all possible combinations of vectors of unknown quantity and length

let's suppose I want to find all combinations of vectors , so I have as for example in input a matrix

A=[2 5 8 9];

which gives me the length of the vectors (from 1 to specific value, 1D vectors) I should compute combinations, i.e. for this specific case a good choice would be:

allComb=combvec(1:2,1:5,1:8,1:9)'

in order to have the combination values written in rows.

The problem is: in my code the INPUT MATRIX A can change values and dimension (2nd) and I don't know how to write a code, because even if I organize in cell the vectors and perform a FOR loop, then I don't know how to call back my vectors in combvec function.

thank you whoever could help me facing this.

Answer 1

[Bruno Luong]

Generate vectors of consecutive integers to be combined

A = [2 5 8 9];
c = arrayfun(@(n) 1:n, A, 'unif', 0)

Generate combinations

c = flip(c);
[c{:}] = ndgrid(c{:});
c = cellfun(@(x) x(:), flip(c), 'unif', 0);
c = cat(2, c{:});

Display

disp(c)

[gabriele fadanelli]

so there is no way to use combvec instead? thank you, btw

[Bruno Luong]

>> combvec
'combvec' requires Deep Learning Toolbox.

As you see I don't have the tbx. My code works with MATLAB alone.

[gabriele fadanelli]

Ok, thank you. This is a nice answer.