Dispositions with repetitions; dispositions without repetitions; combinations with repetitions.

Good morning,

I use Matlab version 7.9 ; I already know the functions nchoosek(v,k) or combnk(v,k) to generate vectors of k components taking all the possible combinations without repetitions of k components among the n components of the vector v.

Now I need to do the same thing to generate vectors of k components:

• taking all the possible combinations with repetitions of k components among the n components of the vector v;
• taking all the possible dispositions without repetitions of k components among the n components of the vector v;
• taking all the possible dispositions with repetitions of k components among the n components of the vector v.

Are there any functions for doing these things? If not, it is possible to do these things writing a short m-file?

Thank you.

Bussoli Lorenzo (Ph.d student in mathematics at the university of Florence).

[Walter Roberson]

I do not recall hearing "dispositions" used in this context. Could you briefly define it?

[Andrei Bobrov]

may be "permutations"?

[Lorenzo]

Sorry, I wrote the wrong word: I meant exactly "permutations" (that are combinations but considering the order); I wrongly wrote "dispositions" because in italian we call them "disposizioni".

Lorenzo Bussoli

Answer 1

[Jan]

Assuming that you want "permutation", there are some corresponding functions in the FEX:

• Combinator
• Fas C-Mex implementations: VChooseKO, VChooseKR, VChooseKRO, VChooseK

[Lorenzo]

Thanks very much Jan Simon, this is what I was looking for; in the question I wrote the wrong word "disposition" when I wanted to say "permutations"; the reason was because in italian we call them "disposizioni".

Lorenzo Bussoli