Date: Wed, 25 Jul 2012 12:37:56 -0500 From: Stephen Montgomery-Smith <stephen@missouri.edu> To: Steve Kargl <sgk@troutmask.apl.washington.edu> Cc: David Schultz <das@freebsd.org>, Bruce Evans <bde@freebsd.org>, freebsd-current@freebsd.org Subject: Re: Use of C99 extra long double math functions after r236148 Message-ID: <50102EF4.2080601@missouri.edu> In-Reply-To: <20120725173147.GA72824@troutmask.apl.washington.edu> References: <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> <50102C8F.2080901@missouri.edu> <20120725173147.GA72824@troutmask.apl.washington.edu>
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On 07/25/12 12:31, Steve Kargl wrote: > On Wed, Jul 25, 2012 at 12:27:43PM -0500, Stephen Montgomery-Smith wrote: >> 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? >>> >>> > > (program deleted) > >>> >>> Compiled with 'c99 -o math_expl math_expl.c -lm' and running afterwards >>> it gives me: >>> >>> exp(2.000000) is >>> 7.3890560989306504069 >>> >>> expl(2.000000) is >>> 7.38905609893065022739794 >>> >> >> 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. > > Unless you are using sparc64 hardware. > > flame:kargl[204] ./testl -V 2 > ULP = 0.2670 for x = 2.000000000000000000000000000000000e+00 > mpfr exp: 7.389056098930650227230427460575008e+00 > libm exp: 7.389056098930650227230427460575008e+00 Yes. It would be nice if long on the Intel was as long as the sparc64.
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