#17695: Slightly fasten is_cyclotomic()
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Reporter: bruno | Owner:
Type: enhancement | Status: needs_review
Priority: minor | Milestone: sage-6.5
Component: number theory | Resolution:
Keywords: cyclotomic | Merged in:
polynomials | Reviewers:
Authors: Bruno Grenet | Work issues:
Report Upstream: N/A | Commit:
Branch: | f79eeaaa630b1bd966a25a2f7b0f7a5f1dda3378
u/bruno/slightly_fasten_is_cyclotomic__| Stopgaps:
Dependencies: |
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Comment (by vdelecroix):
Hello Bruno,
Actually, I discussed this with Karim Belabas in Bordeaux about it few
weeks ago. We should either call Pari or stick to their implementation. It
is much faster:
{{{
sage: p = cyclotomic_polynomial(150)
sage: pp = p._gp_()
sage: timeit("pp.poliscyclo()")
625 loops, best of 3: 697 µs per loop
sage: timeit("p.is_cyclotomic()")
125 loops, best of 3: 2.78 ms per loop
}}}
Moreover they do have the function `poliscycloprod` that checks if all
roots are roots of unity (which is even faster).
Vincent
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Ticket URL: <http://trac.sagemath.org/ticket/17695#comment:3>
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