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* [Bug math/12144] New: gamma function still returns absurd values @ 2010-10-21 3:58 support at transpacific dot net 2010-10-21 8:40 ` [Bug math/12144] " schwab@linux-m68k.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: support at transpacific dot net @ 2010-10-21 3:58 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=12144 Summary: gamma function still returns absurd values Product: glibc Version: unspecified Status: NEW Severity: critical Priority: P2 Component: math AssignedTo: aj@suse.de ReportedBy: support@transpacific.net On Ubuntu 10.04 with latest libm and on older FreeBSD 6.2, gamma() returns bad values. I see references to this by other people; it has not been addressed. How serious it is is demonstrated by relating that libm says gamma(2.0) = 0.0 and that gamma(3.0) - 0.39, when both answers should be 1.0. Mathematically 1/gamma(2) is legal but not with this bug. Most statistical modeling is screwed. I had to migrate to the GSL library to get correct results. OUCH! -- 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] 5+ messages in thread
* [Bug math/12144] gamma function still returns absurd values 2010-10-21 3:58 [Bug math/12144] New: gamma function still returns absurd values support at transpacific dot net @ 2010-10-21 8:40 ` schwab@linux-m68k.org 2010-10-21 19:17 ` support at transpacific dot net ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: schwab@linux-m68k.org @ 2010-10-21 8:40 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=12144 Andreas Schwab <schwab@linux-m68k.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |INVALID --- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> 2010-10-21 08:40:00 UTC --- gamma is a non-standard function that returns $log_e |Γ(x)|$. Use tgamma for the gramma function. And Γ(3) ≠ 1. -- 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] 5+ messages in thread
* [Bug math/12144] gamma function still returns absurd values 2010-10-21 3:58 [Bug math/12144] New: gamma function still returns absurd values support at transpacific dot net 2010-10-21 8:40 ` [Bug math/12144] " schwab@linux-m68k.org @ 2010-10-21 19:17 ` support at transpacific dot net 2010-10-27 2:50 ` pasky at suse dot cz 2014-06-30 7:24 ` fweimer at redhat dot com 3 siblings, 0 replies; 5+ messages in thread From: support at transpacific dot net @ 2010-10-21 19:17 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=12144 --- Comment #2 from Eric Dynamic <support at transpacific dot net> 2010-10-21 19:16:51 UTC --- Sorry about the 2/3, I meant 1/2. I tried tgamma but it does not exist in the library on Ubuntu (meaning the latest.) lgamma() of course returns the error I mention. Therefore there is still no working gamma. If in libm "gamma" is the function that ought to be named "lngamma" or "loggamma", then that's an error that should be corrected despite any "historical precendent" in my opinion. schwab@linux-m68k.org wrote: > http://sourceware.org/bugzilla/show_bug.cgi?id=12144 > > Andreas Schwab <schwab@linux-m68k.org> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > Status|NEW |RESOLVED > Resolution| |INVALID > > --- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> 2010-10-21 08:40:00 UTC --- > gamma is a non-standard function that returns $log_e |Γ(x)|$. Use tgamma for > the gramma function. And Γ(3) ≠ 1. > > -- 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] 5+ messages in thread
* [Bug math/12144] gamma function still returns absurd values 2010-10-21 3:58 [Bug math/12144] New: gamma function still returns absurd values support at transpacific dot net 2010-10-21 8:40 ` [Bug math/12144] " schwab@linux-m68k.org 2010-10-21 19:17 ` support at transpacific dot net @ 2010-10-27 2:50 ` pasky at suse dot cz 2014-06-30 7:24 ` fweimer at redhat dot com 3 siblings, 0 replies; 5+ messages in thread From: pasky at suse dot cz @ 2010-10-27 2:50 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=12144 Petr Baudis <pasky at suse dot cz> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |pasky at suse dot cz --- Comment #3 from Petr Baudis <pasky at suse dot cz> 2010-10-27 02:49:42 UTC --- If tgamma() truly is not present in Ubuntu's libm (it sure is in Debian's at least), report that to your distributor. The gamma() function naming is unfortunate, sadly we cannot reshape the word to be pretty without any regard to compatibility. I suggest you at least read through the related Linux manpages which explain the gamma() family of functions and historical story behind. -- 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] 5+ messages in thread
* [Bug math/12144] gamma function still returns absurd values 2010-10-21 3:58 [Bug math/12144] New: gamma function still returns absurd values support at transpacific dot net ` (2 preceding siblings ...) 2010-10-27 2:50 ` pasky at suse dot cz @ 2014-06-30 7:24 ` fweimer at redhat dot com 3 siblings, 0 replies; 5+ messages in thread From: fweimer at redhat dot com @ 2014-06-30 7:24 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=12144 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] 5+ messages in thread
end of thread, other threads:[~2014-06-30 7:24 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2010-10-21 3:58 [Bug math/12144] New: gamma function still returns absurd values support at transpacific dot net 2010-10-21 8:40 ` [Bug math/12144] " schwab@linux-m68k.org 2010-10-21 19:17 ` support at transpacific dot net 2010-10-27 2:50 ` pasky at suse dot cz 2014-06-30 7:24 ` fweimer at redhat dot com
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