MATLAB: All possible combinations such that sum of all numbers is a fixed number

Question

I need to find all possible combinations of numbers 1:8 such that sum of all elements is equal to 8

Eg

   1 7
   2 2 4
   1 3 5
   1 2 2 3
   1 1 1 1 1 1 1 1

A number can repeat itself. But a combination must not.. i.e 1 2 2 3 and 2 1 2 3 I need the the solution in ascending order So there will be only one possibility of every combination

I tried a few codes online suggested on http://stackoverflow.com/questions/14848731/find-vector-elements-that-sum-up-to-specific-number-in-matlab

        VEC = [1:8];
        NUM = 8;
        n = length(VEC);
        finans = zeros(2^n-1,NUM);
        for i = 1:(2^n - 1)
          ndx = dec2bin(i,n) == '1';
          if sum(VEC(ndx)) == NUM
          l = length(VEC(ndx));
          VEC(ndx)
          end
      end

but they dont include the possibilities where the numbers repeat.

Answer 1

No need to reinvent the wheel. There's several entries on FEX. See John D'errico's partitions for example.