glibc/sysdeps/ieee754/ldbl-128/s_erfl.c

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/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
2002-08-26 Brian Youmans <3diff@gnu.org> * crypt/crypt.c: Changed copying permission notice to Lesser GPL from Library GPL. * crypt/crypt_util.c: Likewise. * crypt/ufc.c: Likewise. * elf/dl-conflict.c: Likewise. * elf/dl-iteratephdr.c: Likewise. * iconv/iconvconfig.h: Likewise. * linuxthreads/Examples/ex10.c: Likewise. * linuxthreads/Examples/ex11.c: Likewise. * linuxthreads/Examples/ex13.c: Likewise. * linuxthreads/Examples/ex8.c: Likewise. * linuxthreads/Examples/ex9.c: Likewise. * linuxthreads/barrier.c: Likewise. * linuxthreads/events.c: Likewise. * linuxthreads/lockfile.c: Likewise. * linuxthreads/no-tsd.c: Likewise. * linuxthreads/pt-machine.c: Likewise. * linuxthreads/ptclock_gettime.c: Likewise. * linuxthreads/ptclock_settime.c: Likewise. * linuxthreads/rwlock.c: Likewise. * linuxthreads/sysdeps/alpha/pspinlock.c: Likewise. * linuxthreads/sysdeps/alpha/pt-machine.h: Likewise. * linuxthreads/sysdeps/arm/pspinlock.c: Likewise. * linuxthreads/sysdeps/arm/pt-machine.h: Likewise. * linuxthreads/sysdeps/cris/pspinlock.c: Likewise. * linuxthreads/sysdeps/cris/pt-machine.h: Likewise. * linuxthreads/sysdeps/hppa/pspinlock.c: Likewise. * linuxthreads/sysdeps/hppa/pt-machine.h: Likewise. * linuxthreads/sysdeps/i386/i686/pt-machine.h: Likewise. * linuxthreads/sysdeps/i386/pspinlock.c: Likewise. * linuxthreads/sysdeps/i386/pt-machine.h: Likewise. * linuxthreads/sysdeps/i386/useldt.h: Likewise. * linuxthreads/sysdeps/ia64/pspinlock.c: Likewise. * linuxthreads/sysdeps/ia64/pt-machine.h: Likewise. * linuxthreads/sysdeps/m68k/pspinlock.c: Likewise. * linuxthreads/sysdeps/m68k/pt-machine.h: Likewise. * linuxthreads/sysdeps/mips/pspinlock.c: Likewise. * linuxthreads/sysdeps/mips/pt-machine.h: Likewise. * linuxthreads/sysdeps/powerpc/pspinlock.c: Likewise. * linuxthreads/sysdeps/powerpc/pt-machine.h: Likewise. * linuxthreads/sysdeps/pthread/bits/initspin.h: Likewise. * linuxthreads/sysdeps/pthread/bits/libc-lock.h: Likewise. * linuxthreads/sysdeps/pthread/bits/libc-tsd.h: Likewise. * linuxthreads/sysdeps/pthread/getcpuclockid.c: Likewise. * linuxthreads/sysdeps/pthread/posix-timer.h: Likewise. * linuxthreads/sysdeps/pthread/timer_create.c: Likewise. * linuxthreads/sysdeps/pthread/timer_delete.c: Likewise. * linuxthreads/sysdeps/pthread/timer_getoverr.c: Likewise. * linuxthreads/sysdeps/pthread/timer_gettime.c: Likewise. * linuxthreads/sysdeps/pthread/timer_routines.c: Likewise. * linuxthreads/sysdeps/pthread/timer_settime.c: Likewise. * linuxthreads/sysdeps/pthread/tst-timer.c: Likewise. * linuxthreads/sysdeps/s390/pspinlock.c: Likewise. * linuxthreads/sysdeps/s390/s390-32/pt-machine.h: Likewise. * linuxthreads/sysdeps/s390/s390-64/pt-machine.h: Likewise. * linuxthreads/sysdeps/sh/pspinlock.c: Likewise. * linuxthreads/sysdeps/sh/pt-machine.h: Likewise. * linuxthreads/sysdeps/sparc/sparc32/pspinlock.c: Likewise. * linuxthreads/sysdeps/sparc/sparc32/pt-machine.h: Likewise. * linuxthreads/sysdeps/sparc/sparc32/sparcv9/pspinlock.c: Likewise. * linuxthreads/sysdeps/sparc/sparc64/pspinlock.c: Likewise. * linuxthreads/sysdeps/sparc/sparc64/pt-machine.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/bits/local_lim.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/bits/posix_opt.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/bits/sigthread.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/hppa/bits/initspin.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/i386/bits/posix_opt.h: Likewise. * linuxthreads/tststack.c: Likewise. * linuxthreads/unload.c: Likewise. * linuxthreads/weaks.c: Likewise. * linuxthreads/wrapsyscall.c: Likewise. * malloc/arena.c: Likewise. * malloc/hooks.c: Likewise. * malloc/malloc.c: Likewise. * posix/glob/Makefile.ami: Likewise. * posix/glob/Makefile.in: Likewise. * stdlib/gmp-impl.h: Likewise. * stdlib/gmp.h: Likewise. * sysdeps/generic/dl-iteratephdr-static.c: Likewise. * sysdeps/generic/strnlen.c: Likewise. * sysdeps/mach/hurd/powerpc/bits/sigcontext.h: Likewise. * sysdeps/mach/hurd/recvmsg.c: Likewise. * sysdeps/mach/hurd/sendmsg.c: Likewise. * sysdeps/mach/hurd/spawni.c: Likewise. * sysdeps/mach/powerpc/machine-sp.h: Likewise. * sysdeps/mach/powerpc/sysdep.h: Likewise. * sysdeps/mach/powerpc/thread_state.h: Likewise. * sysdeps/unix/bsd/bsd4.4/bits/socket.h: Likewise. * sysdeps/unix/sysv/linux/ia64/dl-iteratephdr-static.c: Likewise. * sysdeps/x86_64/gmp-mparam.h: Likewise.
