Opened 7 years ago
Last modified 21 months ago
#18426 new enhancement
Memory leaks in RootSystem — at Initial Version
Reported by: | tscrim | Owned by: | sage-combinat |
---|---|---|---|
Priority: | critical | Milestone: | sage-6.7 |
Component: | memleak | Keywords: | memory leak |
Cc: | sage-combinat, nthiery, slelievre | Merged in: | |
Authors: | Travis Scrimshaw | Reviewers: | |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
RootSystem
is currently creating memory leaks in the following way:
Upon creating a root system, say of type B3, this line:
self.dual = RootSystem(self._cartan_type.dual(), as_dual_of=self);
causes the B3 root system to be used as a key in the UniqueRepresentation
of the C3 root system (I call it so, but note it is the dual of the B3, which will be different than the honest C3 root system), which is a strong reference that can never be deleted. Moreover, the B3 root system then holds a (strong) reference to the C3 root system, so the C3 root system never gets collected either.
Some data:
sage: from collections import Counter sage: import gc sage: gc.collect() 91 sage: pre = {id(a) for a in gc.get_objects()} sage: get_memory_usage() 1022.7890625 sage: for n in range(5,3000): RS = RootSystem(['A',n]) ....: sage: gc.collect() 0 sage: get_memory_usage() 1031.359375 sage: post = Counter(str(type(a)) for a in gc.get_objects() if id(a) not in pre) sage: [p for p in post.iteritems() if p[1] > 2000] [("<class 'weakref.KeyedRef'>", 8985), ("<class 'sage.combinat.root_system.type_A.CartanType'>", 2994), ("<class 'sage.combinat.root_system.root_system.RootSystem'>", 5990), ("<type 'dict'>", 6012), ("<type 'tuple'>", 29952)]
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