Re: Comparison of multiple-precision floating-point software

[Karim Belabas <Karim.Belabas@math.u-bordeaux.fr>]

* paul zimmermann [2018-04-25 11:26]:
>        Dear Pari developers,
> 
> I have updated my comparison of multiple-precision floating-point software:
> 
> 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 : 

- I believe it will make no difference at small accuracy and provide a
  small improvement for huge accuracies; but it's important to me as a
  developper to be aware of the caching impact !

- algorithms and implementations were chosen with the precondition that
  some constants would be available for free [ at least from the second
  call on ].
  
I believe it's more relevant to compare actual user experience for
a given system, not restricted to an idealized (in this case crippled)
"benchmark environment". (All benchmarks will be biased towards specific
uses which may or may not be the system's primary target, but I don't
think one should add to the bias.)

Cheers,

    K.B.
--
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]
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