2002-08-26 22:40:48 +00:00
/* Modifications and expansions for 128-bit long double are
Copyright (C) 2001 Stephen L. Moshier <moshier@na-net.ornl.gov>
2013-06-05 20:44:03 +00:00
and are incorporated herein by permission of the author. The author
reserves the right to distribute this material elsewhere under different
2013-06-05 20:44:03 +00:00
copying permissions. These modifications are distributed here under
the following terms:
2002-08-26 Brian Youmans <3diff@gnu.org> * crypt/crypt.c: Changed copying permission notice to Lesser GPL from Library GPL. * crypt/crypt_util.c: Likewise. * crypt/ufc.c: Likewise. * elf/dl-conflict.c: Likewise. * elf/dl-iteratephdr.c: Likewise. * iconv/iconvconfig.h: Likewise. * linuxthreads/Examples/ex10.c: Likewise. * linuxthreads/Examples/ex11.c: Likewise. * linuxthreads/Examples/ex13.c: Likewise. * linuxthreads/Examples/ex8.c: Likewise. * linuxthreads/Examples/ex9.c: Likewise. * linuxthreads/barrier.c: Likewise. * linuxthreads/events.c: Likewise. * linuxthreads/lockfile.c: Likewise. * linuxthreads/no-tsd.c: Likewise. * linuxthreads/pt-machine.c: Likewise. * linuxthreads/ptclock_gettime.c: Likewise. * linuxthreads/ptclock_settime.c: Likewise. * linuxthreads/rwlock.c: Likewise. * linuxthreads/sysdeps/alpha/pspinlock.c: Likewise. * linuxthreads/sysdeps/alpha/pt-machine.h: Likewise. * linuxthreads/sysdeps/arm/pspinlock.c: Likewise. * linuxthreads/sysdeps/arm/pt-machine.h: Likewise. * linuxthreads/sysdeps/cris/pspinlock.c: Likewise. * linuxthreads/sysdeps/cris/pt-machine.h: Likewise. * linuxthreads/sysdeps/hppa/pspinlock.c: Likewise. * linuxthreads/sysdeps/hppa/pt-machine.h: Likewise. * linuxthreads/sysdeps/i386/i686/pt-machine.h: Likewise. * linuxthreads/sysdeps/i386/pspinlock.c: Likewise. * linuxthreads/sysdeps/i386/pt-machine.h: Likewise. * linuxthreads/sysdeps/i386/useldt.h: Likewise. * linuxthreads/sysdeps/ia64/pspinlock.c: Likewise. * linuxthreads/sysdeps/ia64/pt-machine.h: Likewise. * linuxthreads/sysdeps/m68k/pspinlock.c: Likewise. * linuxthreads/sysdeps/m68k/pt-machine.h: Likewise. * linuxthreads/sysdeps/mips/pspinlock.c: Likewise. * linuxthreads/sysdeps/mips/pt-machine.h: Likewise. * linuxthreads/sysdeps/powerpc/pspinlock.c: Likewise. * linuxthreads/sysdeps/powerpc/pt-machine.h: Likewise. * linuxthreads/sysdeps/pthread/bits/initspin.h: Likewise. * linuxthreads/sysdeps/pthread/bits/libc-lock.h: Likewise. * linuxthreads/sysdeps/pthread/bits/libc-tsd.h: Likewise. * linuxthreads/sysdeps/pthread/getcpuclockid.c: Likewise. * linuxthreads/sysdeps/pthread/posix-timer.h: Likewise. * linuxthreads/sysdeps/pthread/timer_create.c: Likewise. * linuxthreads/sysdeps/pthread/timer_delete.c: Likewise. * linuxthreads/sysdeps/pthread/timer_getoverr.c: Likewise. * linuxthreads/sysdeps/pthread/timer_gettime.c: Likewise. * linuxthreads/sysdeps/pthread/timer_routines.c: Likewise. * linuxthreads/sysdeps/pthread/timer_settime.c: Likewise. * linuxthreads/sysdeps/pthread/tst-timer.c: Likewise. * linuxthreads/sysdeps/s390/pspinlock.c: Likewise. * linuxthreads/sysdeps/s390/s390-32/pt-machine.h: Likewise. * linuxthreads/sysdeps/s390/s390-64/pt-machine.h: Likewise. * linuxthreads/sysdeps/sh/pspinlock.c: Likewise. * linuxthreads/sysdeps/sh/pt-machine.h: Likewise. * linuxthreads/sysdeps/sparc/sparc32/pspinlock.c: Likewise. * linuxthreads/sysdeps/sparc/sparc32/pt-machine.h: Likewise. * linuxthreads/sysdeps/sparc/sparc32/sparcv9/pspinlock.c: Likewise. * linuxthreads/sysdeps/sparc/sparc64/pspinlock.c: Likewise. * linuxthreads/sysdeps/sparc/sparc64/pt-machine.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/bits/local_lim.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/bits/posix_opt.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/bits/sigthread.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/hppa/bits/initspin.h: Likewise. * linuxthreads/sysdeps/unix/sysv/linux/i386/bits/posix_opt.h: Likewise. * linuxthreads/tststack.c: Likewise. * linuxthreads/unload.c: Likewise. * linuxthreads/weaks.c: Likewise. * linuxthreads/wrapsyscall.c: Likewise. * malloc/arena.c: Likewise. * malloc/hooks.c: Likewise. * malloc/malloc.c: Likewise. * posix/glob/Makefile.ami: Likewise. * posix/glob/Makefile.in: Likewise. * stdlib/gmp-impl.h: Likewise. * stdlib/gmp.h: Likewise. * sysdeps/generic/dl-iteratephdr-static.c: Likewise. * sysdeps/generic/strnlen.c: Likewise. * sysdeps/mach/hurd/powerpc/bits/sigcontext.h: Likewise. * sysdeps/mach/hurd/recvmsg.c: Likewise. * sysdeps/mach/hurd/sendmsg.c: Likewise. * sysdeps/mach/hurd/spawni.c: Likewise. * sysdeps/mach/powerpc/machine-sp.h: Likewise. * sysdeps/mach/powerpc/sysdep.h: Likewise. * sysdeps/mach/powerpc/thread_state.h: Likewise. * sysdeps/unix/bsd/bsd4.4/bits/socket.h: Likewise. * sysdeps/unix/sysv/linux/ia64/dl-iteratephdr-static.c: Likewise. * sysdeps/x86_64/gmp-mparam.h: Likewise.
2002-08-26 22:40:48 +00:00
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see
<http://www.gnu.org/licenses/>. */
/* double erf(double x)
* double erfc(double x)
* x
* 2 |\
* erf(x) = --------- | exp(-t*t)dt
* sqrt(pi) \|
* 0
*
* erfc(x) = 1-erf(x)
* Note that
* erf(-x) = -erf(x)
* erfc(-x) = 2 - erfc(x)
*
* Method:
* 1. erf(x) = x + x*R(x^2) for |x| in [0, 7/8]
* Remark. The formula is derived by noting
* erf(x) = (2/sqrt(pi))*(x - x^3/3 + x^5/10 - x^7/42 + ....)
* and that
* 2/sqrt(pi) = 1.128379167095512573896158903121545171688
* is close to one.
*
* 1a. erf(x) = 1 - erfc(x), for |x| > 1.0
* erfc(x) = 1 - erf(x) if |x| < 1/4
*
* 2. For |x| in [7/8, 1], let s = |x| - 1, and
* c = 0.84506291151 rounded to single (24 bits)
* erf(s + c) = sign(x) * (c + P1(s)/Q1(s))
* Remark: here we use the taylor series expansion at x=1.
* erf(1+s) = erf(1) + s*Poly(s)
* = 0.845.. + P1(s)/Q1(s)
* Note that |P1/Q1|< 0.078 for x in [0.84375,1.25]
*
* 3. For x in [1/4, 5/4],
* erfc(s + const) = erfc(const) + s P1(s)/Q1(s)
* for const = 1/4, 3/8, ..., 9/8
* and 0 <= s <= 1/8 .
*
* 4. For x in [5/4, 107],
* erfc(x) = (1/x)*exp(-x*x-0.5625 + R(z))
* z=1/x^2
* The interval is partitioned into several segments
* of width 1/8 in 1/x.
*
* Note1:
* To compute exp(-x*x-0.5625+R/S), let s be a single
* precision number and s := x; then
* -x*x = -s*s + (s-x)*(s+x)
* exp(-x*x-0.5626+R/S) =
* exp(-s*s-0.5625)*exp((s-x)*(s+x)+R/S);
* Note2:
* Here 4 and 5 make use of the asymptotic series
* exp(-x*x)
* erfc(x) ~ ---------- * ( 1 + Poly(1/x^2) )
* x*sqrt(pi)
*
* 5. For inf > x >= 107
* erf(x) = sign(x) *(1 - tiny) (raise inexact)
* erfc(x) = tiny*tiny (raise underflow) if x > 0
* = 2 - tiny if x<0
*
* 7. Special case:
* erf(0) = 0, erf(inf) = 1, erf(-inf) = -1,
* erfc(0) = 1, erfc(inf) = 0, erfc(-inf) = 2,
* erfc/erf(NaN) is NaN
*/
#include <errno.h>
Fix erf underflow handling near 0 (bug 16516). Bug 16516 reports spurious underflows from erf (for all floating-point types), when the result is close to underflowing but does not actually underflow. erf (x) is about (2/sqrt(pi))*x for x close to 0, so there are subnormal arguments for which it does not underflow. The various implementations do (x + efx*x) (for efx = 2/sqrt(pi) - 1), for greater accuracy than if just using a single multiplication by an approximation to 2/sqrt(pi) (effectively, this way there are a few more bits in the approximation to 2/sqrt(pi)). This can introduce underflows when efx*x underflows even though the final result does not, so a scaled calculation with 8*efx is done in these cases - but 8 is not a big enough scale factor to avoid all such underflows. 16 is (any underflows with a scale factor of 16 would only occur when the final result underflows), so this patch changes the code to use that factor. Rather than recomputing all the values of the efx8 variable, it is removed, leaving it to the compiler's constant folding to compute 16*efx. As such scaling can also lose underflows when the final scaling down happens to be exact, appropriate checks are added to ensure underflow exceptions occur when required in such cases. Tested x86_64 and x86; no ulps updates needed. Also spot-checked for powerpc32 and mips64 to verify the changes to the ldbl-128ibm and ldbl-128 implementations. [BZ #16516] * sysdeps/ieee754/dbl-64/s_erf.c (efx8): Remove variable. (__erf): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/flt-32/s_erff.c (efx8): Remove variable. (__erff): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-96/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * math/auto-libm-test-in: Add more tests of erf. * math/auto-libm-test-out: Regenerated.
