On Monday, May 29, 2017 at 12:03:59 PM UTC+1, Ralf Stephan wrote: > > Yes but if Pynac had such a type, and fast, the operations with any roots > (as parts of expressions) would be much simplified. Relying on > Python/Cython code from the C++ end is always tedious and slow. >
I don't know a library like this that allows you to directly manipulate non-integer powers of (real, or not) algebraic numbers. I am aware of GAP packages Alnuth and Radiroot (Radiroot can show you roots of polynomial equations with solvable Galois group, expressed via radicals, so this seems to come close to what you'd like to have) that provide some functionality to deal with roots of algebraic numbers; they interface Pari/GP for this purpose. (they use a simple and slow interface via files, AFAIK, but that's beside the point). Pari/GP has a C library interface, which is a part of Sage. > On Mon, May 29, 2017, 10:12 John Cremona <john.c...@gmail.com > <javascript:>> wrote: > >> >> >> On 29 May 2017 07:59, "Ralf Stephan" <gtr...@gmail.com <javascript:>> >> wrote: >> >> The case that started me was >> >> sage: a=SR(1/2) >> sage: b=SR(3) >> sage: %timeit _=a^b >> The slowest run took 9.38 times longer than the fastest. This could mean >> that an intermediate result is being cached. >> 100000 loops, best of 3: 2.14 µs per loop >> sage: %timeit _=b^a >> 10000 loops, best of 3: 62.1 µs per loop >> >> but I think I can shortcut >> >> >> Your example does not use QQbar at all! It uses SR (Symbolic Ring) which >> is quite different. >> >> >> >> Python/Cython usage here. >> I also wanted to scout the software landscape before any other decisions. >> >> >> On Monday, May 29, 2017 at 8:39:59 AM UTC+2, Dima Pasechnik wrote: >>> >>> >>> >>> On Monday, May 29, 2017 at 6:09:33 AM UTC+1, Ralf Stephan wrote: >>>> >>>> On Sunday, May 28, 2017 at 11:40:08 PM UTC+2, Jeroen Demeyer wrote: >>>>> >>>>> On 2017-05-26 15:19, Ralf Stephan wrote: >>>>> > The qqbar source does not use a lower-level library. >>>>> >>>>> What do you mean with this? It actually uses quite a large fraction of >>>>> Sage (number fields, polynomials, interval arithmetic, ...) >>>>> >>>> >>>> Make that "lower-language-level" i.e. C/C++. There was also >>>> the words "one" and "fast" in my original post. >>>> >>> >>> Is qqbar really so slow? Perhaps you could point out particularly slow >>> for your purposes parts ? >>> >>> >> -- >> 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+...@googlegroups.com <javascript:>. >> >> >> To post to this group, send email to sage-...@googlegroups.com >> <javascript:>. >> Visit this group at https://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 a topic in the >> Google Groups "sage-devel" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/sage-devel/3cSPt18Fv7Y/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> sage-devel+...@googlegroups.com <javascript:>. >> To post to this group, send email to sage-...@googlegroups.com >> <javascript:>. >> Visit this group at https://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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
