Opened 4 years ago

Closed 4 years ago

#23891 closed defect (fixed)

Permutation.descents does not take an index_set argument

Reported by: mantepse Owned by:
Priority: major Milestone: sage-8.2
Component: combinatorics Keywords:
Cc: sage-combinat, darij Merged in:
Authors: Travis Scrimshaw Reviewers: Darij Grinberg
Report Upstream: N/A Work issues:
Branch: a7b05fe (Commits, GitHub, GitLab) Commit: a7b05fe11efad39ed7b62f84d9356ebd51c5a7f1
Dependencies: Stopgaps:

Status badges

Description (last modified by tscrim)

This is a requirement now that Permutations(n) are in the category of Coxeter groups.

This was originally noticed by: 

sage: Permutations(4)([1,4,3,2]).weak_covers()
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-61-3fd0d11884fd> in <module>()
----> 1 Permutations(Integer(4))([Integer(1),Integer(4),Integer(3),Integer(2)]).weak_covers()

/home/martin/sage-develop/local/lib/python2.7/site-packages/sage/categories/coxeter_groups.pyc in weak_covers(self, side, index_set, positive)
   1922             """
   1923             return [ self.apply_simple_reflection(i, side=side)
-> 1924                      for i in self.descents(side=side, index_set = index_set, positive = positive) ]
   1925 
   1926         def coxeter_sorting_word(self,c):

TypeError: descents() got an unexpected keyword argument 'index_set'

Change History (8)

comment:1 Changed 4 years ago by mantepse

  • Component changed from PLEASE CHANGE to combinatorics
  • Description modified (diff)
  • Summary changed from weak_covers is a method of Permutations(4), but does not work to weak_covers is a method of Permutations(n), but does not work
  • Type changed from PLEASE CHANGE to defect

comment:2 Changed 4 years ago by tscrim

  • Authors set to Travis Scrimshaw
  • Branch set to public/combinat/permutation_descents_index_set-23891
  • Cc sage-combinat darij added
  • Commit set to 370ae9220bc843dc2c1d161ee94be5199ff5c6e2
  • Description modified (diff)
  • Milestone changed from sage-8.1 to sage-8.2
  • Status changed from new to needs_review
  • Summary changed from weak_covers is a method of Permutations(n), but does not work to Permutation.descents does not take an index_set argument

I also took the opportunity to remove the deprecation of from_zero=True default from #20555.

New commits:

​370ae92Add index_set to descents and removed deprecated from_zero=True default.

comment:3 Changed 4 years ago by darij 

+            By default, the descents are returned as elements in the
+            index set, i.e., starting at `1`. If you want them to
+            start at `0`, set the keyword ``from_zero`` to ``False``.

That should be "... to True".

(twice).

Last edited 4 years ago by darij (previous) (diff)

comment:4 Changed 4 years ago by git

  • Commit changed from 370ae9220bc843dc2c1d161ee94be5199ff5c6e2 to a7b05fe11efad39ed7b62f84d9356ebd51c5a7f1

Branch pushed to git repo; I updated commit sha1. New commits:

​a7b05feFixing True and False statements.

comment:5 Changed 4 years ago by tscrim

Yes, right. Fixed.

comment:6 Changed 4 years ago by darij

LGTM. If the tests pass, positive review.

comment:7 Changed 4 years ago by tscrim

  • Reviewers set to Darij Grinberg
  • Status changed from needs_review to positive_review

comment:8 Changed 4 years ago by vbraun

  • Branch changed from public/combinat/permutation_descents_index_set-23891 to a7b05fe11efad39ed7b62f84d9356ebd51c5a7f1
  • Resolution set to fixed
  • Status changed from positive_review to closed
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