R: Generating all possible combinations of 1 and 0

Question

I am trying to generate all possible permutations of a long vector (30 elements) consisting of 0 and 1. I have tried several functions including permn and expand.grid , but none of them seems to be able to cope with this issue (due to size constraints).

Any advice would be really helpful!

Answer 1

What you need is a multiset permutation.

> library(iterpc)
> I <- iterpc(c(16, 14), labels=c(0,1), ordered=TRUE)
> getlength(I)
[1] 145422675

The matrix is 145422675 by 30, too large to be stored in a single matrix. Use getnext to get the next 10000000 permutations.

> getnext(I, 10000000)

You could repeat the above 15 times in order to get all the permutations.