Generate all possible combinations for the column vectors of a matrix

If B=[1; 2] and A=[B B B...(n times B)], how to obtain the matrix C corresponding to all the possible combinations between the column vectors of A .i.e. i want to get the combinations between n copies of the same vector :

For example, for n=3 :

A =

1 1 1

2 2 2

So, 'C' can be obtained using "allcomb" function: "C=allcomb(A(:,1),A(:,2),A(:,3))"

C =

1 1 1

1 1 2

1 2 1

1 2 2

2 1 1

2 1 2

2 2 1

2 2 2

In my case n is variable. How to obtain C for any value of n ?

Answer 1

[James Tursa]

E.g.,

>> B = [1;2];
>> n = 3;
>> Bcell = arrayfun(@(k)B,1:n,'uni',false);
>> C = allcomb(Bcell{:})
Warning: NARGCHK will be removed in a future release. Use NARGINCHK or NARGOUTCHK
instead. 
> In allcomb (line 63) 
C =
     1     1     1
     1     1     2
     1     2     1
     1     2     2
     2     1     1
     2     1     2
     2     2     1
     2     2     2
>> n = 4;
>> Bcell = arrayfun(@(k)B,1:n,'uni',false);
>> C = allcomb(Bcell{:})
Warning: NARGCHK will be removed in a future release. Use NARGINCHK or NARGOUTCHK
instead. 
> In allcomb (line 63) 
C =
     1     1     1     1
     1     1     1     2
     1     1     2     1
     1     1     2     2
     1     2     1     1
     1     2     1     2
     1     2     2     1
     1     2     2     2
     2     1     1     1
     2     1     1     2
     2     1     2     1
     2     1     2     2
     2     2     1     1
     2     2     1     2
     2     2     2     1
     2     2     2     2

Another way to make Bcell is

     Bcell = {B};  Bcell(2:n) = Bcell(1);

[MOHAMMED ABDELGHANI BOUCHAALA]

Thank you for your answer, this does exactly what i need.

Is there anything you recommend to accelerate the code knowing that:

• I have a long 'B' vector (length(B)=100)), constitued of consecutive decimal numbers.
• I need only the rows of 'C' that sums to a given number 'S'.