2014-05-14 12:34:03 +00:00
#include <float.h>
#include <math.h>
#include <math_private.h>
/* Evaluate P[n] x^n + P[n-1] x^(n-1) + ... + P[0] */
static long double
neval (long double x, const long double *p, int n)
{
long double y;
p += n;
y = *p--;
do
{
y = y * x + *p--;
}
while (--n > 0);
return y;
}
/* Evaluate x^n+1 + P[n] x^(n) + P[n-1] x^(n-1) + ... + P[0] */
static long double
deval (long double x, const long double *p, int n)
{
long double y;
p += n;
y = x + *p--;
do
{
y = y * x + *p--;
}
while (--n > 0);
return y;
}
static const long double
tiny = 1e-4931L,
one = 1.0L,
two = 2.0L,
/* 2/sqrt(pi) - 1 */
Fix erf underflow handling near 0 (bug 16516). Bug 16516 reports spurious underflows from erf (for all floating-point types), when the result is close to underflowing but does not actually underflow. erf (x) is about (2/sqrt(pi))*x for x close to 0, so there are subnormal arguments for which it does not underflow. The various implementations do (x + efx*x) (for efx = 2/sqrt(pi) - 1), for greater accuracy than if just using a single multiplication by an approximation to 2/sqrt(pi) (effectively, this way there are a few more bits in the approximation to 2/sqrt(pi)). This can introduce underflows when efx*x underflows even though the final result does not, so a scaled calculation with 8*efx is done in these cases - but 8 is not a big enough scale factor to avoid all such underflows. 16 is (any underflows with a scale factor of 16 would only occur when the final result underflows), so this patch changes the code to use that factor. Rather than recomputing all the values of the efx8 variable, it is removed, leaving it to the compiler's constant folding to compute 16*efx. As such scaling can also lose underflows when the final scaling down happens to be exact, appropriate checks are added to ensure underflow exceptions occur when required in such cases. Tested x86_64 and x86; no ulps updates needed. Also spot-checked for powerpc32 and mips64 to verify the changes to the ldbl-128ibm and ldbl-128 implementations. [BZ #16516] * sysdeps/ieee754/dbl-64/s_erf.c (efx8): Remove variable. (__erf): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/flt-32/s_erff.c (efx8): Remove variable. (__erff): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-96/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * math/auto-libm-test-in: Add more tests of erf. * math/auto-libm-test-out: Regenerated.
2014-05-14 12:34:03 +00:00
efx = 1.2837916709551257389615890312154517168810E-1L;
/* erf(x) = x + x R(x^2)
0 <= x <= 7/8
Peak relative error 1.8e-35 */
#define NTN1 8
static const long double TN1[NTN1 + 1] =
{
-3.858252324254637124543172907442106422373E10L,
9.580319248590464682316366876952214879858E10L,
1.302170519734879977595901236693040544854E10L,
2.922956950426397417800321486727032845006E9L,
1.764317520783319397868923218385468729799E8L,
1.573436014601118630105796794840834145120E7L,
4.028077380105721388745632295157816229289E5L,
1.644056806467289066852135096352853491530E4L,
3.390868480059991640235675479463287886081E1L
};
#define NTD1 8
static const long double TD1[NTD1 + 1] =
{
-3.005357030696532927149885530689529032152E11L,
-1.342602283126282827411658673839982164042E11L,
-2.777153893355340961288511024443668743399E10L,
-3.483826391033531996955620074072768276974E9L,
-2.906321047071299585682722511260895227921E8L,
-1.653347985722154162439387878512427542691E7L,
-6.245520581562848778466500301865173123136E5L,
-1.402124304177498828590239373389110545142E4L,
-1.209368072473510674493129989468348633579E2L
/* 1.0E0 */
};
/* erf(z+1) = erf_const + P(z)/Q(z)
-.125 <= z <= 0
Peak relative error 7.3e-36 */
static const long double erf_const = 0.845062911510467529296875L;
#define NTN2 8
static const long double TN2[NTN2 + 1] =
{
-4.088889697077485301010486931817357000235E1L,
7.157046430681808553842307502826960051036E3L,
-2.191561912574409865550015485451373731780E3L,
2.180174916555316874988981177654057337219E3L,
2.848578658049670668231333682379720943455E2L,
1.630362490952512836762810462174798925274E2L,
6.317712353961866974143739396865293596895E0L,
2.450441034183492434655586496522857578066E1L,
5.127662277706787664956025545897050896203E-1L
};
#define NTD2 8
static const long double TD2[NTD2 + 1] =
{
1.731026445926834008273768924015161048885E4L,
1.209682239007990370796112604286048173750E4L,
1.160950290217993641320602282462976163857E4L,
5.394294645127126577825507169061355698157E3L,
2.791239340533632669442158497532521776093E3L,
8.989365571337319032943005387378993827684E2L,
2.974016493766349409725385710897298069677E2L,
6.148192754590376378740261072533527271947E1L,
1.178502892490738445655468927408440847480E1L
/* 1.0E0 */
};
/* erfc(x + 0.25) = erfc(0.25) + x R(x)
0 <= x < 0.125
Peak relative error 1.4e-35 */
#define NRNr13 8
static const long double RNr13[NRNr13 + 1] =
{
-2.353707097641280550282633036456457014829E3L,
3.871159656228743599994116143079870279866E2L,
-3.888105134258266192210485617504098426679E2L,
-2.129998539120061668038806696199343094971E1L,
-8.125462263594034672468446317145384108734E1L,
8.151549093983505810118308635926270319660E0L,
-5.033362032729207310462422357772568553670E0L,
-4.253956621135136090295893547735851168471E-2L,
-8.098602878463854789780108161581050357814E-2L
};
#define NRDr13 7
static const long double RDr13[NRDr13 + 1] =
{
2.220448796306693503549505450626652881752E3L,
1.899133258779578688791041599040951431383E2L,
1.061906712284961110196427571557149268454E3L,
7.497086072306967965180978101974566760042E1L,
2.146796115662672795876463568170441327274E2L,
1.120156008362573736664338015952284925592E1L,
2.211014952075052616409845051695042741074E1L,
6.469655675326150785692908453094054988938E-1L
/* 1.0E0 */
};
/* erfc(0.25) = C13a + C13b to extra precision. */
static const long double C13a = 0.723663330078125L;
static const long double C13b = 1.0279753638067014931732235184287934646022E-5L;
/* erfc(x + 0.375) = erfc(0.375) + x R(x)
0 <= x < 0.125
Peak relative error 1.2e-35 */
#define NRNr14 8
static const long double RNr14[NRNr14 + 1] =
{
-2.446164016404426277577283038988918202456E3L,
6.718753324496563913392217011618096698140E2L,
-4.581631138049836157425391886957389240794E2L,
-2.382844088987092233033215402335026078208E1L,
-7.119237852400600507927038680970936336458E1L,
1.313609646108420136332418282286454287146E1L,
-6.188608702082264389155862490056401365834E0L,
-2.787116601106678287277373011101132659279E-2L,
-2.230395570574153963203348263549700967918E-2L
};
#define NRDr14 7
static const long double RDr14[NRDr14 + 1] =
{
2.495187439241869732696223349840963702875E3L,
2.503549449872925580011284635695738412162E2L,
