On Wednesday, March 20, 2013 2:16:47 PM UTC-7, Nathann Cohen wrote: > > Hmmmm... If you want to enumerate all "partial permutations then you have > much better to do. If you have a n x m matrix with n<m what you should do > it take all subsets of n elements of n, and enumerate all permutations > using those n columns among m. Even if I would LOVE to have a way to > enumerate all matchings of a bipartite graph. It remains that when your > graph is the complete bipartite graph the problem is a bit easier :-P > > Nathann > > On Wednesday, March 20, 2013 9:05:54 PM UTC+1, Tom Boothby wrote: >> >> Note that that code only works for graphs whose vertices are labeled >> [0...n]. >> >> On Wed, Mar 20, 2013 at 1:03 PM, Tom Boothby <tomas....@gmail.com> >> wrote: >> > I use the following to iterate over all matchings and perfect >> matchings. >> > >> > def matchings(G): >> > edges = G.edges(labels = False) >> > verts = [[v] for v in G] >> > m = len(edges) >> > for match in DLXCPP(edges+verts): >> > yield [edges[t] for t in match if t < m] >> > >> > def perfect_matchings(G): >> > edges = G.edges(labels = False) >> > for match in DLXCPP(edges): >> > yield [edges[t] for t in match] >> > I'm sure it's not fast, but in the file devel/sage/sage/homology/examples.py, there is a function "matching" which gets used in "simplicial_complexes.ChessboardComplex(...)".
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