Interface to Fokko Ducloux's Coxeter 3

[nthiery]

Coxeter3 is a C implementation of Coxeter groups. Beside computing with elements (using the combinatorics of reduced words) it contains super fast code for bruhat order, Kazdhan-Lusztig polynomials and the like.

http://boxen.math.washington.edu/home/jpflori/coxeter3-1.1.spkg

---

Apply attachment: trac_12912-coxeter3-mh.patch

Add coxeter-3-1.1.spkg as optional package.

Depends on #8359

CC: @sagetrac-sage-combinat @anneschilling @jpflori

Component: packages: optional

Keywords: coxeter, days45

Author: Mike Hansen

Reviewer: Anne Schilling, Nicolas M. Thiéry, Jean-Pierre Flori

Merged: sage-5.8.beta1

Issue created by migration from https://trac.sagemath.org/ticket/12912

[nthiery]

Description changed:

--- 
+++ 
@@ -1 +1,5 @@
+[Coxeter3|http://math.univ-lyon1.fr/~ducloux/coxeter/coxeter3/english/coxeter3_e.html] is a C implementation of Coxeter groups. Beside computing with elements (using the combinatorics of reduced words) it contains super fast code for bruhat order, Kazdhan-Lusztig polynomials and the like.
+
+
+
 Mike Hansen wrote a prototype on the sage-combinat patch queue. See http://combinat.sagemath.org/patches/file/tip/coxeter3-mh.patch and friends

[kini]

comment:2

Please set this ticket back to needs_review when there is a finished patch posted on the ticket! (I'm cleaning up needs_review tickets with no patches attached.)

[fchapoton]

Changed keywords from none to coxeter

[mwhansen]

Description changed:

--- 
+++ 
@@ -3,3 +3,5 @@
 
 
 Mike Hansen wrote a prototype on the sage-combinat patch queue. See http://combinat.sagemath.org/patches/file/tip/coxeter3-mh.patch and friends
+
+http://sage.math.washington.edu/home/mhansen/coxeter-3.0.beta3.spkg

[tscrim]

Description changed:

--- 
+++ 
@@ -4,4 +4,4 @@
 
 Mike Hansen wrote a prototype on the sage-combinat patch queue. See http://combinat.sagemath.org/patches/file/tip/coxeter3-mh.patch and friends
 
-http://sage.math.washington.edu/home/mhansen/coxeter-3.0.beta3.spkg
+http://sage.math.washington.edu/home/mhansen/coxeter-3.0.spkg

[anneschilling]

comment:6

Nicolas figured out that the following triggers the seg fault in /libs/coxeter/coxeter.pyx

sage: from sage.libs.coxeter.co
sage.libs.coxeter.coxeter        sage.libs.coxeter.coxeter_group  
sage: from sage.libs.coxeter.coxeter import get_CoxGroup as CoxGroup
sage: W = CoxGroup(['A',1])
sage: W.bruhat_interval([],[])
[[]]
sage: W = CoxGroup(['A',2])

[anneschilling]

comment:7

The current patch does not handle the Coxeter group of type ['A',0] properly!