1.159033560988895481698051531263861842461E3L,
9.493751466542304491261487998684383688622E1L,
2.276214929562354328261422263078480321204E2L,
1.367697521219069280358984081407807931847E1L,
2.276988395995528495055594829206582732682E1L,
7.647745753648996559837591812375456641163E-1L
/* 1.0E0 */
};
/* erfc(0.375) = C14a + C14b to extra precision. */
static const long double C14a = 0.5958709716796875L;
static const long double C14b = 1.2118885490201676174914080878232469565953E-5L;
/* erfc(x + 0.5) = erfc(0.5) + x R(x)
0 <= x < 0.125
Peak relative error 4.7e-36 */
#define NRNr15 8
static const long double RNr15[NRNr15 + 1] =
{
-2.624212418011181487924855581955853461925E3L,
8.473828904647825181073831556439301342756E2L,
-5.286207458628380765099405359607331669027E2L,
-3.895781234155315729088407259045269652318E1L,
-6.200857908065163618041240848728398496256E1L,
1.469324610346924001393137895116129204737E1L,
-6.961356525370658572800674953305625578903E0L,
5.145724386641163809595512876629030548495E-3L,
1.990253655948179713415957791776180406812E-2L
};
#define NRDr15 7
static const long double RDr15[NRDr15 + 1] =
{
2.986190760847974943034021764693341524962E3L,
5.288262758961073066335410218650047725985E2L,
1.363649178071006978355113026427856008978E3L,
1.921707975649915894241864988942255320833E2L,
2.588651100651029023069013885900085533226E2L,
2.628752920321455606558942309396855629459E1L,
2.455649035885114308978333741080991380610E1L,
1.378826653595128464383127836412100939126E0L
/* 1.0E0 */
};
/* erfc(0.5) = C15a + C15b to extra precision. */
static const long double C15a = 0.4794921875L;
static const long double C15b = 7.9346869534623172533461080354712635484242E-6L;
/* erfc(x + 0.625) = erfc(0.625) + x R(x)
0 <= x < 0.125
Peak relative error 5.1e-36 */
#define NRNr16 8
static const long double RNr16[NRNr16 + 1] =
{
-2.347887943200680563784690094002722906820E3L,
8.008590660692105004780722726421020136482E2L,
-5.257363310384119728760181252132311447963E2L,
-4.471737717857801230450290232600243795637E1L,
-4.849540386452573306708795324759300320304E1L,
1.140885264677134679275986782978655952843E1L,
-6.731591085460269447926746876983786152300E0L,
1.370831653033047440345050025876085121231E-1L,
2.022958279982138755020825717073966576670E-2L,
};
#define NRDr16 7
static const long double RDr16[NRDr16 + 1] =
{
3.075166170024837215399323264868308087281E3L,
8.730468942160798031608053127270430036627E2L,
1.458472799166340479742581949088453244767E3L,
3.230423687568019709453130785873540386217E2L,
2.804009872719893612081109617983169474655E2L,
4.465334221323222943418085830026979293091E1L,
2.612723259683205928103787842214809134746E1L,
2.341526751185244109722204018543276124997E0L,
/* 1.0E0 */
};
/* erfc(0.625) = C16a + C16b to extra precision. */
static const long double C16a = 0.3767547607421875L;
static const long double C16b = 4.3570693945275513594941232097252997287766E-6L;
/* erfc(x + 0.75) = erfc(0.75) + x R(x)
0 <= x < 0.125
Peak relative error 1.7e-35 */
#define NRNr17 8
static const long double RNr17[NRNr17 + 1] =
{
-1.767068734220277728233364375724380366826E3L,
6.693746645665242832426891888805363898707E2L,
-4.746224241837275958126060307406616817753E2L,
-2.274160637728782675145666064841883803196E1L,
-3.541232266140939050094370552538987982637E1L,
6.988950514747052676394491563585179503865E0L,
-5.807687216836540830881352383529281215100E0L,
3.631915988567346438830283503729569443642E-1L,
-1.488945487149634820537348176770282391202E-2L
};
#define NRDr17 7
static const long double RDr17[NRDr17 + 1] =
{
2.748457523498150741964464942246913394647E3L,
1.020213390713477686776037331757871252652E3L,
1.388857635935432621972601695296561952738E3L,
3.903363681143817750895999579637315491087E2L,
2.784568344378139499217928969529219886578E2L,
5.555800830216764702779238020065345401144E1L,
2.646215470959050279430447295801291168941E1L,
2.984905282103517497081766758550112011265E0L,
/* 1.0E0 */
};
/* erfc(0.75) = C17a + C17b to extra precision. */
static const long double C17a = 0.2888336181640625L;
static const long double C17b = 1.0748182422368401062165408589222625794046E-5L;
/* erfc(x + 0.875) = erfc(0.875) + x R(x)
0 <= x < 0.125
Peak relative error 2.2e-35 */
#define NRNr18 8
static const long double RNr18[NRNr18 + 1] =
{
-1.342044899087593397419622771847219619588E3L,
6.127221294229172997509252330961641850598E2L,
-4.519821356522291185621206350470820610727E2L,
1.223275177825128732497510264197915160235E1L,
-2.730789571382971355625020710543532867692E1L,
4.045181204921538886880171727755445395862E0L,
-4.925146477876592723401384464691452700539E0L,
5.933878036611279244654299924101068088582E-1L,
-5.557645435858916025452563379795159124753E-2L
};
#define NRDr18 7
static const long double RDr18[NRDr18 + 1] =
{
2.557518000661700588758505116291983092951E3L,
1.070171433382888994954602511991940418588E3L,
1.344842834423493081054489613250688918709E3L,
4.161144478449381901208660598266288188426E2L,
2.763670252219855198052378138756906980422E2L,
5.998153487868943708236273854747564557632E1L,
2.657695108438628847733050476209037025318E1L,
3.252140524394421868923289114410336976512E0L,
/* 1.0E0 */
};
/* erfc(0.875) = C18a + C18b to extra precision. */
static const long double C18a = 0.215911865234375L;
static const long double C18b = 1.3073705765341685464282101150637224028267E-5L;
/* erfc(x + 1.0) = erfc(1.0) + x R(x)
0 <= x < 0.125
Peak relative error 1.6e-35 */
#define NRNr19 8
static const long double RNr19[NRNr19 + 1] =
{
-1.139180936454157193495882956565663294826E3L,
6.134903129086899737514712477207945973616E2L,
-4.628909024715329562325555164720732868263E2L,
4.165702387210732352564932347500364010833E1L,
-2.286979913515229747204101330405771801610E1L,
1.870695256449872743066783202326943667722E0L,
-4.177486601273105752879868187237000032364E0L,
7.533980372789646140112424811291782526263E-1L,
-8.629945436917752003058064731308767664446E-2L
};
#define NRDr19 7
static const long double RDr19[NRDr19 + 1] =
{
2.744303447981132701432716278363418643778E3L,
1.266396359526187065222528050591302171471E3L,
1.466739461422073351497972255511919814273E3L,
4.868710570759693955597496520298058147162E2L,
2.993694301559756046478189634131722579643E2L,
6.868976819510254139741559102693828237440E1L,
2.801505816247677193480190483913753613630E1L,
3.604439909194350263552750347742663954481E0L,
/* 1.0E0 */
};
/* erfc(1.0) = C19a + C19b to extra precision. */
static const long double C19a = 0.15728759765625L;
static const long double C19b = 1.1609394035130658779364917390740703933002E-5L;
/* erfc(x + 1.125) = erfc(1.125) + x R(x)
0 <= x < 0.125
Peak relative error 3.6e-36 */
#define NRNr20 8
static const long double RNr20[NRNr20 + 1] =
