#5213: make charpoly/minpoly of number field elements use matrix()
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Reporter: ncalexan | Owner: was
Type: defect | Status: new
Priority: minor | Milestone: sage-3.3
Component: number theory | Resolution:
Keywords: number field element minpoly charpoly |
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Comment (by AlexGhitza):
Actually, on my laptop, with the example
{{{
sage: R.<x> = ZZ[]
sage: f = x^32 - x^31 + 2*x^30 - x^28 - 2*x^27 + 8*x^26 + 2*x^25 + 2*x^24
+ x^22 - 2*x^20 + x^18 + x^17 - 3*x^16 + 51*x^15 - 2*x^14 - 5*x^13 +
3*x^12 - x^9 + x^8 - x^7 - 2*x^6 - 2*x^5 - x^4 + 5
sage: K.<a> = NumberField(f)
sage: b = -1/2*a^31 - 12*a^30 + a^29 - 1/64*a^28 + 2/3*a^26 + 1/7*a^25 -
2*a^24 + 1/3*a^19 - 6*a^18 - 11*a^17 - 2*a^15 + 1/32*a^14 + a^13 + a^11 -
1/17*a^9 + 2*a^8 + 1/32*a^6 + a^5 + 1/6*a^4 + 2*a^3 - 2/3*a^2 - 59*a + 1
}}}
I get, before the patch:
{{{
sage: time c = b.charpoly()
CPU times: user 0.15 s, sys: 0.00 s, total: 0.15 s
Wall time: 0.14 s
}}}
and after the patch:
{{{
sage: time c = b.charpoly()
CPU times: user 0.03 s, sys: 0.00 s, total: 0.03 s
Wall time: 0.04 s
}}}
Just for the heck of it, I tried a degree 61 extension, and I get 7.44
seconds before the patch, and 0.26 seconds after it.
So I'm motivated to review it :)
Nick, if you're reading this, do you have an example where the new code is
significantly slower?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5213#comment:4>
Sage <http://sagemath.org/>
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Reinventing the Wheel
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