#18304: Integer and Rational comparisons
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Reporter: vdelecroix | Owner:
Type: enhancement | Status: needs_review
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 | e03a26e63dd50f79fc7ada885daefd8c9970c482
Dependencies: | Stopgaps:
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Changes (by vdelecroix):
* status: needs_work => needs_review
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
> }}}
>
> Upstream mpir pull request for the `mpq_cmp_mpz` function:
>
> [https://github.com/wbhart/mpir/pull/157
> https://github.com/wbhart/mpir/pull/157]
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: 84 ns per loop
sage: a = 1; b = QQ(18)
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 405 ns per loop
}}}
With the branch applied, it gets better
{{{
sage: a = 1; b = 18
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 64 ns per loop
sage: a = QQ(1); b = QQ(18)
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 65.6 ns per loop
sage: a = 1; b = QQ(18)
sage: timeit("a < b", number=500000, repeat=100)
500000 loops, best of 100: 87.1 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]
Warning: if you pull the branch and run `make` then you will likely
rebuild your whole Sage!
--
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Ticket URL: <http://trac.sagemath.org/ticket/18304#comment:14>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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