{
-9.652706916457973956366721379612508047640E2L,
5.577066396050932776683469951773643880634E2L,
-4.406335508848496713572223098693575485978E2L,
5.202893466490242733570232680736966655434E1L,
-1.931311847665757913322495948705563937159E1L,
-9.364318268748287664267341457164918090611E-2L,
-3.306390351286352764891355375882586201069E0L,
7.573806045289044647727613003096916516475E-1L,
-9.611744011489092894027478899545635991213E-2L
};
#define NRDr20 7
static const long double RDr20[NRDr20 + 1] =
{
3.032829629520142564106649167182428189014E3L,
1.659648470721967719961167083684972196891E3L,
1.703545128657284619402511356932569292535E3L,
6.393465677731598872500200253155257708763E2L,
3.489131397281030947405287112726059221934E2L,
8.848641738570783406484348434387611713070E1L,
3.132269062552392974833215844236160958502E1L,
4.430131663290563523933419966185230513168E0L
/* 1.0E0 */
};
/* erfc(1.125) = C20a + C20b to extra precision. */
static const long double C20a = 0.111602783203125L;
static const long double C20b = 8.9850951672359304215530728365232161564636E-6L;
/* erfc(1/x) = 1/x exp (-1/x^2 - 0.5625 + R(1/x^2))
7/8 <= 1/x < 1
Peak relative error 1.4e-35 */
#define NRNr8 9
static const long double RNr8[NRNr8 + 1] =
{
3.587451489255356250759834295199296936784E1L,
5.406249749087340431871378009874875889602E2L,
2.931301290625250886238822286506381194157E3L,
7.359254185241795584113047248898753470923E3L,
9.201031849810636104112101947312492532314E3L,
5.749697096193191467751650366613289284777E3L,
1.710415234419860825710780802678697889231E3L,
2.150753982543378580859546706243022719599E2L,
8.740953582272147335100537849981160931197E0L,
4.876422978828717219629814794707963640913E-2L
};
#define NRDr8 8
static const long double RDr8[NRDr8 + 1] =
{
6.358593134096908350929496535931630140282E1L,
9.900253816552450073757174323424051765523E2L,
5.642928777856801020545245437089490805186E3L,
1.524195375199570868195152698617273739609E4L,
2.113829644500006749947332935305800887345E4L,
1.526438562626465706267943737310282977138E4L,
5.561370922149241457131421914140039411782E3L,
9.394035530179705051609070428036834496942E2L,
6.147019596150394577984175188032707343615E1L
/* 1.0E0 */
};
/* erfc(1/x) = 1/x exp (-1/x^2 - 0.5625 + R(1/x^2))
0.75 <= 1/x <= 0.875
Peak relative error 2.0e-36 */
#define NRNr7 9
static const long double RNr7[NRNr7 + 1] =
{
1.686222193385987690785945787708644476545E1L,
1.178224543567604215602418571310612066594E3L,
1.764550584290149466653899886088166091093E4L,
1.073758321890334822002849369898232811561E5L,
3.132840749205943137619839114451290324371E5L,
4.607864939974100224615527007793867585915E5L,
3.389781820105852303125270837910972384510E5L,
1.174042187110565202875011358512564753399E5L,
1.660013606011167144046604892622504338313E4L,
6.700393957480661937695573729183733234400E2L
};
#define NRDr7 9
static const long double RDr7[NRDr7 + 1] =
{
-1.709305024718358874701575813642933561169E3L,
-3.280033887481333199580464617020514788369E4L,
-2.345284228022521885093072363418750835214E5L,
-8.086758123097763971926711729242327554917E5L,
-1.456900414510108718402423999575992450138E6L,
-1.391654264881255068392389037292702041855E6L,
-6.842360801869939983674527468509852583855E5L,
-1.597430214446573566179675395199807533371E5L,
-1.488876130609876681421645314851760773480E4L,
-3.511762950935060301403599443436465645703E2L
/* 1.0E0 */
};
/* erfc(1/x) = 1/x exp(-1/x^2 - 0.5625 + R(1/x^2))
5/8 <= 1/x < 3/4
Peak relative error 1.9e-35 */
#define NRNr6 9
static const long double RNr6[NRNr6 + 1] =
{
1.642076876176834390623842732352935761108E0L,
1.207150003611117689000664385596211076662E2L,
2.119260779316389904742873816462800103939E3L,
1.562942227734663441801452930916044224174E4L,
5.656779189549710079988084081145693580479E4L,
1.052166241021481691922831746350942786299E5L,
9.949798524786000595621602790068349165758E4L,
4.491790734080265043407035220188849562856E4L,
8.377074098301530326270432059434791287601E3L,
4.506934806567986810091824791963991057083E2L
};
#define NRDr6 9
static const long double RDr6[NRDr6 + 1] =
{
-1.664557643928263091879301304019826629067E2L,
-3.800035902507656624590531122291160668452E3L,
-3.277028191591734928360050685359277076056E4L,
-1.381359471502885446400589109566587443987E5L,
-3.082204287382581873532528989283748656546E5L,
-3.691071488256738343008271448234631037095E5L,
-2.300482443038349815750714219117566715043E5L,
-6.873955300927636236692803579555752171530E4L,
-8.262158817978334142081581542749986845399E3L,
-2.517122254384430859629423488157361983661E2L
/* 1.00 */
};
/* erfc(1/x) = 1/x exp(-1/x^2 - 0.5625 + R(1/x^2))
1/2 <= 1/x < 5/8
Peak relative error 4.6e-36 */
#define NRNr5 10
static const long double RNr5[NRNr5 + 1] =
{
-3.332258927455285458355550878136506961608E-3L,
-2.697100758900280402659586595884478660721E-1L,
-6.083328551139621521416618424949137195536E0L,
-6.119863528983308012970821226810162441263E1L,
-3.176535282475593173248810678636522589861E2L,
-8.933395175080560925809992467187963260693E2L,
-1.360019508488475978060917477620199499560E3L,
-1.075075579828188621541398761300910213280E3L,
-4.017346561586014822824459436695197089916E2L,
-5.857581368145266249509589726077645791341E1L,
-2.077715925587834606379119585995758954399E0L
};
#define NRDr5 9
static const long double RDr5[NRDr5 + 1] =
{
3.377879570417399341550710467744693125385E-1L,
1.021963322742390735430008860602594456187E1L,
1.200847646592942095192766255154827011939E2L,
7.118915528142927104078182863387116942836E2L,
2.318159380062066469386544552429625026238E3L,
4.238729853534009221025582008928765281620E3L,
4.279114907284825886266493994833515580782E3L,
2.257277186663261531053293222591851737504E3L,
5.570475501285054293371908382916063822957E2L,
5.142189243856288981145786492585432443560E1L
/* 1.0E0 */
};
/* erfc(1/x) = 1/x exp(-1/x^2 - 0.5625 + R(1/x^2))
3/8 <= 1/x < 1/2
Peak relative error 2.0e-36 */
#define NRNr4 10
static const long double RNr4[NRNr4 + 1] =
{
3.258530712024527835089319075288494524465E-3L,
2.987056016877277929720231688689431056567E-1L,
8.738729089340199750734409156830371528862E0L,
1.207211160148647782396337792426311125923E2L,
8.997558632489032902250523945248208224445E2L,
3.798025197699757225978410230530640879762E3L,
9.113203668683080975637043118209210146846E3L,
1.203285891339933238608683715194034900149E4L,
8.100647057919140328536743641735339740855E3L,
2.383888249907144945837976899822927411769E3L,
2.127493573166454249221983582495245662319E2L
};
#define NRDr4 10
static const long double RDr4[NRDr4 + 1] =
{
-3.303141981514540274165450687270180479586E-1L,
-1.353768629363605300707949368917687066724E1L,
-2.206127630303621521950193783894598987033E2L,
