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* [Bug math/13884] New: exp10 inaccurate @ 2012-03-20 21:45 jsm28 at gcc dot gnu.org 2012-04-30 9:41 ` [Bug math/13884] " jsm28 at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: jsm28 at gcc dot gnu.org @ 2012-03-20 21:45 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13884 Bug #: 13884 Summary: exp10 inaccurate Product: glibc Version: 2.15 Status: NEW Severity: normal Priority: P2 Component: math AssignedTo: unassigned@sourceware.org ReportedBy: jsm28@gcc.gnu.org Classification: Unclassified The generic implementations of exp10, exp10f, exp10l (math/e_exp10*) use exp (arg * log (10)) as their algorithm, which is inaccurate for large inputs (you need some extra precision for calculating log (10) and doing the multiplication). For example, on x86_64, exp10f (36) has a 39ulp error, exp10 (305) has a 217ulp error and exp10l (4932) has a 5612ulp error. It is likely that the x86 implementations of exp10f and exp10 are OK (because of the extra x87 precision used for internal calculations), but that of exp10l probably suffers the same issue as reported here (but I haven't tested the x86 functions). -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug math/13884] exp10 inaccurate 2012-03-20 21:45 [Bug math/13884] New: exp10 inaccurate jsm28 at gcc dot gnu.org @ 2012-04-30 9:41 ` jsm28 at gcc dot gnu.org 2012-05-06 18:25 ` jsm28 at gcc dot gnu.org 2014-06-26 13:47 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: jsm28 at gcc dot gnu.org @ 2012-04-30 9:41 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13884 --- Comment #1 from Joseph Myers <jsm28 at gcc dot gnu.org> 2012-04-30 09:41:34 UTC --- Accuracy for float only fixed by: commit 9568c0c2255045456a09b441f89c6641e27a4bec Author: Joseph Myers <joseph@codesourcery.com> Date: Mon Apr 30 09:37:01 2012 +0000 Fix exp10 spurious overflows (bug 13924). double and long double still need to be fixed. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug math/13884] exp10 inaccurate 2012-03-20 21:45 [Bug math/13884] New: exp10 inaccurate jsm28 at gcc dot gnu.org 2012-04-30 9:41 ` [Bug math/13884] " jsm28 at gcc dot gnu.org @ 2012-05-06 18:25 ` jsm28 at gcc dot gnu.org 2014-06-26 13:47 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: jsm28 at gcc dot gnu.org @ 2012-05-06 18:25 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13884 Joseph Myers <jsm28 at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |FIXED --- Comment #2 from Joseph Myers <jsm28 at gcc dot gnu.org> 2012-05-06 18:24:49 UTC --- Fixed by: commit d8b82cad1b525bdcbfff88d218c7c45032e4a3af Author: Joseph Myers <joseph@codesourcery.com> Date: Sun May 6 18:23:44 2012 +0000 Fix exp10 inaccuracy and exceptions (bugs 13884, 13914). -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug math/13884] exp10 inaccurate 2012-03-20 21:45 [Bug math/13884] New: exp10 inaccurate jsm28 at gcc dot gnu.org 2012-04-30 9:41 ` [Bug math/13884] " jsm28 at gcc dot gnu.org 2012-05-06 18:25 ` jsm28 at gcc dot gnu.org @ 2014-06-26 13:47 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2014-06-26 13:47 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=13884 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Flags| |security- -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-06-26 13:47 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-03-20 21:45 [Bug math/13884] New: exp10 inaccurate jsm28 at gcc dot gnu.org 2012-04-30 9:41 ` [Bug math/13884] " jsm28 at gcc dot gnu.org 2012-05-06 18:25 ` jsm28 at gcc dot gnu.org 2014-06-26 13:47 ` fweimer at redhat dot com
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