Karim Belabas on Wed, 25 Apr 2018 19:14:33 +0200 |
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Re: Comparison of multiple-precision floating-point software |
* paul zimmermann [2018-04-25 17:19]: > > > https://members.loria.fr/PZimmermann/timings.html > > > > > > Pari is within a factor of 2 of MPFR for basic arithmetic, except for the > > > square root, mul/sqr at 1000d, sqr/div at 10000d. > > > > > > Your feedback is welcome. > > > > Hi Paul, > > > > Thanks for the data and update ! > > > > We already had this discussion a while back (in Medicis times...) > > but I still believe you should enable the 3 precomputed constants > > (log(2), Pi, Euler) in your timings-pari.c : [...] > feel free to try on your own. It is easy to get an account on the > gcc67 machine. Fair enough, that's what I ended up doing for the past 14 years or so because we want to have timings for 32-bit and non-GMP pari anyway: https://pari.math.u-bordeaux.fr/benchs/pari-2.9.0/timings-float.html (PARI and MPFR only; outdated versions, sorry...). Anyway, thanks again for sharing your benchmarks and results ! Cheers, K.B. P.S. > I bet it will give at best a speedup of less than 1%, since for 10000 > digits we evaluate at least 127 times each function: Possibly. If C is the time to compute a constant for a given accuracy and F the time for a function call given the constant (for your specific input). Then you measure C/127 + F, while I would measure F. So I agree with your comment if C is of the order of F (or less, which it should be for the tested functions). -- Karim Belabas, IMB (UMR 5251) Tel: (+33) (0)5 40 00 26 17 Universite de Bordeaux Fax: (+33) (0)5 40 00 21 23 351, cours de la Liberation http://www.math.u-bordeaux.fr/~kbelabas/ F-33405 Talence (France) http://pari.math.u-bordeaux.fr/ [PARI/GP] `