-1.861800338758066696514480386180875607204E3L,
-8.889048775872605708249140016201753255599E3L,
-2.465888106627948210478692168261494857089E4L,
-3.934642211710774494879042116768390014289E4L,
-3.455077258242252974937480623730228841003E4L,
-1.524083977439690284820586063729912653196E4L,
-2.810541887397984804237552337349093953857E3L,
-1.343929553541159933824901621702567066156E2L
/* 1.0E0 */
};
/* erfc(1/x) = 1/x exp(-1/x^2 - 0.5625 + R(1/x^2))
1/4 <= 1/x < 3/8
Peak relative error 8.4e-37 */
#define NRNr3 11
static const long double RNr3[NRNr3 + 1] =
{
-1.952401126551202208698629992497306292987E-6L,
-2.130881743066372952515162564941682716125E-4L,
-8.376493958090190943737529486107282224387E-3L,
-1.650592646560987700661598877522831234791E-1L,
-1.839290818933317338111364667708678163199E0L,
-1.216278715570882422410442318517814388470E1L,
-4.818759344462360427612133632533779091386E1L,
-1.120994661297476876804405329172164436784E2L,
-1.452850765662319264191141091859300126931E2L,
-9.485207851128957108648038238656777241333E1L,
-2.563663855025796641216191848818620020073E1L,
-1.787995944187565676837847610706317833247E0L
};
#define NRDr3 10
static const long double RDr3[NRDr3 + 1] =
{
1.979130686770349481460559711878399476903E-4L,
1.156941716128488266238105813374635099057E-2L,
2.752657634309886336431266395637285974292E-1L,
3.482245457248318787349778336603569327521E0L,
2.569347069372696358578399521203959253162E1L,
1.142279000180457419740314694631879921561E2L,
3.056503977190564294341422623108332700840E2L,
4.780844020923794821656358157128719184422E2L,
4.105972727212554277496256802312730410518E2L,
1.724072188063746970865027817017067646246E2L,
2.815939183464818198705278118326590370435E1L
/* 1.0E0 */
};
/* erfc(1/x) = 1/x exp(-1/x^2 - 0.5625 + R(1/x^2))
1/8 <= 1/x < 1/4
Peak relative error 1.5e-36 */
#define NRNr2 11
static const long double RNr2[NRNr2 + 1] =
{
-2.638914383420287212401687401284326363787E-8L,
-3.479198370260633977258201271399116766619E-6L,
-1.783985295335697686382487087502222519983E-4L,
-4.777876933122576014266349277217559356276E-3L,
-7.450634738987325004070761301045014986520E-2L,
-7.068318854874733315971973707247467326619E-1L,
-4.113919921935944795764071670806867038732E0L,
-1.440447573226906222417767283691888875082E1L,
-2.883484031530718428417168042141288943905E1L,
-2.990886974328476387277797361464279931446E1L,
-1.325283914915104866248279787536128997331E1L,
-1.572436106228070195510230310658206154374E0L
};
#define NRDr2 10
static const long double RDr2[NRDr2 + 1] =
{
2.675042728136731923554119302571867799673E-6L,
2.170997868451812708585443282998329996268E-4L,
7.249969752687540289422684951196241427445E-3L,
1.302040375859768674620410563307838448508E-1L,
1.380202483082910888897654537144485285549E0L,
8.926594113174165352623847870299170069350E0L,
3.521089584782616472372909095331572607185E1L,
8.233547427533181375185259050330809105570E1L,
1.072971579885803033079469639073292840135E2L,
6.943803113337964469736022094105143158033E1L,
1.775695341031607738233608307835017282662E1L
/* 1.0E0 */
};
/* erfc(1/x) = 1/x exp(-1/x^2 - 0.5625 + R(1/x^2))
1/128 <= 1/x < 1/8
Peak relative error 2.2e-36 */
#define NRNr1 9
static const long double RNr1[NRNr1 + 1] =
{
-4.250780883202361946697751475473042685782E-8L,
-5.375777053288612282487696975623206383019E-6L,
-2.573645949220896816208565944117382460452E-4L,
-6.199032928113542080263152610799113086319E-3L,
-8.262721198693404060380104048479916247786E-2L,
-6.242615227257324746371284637695778043982E-1L,
-2.609874739199595400225113299437099626386E0L,
-5.581967563336676737146358534602770006970E0L,
-5.124398923356022609707490956634280573882E0L,
-1.290865243944292370661544030414667556649E0L
};
#define NRDr1 8
static const long double RDr1[NRDr1 + 1] =
{
4.308976661749509034845251315983612976224E-6L,
3.265390126432780184125233455960049294580E-4L,
9.811328839187040701901866531796570418691E-3L,
1.511222515036021033410078631914783519649E-1L,
1.289264341917429958858379585970225092274E0L,
6.147640356182230769548007536914983522270E0L,
1.573966871337739784518246317003956180750E1L,
1.955534123435095067199574045529218238263E1L,
9.472613121363135472247929109615785855865E0L
/* 1.0E0 */
};
long double
__erfl (long double x)
{
long double a, y, z;
int32_t i, ix, sign;
ieee854_long_double_shape_type u;
u.value = x;
sign = u.parts32.w0;
ix = sign & 0x7fffffff;
if (ix >= 0x7fff0000)
{ /* erf(nan)=nan */
i = ((sign & 0xffff0000) >> 31) << 1;
return (long double) (1 - i) + one / x; /* erf(+-inf)=+-1 */
}
if (ix >= 0x3fff0000) /* |x| >= 1.0 */
{
if (ix >= 0x40030000 && sign > 0)
return one; /* x >= 16, avoid spurious underflow from erfc. */
y = __erfcl (x);
return (one - y);
/* return (one - __erfcl (x)); */
}
u.parts32.w0 = ix;
a = u.value;
z = x * x;
if (ix < 0x3ffec000) /* a < 0.875 */
{
if (ix < 0x3fc60000) /* |x|<2**-57 */
{
if (ix < 0x00080000)
Fix erf underflow handling near 0 (bug 16516). Bug 16516 reports spurious underflows from erf (for all floating-point types), when the result is close to underflowing but does not actually underflow. erf (x) is about (2/sqrt(pi))*x for x close to 0, so there are subnormal arguments for which it does not underflow. The various implementations do (x + efx*x) (for efx = 2/sqrt(pi) - 1), for greater accuracy than if just using a single multiplication by an approximation to 2/sqrt(pi) (effectively, this way there are a few more bits in the approximation to 2/sqrt(pi)). This can introduce underflows when efx*x underflows even though the final result does not, so a scaled calculation with 8*efx is done in these cases - but 8 is not a big enough scale factor to avoid all such underflows. 16 is (any underflows with a scale factor of 16 would only occur when the final result underflows), so this patch changes the code to use that factor. Rather than recomputing all the values of the efx8 variable, it is removed, leaving it to the compiler's constant folding to compute 16*efx. As such scaling can also lose underflows when the final scaling down happens to be exact, appropriate checks are added to ensure underflow exceptions occur when required in such cases. Tested x86_64 and x86; no ulps updates needed. Also spot-checked for powerpc32 and mips64 to verify the changes to the ldbl-128ibm and ldbl-128 implementations. [BZ #16516] * sysdeps/ieee754/dbl-64/s_erf.c (efx8): Remove variable. (__erf): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/flt-32/s_erff.c (efx8): Remove variable. (__erff): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-96/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * math/auto-libm-test-in: Add more tests of erf. * math/auto-libm-test-out: Regenerated.
