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From:  Le Chaud Lapin <jaibuduvin@gmail.com>
Newsgroups: comp.soft-sys.matlab,comp.dsp
Subject: Re: Seeking numerical package for quadruple precision...
Date: Wed, 04 Jul 2007 19:08:13 -0000
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On Jul 4, 7:21 am, "Vista" <a...@gmai.com> wrote:
> "Le Chaud Lapin" <jaibudu...@gmail.com> wrote in messagenews:1183534955.773488.278220@k79g2000hse.googlegroups.com...
>
>
>
> > On Jul 3, 8:53 pm, "Vista" <a...@gmai.com> wrote:
> >> I mean, I am looking for the fastest one, not just any one...
>
> >> I know from Google there are quite a few quadruple packages out there.
>
> >> But I need the fastest ones... Speed is really critical...
>
> >> "Vista" <a...@gmai.com> wrote in message
>
> >>news:f6etbs$2of$1@news.Stanford.EDU...
>
> >> > Hi all,
>
> >> > I have some computation and simulation which need quadruple precision.
> >> > I
> >> > mean, the double precision is not enough, while high precision such as
> >> > 1000 digits is not needed, and that's too slow. I guess quadruple
> >> > precision exactly fits my problem and should be much faster than double
> >> > precision.
>
> >> > Could anybody tell me if MS Visual C++, or Intel C, Intel Fortran have
> >> > already got quadruple precision in them and they are fully supported on
> >> > Intel based cpus? I guess Intel Fortran has quadruple precision, but
> >> > since
> >> > I prefer C/C++ so my first choices are within C/C++ languages.
>
> >> > Moreover, do GSL, Intel MKL, and IMSL etc. have got quadruple precision
> >> > support? I only need +, -, *, /, exp, and log.
>
> >> > I eventually have to do everything in C/C++ so I am primarily looking
> >> > for
> >> > numerical libraries, instead of Matlab or Maple or Mathematica's
> >> > symbolic
> >> > capability.
>
> >> > But if you know how to "simulate" quadruple precision in Matlab or
> >> > Maple,
> >> > or Mathematica, in order to see if an algorithm will overslow when
> >> > converting into C/C++/Fortran, please let me know. I want to do the
> >> > algorithm design in Matlab, and test if it will overflow, before
> >> > converting everything into C/C++/Fortran.
>
> >> > If you know how to "simulate" quadruple precision in Matlab, Maple or
> >> > Mathematica even with the symbolic toolbox, please let me know too...
> >> > this
> >> > is for algorithm design and testing...
>
> >> > Moreover, are there popular quadruple precision packages? Please
> >> > recommend
> >> > the fastest one. I am really in huge need of speed.
>
> >> > Thank you very much!
>
> > In C++:
>
> > long double x;
>
> > You can tweak the compiler options for optimum speed on your
> > particular CPU.
>
> > -Le Chaud Lapin-
>
> I need 30 digits of precision digits. Will "long double" give me that?
>
> Thanks!

I think you mean to ask for "multiple precision", not "quadruple"
precision.

In C++, one of the top dogs for speed is GMP.

http://gmplib.org/

To a C++ programmer, the naming using in the code might be
surprising.  For example, if you are looking for the "big integer"
class, don't expect it to be named "Integer" or anything like that.
Same for floating-point.

-Le Chaud Lapin-