From: "Carlos O'Donell" <carlos@redhat.com>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: GNU C Library <libc-alpha@sourceware.org>,
"libc-ports@sourceware.org" <libc-ports@sourceware.org>
Subject: Re: Results of cos(pi/2) tests are dependent on error rounding pi/2 to a type.
Date: Fri, 12 Apr 2013 02:22:00 -0000 [thread overview]
Message-ID: <51676FFC.2090301@redhat.com> (raw)
In-Reply-To: <m238uxaroc.fsf@igel.home>
On 04/11/2013 01:44 PM, Andreas Schwab wrote:
> I'm getting this result on ppc for long double:
>
> Failure: Test: cos (pi/2) == 1.082856673921913968223746169860580e-32
> Result:
> is: 1.08285667392191396822e-32 0x1.c1cd129024e088a67cc7p-107
> should be: 1.08285667392191396822e-32 0x1.c1cd129024e088a67cc7p-107
> difference: 5.71253355584909492648e-62 0x1.78000000000000000000p-204
> ulp : 376.0000
> max.ulp : 0.0000
> Maximal error of `cos'
> is : 376 ulp
> accepted: 1 ulp
> Failure: Test: sincos (pi/2, &sin_res, &cos_res) puts 1.082856673921913968223746169860580e-32 in cos_res
> Result:
> is: 1.08285667392191396822e-32 0x1.c1cd129024e088a67cc7p-107
> should be: 1.08285667392191396822e-32 0x1.c1cd129024e088a67cc7p-107
> difference: 5.71253355584909492648e-62 0x1.78000000000000000000p-204
> ulp : 376.0000
> max.ulp : 0.0000
> Maximal error of `sincos'
> is : 376 ulp
> accepted: 1 ulp
>
> Filed as PR15359.
Could you print the following for me?
printf ("%.100000g\n", (long double)(M_PIl/2.0L));
The most likely scenario is that I lost digits of precision when using only %.100Le.
I'm trying to get my hands on a fast ppc box to test stuff on.
Cheers,
Carlos.
prev parent reply other threads:[~2013-04-12 2:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-11 12:59 Carlos O'Donell
2013-04-11 17:44 ` Andreas Schwab
2013-04-12 2:22 ` Carlos O'Donell [this message]
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