I wa going to write: "Is there any reason not to do sage: m=random_prime(10^5) sage: K.<r> = CyclotomicField(m) sage: R = K.ring_of_integers() "
but I tried it and the last line is (much too) slow, which probably means that a generic algorithm is being used even though one knows that R = Z[r]. John On 15 April 2014 17:48, Vincent Delecroix <20100.delecr...@gmail.com> wrote: > Hi François, > > Might be related to the ticket #16116 on trac > (http://trac.sagemath.org/ticket/16116). Note that for performance, it > is possible to use multivariate polynomials as described in the > ticket. > > Best > Vincent > > 2014-04-15 18:30 UTC+02:00, François Colas <fco...@gmail.com>: >> Hello group, >> >> I am playing with quotient ring of Z over cyclotomic polynomial but it is >> strangely slow: >> >> sage: m = random_prime(10^4); m >> 2437 >> sage: %time R.<r> = ZZ['z'].quotient(cyclotomic_polynomial(m)) >> CPU times: user 2.50 s, sys: 0.00 s, total: 2.50 s >> Wall time: 2.50 s >> >> cyclotomic_polynomial(m) is created instantly whatever the size of m but >> the quotient becomes very long: >> >> sage: m = random_prime(10^5); m >> 16231 >> sage: %time R.<r> = ZZ['z'].quotient(cyclotomic_polynomial(m)) >> CPU times: user 217.82 s, sys: 0.00 s, total: 217.82 s >> Wall time: 217.65 s >> >> >> I am using Sage Version 6.1.1, does anyone could confirm this problem? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sage-devel" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sage-devel+unsubscr...@googlegroups.com. >> To post to this group, send email to sage-devel@googlegroups.com. >> Visit this group at http://groups.google.com/group/sage-devel. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
