empty partition causes error for down_list

[pdehaye]

sage: p = Partition([])
sage: p.down_list()
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)

/Volumes/Scratch/Users/duser1/sage/<ipython console> in <module>()

/Users/duser1/sage/local/lib/python2.6/site-packages/sage/combinat/partition.pyc in down_list(self)
    643             [[2, 2, 1], [3, 1, 1], [3, 2]]
    644         """
--> 645         return [p for p in self.down()]
    646 
    647     def dominates(self, p2):

/Users/duser1/sage/local/lib/python2.6/site-packages/sage/combinat/partition.pyc in down(self)
    622                 yield Partition(p[:i] + [ p[i]-1 ] + p[i+1:])
    623 
--> 624         last = p[-1]
    625         if last == 1:
    626             yield Partition(p[:-1])

/Users/duser1/sage/local/lib/python2.6/site-packages/sage/combinat/combinat.pyc in __getitem__(self, key)
    905             <type 'list'>
    906         """
--> 907         return self._list.__getitem__(key)
    908 
    909     def __iter__(self):

IndexError: list index out of range
sage: 

CC: @jbandlow

Component: combinatorics

Author: Paul-Olivier Dehaye

Reviewer: Nathann Cohen

Merged: sage-4.7.2.alpha1

Issue created by migration from https://trac.sagemath.org/ticket/11435

[pdehaye]

comment:1

Attachment: trac_11435-Downlist_on_empty_partition-pod.patch.gz

fixed

[nathanncohen]

comment:2

Good to go :-)

Nathann

[jdemeyer]

comment:4

Dear author/reviewer: please add your real name in the Author and Reviewer fields.

[nathanncohen]

Author: Paul-Olivier Dehaye

[nathanncohen]

Reviewer: Nathann Cohen

[jdemeyer]

Merged: sage-4.7.2.alpha1