#18304: Integer and Rational comparisons
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Reporter: vdelecroix | Owner:
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-6.9
Component: performance | Resolution:
Keywords: | Merged in:
Authors: Vincent Delecroix | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/vdelecroix/18304 | 554c4358bc0e470ec0c72c2a24251f4a6978a12e
Dependencies: | Stopgaps:
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Changes (by vdelecroix):
* milestone: sage-6.7 => sage-6.9
Old description:
> Comparing integers is very fast, comparing rationals is very fast but
> comparing integer with rational is about 5x slower:
> {{{
> sage: a = 1; b = 18
> sage: timeit("a < b", number=500000, repeat=100)
> 500000 loops, best of 100: 64.3 ns per loop
> sage: a = QQ(1); b = QQ(18)
> sage: timeit("a < b", number=500000, repeat=100)
> 500000 loops, best of 100: 88.4 ns per loop
> sage: a = 1; b = QQ(18)
> sage: timeit("a < b", number=500000, repeat=100)
> 500000 loops, best of 100: 416 ns per loop
> }}}
>
> With the branch applied all comparisons involving only Sage integers,
> Sage rationals and Python int/long are about the same time. With the
> branch applied, I got
>
> {{{
> sage: a = 1; b = 18
> sage: timeit("a < b", number=500000, repeat=100)
> 500000 loops, best of 100: 62.2 ns per loop
> sage: a = QQ(1); b = QQ(18)
> sage: timeit("a < b", number=500000, repeat=100)
> 500000 loops, best of 100: 65.3 ns per loop
> sage: a = 1; b = QQ(18)
> sage: timeit("a < b", number=500000, repeat=100)
> 500000 loops, best of 100: 82.8 ns per loop
> }}}
New description:
Comparing integers is very fast, comparing rationals is very fast but
comparing integer with rational is about 5x slower:
{{{
sage: a = 1; b = 18
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 64.3 ns per loop
sage: a = QQ(1); b = QQ(18)
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 88.4 ns per loop
sage: a = 1; b = QQ(18)
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 416 ns per loop
}}}
Upstream mpir pull request for the `mpq_cmp_mpz` function:
[https://github.com/wbhart/mpir/pull/157
https://github.com/wbhart/mpir/pull/157]
--
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Ticket URL: <http://trac.sagemath.org/ticket/18304#comment:12>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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