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From: "aj at suse dot de" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sources.redhat.com Subject: [Bug math/13854] New: tan() is incorrect for large inputs on x86_64 and x86 Date: Thu, 15 Mar 2012 15:14:00 -0000 [thread overview] Message-ID: <bug-13854-131@http.sourceware.org/bugzilla/> (raw) http://sourceware.org/bugzilla/show_bug.cgi?id=13854 Bug #: 13854 Summary: tan() is incorrect for large inputs on x86_64 and x86 Product: glibc Version: 2.13 Status: NEW Keywords: glibc_2.15 Severity: normal Priority: P2 Component: math AssignedTo: unassigned@sourceware.org ReportedBy: aj@suse.de CC: aj@suse.de, bugdal@aerifal.cx, carlos@systemhalted.org, ppluzhnikov@google.com, vincent-srcware@vinc17.net Depends on: 13658 Blocks: 13851, 13852 Classification: Unclassified +++ This bug was initially created as a clone of Bug #13658 +++ tan is inaccurate, see bug #13658 for a reference. Test program: #define _GNU_SOURCE #include <stdio.h> #include <math.h> int main (void) { volatile float xf = 1e22; float s1f, s2f; volatile double xd = 1e22; double s1d, s2d; volatile long double xl = 1e22; long double s1l, s2l; s1d = tan (xd); printf ("double: \n"); printf ("x = %.17g\n", xd); printf ("s1 = %.17g\n", s1d); s1f = tanf (xf); printf ("\nfloat: \n"); printf ("x = %.17g\n", xf); printf ("s1 = %.17g\n", s1f); s1l = tanl (xl); printf ("\nlong double: \n"); printf ("x = %.17Lg\n", xl); printf ("s1 = %.17Lg\n", s1l); return 0; } On x86-64: double: x = 1e+22 s1 = -1.6287782256068988 float: x = 9.9999997781963084e+21 s1 = -1.0810239315032959 long double: x = 1e+22 s1 = -0.52180662513577755 And on x86: double: x = 1e+22 s1 = -0.52180662513577758 float: x = 9.9999997781963084e+21 s1 = -0.29305437207221985 long double: x = 1e+22 s1 = -0.52180662513577755 The correct result of tan (1e22) is: s1 = -1.6287782256068988 -- 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 reply other threads:[~2012-03-15 15:14 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-03-15 15:14 aj at suse dot de [this message] 2012-03-15 15:38 ` [Bug math/13854] " aj at suse dot de 2012-03-16 20:13 ` jsm28 at gcc dot gnu.org 2013-06-03 16:05 ` carlos at redhat dot com 2013-06-03 17:47 ` carlos at redhat dot com 2014-06-26 13:52 ` fweimer at redhat dot com
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