#715: Parents probably not reclaimed due to too much caching
-------------------------------------------------------------------+--------
Reporter: robertwb |
Owner: somebody
Type: defect |
Status: needs_review
Priority: major |
Milestone: sage-5.4
Component: coercion |
Resolution:
Keywords: weak cache coercion Cernay2012 | Work
issues:
Report Upstream: N/A |
Reviewers: Jean-Pierre Flori, Simon King, Nils Bruin
Authors: Simon King, Jean-Pierre Flori | Merged
in:
Dependencies: #9138, #11900, #11599, to be merged with #11521 |
Stopgaps:
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Comment (by SimonKing):
It seems to me that it is ''not'' a side effect. Namely, I put
{{{
class Foo:
def bar(self):
"""
Cache values for a number of inputs. Do the computation
in parallel, and only bother to compute values that we
haven't already cached.
EXAMPLES::
sage: @cached_function
... def oddprime_factors(n):
... l = [p for p,e in factor(n) if p != 2]
... return len(l)
sage: oddprime_factors.precompute(range(1,100), 4)
sage: oddprime_factors.cache[(25,),()]
1
"""
pass
}}}
into a file and run `sage -t` on it. All tests pass -- '''__BUT__'''
running `sage -t -gdb`, I get the same error as in cachefunc.pyx, where
the test above is just one among many other tests:
{{{
Failed example:
oddprime_factors.precompute(range(Integer(1),Integer(100)),
Integer(4))###line 14:_sage_ >>>
oddprime_factors.precompute(range(1,100), 4)
Expected nothing
Got:
[Errno 4] Interrupted system call
Killing any remaining workers...
**********************************************************************
File "/scratch/sking/sage-5.4.beta0/devel/sage-main/sage/misc/blubb.py",
line ?, in __main__.example_0
Failed example:
oddprime_factors.cache[(Integer(25),),()]###line 15:_sage_ >>>
oddprime_factors.cache[(25,),()]
Exception raised:
Traceback (most recent call last):
File "/scratch/sking/sage-5.4.beta0/local/bin/ncadoctest.py", line
1231, in run_one_test
self.run_one_example(test, example, filename, compileflags)
File "/scratch/sking/sage-5.4.beta0/local/bin/sagedoctest.py", line
38, in run_one_example
OrigDocTestRunner.run_one_example(self, test, example, filename,
compileflags)
File "/scratch/sking/sage-5.4.beta0/local/bin/ncadoctest.py", line
1172, in run_one_example
compileflags, 1) in test.globs
File "<doctest __main__.example_0[4]>", line 1, in <module>
oddprime_factors.cache[(Integer(25),),()]###line 15:_sage_ >>>
oddprime_factors.cache[(25,),()]
KeyError: ((25,), ())
}}}
The "Killing any remaining workers" comes from a parallel computation,
isn't it? The `precompute()` method is parallel. Let us see whether it
also fails in an interactive session under gdb!
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/715#comment:251>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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