This is now #23395 <https://trac.sagemath.org/ticket/23395>
El lunes, 10 de julio de 2017, 13:43:46 (UTC+2), mmarco escribió: > > If you used quo_rem, beware that Sage only uses Singular if the > coefficient ring is a field. So if you define your polynomials over QQ > instead of ZZ you will get timings similar to those of Singular. In the > case of ZZ, it will do so with some generic python implementation of > division. > > I guess we could rely on Singular also for the case of Integers. > > El lunes, 10 de julio de 2017, 12:48:55 (UTC+2), mmarco escribió: >> >> It is surprising the difference between singular and Sage, considering >> that Sage mostly relies on Singular for multivariate polynomial arithmetic. >> In the case of divisions, I suspect that it has to do with the fact that >> Sage treats division of polynomials as an operation in the fraction field, >> so it would construct the fraction, look for common factors in the >> numerator and denominator, and cancel them. That is probably not what other >> systems do. >> >> Which commands/instructions did you use in your benchmarks? >> >> El lunes, 10 de julio de 2017, 12:13:00 (UTC+2), Bill Hart escribió: >>> >>> The reason that I required the quotient as well in the divisibility >>> benchmark was that Magma does the n = 20 dense case in 0.15s otherwise, and >>> I don't believe it is possible to do it that fast if you aren't doing it >>> heuristically, as I explained in the blog post. Therefore, all the systems >>> timed must return the quotient if the division is exact (which it is in the >>> benchmark examples, since that is the hard case), so that Magma can't >>> possibly "cheat". >>> >>> As mentioned, if the various systems don't provide such a function, I >>> substituted divrem, since it is possible to look at the remainder to see if >>> it was divisible, and then take the quotient as required by the benchmark. >>> >>> It is really hard to benchmark a bunch of systems against one another. >>> When I first timed Giac, I wasn't aware of a bunch of special parameters >>> you can pass to the Giac functions which make them run much faster. And >>> basically, there aren't many functions that all the systems happen to >>> implement with the same semantics, so I have to simulate what a user would >>> do if that is the semantics they want. I didn't do it to make Sage look >>> bad, honest! >>> >>> On Monday, 10 July 2017 12:05:28 UTC+2, Bill Hart wrote: >>>> >>>> 7.6 >>>> >>>> On Monday, 10 July 2017 11:56:32 UTC+2, vdelecroix wrote: >>>>> >>>>> On 10/07/2017 09:34, Ralf Stephan wrote: >>>>> > On Monday, July 10, 2017 at 8:55:23 AM UTC+2, vdelecroix wrote: >>>>> >> >>>>> >> He was certainly not using the awfully slow symbolic ring >>>>> >> >>>>> > >>>>> > Then his slow timings for e.g. "Divisibility test with quotient >>>>> (sparse)" >>>>> > needs a different explanation. >>>>> >>>>> Sage version? >>>>> >>>>> -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
