mirror of
https://github.com/ruby/ruby.git
synced 2022-11-09 12:17:21 -05:00
* missing/crypt.c: replaced with 4.4BSD version.
* missing/erf.c: ditto. * missing/vsnprintf.c: removed the third provision from the old BSD license. [ruby-core:05177] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@8687 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
matz
parent
aa28f4671c
commit
626f1ee196
4 changed files with 1311 additions and 319 deletions
|
|
@ -1,3 +1,12 @@
|
|||
Fri Jul 1 11:34:08 2005 Yukihiro Matsumoto <matz@ruby-lang.org>
|
||||
|
||||
* missing/crypt.c: replaced with 4.4BSD version.
|
||||
|
||||
* missing/erf.c: ditto.
|
||||
|
||||
* missing/vsnprintf.c: removed the third provision from the old
|
||||
BSD license. [ruby-core:05177]
|
||||
|
||||
Fri Jul 1 01:45:21 2005 Nobuyoshi Nakada <nobu@ruby-lang.org>
|
||||
|
||||
* enum.c (enum_min, enum_max): must not return Qundef.
|
||||
|
|
|
|||
1168
missing/crypt.c
1168
missing/crypt.c
File diff suppressed because it is too large
Load diff
449
missing/erf.c
449
missing/erf.c
|
|
@ -1,91 +1,392 @@
|
|||
/* erf.c
|
||||
reference - Haruhiko Okumura: C-gengo niyoru saishin algorithm jiten
|
||||
(New Algorithm handbook in C language) (Gijyutsu hyouron
|
||||
sha, Tokyo, 1991) p.227 [in Japanese] */
|
||||
#include <stdio.h>
|
||||
#include <math.h>
|
||||
/*-
|
||||
* Copyright (c) 1992, 1993
|
||||
* The Regents of the University of California. All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. Neither the name of the University nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||||
* SUCH DAMAGE.
|
||||
*/
|
||||
|
||||
#ifdef _WIN32
|
||||
# include <float.h>
|
||||
# if !defined __MINGW32__ || defined __NO_ISOCEXT
|
||||
# ifndef isnan
|
||||
# define isnan(x) _isnan(x)
|
||||
# endif
|
||||
# ifndef isinf
|
||||
# define isinf(x) (!_finite(x) && !_isnan(x))
|
||||
# endif
|
||||
# ifndef finite
|
||||
# define finite(x) _finite(x)
|
||||
# endif
|
||||
# endif
|
||||
#ifndef lint
|
||||
static char sccsid[] = "@(#)erf.c 8.1 (Berkeley) 6/4/93";
|
||||
#endif /* not lint */
|
||||
|
||||
/* Modified Nov 30, 1992 P. McILROY:
|
||||
* Replaced expansions for x >= 1.25 (error 1.7ulp vs ~6ulp)
|
||||
* Replaced even+odd with direct calculation for x < .84375,
|
||||
* to avoid destructive cancellation.
|
||||
*
|
||||
* Performance of erfc(x):
|
||||
* In 300000 trials in the range [.83, .84375] the
|
||||
* maximum observed error was 3.6ulp.
|
||||
*
|
||||
* In [.84735,1.25] the maximum observed error was <2.5ulp in
|
||||
* 100000 runs in the range [1.2, 1.25].
|
||||
*
|
||||
* In [1.25,26] (Not including subnormal results)
|
||||
* the error is < 1.7ulp.
|
||||
*/
|
||||
|
||||
/* double erf(double x)
|
||||
* double erfc(double x)
|
||||
* x
|
||||
* 2 |\
|
||||
* erf(x) = --------- | exp(-t*t)dt
|
||||
* sqrt(pi) \|
|
||||
* 0
|
||||
*
|
||||
* erfc(x) = 1-erf(x)
|
||||
*
|
||||
* Method:
|
||||
* 1. Reduce x to |x| by erf(-x) = -erf(x)
|
||||
* 2. For x in [0, 0.84375]
|
||||
* erf(x) = x + x*P(x^2)
|
||||
* erfc(x) = 1 - erf(x) if x<=0.25
|
||||
* = 0.5 + ((0.5-x)-x*P) if x in [0.25,0.84375]
|
||||
* where
|
||||
* 2 2 4 20
|
||||
* P = P(x ) = (p0 + p1 * x + p2 * x + ... + p10 * x )
|
||||
* is an approximation to (erf(x)-x)/x with precision
|
||||
*
|
||||
* -56.45
|
||||
* | P - (erf(x)-x)/x | <= 2
|
||||
*
|
||||
*
|
||||
* 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. The interval is chosen because the fixed
|
||||
* point of erf(x) is near 0.6174 (i.e., erf(x)=x when x is
|
||||
* near 0.6174), and by some experiment, 0.84375 is chosen to
|
||||
* guarantee the error is less than one ulp for erf.
