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

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.

[Jan]

While a simple brute force approach solves this for small numbers easuily, for large numbers even stroing the results is not trivial due to the huge number of results. So please specify for which range of values you want the function to work.

[VRUSHALI PRASADE]

I need to compute for numbers varying from 1:15. Such that their sum is 15.

Answer 1

[Guillaume]

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

[VRUSHALI PRASADE]

thank you very much this is exactly what i was looking for :)