#864: Asymptotically slow PARI --> Python long conversions
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Reporter: craigcitro | Owner: craigcitro
Type: enhancement | Status: needs_review
Priority: minor | Milestone: sage-5.13
Component: performance | Resolution:
Keywords: pari | Merged in:
Authors: Peter Bruin | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Comment (by pbruin):
Replying to [comment:5 jdemeyer]:
> Replying to [comment:4 pbruin]:
> > so `long(y)` essentially does `long(Integer(y))`.
> Why not literally do `long(Integer(y))` then and save many lines of
code?
I thought that the penalty for creating an `Integer` was quite heavy in
some cases; for example, with the current patch applied, I get
{{{
sage: y=pari(10^10000)
sage: %timeit -c -r 1 u=long(y)
100000 loops, best of 1: 12.2 us per loop
sage: %timeit -c -r 1 u=long(Integer(y))
10000 loops, best of 1: 19.6 us per loop
}}}
However, I just tried implementing `gen.__long__(self)` as `return
long(Integer(self))`, and it is just as fast, thanks to Cython I guess. I
also agree that `long(pari("Mod(2,7)"))` is nice to get for free. New
patch coming soon.
--
Ticket URL: <http://trac.sagemath.org/ticket/864#comment:7>
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