Date: Wed, 25 Jul 2012 12:27:43 -0500 From: Stephen Montgomery-Smith <stephen@missouri.edu> To: Rainer Hurling <rhurlin@gwdg.de> Cc: David Schultz <das@freebsd.org>, freebsd-current@freebsd.org, Bruce Evans <bde@freebsd.org>, Steve Kargl <sgk@troutmask.apl.washington.edu> Subject: Re: Use of C99 extra long double math functions after r236148 Message-ID: <50102C8F.2080901@missouri.edu> In-Reply-To: <50101EDE.6030509@gwdg.de> References: <4FC43C8F.5090509@missouri.edu> <20120529045612.GB4445@server.rulingia.com> <20120708124047.GA44061@zim.MIT.EDU> <210816F0-7ED7-4481-ABFF-C94A700A3EA0@bsdimp.com> <20120708233624.GA53462@troutmask.apl.washington.edu> <4FFBF16D.2030007@gwdg.de> <2A1DE516-ABB4-49D7-8C3D-2C4DA2D9FCF5@bsdimp.com> <4FFC412B.4090202@gwdg.de> <20120710151115.GA56950@zim.MIT.EDU> <4FFC5E5D.8000502@gwdg.de> <20120710225801.GB58778@zim.MIT.EDU> <50101EDE.6030509@gwdg.de>
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On 07/25/12 11:29, Rainer Hurling wrote:
> Many thanks to you three for implementing expl() with r238722 and r238724.
>
> I am not a C programmer, but would like to ask if the following example
> is correct and suituable as a minimalistic test of this new C99 function?
>
>
> //-----------------------------------
> #include <stdio.h>
> #include <math.h>
>
> int main(void)
> {
> double c = 2.0;
> long double d = 2.0;
>
> double e = exp(c);
> long double f = expl(d);
>
> printf("exp(%f) is %.*f\n", c, 90, e);
> printf("expl(%Lf) is %.*Lf\n", d, 90, f);
>
> return 0;
> }
> //-----------------------------------
>
>
> Compiled with 'c99 -o math_expl math_expl.c -lm' and running afterwards
> it gives me:
>
> exp(2.000000) is
> 7.389056098930650406941822438966482877731323242187500000000000000000000000000000000000000000
>
> expl(2.000000) is
> 7.389056098930650227397942675366948606097139418125152587890625000000000000000000000000000000
>
Just as a point of comparison, here is the answer computed using
Mathematica:
N[Exp[2], 50]
7.3890560989306502272304274605750078131803155705518
As you can see, the expl solution has only a few digits more accuracy
that exp.
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