[Bug 583475] New: glibc/libm: Wrong result for Bessel function jn on x86-64

http://bugzilla.novell.com/show_bug.cgi?id=583475 http://bugzilla.novell.com/show_bug.cgi?id=583475#c0 Summary: glibc/libm: Wrong result for Bessel function jn on x86-64 Classification: openSUSE Product: openSUSE 11.3 Version: Factory Platform: Other OS/Version: Other Status: NEW Severity: Normal Priority: P5 - None Component: Basesystem AssignedTo: bnc-team-screening@forge.provo.novell.com ReportedBy: burnus@gmx.de QAContact: qa@suse.de Found By: --- Blocker: --- User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; de; rv:1.9.2.0) Gecko/20100115 SUSE/3.6.0-1.6 Firefox/3.6 The Bessel function "jn" gives -INF on x86-64; the 32bit version and the float/long double version work OK, as the example shows below. As I am more familiar with Fortran, I only included the float/long double version as Fortran version. Note: The compile-time result using MPFR is OK; the long double version is also fine. However, the float version is a bit imprecise - especially on x86-64. $ cat bessel.c #include #include int main () { double r8 = 2.4048255576957729; printf("%f\n", jn (3, r8)); return 0; } $ gcc -m64 bessel.c -lm && ./a.out -inf $ gcc -m32 bessel.c -lm && ./a.out 0.185007 $ cat bessel.f90 real(4) :: r4 = 2.4048255576957729_8 real(8) :: r8 = 2.4048255576957729_8 real(10):: r10 = 2.4048255576957729_8 print *, besjn(3,r4) print *, besjn(3,r8) print *, besjn(3,r10) print *, besjn(3,2.4048255576957729_4) print *, besjn(3,2.4048255576957729_8) print *, besjn(3,2.4048255576957729_10) end $ gfortran bess.f90 && ./a.out 0.23056939 -Infinity 0.19899961853217685017 0.19899988 0.19899990535769083 0.19899990535769083403 $ gfortran -m32 bess.f90 && ./a.out 0.21264313 0.18500707660808169 0.19899961853217685017 0.19899988 0.19899990535769083 0.19899990535769083403 For comparison, Mathematica prints: In[9]:= N[BesselJ[3,24048255576957729/10^16],100] Out[9]= 0.1989999053576908340404214676453081343062074878596551788786229685276\

034212501569217985245804444265895

Reproducible: Always -- Configure bugmail: http://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.