flori/permutation — pull request #1 by prakatmac (2012-07-27 12:56:10+00:00)
Title: new features for your permutations lib

I added a couple of new features to your permutations lib for a toy project I'm working on. They add the ability to construct permutations by example and computing permutation powers. I also added a quick shortcuts to get identity permutations. There are tests for these routines as well.

I did make one change to the rank_indices method to have it work with a copy of the provided indices. If I didn't make that change, the array provided to Permutation#from_value seemed to end up broken after the call.

If you are still maintaining this, could you merge these changes in? Thanks.