Thanks Travis! Obviously I didn't read the documentation well enough as I thought `Facade` was `False` by default -- so I'd tried setting `Facade=True` with no joy.
Cheers, Andrew pd. I will have a look at your ticket. On Thursday, 16 February 2017 13:52:22 UTC+11, Travis Scrimshaw wrote: > > Hey Andrew, > Well, I've recently been looking at DisjointUnionEnumeratedSets (see > https://trac.sagemath.org/ticket/22382) and came across this problem. The > first issue is that DisjointUnionEnumeratedSets does not behave like an > actual facade parent like it claims to be (at least with default values). > The second is that __call__ calls a morphism, which in turn calls > _element_constructor_ and expects a subclass of element to be returned. > Thus for facade parents that want to return a tuple, this causes a problem > (see the ticket). > > Actually, looking at what you want more closely now, you want this to > be a proper parent, so just pass the facade=False. This works with the > current Sage: > > sage: tabs = DisjointUnionEnumeratedSets(Family(Partitions(3), lambda mu: > cartesian_product([mu.standard_tableaux(),mu.standard_tableaux()])), > facade=False) > sage: s = StandardTableau([[1,2],[3]]) > sage: (s,s) in tabs > True > sage: tabs((s,s)) > ([[1, 2], [3]], [[1, 2], [3]]) > > Best, > Travis > > On Wednesday, February 15, 2017 at 6:01:17 PM UTC-6, Andrew wrote: >> >> I am working with disjoint enumerated sets like the following >> >> sage: tabs = DisjointUnionEnumeratedSets(Family(Partitions(3), lambda mu: >> cartesian_product([mu.standard_tableaux(),mu.standard_tableaux()]))) >> sage: tabs[:] >> [([[1, 2, 3]], [[1, 2, 3]]), >> ([[1, 3], [2]], [[1, 3], [2]]), >> ([[1, 3], [2]], [[1, 2], [3]]), >> ([[1, 2], [3]], [[1, 3], [2]]), >> ([[1, 2], [3]], [[1, 2], [3]]), >> ([[1], [2], [3]], [[1], [2], [3]])] >> >> I need to be able to construct elements of this set from a tuple of >> elements in the underlying sets but I can't work out a nice way to do this. >> I thought that the following would work but it doesn't: >> >> sage: s = StandardTableau([[1,2],[3]]) >> sage: (s, s) in tabs >> True >> sage: tabs( (s,s) ) >> >> --------------------------------------------------------------------------- >> NotImplementedError Traceback (most recent call >> last) >> <ipython-input-67-3fe9605dd49e> in <module>() >> ----> 1 tabs( (s,s) ) >> >> /usr/local/src/sage/src/sage/structure/parent.pyx in sage.structure. >> parent.Parent.__call__ (build/cythonized/sage/structure/parent.c:9584)() >> 934 self._element_init_pass_parent = >> guess_pass_parent(self, self._element_constructor) >> 935 except (AttributeError, AssertionError): >> --> 936 raise NotImplementedError >> 937 cdef Py_ssize_t i >> 938 cdef R = parent_c(x) >> >> NotImplementedError: >> >> One way around this is the following, but I would guess that this is far >> too inefficient to use inside an element_constructor method: >> >> sage: ss = tabs.unrank( tabs.rank( (s,s) ) ) >> sage: type(ss) >> <class >> 'sage.sets.cartesian_product.CartesianProduct_with_category.element_class' >> > >> >> Is there a better way to do his? >> >> Andrew >> > -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-combinat-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-combinat-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-combinat-devel. For more options, visit https://groups.google.com/d/optout.
