npermutek([x1 x2],3);

xx =

       7     7     7
       7     7     9
       7     9     7
       7     9     9
       9     7     7
       9     7     9
       9     9     7
       9     9     9

NPERMUTEK is found here.