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From: "vincent-srcware at vinc17 dot net" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sources.redhat.com Subject: [Bug math/706] pow() produces inaccurate results for base ~ 1.0, and large integer exponent on 32-bit x86 Date: Tue, 28 Feb 2012 16:36:00 -0000 [thread overview] Message-ID: <bug-706-131-ahJXhkaoST@http.sourceware.org/bugzilla/> (raw) In-Reply-To: <bug-706-131@http.sourceware.org/bugzilla/> http://sourceware.org/bugzilla/show_bug.cgi?id=706 Vincent Lefèvre <vincent-srcware at vinc17 dot net> changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|pow() produces inaccurate |pow() produces inaccurate |results for base ~ 1.0, and |results for base ~ 1.0, and |large exponent on 32-bit |large integer exponent on |x86 |32-bit x86 --- Comment #14 from Vincent Lefèvre <vincent-srcware at vinc17 dot net> 2012-02-28 16:36:13 UTC --- I've done some tests, and it seems that pow(x,y) for large y is inaccurate only when y is an integer. So, if I understand correctly, an iterative algorithm is used for integers y, and a log-exp algorithm (which seems accurate enough on the few values I've tested) is used for other values. So, a possible easy fix would be to always use the log-exp algorithm, possibly except for small integers y. Note: I've updated the bug summary following this observation (large exponent → large integer exponent). -- 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.
next prev parent reply other threads:[~2012-02-28 16:36 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-706-131@http.sourceware.org/bugzilla/> 2012-02-14 14:49 ` [Bug math/706] pow() produces inaccurate results for base ~ 1.0, and large " vincent-srcware at vinc17 dot net 2012-02-22 21:30 ` jsm28 at gcc dot gnu.org 2012-02-22 21:54 ` jsm28 at gcc dot gnu.org 2012-02-25 16:06 ` calixte.denizet@scilab-enterprises.com 2012-02-27 15:41 ` vincent-srcware at vinc17 dot net 2012-02-28 12:35 ` calixte.denizet@scilab-enterprises.com 2012-02-28 14:04 ` vincent-srcware at vinc17 dot net 2012-02-28 14:59 ` vincent-srcware at vinc17 dot net 2012-02-28 16:36 ` vincent-srcware at vinc17 dot net [this message] 2012-04-09 9:49 ` [Bug math/706] pow() produces inaccurate results for base ~ 1.0, and large integer " jsm28 at gcc dot gnu.org 2014-02-16 18:27 ` jackie.rosen at hushmail dot com 2014-05-28 19:45 ` schwab at sourceware dot org
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