From: Paul Zimmermann <Paul.Zimmermann@inria.fr>
To: newlib@sourceware.org
Cc: vincenzo.innocente@cern.ch
Subject: huge error for pow
Date: Tue, 07 Feb 2023 15:27:42 +0100 [thread overview]
Message-ID: <mwa61p7dpd.fsf@coriandre.loria.fr> (raw)
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
next reply other threads:[~2023-02-07 14:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-07 14:27 Paul Zimmermann [this message]
2023-02-07 21:48 ` Jeff Johnston
2023-02-08 7:02 ` Paul Zimmermann
2023-04-08 6:00 Paul Zimmermann
2023-04-11 9:18 ` Corinna Vinschen
2023-04-11 9:37 ` Paul Zimmermann
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