CODEWITHSUNDEEP
combinatorics
user494461
user494461

Reputation:

How to generate all possible combinations of values from n different sets?

I have n sets, each having n1,n2,n3...nN distinct members. How do I generate n1*n2*n3...*nN possible combinations from them

e.g

[6] [4 5] [1 2 3 4]
will give
6 4 1 
6 4 2
6 4 3 
6 4 4
6 5 1 
6 5 2
6 5 3
6 5 4

I want to do this in matlab, but a normal algorithm would also be fine

Upvotes: 0

Views: 1478

Answers (2)

ClemKeirua
ClemKeirua

Reputation: 504

An easy solution is to simulate a sum !

Start with a list of indices 0 0 0, corresponding to the indices of your values. That leads you to the value 6 4 1 in your example. then add 1. You now have indices 001, so 642 and so on.

at 004, you overflow, so your indices become 010, having 6 5 1

Keep doing that, and keep a counter of the visited possibilites. There are 1 * 2 * 4 possibilities, so it's easy to know when you are done.

Upvotes: 2

nullpotent
nullpotent

Reputation: 9260

I think you're looking for Cartesian product of sets:

This should help:

cartprod(N1,N2,N3, ...)

http://www.mathworks.com/matlabcentral/fileexchange/5475-cartprod-cartesian-product-of-multiple-sets

There's another one here

set = {n1, n2, n3, ...}
allcomb(set{:})

Upvotes: 1

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