#14955: HeilbronnMerel(50000) raises a RuntimeError
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Reporter: tian | Owner:
Type: defect | Status: new
Priority: minor | Milestone:
Component: modular forms | Resolution:
Keywords: sd51 | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Comment (by pbruin):
Replying to [comment:1 AlexGhitza]:
> For the record, {{{HeilbronnMerel(46342)}}} seems to be the earliest
point of failure.
This looks like an integer overflow. The method
`HeilbronnMerel._initialize_list()` sets `bc = a*d - n`, where `a` and `d`
are `<= n`, and `bc` is an `int`.
{{{
sage: n = 46342
sage: n^2 - n < 2^31
False
sage: (n-1)^2 - (n-1) < 2^31
True
}}}
I guess making `bc` a `long long` will solve this.
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Ticket URL: <http://trac.sagemath.org/ticket/14955#comment:3>
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