Can't make subposets
I'm running into a problem trying to construct a subposet.
sage: L #poset of permutations Finite poset containing 14 elements sage: L.random_subposet(.5) Finite poset containing 10 elements sage: SPG=ShortestPathGraph(L) #constructs a graph that is the Hasse diagram #of L with some edges deleted sage: SPG Digraph on 14 vertices sage: S=Poset(SPG) sage: S.random_subposet(.5)
results in an error message ending
AttributeError: 'Permutation_class' object has no attribute 'parent'
I get the same error when I try to construct a specific subposet (what I actually want to do), but I can't create duplicate the error in a small example.
random_subposet() works just fine for a small poset created from a digraph whose vertices are permutations. Any ideas what could be going on? (I suspect whatever it is may have to be in ShortestPathGraph, given that I can't duplicate the error with a small digraph, but that doesn't really make sense, so I'd appreciate that sort of answer as well.)