#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 bruno):

 Replying to [comment:3 vdelecroix]:
 > Hello Bruno,
 >
 > Actually, I discussed this with Karim Belabas in Bordeaux 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

 It is not surprising indeed that Pari is faster for this. I don't
 understand what you mean by
 > either call Pari or stick to their implementation.
 Do you mean there are two ways to use Pari's implementation?

--
Ticket URL: <http://trac.sagemath.org/ticket/17695#comment:5>
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