2014-05-14 12:34:03 +00:00
{
/* Avoid spurious underflow. */
long double ret = 0.0625 * (16.0 * x + (16.0 * efx) * x);
Refactor code forcing underflow exceptions. Various floating-point functions have code to force underflow exceptions if a tiny result was computed in a way that might not have resulted in such exceptions even though the result is inexact. This typically uses math_force_eval to ensure that the underflowing expression is evaluated, but sometimes uses volatile. This patch refactors such code to use three new macros math_check_force_underflow, math_check_force_underflow_nonneg and math_check_force_underflow_complex (which in turn use math_force_eval). In the limited number of cases not suited to a simple conversion to these macros, existing uses of volatile are changed to use math_force_eval instead. The converted code does not always execute exactly the same sequence of operations as the original code, but the overall effects should be the same. Tested for x86_64, x86, mips64 and powerpc. * sysdeps/generic/math_private.h (fabs_tg): New macro. (min_of_type): Likewise. (math_check_force_underflow): Likewise. (math_check_force_underflow_nonneg): Likewise. (math_check_force_underflow_complex): Likewise. * math/e_exp2l.c (__ieee754_exp2l): Use math_check_force_underflow_nonneg. * math/k_casinh.c (__kernel_casinh): Likewise. * math/k_casinhf.c (__kernel_casinhf): Likewise. * math/k_casinhl.c (__kernel_casinhl): Likewise. * math/s_catan.c (__catan): Use math_check_force_underflow_complex. * math/s_catanf.c (__catanf): Likewise. * math/s_catanh.c (__catanh): Likewise. * math/s_catanhf.c (__catanhf): Likewise. * math/s_catanhl.c (__catanhl): Likewise. * math/s_catanl.c (__catanl): Likewise. * math/s_ccosh.c (__ccosh): Likewise. * math/s_ccoshf.c (__ccoshf): Likewise. * math/s_ccoshl.c (__ccoshl): Likewise. * math/s_cexp.c (__cexp): Likewise. * math/s_cexpf.c (__cexpf): Likewise. * math/s_cexpl.c (__cexpl): Likewise. * math/s_clog.c (__clog): Use math_check_force_underflow_nonneg. * math/s_clog10.c (__clog10): Likewise. * math/s_clog10f.c (__clog10f): Likewise. * math/s_clog10l.c (__clog10l): Likewise. * math/s_clogf.c (__clogf): Likewise. * math/s_clogl.c (__clogl): Likewise. * math/s_csin.c (__csin): Use math_check_force_underflow_complex. * math/s_csinf.c (__csinf): Likewise. * math/s_csinh.c (__csinh): Likewise. * math/s_csinhf.c (__csinhf): Likewise. * math/s_csinhl.c (__csinhl): Likewise. * math/s_csinl.c (__csinl): Likewise. * math/s_csqrt.c (__csqrt): Use math_check_force_underflow. * math/s_csqrtf.c (__csqrtf): Likewise. * math/s_csqrtl.c (__csqrtl): Likewise. * math/s_ctan.c (__ctan): Use math_check_force_underflow_complex. * math/s_ctanf.c (__ctanf): Likewise. * math/s_ctanh.c (__ctanh): Likewise. * math/s_ctanhf.c (__ctanhf): Likewise. * math/s_ctanhl.c (__ctanhl): Likewise. * math/s_ctanl.c (__ctanl): Likewise. * stdlib/strtod_l.c (round_and_return): Use math_force_eval instead of volatile. * sysdeps/ieee754/dbl-64/e_asin.c (__ieee754_asin): Use math_check_force_underflow. * sysdeps/ieee754/dbl-64/e_atanh.c (__ieee754_atanh): Likewise. * sysdeps/ieee754/dbl-64/e_exp.c (__ieee754_exp): Do not use volatile when forcing underflow. * sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/dbl-64/e_gamma_r.c (__ieee754_gamma_r): Likewise. * sysdeps/ieee754/dbl-64/e_j1.c (__ieee754_j1): Use math_check_force_underflow. * sysdeps/ieee754/dbl-64/e_jn.c (__ieee754_jn): Likewise. * sysdeps/ieee754/dbl-64/e_sinh.c (__ieee754_sinh): Likewise. * sysdeps/ieee754/dbl-64/s_asinh.c (__asinh): Likewise. * sysdeps/ieee754/dbl-64/s_atan.c (atan): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/dbl-64/s_erf.c (__erf): Use math_check_force_underflow. * sysdeps/ieee754/dbl-64/s_expm1.c (__expm1): Likewise. * sysdeps/ieee754/dbl-64/s_fma.c (__fma): Use math_force_eval instead of volatile. * sysdeps/ieee754/dbl-64/s_log1p.c (__log1p): Use math_check_force_underflow. * sysdeps/ieee754/dbl-64/s_sin.c (__sin): Likewise. * sysdeps/ieee754/dbl-64/s_tan.c (tan): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/dbl-64/s_tanh.c (__tanh): Use math_check_force_underflow. * sysdeps/ieee754/flt-32/e_asinf.c (__ieee754_asinf): Likewise. * sysdeps/ieee754/flt-32/e_atanhf.c (__ieee754_atanhf): Likewise. * sysdeps/ieee754/flt-32/e_exp2f.c (__ieee754_exp2f): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/flt-32/e_gammaf_r.c (__ieee754_gammaf_r): Likewise. * sysdeps/ieee754/flt-32/e_j1f.c (__ieee754_j1f): Use math_check_force_underflow. * sysdeps/ieee754/flt-32/e_jnf.c (__ieee754_jnf): Likewise. * sysdeps/ieee754/flt-32/e_sinhf.c (__ieee754_sinhf): Likewise. * sysdeps/ieee754/flt-32/k_sinf.c (__kernel_sinf): Likewise. * sysdeps/ieee754/flt-32/k_tanf.c (__kernel_tanf): Likewise. * sysdeps/ieee754/flt-32/s_asinhf.c (__asinhf): Likewise. * sysdeps/ieee754/flt-32/s_atanf.c (__atanf): Likewise. * sysdeps/ieee754/flt-32/s_erff.c (__erff): Likewise. * sysdeps/ieee754/flt-32/s_expm1f.c (__expm1f): Likewise. * sysdeps/ieee754/flt-32/s_log1pf.c (__log1pf): Likewise. * sysdeps/ieee754/flt-32/s_tanhf.c (__tanhf): Likewise. * sysdeps/ieee754/ldbl-128/e_asinl.c (__ieee754_asinl): Likewise. * sysdeps/ieee754/ldbl-128/e_atanhl.c (__ieee754_atanhl): Likewise. * sysdeps/ieee754/ldbl-128/e_expl.c (__ieee754_expl): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/ldbl-128/e_gammal_r.c (__ieee754_gammal_r): Likewise. * sysdeps/ieee754/ldbl-128/e_j1l.c (__ieee754_j1l): Use math_check_force_underflow. * sysdeps/ieee754/ldbl-128/e_jnl.c (__ieee754_jnl): Likewise. * sysdeps/ieee754/ldbl-128/e_sinhl.c (__ieee754_sinhl): Likewise. * sysdeps/ieee754/ldbl-128/k_sincosl.c (__kernel_sincosl): Likewise. * sysdeps/ieee754/ldbl-128/k_sinl.c (__kernel_sinl): Likewise. * sysdeps/ieee754/ldbl-128/k_tanl.c (__kernel_tanl): Likewise. * sysdeps/ieee754/ldbl-128/s_asinhl.c (__asinhl): Likewise. * sysdeps/ieee754/ldbl-128/s_atanl.c (__atanl): Likewise. * sysdeps/ieee754/ldbl-128/s_erfl.c (__erfl): Likewise. * sysdeps/ieee754/ldbl-128/s_expm1l.c (__expm1l): Likewise. * sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Use math_force_eval instead of volatile. * sysdeps/ieee754/ldbl-128/s_log1pl.c (__log1pl): Use math_check_force_underflow. * sysdeps/ieee754/ldbl-128/s_tanhl.c (__tanhl): Likewise. * sysdeps/ieee754/ldbl-128ibm/e_asinl.c (__ieee754_asinl): Use math_check_force_underflow. * sysdeps/ieee754/ldbl-128ibm/e_atanhl.c (__ieee754_atanhl): Likewise. * sysdeps/ieee754/ldbl-128ibm/e_gammal_r.c (__ieee754_gammal_r): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Use math_check_force_underflow. * sysdeps/ieee754/ldbl-128ibm/e_sinhl.c (__ieee754_sinhl): Likewise. * sysdeps/ieee754/ldbl-128ibm/k_sincosl.c (__kernel_sincosl): Likewise. * sysdeps/ieee754/ldbl-128ibm/k_sinl.c (__kernel_sinl): Likewise. * sysdeps/ieee754/ldbl-128ibm/k_tanl.c (__kernel_tanl): Likewise. * sysdeps/ieee754/ldbl-128ibm/s_asinhl.c (__asinhl): Likewise. * sysdeps/ieee754/ldbl-128ibm/s_atanl.c (__atanl): Likewise. * sysdeps/ieee754/ldbl-128ibm/s_erfl.c (__erfl): Likewise. * sysdeps/ieee754/ldbl-128ibm/s_tanhl.c (__tanhl): Likewise. * sysdeps/ieee754/ldbl-96/e_asinl.c (__ieee754_asinl): Likewise. * sysdeps/ieee754/ldbl-96/e_atanhl.c (__ieee754_atanhl): Likewise. * sysdeps/ieee754/ldbl-96/e_gammal_r.c (__ieee754_gammal_r): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/ldbl-96/e_j1l.c (__ieee754_j1l): Use math_check_force_underflow. * sysdeps/ieee754/ldbl-96/e_jnl.c (__ieee754_jnl): Likewise. * sysdeps/ieee754/ldbl-96/e_sinhl.c (__ieee754_sinhl): Likewise. * sysdeps/ieee754/ldbl-96/k_sinl.c (__kernel_sinl): Likewise. * sysdeps/ieee754/ldbl-96/k_tanl.c (__kernel_tanl): Use math_check_force_underflow_nonneg. * sysdeps/ieee754/ldbl-96/s_asinhl.c (__asinhl): Use math_check_force_underflow. * sysdeps/ieee754/ldbl-96/s_erfl.c (__erfl): Likewise. * sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Use math_force_eval instead of volatile. * sysdeps/ieee754/ldbl-96/s_tanhl.c (__tanhl): Use math_check_force_underflow.
