Hi Darij,
I still have a sage-5.4.1 with all combinat patches up to december 2012 on another machine, and t.descents() does what I expect. I admit that "descents" is a bad name for this (these are the descents of the inverse permutation of the row reading in French convention, in French we use "reculs" ( = recoils, or backsteps), but it is traditional to use "descents" in English. Btw, the name "major index" comes from the military rank of McMahon (Foata and Schutzenberger called it "the major's index") , so there is only one "major index" .... All the best, Jean-Yves Le mercredi 16 octobre 2013 22:07:38 UTC+2, Andrew Mathas a écrit : > > Hi Darij, > > I've not yet needed descent sets of tableaux in sage so I don't know what > the code did previously or what it does now in this respect. I would hope, > however, that a descents method for tableaux would return the descent set > of a tableau, so if you have ensured that this is now happening I think > that's great! > > Andrew > > On Wednesday, 16 October 2013 20:32:11 UTC+2, darijgrinberg wrote: >> >> Hello Jean-Yves, hello Andrew, >> >> I guess I should have something to say about this but I don't really >> understand what is happening. When I wrote the #7983 patch, I was >> being annoyed by the fact that there was no method on the Tableaux >> class computing what everyone in combinatorics calls the descents, >> whereas the descents() method on tableaux was computing something >> rather unrelated (that, moreover, depends only on the shape if the >> tableau is semistandard). I suspect the descents() method was some >> kind of helper function for Jack or H-L related code. Anyway, I >> decided to rename the old descents() method into a less ambiguous name >> and to make descents() compute the actual descents. But I've quickly >> got talked out of this, as this would deprecate some userbase code, so >> instead I added a standard_descents() method and left descents() >> untouched (only adding the warning to its doc). I was working on >> sage-main all the time. >> >> Now, Jean-Yves (who, as far as I understand, has been using >> sage-combinat) is saying he has been using descents() all the time and >> since he is talking about standard tableaux, I assume that function >> has been computing the actual descents rather than whatever it has >> been computing on sage-main. Does this mean that the descents() >> function on sage-combinat has been doing something completely >> different from that on sage-main all the time before my #7983 patch? >> That someone had done what I first had in mind (rename the old >> descents() and reuse the name for the actual descents) long ago, and >> now that my #7983 got merged in, the roles have switched? >> >> Either way, sorry for contributing to this muckup and thanks a lot for >> any help in understanding it. >> >> Best regards, >> Darij >> > -- 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 http://groups.google.com/group/sage-combinat-devel. For more options, visit https://groups.google.com/groups/opt_out.
