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Date: Wed, 25 Jul 2012 12:37:56 -0500
From: Stephen Montgomery-Smith <stephen@missouri.edu>
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To: Steve Kargl <sgk@troutmask.apl.washington.edu>
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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
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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.