Re: how to make a matrix with all combinations of digits efficiently

[Juan Pablo Carbajal]

On Thu, Dec 28, 2017 at 9:25 PM, Jean Dubois <address@hidden> wrote:
> I'd like to generate a matrix like this (small version to give you the idea):
>
> 0 0 0 (three columns in this example)
> 0 0 1
> 0 0 2
> 0 0 3
> .
> .
> .
> 9 9 8
> 9 9 9
>
> Could anyone here show me how to do this efficiently?
>
> thanks in advance
>
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This is the decomposition on base 10, a way of doing it is

nc         = 3; # number of columns
base     = 10;
i            = (0:(base^nc-1)).'; # row index - 1
counter = mod( floor (i ./ base.^[(nc-1):-1:0]), base);

it should work for any integer base, but please do check.