Opened 7 years ago

Closed 5 years ago

#8359 closed enhancement (fixed)

Coxeter groups as permutation groups

Reported by: nthiery Owned by: sage-combinat
Priority: major Milestone: sage-5.7
Component: combinatorics Keywords: Coxeter groups, permutation groups, chevie
Cc: sage-combinat Merged in: sage-5.7.beta3
Authors: Nicolas M. Thiéry Reviewers: Anne Schilling, Mike Hansen
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description (last modified by jdemeyer)

This patch adds a function: 

    CoxeterGroup(cartan_type, implementation = "matrix" / "permutation")

to construct Coxeter groups. Whenever possible, the Coxeter group is constructed as a permutation group, using data from GAP3/Chevie; otherwise a Weyl group is returned, as a matrix group. An upcoming implementation is by reduced words, using the Coxeter 3 package.

Attachments (1)

trac_8359-coxeter-groups-permutation-nt.patch​ (20.9 KB) - added by aschilling 5 years ago.

Download all attachments as: .zip

Change History (16)

comment:1 Changed 7 years ago by nthiery

  • Cc sage-combinat added
  • Description modified (diff)
  • Status changed from new to needs_work

comment:2 Changed 5 years ago by aschilling

  • Description modified (diff)
  • Reviewers set to Anne Schilling, Mike Hansen

comment:3 Changed 5 years ago by aschilling

This patch was developed and tested on the sage-combinat queue by myself and Mike Hansen. It is ready to go!

comment:4 Changed 5 years ago by aschilling

  • Status changed from needs_work to needs_review

comment:5 Changed 5 years ago by aschilling

  • Status changed from needs_review to positive_review

comment:6 follow-up: Changed 5 years ago by jdemeyer

  • Description modified (diff)
  • Milestone set to sage-5.7

comment:7 in reply to: ↑ 6 Changed 5 years ago by aschilling

We made changes to make the doctests pass. Not sure what the problem with the plugins are.

comment:8 Changed 5 years ago by jdemeyer

You should never use except: without an exception type, otherwise you would catch some unwanted exceptions. Catch specific exceptions instead (or except Exception: if you want to catch all actual exceptions).

comment:9 follow-up: Changed 5 years ago by jdemeyer

  • Status changed from positive_review to needs_work

There is a problem with the documentation: 

/release/merger/sage-5.7.beta2/local/lib/python2.7/site-packages/sage/combinat/root_system/coxeter_group.py:docstring of sage.combinat.root_system.coxeter_group.CoxeterGroupAsPermutationGroup.Element.has_descent:3: WARNING: more than one target found for cross-reference u'descents': sage.combinat.root_system.root_lattice_realizations.RootLatticeRealizations.ElementMethods.descents, sage.categories.coxeter_groups.CoxeterGroups.ElementMethods.descents, sage.combinat.tableau.Tableau.descents, sage.combinat.sf.ns_macdonald.AugmentedLatticeDiagramFilling.descents, sage.combinat.permutation.Permutation_class.descents, sage.combinat.composition.Composition_class.descents

comment:10 in reply to: ↑ 9 Changed 5 years ago by aschilling

Both issues fixed!

comment:11 Changed 5 years ago by aschilling

  • Status changed from needs_work to positive_review

comment:12 follow-up: Changed 5 years ago by nthiery

Hi Jeroen,

Should we ignore jehova's patchbot failure (the log and shortlog seem empty)?

Is the plugin.startup failure a suggestion for lazy importing CoxeterGroup??

Thanks!

Nicolas

comment:13 in reply to: ↑ 12 ; follow-up: Changed 5 years ago by aschilling

In consultation with Nicolas, I fixed some failing doctests in /combinat/root_systems/coxeter_group.py for type H3.

Anne

Changed 5 years ago by aschilling

comment:14 in reply to: ↑ 13 Changed 5 years ago by aschilling

Removed trailing white spaces.

Anne

comment:15 Changed 5 years ago by jdemeyer

  • Merged in set to sage-5.7.beta3
  • Resolution set to fixed
  • Status changed from positive_review to closed
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