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From: "liubov.dmitrieva at gmail dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sources.redhat.com Subject: [Bug math/14473] New: Inaccurate CPOWF function on x86_32 and x86_64 Date: Wed, 15 Aug 2012 15:10:00 -0000 [thread overview] Message-ID: <bug-14473-131@http.sourceware.org/bugzilla/> (raw) http://sourceware.org/bugzilla/show_bug.cgi?id=14473 Bug #: 14473 Summary: Inaccurate CPOWF function on x86_32 and x86_64 Product: glibc Version: 2.17 Status: NEW Severity: normal Priority: P2 Component: math AssignedTo: unassigned@sourceware.org ReportedBy: liubov.dmitrieva@gmail.com Classification: Unclassified // gcc main.c -std=c99 -lm <-m32> #include <stdio.h> #include <math.h> #include <complex.h> #include <fenv.h> #include <stdlib.h> // abs function for int argument #define ireal(a) (((int*)&(a))[0]) #define iimag(a) (((int*)&(a))[1]) #define real(a) (((float*)&(a))[0]) #define imag(a) (((float*)&(a))[1]) int main() { float _Complex a,b,r1,r2; ireal(a)=0xbf0e38e4; iimag(a)=0xbde38e3e; //argument ireal(b)=0x3f0e38e3; iimag(b)=0xbde38e3e; //argument fesetround(FE_TONEAREST); r1 = cpowf(a,b); //actual result r2 = cpow(a,b); //actual result 2 printf("inputs: a.real = (0x%08x)\t%e\n", ireal(a), real(a)); printf(" a.imag = (0x%08x)\t%e\n", iimag(a), imag(a)); printf("\n"); printf("inputs: b.real = (0x%08x)\t%e\n", ireal(b), real(b)); printf(" b.imag = (0x%08x)\t%e\n", iimag(b), imag(b)); printf("\n"); printf("actual.real = (0x%08x)\t%.13e\n", ireal(r1), real(r1)); printf("expected.real = (0x%08x)\t%.13e\n", ireal(r2), real(r2)); printf("error.real = %d ulp\n", abs(ireal(r1) - ireal(r2))); printf("\n"); printf("actual.imag = (0x%08x)\t%.13e\n", iimag(r1), imag(r1)); printf("expected.imag = (0x%08x)\t%.13e\n", iimag(r2), imag(r2)); printf("error.imag = %d ulp\n", abs(iimag(r1) - iimag(r2))); return 0; } Result x86_32 (core2): inputs: a.real = (0xbf0e38e4) -5.555556e-01 a.imag = (0xbde38e3e) -1.111111e-01 inputs: b.real = (0x3f0e38e3) 5.555555e-01 b.imag = (0xbde38e3e) -1.111111e-01 actual.real = (0xba6f8923) -9.1375614283606e-04 expected.real = (0xba6f8d77) -9.1382063692436e-04 error.real = 1108 ulp actual.imag = (0xbf069c6d) -5.2582436800003e-01 expected.imag = (0xbf069c6d) -5.2582436800003e-01 error.imag = 0 ulp Result x86_64 (core2): inputs: a.real = (0xbf0e38e4) -5.555556e-01 a.imag = (0xbde38e3e) -1.111111e-01 inputs: b.real = (0x3f0e38e3) 5.555555e-01 b.imag = (0xbde38e3e) -1.111111e-01 actual.real = (0xba6f8923) -9.1375614283606e-04 expected.real = (0xba6f8d77) -9.1382063692436e-04 error.real = 1108 ulp actual.imag = (0xbf069c6d) -5.2582436800003e-01 expected.imag = (0xbf069c6d) -5.2582436800003e-01 error.imag = 0 ulp -- 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:[~2012-08-15 15:10 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-08-15 15:10 liubov.dmitrieva at gmail dot com [this message] 2012-08-15 15:23 ` [Bug math/14473] " joseph at codesourcery dot com 2012-08-16 7:52 ` liubov.dmitrieva at gmail dot com 2013-01-25 16:49 ` glisse at gcc dot gnu.org 2013-04-04 16:12 ` [Bug math/14473] Inaccurate CPOW* function on all machines carlos at redhat dot com 2013-04-04 16:13 ` carlos at redhat dot com 2013-08-05 19:27 ` licquia at linuxfoundation dot org 2013-12-06 14:07 ` mwelinder at gmail dot com 2013-12-06 14:17 ` mwelinder at gmail dot com 2014-06-17 18:38 ` fweimer at redhat dot com
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