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[Bug math/4108] New: erfcf returns incorrectly rounded results compared to erfc
- From: "myles at peakstreaminc dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 28 Feb 2007 02:34:18 -0000
- Subject: [Bug math/4108] New: erfcf returns incorrectly rounded results compared to erfc
- Reply-to: sourceware-bugzilla at sourceware dot org
In the attached program results from erfc are compared with results from erfcf
and large differences are flagged. The errors occur for values near 4.0 and 8.0,
but slightly under.
Two examples:
x: 3.9311595 (407b981e) float(erfc): 2.7055004e-08 (32e86695) erfcf: 2.705503e
-08 (32e866a4) diff: 2.6645353e-14 (45 ULP)
x: 7.9999866 (40ffffe4) float(erfc): 1.1226714e-29 (f63b46e) erfcf: 1.1226756e
-29 (f63b4a7) diff: 4.2882034e-35 (114 ULP)
It is possible the values for erfc are incorrect, as I don't have another source
to check that.
Also happens on x86_64-redhat-linux
--
Summary: erfcf returns incorrectly rounded results compared to
erfc
Product: glibc
Version: 2.3.4
Status: NEW
Severity: normal
Priority: P2
Component: math
AssignedTo: aj at suse dot de
ReportedBy: myles at peakstreaminc dot com
CC: glibc-bugs at sources dot redhat dot com
GCC build triplet: i386-redhat-linux
GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux
http://sourceware.org/bugzilla/show_bug.cgi?id=4108
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