#13991: Mitigate speed regressions in symmetric function related code due to
#12313
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Reporter: nbruin | Owner: sage-combinat
Type: enhancement | Status: new
Priority: major | Milestone: sage-5.8
Component: combinatorics | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: #13605 | Stopgaps:
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Comment (by SimonKing):
I found that the Weyl group `WeylGroup(['A',k,1])` created in
`sage.combinat.partition.Partition.from_kbounded_to_grassmannian` gets
garbage collected repeatedly.
Suggestion: Store these Weyl groups via a cached method of the partition,
so that the Weyl group will only be garbage collected if the partition is
garbage collected, too.
My base line is sage-5.8.beta0 with patches as stated in my previous post.
When I add the following patch,
{{{
#!patch
# HG changeset patch
# User Simon King <[email protected]>
# Date 1362415985 -3600
# Node ID 0ce4256bfbbf4b601e931bcc3fab6dea898b1138
# Parent 0140ddcd1451ed7504456a7b72e9f2dc03ec2511
imported patch trac_13991_cache_Weyl_partitions.patch
diff --git a/sage/combinat/partition.py b/sage/combinat/partition.py
--- a/sage/combinat/partition.py
+++ b/sage/combinat/partition.py
@@ -277,6 +277,7 @@
from sage.misc.all import prod
from sage.misc.prandom import randrange
from sage.misc.classcall_metaclass import ClasscallMetaclass
+from sage.misc.cachefunc import cached_method
from sage.categories.infinite_enumerated_sets import
InfiniteEnumeratedSets
from sage.categories.finite_enumerated_sets import FiniteEnumeratedSets
@@ -295,6 +296,7 @@
from sage.combinat.integer_vector import IntegerVectors
from sage.combinat.cartesian_product import CartesianProduct
from sage.combinat.integer_list import IntegerListsLex
+from sage.combinat.root_system.weyl_group import WeylGroup
from sage.groups.perm_gps.permgroup import PermutationGroup
@@ -3062,6 +3064,10 @@
p = p.remove_cell(x[0])
return result
+ @cached_method
+ def _Weyl_group_A(self, k):
+ return WeylGroup(['A',k,1])
+
def from_kbounded_to_grassmannian(self, k):
r"""
Maps a `k`-bounded partition to a Grassmannian element in
@@ -3083,9 +3089,7 @@
[0 1 0]
[0 0 1]
"""
- from sage.combinat.root_system.weyl_group import WeylGroup
- W=WeylGroup(['A',k,1])
- return W.from_reduced_word(self.from_kbounded_to_reduced_word(k))
+ return
self._Weyl_group_A(k).from_reduced_word(self.from_kbounded_to_reduced_word(k))
def to_list(self):
r"""
}}}
the time for this test
{{{
sage: from sage.combinat.sf.k_dual import AffineSchurFunctions
sage: F =
AffineSchurFunctions(SymmetricFunctions(QQ['t']).kBoundedQuotient(Integer(4),t=Integer(1)))
sage: %time TestSuite(F).run()
}}}
drops from
{{{
CPU times: user 10.96 s, sys: 0.15 s, total: 11.11 s
Wall time: 11.29 s
}}}
to
{{{
CPU times: user 10.11 s, sys: 0.25 s, total: 10.36 s
Wall time: 10.48 s
}}}
This is at least something, and I could imagine that one could get more
progress by further cached methods. Note that this would not open memory
leaks, since the cache of the data happens only in the parent that needs
these data.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13991#comment:40>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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