#12265: massively optimize f.change_ring(QQ) for f in ZZ['x']
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Reporter: was | Owner: tbd
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.0
Component: performance | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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Changes (by was):
* status: new => needs_review
Old description:
> I needed to massively optimize f.change_ring(QQ) for f in ZZ['x'] so that
> #11375 would not suck.
>
> For me,
> {{{
> BEFORE:
> sage: R.<x> = ZZ[]; v = [1..10^6]; f = R(v);
> sage: time g = f.change_ring(QQ)
> Time: CPU 4.39 s, Wall: 4.39 s
> sage: R.<x> = ZZ[]; v = [1..10^3]; f = R(v);
> sage: timeit('g = f.change_ring(QQ)')
> 125 loops, best of 3: 1.79 ms per loop
>
> AFTER:
> sage: R.<x> = ZZ[]; v = [1..10^6]; f = R(v);
> sage: time g = f.change_ring(QQ)
> Time: CPU 0.05 s, Wall: 0.05 s
> sage: R.<x> = ZZ[]; v = [1..10^3]; f = R(v);
> sage: timeit('g = f.change_ring(QQ)')
> 625 loops, best of 3: 107 µs per loop
> }}}
>
> So we get nearly a 100-fold speedup.
>
> }}}
New description:
I needed to massively optimize f.change_ring(QQ) for f in ZZ['x'] so that
#11375 would not suck.
For me,
{{{
BEFORE:
sage: R.<x> = ZZ[]; v = [1..10^6]; f = R(v);
sage: time g = f.change_ring(QQ)
Time: CPU 4.39 s, Wall: 4.39 s
sage: R.<x> = ZZ[]; v = [1..10^3]; f = R(v);
sage: timeit('g = f.change_ring(QQ)')
125 loops, best of 3: 1.79 ms per loop
AFTER:
sage: R.<x> = ZZ[]; v = [1..10^6]; f = R(v);
sage: time g = f.change_ring(QQ)
Time: CPU 0.05 s, Wall: 0.05 s
sage: R.<x> = ZZ[]; v = [1..10^3]; f = R(v);
sage: timeit('g = f.change_ring(QQ)')
625 loops, best of 3: 107 µs per loop
}}}
So we get nearly a 100-fold speedup.
--
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12265#comment:2>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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