This is the mail archive of the
glibc-bugs@sourceware.org
mailing list for the glibc project.
[Bug math/14472] New: Inaccurate y1f function on x86_32
- From: "liubov.dmitrieva at gmail dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: Wed, 15 Aug 2012 14:18:28 +0000
- Subject: [Bug math/14472] New: Inaccurate y1f function on x86_32
- Auto-submitted: auto-generated
http://sourceware.org/bugzilla/show_bug.cgi?id=14472
Bug #: 14472
Summary: Inaccurate y1f function on x86_32
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 <fenv.h>
#include <stdlib.h> // abs function for int argument
extern float y1f(float);
extern double y1(double);
#define i32(a) (((int*)&(a))[0])
int main() {
float a,r1,r2;
i32(a)=0x422cc0bc; //argument
fesetround(FE_TONEAREST); // FE_TONEAREST
r1 = y1f(a); //actual result
r2 = y1(a); //actual result 2
printf("inputs: a = (0x%08x)\t%e\n", i32(a), a);
printf("actual = (0x%08x)\t%.13e\n", i32(r1), r1);
printf("expected = (0x%08x)\t%.13e\n", i32(r2), r2);
printf("error = %d ulp\n", abs(i32(r1) - i32(r2)));
return 0;
}
Result:
inputs: a = (0x422cc0bc) 4.318822e+01
actual = (0x33f3b02b) 1.1347614048418e-07
expected = (0x33f3934c) 1.1342362427058e-07
error = 7391 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.