#14388: Fix Cygwin failure in plural polynomials overflow error
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Reporter: kcrisman | Owner: tbd
Type: defect | Status: new
Priority: major | Milestone: sage-5.9
Component: porting: Cygwin | Resolution:
Keywords: Cygwin | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by nbruin):
Replying to [comment:3 kcrisman]:
> So you think it could be basically the same type of problem as #14254?
Unfortunately this particular set of errors wasn't fixed by that ticket.
It looks like it's exactly that problem. Look at line 573 of plural.pyx
{{{
def __hash__(self):
...
return id(self)
}}}
The special method `__hash__` is supposed to return a `Py_hash_t`
(probably a "long"). The code is trying to return `id`, which is a python
integer, and on a machine where ints are 32 bits, can easily exceed
`2^31`. So it won't be able to convert to an int. Explicitly cast instead,
via something like
{{{
return <Py_hash_t><void*>self
}}}
which will be orders of magnitude faster too.
Incidentally, Python itself shifts right by 2 any time an id gets used as
a hash, because the lowest two bits are almost certainly 0.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14388#comment:5>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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