#715: Parents probably not reclaimed due to too much caching
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Reporter: robertwb | Owner: somebody
Type: defect | Status: new
Priority: major | Milestone: sage-4.8
Component: coercion | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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Comment(by SimonKing):
I try to wrap my mind around weak references. I found that when creating a
weak reference, one can also provide a method that is called when the weak
reference becomes invalid. I propose to use such method to erase the
deleted object from the cache, regardless whether it appears as domain or
codomain.
Here is a proof of concept:
{{{
sage: ref = weakref.ref
sage: D = {}
sage: def remove(x):
....: for a,b,c in D.keys():
....: if a is x or b is x or c is x:
....: D.__delitem__((a,b,c))
....:
sage: class A:
....: def __init__(self,x):
....: self.x = x
....: def __repr__(self):
....: return str(self.x)
....: def __del__(self):
....: print "deleting",self.x
....:
sage: a = A(5)
sage: b = A(6)
sage: r = ref(a,remove)
sage: s = ref(b,remove)
sage: D[r,r,s] = 1
sage: D[s,r,s] = 2
sage: D[s,s,s] = 3
sage: D[s,s,1] = 4
sage: D[r,s,1] = 5
sage: D.values()
[5, 3, 1, 4, 2]
sage: del a
deleting 5
sage: D.values()
[4, 3]
sage: del b
deleting 6
sage: D.values()
[]
}}}
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/715#comment:13>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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