On Thu, Jun 8, 2017 at 10:49 PM, John H Palmieri <jhpalmier...@gmail.com> wrote: > > > On Thursday, June 8, 2017 at 5:16:15 PM UTC-7, David Joyner wrote: >> >> Hi all: >> >> This is kind of a newbie question, as I'm not an expert on simplicial >> complexes. It's also a minor technical issue on the documentation, not >> the code. >> >> I'm trying to debug some code of mine and, on reading the >> documentation for chain_complex on >> >> http://doc.sagemath.org/html/en/reference/homology/sage/homology/simplicial_complex.html, >> found this: "The rows and columns of the boundary matrices are indexed >> by the lists given by the n_cells() method, which by default are >> sorted." On the other hand, the documentation for n_cells has this >> statement: "Sort the list if the argument sort is True. If sort is >> None (the default), then sort depending on the value of the >> sort_facets parameter (from the initialization of the simplicial >> complex)." However, the sort_facets parameter (unless I'm mistaken) >> does not sort the individual faces but rather sorts the vertices in >> each facet. > > > The documentation means that if "sort_facets" was True originally, then > n_cells will also sort its result before returning it. ("then sort depending > on the value of the sort_facets parameter": so if sort_facets was True, then > n_cells should also sort. It doesn't mean "sort using the effect of the > sort_facets parameter", but sort depending on its value, which is True or > False. This could be made clearer, I guess.) >
To be clear, I am getting different computations using the same sage computations on different machines. One (recent, but used, linux) machine consistently gives ones result, the other gives (randomly?) several others. The "other" (a 8 yr old, a mac with possibly memory issues) machine gives different results. I'm not saying your methods are machine dependent, just that *for me* they seem to be. To be clear, these "inconsistent" computations take at least one day. The "toy" (consistent) examples are okay. > I don't know if there is ever a good reason to specify sort_facets=False. > Maybe we should deprecate it? > >> >> In my code, I expected the faces of a fixed dimension to >> be returned as a deterministic sorted list not a set whose ordering >> could be random. Now, it *does* seem as though the faces are sorted. >> It's just that, to me, the documentation of n_cells doesn't make that >> clear. >> >> I'm asking if I'm mis-understanding something here or not. >> >> - David Joyner > > > -- > John > > > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-support+unsubscr...@googlegroups.com. > To post to this group, send email to sage-support@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
