I should note that a couple of routines in PermPlain are not MIT license compatible. But all the code to compute the signature of a permutation most definitely is MIT compatible. I wrote it, although the algorithm is well known.
There is also this code which calls PermPlain: https://github.com/jlapeyre/PermutationsA.jl On Monday, February 16, 2015 at 4:12:10 PM UTC+1, [email protected] wrote: > > Maybe its too late, but here is a fast implementation giving the signature > of the output of randperm(n) > > https://github.com/jlapeyre/PermPlain.jl/blob/master/src/PermPlain.jl#L271 > > > On Monday, February 9, 2015 at 8:41:58 PM UTC+1, Blake Johnson wrote: >> >> I keep writing code that needs the Levi-Civita symbol, i.e.: >> >> \epsilon_{ijk} = { 1 if (i,j,k) is an even permutation, -1 if (i,j,k) is >> an odd permutation, otherwise 0 } >> >> It is used frequently in physics, so I keep expecting it to be in Julia's >> stdlib, perhaps under a different name (in Mathematica, it is called >> Signature[]). But, if it is there, I haven't found it yet. Is it there >> and I just can't find it? >> >