2015-09-23 22:42:30 +00:00
math_check_force_underflow (ret);
Fix erf underflow handling near 0 (bug 16516). Bug 16516 reports spurious underflows from erf (for all floating-point types), when the result is close to underflowing but does not actually underflow. erf (x) is about (2/sqrt(pi))*x for x close to 0, so there are subnormal arguments for which it does not underflow. The various implementations do (x + efx*x) (for efx = 2/sqrt(pi) - 1), for greater accuracy than if just using a single multiplication by an approximation to 2/sqrt(pi) (effectively, this way there are a few more bits in the approximation to 2/sqrt(pi)). This can introduce underflows when efx*x underflows even though the final result does not, so a scaled calculation with 8*efx is done in these cases - but 8 is not a big enough scale factor to avoid all such underflows. 16 is (any underflows with a scale factor of 16 would only occur when the final result underflows), so this patch changes the code to use that factor. Rather than recomputing all the values of the efx8 variable, it is removed, leaving it to the compiler's constant folding to compute 16*efx. As such scaling can also lose underflows when the final scaling down happens to be exact, appropriate checks are added to ensure underflow exceptions occur when required in such cases. Tested x86_64 and x86; no ulps updates needed. Also spot-checked for powerpc32 and mips64 to verify the changes to the ldbl-128ibm and ldbl-128 implementations. [BZ #16516] * sysdeps/ieee754/dbl-64/s_erf.c (efx8): Remove variable. (__erf): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/flt-32/s_erff.c (efx8): Remove variable. (__erff): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * sysdeps/ieee754/ldbl-96/s_erfl.c: Include <float.h>. (efx8): Remove variable. (__erfl): Scale by 16 instead of 8 in potentially underflowing case. Ensure exception if result actually underflows. * math/auto-libm-test-in: Add more tests of erf. * math/auto-libm-test-out: Regenerated.
2014-05-14 12:34:03 +00:00
return ret;
}
return x + efx * x;
}
y = a + a * neval (z, TN1, NTN1) / deval (z, TD1, NTD1);
}
else
{
a = a - one;
y = erf_const + neval (a, TN2, NTN2) / deval (a, TD2, NTD2);
}
if (sign & 0x80000000) /* x < 0 */
y = -y;
return( y );
}
weak_alias (__erfl, erfl)
long double
__erfcl (long double x)
{
long double y, z, p, r;
int32_t i, ix, sign;
ieee854_long_double_shape_type u;
u.value = x;
sign = u.parts32.w0;
ix = sign & 0x7fffffff;
u.parts32.w0 = ix;
if (ix >= 0x7fff0000)
{ /* erfc(nan)=nan */
/* erfc(+-inf)=0,2 */
return (long double) (((u_int32_t) sign >> 31) << 1) + one / x;
}
if (ix < 0x3ffd0000) /* |x| <1/4 */
{
if (ix < 0x3f8d0000) /* |x|<2**-114 */
return one - x;
return one - __erfl (x);
}
if (ix < 0x3fff4000) /* 1.25 */
{
x = u.value;
i = 8.0 * x;
switch (i)
{
case 2:
z = x - 0.25L;
y = C13b + z * neval (z, RNr13, NRNr13) / deval (z, RDr13, NRDr13);
y += C13a;
break;
case 3:
z = x - 0.375L;
y = C14b + z * neval (z, RNr14, NRNr14) / deval (z, RDr14, NRDr14);
y += C14a;
break;
case 4:
z = x - 0.5L;
y = C15b + z * neval (z, RNr15, NRNr15) / deval (z, RDr15, NRDr15);
y += C15a;
break;
case 5:
z = x - 0.625L;
y = C16b + z * neval (z, RNr16, NRNr16) / deval (z, RDr16, NRDr16);
y += C16a;
break;
case 6:
z = x - 0.75L;
y = C17b + z * neval (z, RNr17, NRNr17) / deval (z, RDr17, NRDr17);
y += C17a;
break;
case 7:
z = x - 0.875L;
y = C18b + z * neval (z, RNr18, NRNr18) / deval (z, RDr18, NRDr18);
y += C18a;
break;
case 8:
z = x - 1.0L;
y = C19b + z * neval (z, RNr19, NRNr19) / deval (z, RDr19, NRDr19);
y += C19a;
break;
default: /* i == 9. */
z = x - 1.125L;
y = C20b + z * neval (z, RNr20, NRNr20) / deval (z, RDr20, NRDr20);
y += C20a;
break;
}
if (sign & 0x80000000)
y = 2.0L - y;
return y;
}
/* 1.25 < |x| < 107 */
if (ix < 0x4005ac00)
{
/* x < -9 */
if ((ix >= 0x40022000) && (sign & 0x80000000))
return two - tiny;
x = fabsl (x);
z = one / (x * x);
i = 8.0 / x;
switch (i)
{
default:
case 0:
p = neval (z, RNr1, NRNr1) / deval (z, RDr1, NRDr1);
break;
case 1:
p = neval (z, RNr2, NRNr2) / deval (z, RDr2, NRDr2);
break;
case 2:
p = neval (z, RNr3, NRNr3) / deval (z, RDr3, NRDr3);
break;
case 3:
p = neval (z, RNr4, NRNr4) / deval (z, RDr4, NRDr4);
break;
case 4:
p = neval (z, RNr5, NRNr5) / deval (z, RDr5, NRDr5);
break;
case 5:
p = neval (z, RNr6, NRNr6) / deval (z, RDr6, NRDr6);
break;
case 6:
p = neval (z, RNr7, NRNr7) / deval (z, RDr7, NRDr7);
break;
case 7:
p = neval (z, RNr8, NRNr8) / deval (z, RDr8, NRDr8);
break;
}
u.value = x;
u.parts32.w3 = 0;
u.parts32.w2 &= 0xfe000000;
z = u.value;
r = __ieee754_expl (-z * z - 0.5625) *
__ieee754_expl ((z - x) * (z + x) + p);
if ((sign & 0x80000000) == 0)
{
long double ret = r / x;
if (ret == 0)
__set_errno (ERANGE);
return ret;
}
else
return two - r / x;
}
else
{
if ((sign & 0x80000000) == 0)
{
__set_errno (ERANGE);
return tiny * tiny;
}
else
return two - tiny;
}
}
weak_alias (__erfcl, erfcl)