* huge error for pow
@ 2023-04-08 6:00 Paul Zimmermann
2023-04-11 9:18 ` Corinna Vinschen
0 siblings, 1 reply; 6+ messages in thread
From: Paul Zimmermann @ 2023-04-08 6:00 UTC (permalink / raw)
To: newlib
Hi,
a gentle reminder for this issue reported two months ago:
https://sourceware.org/pipermail/newlib/2023/020164.html
Paul
^ permalink raw reply [flat|nested] 6+ messages in thread* huge error for pow
@ 2023-02-07 14:27 Paul Zimmermann
2023-02-07 21:48 ` Jeff Johnston
0 siblings, 1 reply; 6+ messages in thread
From: Paul Zimmermann @ 2023-02-07 14:27 UTC (permalink / raw)
To: newlib; +Cc: vincenzo.innocente
Hi,
while testing Newlib 4.3.0, I noticed the following huge error:
zimmerma@salade:~/svn/tbd/20/src/binary64$ VERBOSE=-v ./doitb.newlib pow 1000
Checking pow with newlib-4.3.0.20230120
Using seed 1619945
pow 0 -1 -0x1.647ff80007ff8p-576,-0x1.3d018267f12fp+48 [inf] inf inf
libm gives inf
mpfr gives -inf
The exponent y in x^y is a large odd integer, thus since x is negative we
should get a negative number as result.
This issue was apparently already present in 3.3.0, but we only discovered
it now.
Best regards,
Paul
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: huge error for pow
2023-02-07 14:27 Paul Zimmermann
@ 2023-02-07 21:48 ` Jeff Johnston
2023-02-08 7:02 ` Paul Zimmermann
0 siblings, 1 reply; 6+ messages in thread
From: Jeff Johnston @ 2023-02-07 21:48 UTC (permalink / raw)
To: Paul Zimmermann; +Cc: newlib, vincenzo.innocente
[-- Attachment #1: Type: text/plain, Size: 726 bytes --]
Thanks Paul,
Do you think you can put together a patch?
-- Jeff J.
On Tue, Feb 7, 2023 at 9:27 AM Paul Zimmermann <Paul.Zimmermann@inria.fr>
wrote:
> Hi,
>
> while testing Newlib 4.3.0, I noticed the following huge error:
>
> zimmerma@salade:~/svn/tbd/20/src/binary64$ VERBOSE=-v ./doitb.newlib pow
> 1000
> Checking pow with newlib-4.3.0.20230120
> Using seed 1619945
> pow 0 -1 -0x1.647ff80007ff8p-576,-0x1.3d018267f12fp+48 [inf] inf inf
> libm gives inf
> mpfr gives -inf
>
> The exponent y in x^y is a large odd integer, thus since x is negative we
> should get a negative number as result.
>
> This issue was apparently already present in 3.3.0, but we only discovered
> it now.
>
> Best regards,
> Paul
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: huge error for pow
2023-02-07 21:48 ` Jeff Johnston
@ 2023-02-08 7:02 ` Paul Zimmermann
0 siblings, 0 replies; 6+ messages in thread
From: Paul Zimmermann @ 2023-02-08 7:02 UTC (permalink / raw)
To: Jeff Johnston; +Cc: newlib, vincenzo.innocente
Hi Jeff,
this would not make sense on our side, since in CORE-MATH we are currently
completing a correctly rounded pow function, which will be available in a
few weeks, and can then be integrated into newlib.
Best regards,
Paul
> From: Jeff Johnston <jjohnstn@redhat.com>
> Date: Tue, 7 Feb 2023 16:48:14 -0500
> Cc: newlib@sourceware.org, vincenzo.innocente@cern.ch
>
>
> [1:text/plain Show]
>
>
> [2:text/html Hide Save:noname (1kB)]
>
> Thanks Paul,
>
> Do you think you can put together a patch?
>
> -- Jeff J.
>
> On Tue, Feb 7, 2023 at 9:27 AM Paul Zimmermann <Paul.Zimmermann@inria.fr>
> wrote:
>
> Hi,
>
> while testing Newlib 4.3.0, I noticed the following huge error:
>
> zimmerma@salade:~/svn/tbd/20/src/binary64$ VERBOSE=-v ./doitb.newlib pow
> 1000
> Checking pow with newlib-4.3.0.20230120
> Using seed 1619945
> pow 0 -1 -0x1.647ff80007ff8p-576,-0x1.3d018267f12fp+48 [inf] inf inf
> libm gives inf
> mpfr gives -inf
>
> The exponent y in x^y is a large odd integer, thus since x is negative
> we
> should get a negative number as result.
>
> This issue was apparently already present in 3.3.0, but we only
> discovered
> it now.
>
> Best regards,
> Paul
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-04-11 9:37 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-04-08 6:00 huge error for pow Paul Zimmermann
2023-04-11 9:18 ` Corinna Vinschen
2023-04-11 9:37 ` Paul Zimmermann
-- strict thread matches above, loose matches on Subject: below --
2023-02-07 14:27 Paul Zimmermann
2023-02-07 21:48 ` Jeff Johnston
2023-02-08 7:02 ` Paul Zimmermann
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).