|
||||
*
|
||||
* 3. For x in [0.84375,1.25], let s = x - 1, and
|
||||
* c = 0.84506291151 rounded to single (24 bits)
|
||||
* erf(x) = c + P1(s)/Q1(s)
|
||||
* erfc(x) = (1-c) - P1(s)/Q1(s)
|
||||
* |P1/Q1 - (erf(x)-c)| <= 2**-59.06
|
||||
* 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)
|
||||
* That is, we use rational approximation to approximate
|
||||
* erf(1+s) - (c = (single)0.84506291151)
|
||||
* Note that |P1/Q1|< 0.078 for x in [0.84375,1.25]
|
||||
* where
|
||||
* P1(s) = degree 6 poly in s
|
||||
* Q1(s) = degree 6 poly in s
|
||||
*
|
||||
* 4. For x in [1.25, 2]; [2, 4]
|
||||
* erf(x) = 1.0 - tiny
|
||||
* erfc(x) = (1/x)exp(-x*x-(.5*log(pi) -.5z + R(z)/S(z))
|
||||
*
|
||||
* Where z = 1/(x*x), R is degree 9, and S is degree 3;
|
||||
*
|
||||
* 5. For x in [4,28]
|
||||
* erf(x) = 1.0 - tiny
|
||||
* erfc(x) = (1/x)exp(-x*x-(.5*log(pi)+eps + zP(z))
|
||||
*
|
||||
* Where P is degree 14 polynomial in 1/(x*x).
|
||||
*
|
||||
* Notes:
|
||||
* Here 4 and 5 make use of the asymptotic series
|
||||
* exp(-x*x)
|
||||
* erfc(x) ~ ---------- * ( 1 + Poly(1/x^2) );
|
||||
* x*sqrt(pi)
|
||||
*
|
||||
* where for z = 1/(x*x)
|
||||
* P(z) ~ z/2*(-1 + z*3/2*(1 + z*5/2*(-1 + z*7/2*(1 +...))))
|
||||
*
|
||||
* Thus we use rational approximation to approximate
|
||||
* erfc*x*exp(x*x) ~ 1/sqrt(pi);
|
||||
*
|
||||
* The error bound for the target function, G(z) for
|
||||
* the interval
|
||||
* [4, 28]:
|
||||
* |eps + 1/(z)P(z) - G(z)| < 2**(-56.61)
|
||||
* for [2, 4]:
|
||||
* |R(z)/S(z) - G(z)| < 2**(-58.24)
|
||||
* for [1.25, 2]:
|
||||
* |R(z)/S(z) - G(z)| < 2**(-58.12)
|
||||
*
|
||||
* 6. For inf > x >= 28
|
||||
* erf(x) = 1 - tiny (raise inexact)
|
||||
* erfc(x) = tiny*tiny (raise underflow)
|
||||
*
|
||||
* 7. Special cases:
|
||||
* erf(0) = 0, erf(inf) = 1, erf(-inf) = -1,
|
||||
* erfc(0) = 1, erfc(inf) = 0, erfc(-inf) = 2,
|
||||
* erfc/erf(NaN) is NaN
|
||||
*/
|
||||
|
||||
#if defined(vax) || defined(tahoe)
|
||||
#define _IEEE 0
|
||||
#define TRUNC(x) (double) (float) (x)
|
||||
#else
|
||||
#define _IEEE 1
|
||||
#define TRUNC(x) *(((int *) &x) + 1) &= 0xf8000000
|
||||
#define infnan(x) 0.0
|
||||
#endif
|
||||
|
||||
static double q_gamma(double, double, double);
|
||||
#ifdef _IEEE_LIBM
|
||||
/*
|
||||
* redefining "___function" to "function" in _IEEE_LIBM mode
|
||||
*/
|
||||
#include "ieee_libm.h"
|
||||
#endif
|
||||
|
||||
/* Incomplete gamma function
|
||||
1 / Gamma(a) * Int_0^x exp(-t) t^(a-1) dt */
|
||||
static double p_gamma(a, x, loggamma_a)
|
||||
double a, x, loggamma_a;
|
||||
{
|
||||
int k;
|
||||
double result, term, previous;
|
||||
|
||||
if (x >= 1 + a) return 1 - q_gamma(a, x, loggamma_a);
|
||||
if (x == 0) return 0;
|
||||
result = term = exp(a * log(x) - x - loggamma_a) / a;
|
||||
for (k = 1; k < 1000; k++) {
|
||||
term *= x / (a + k);
|
||||
previous = result; result += term;
|
||||
if (result == previous) return result;
|
||||
}
|
||||
fprintf(stderr, "erf.c:%d:p_gamma() could not converge.", __LINE__);
|
||||
return result;
|
||||
}
|
||||
|
||||
/* Incomplete gamma function
|
||||
1 / Gamma(a) * Int_x^inf exp(-t) t^(a-1) dt */
|
||||
static double q_gamma(a, x, loggamma_a)
|
||||
double a, x, loggamma_a;
|
||||
{
|
||||
int k;
|
||||
double result, w, temp, previous;
|
||||
double la = 1, lb = 1 + x - a; /* Laguerre polynomial */
|
||||
|
||||
if (x < 1 + a) return 1 - p_gamma(a, x, loggamma_a);
|
||||
w = exp(a * log(x) - x - loggamma_a);
|
||||
result = w / lb;
|
||||
for (k = 2; k < 1000; k++) {
|
||||
temp = ((k - 1 - a) * (lb - la) + (k + x) * lb) / k;
|
||||
la = lb; lb = temp;
|
||||
w *= (k - 1 - a) / k;
|
||||
temp = w / (la * lb);
|
||||
previous = result; result += temp;
|
||||
if (result == previous) return result;
|
||||
}
|
||||
fprintf(stderr, "erf.c:%d:q_gamma() could not converge.", __LINE__);
|
||||
return result;
|
||||
}
|
||||
|
||||
#define LOG_PI_OVER_2 0.572364942924700087071713675675 /* log_e(PI)/2 */
|
||||
static double
|
||||
tiny = 1e-300,
|
||||
half = 0.5,
|
||||
one = 1.0,
|
||||
two = 2.0,
|
||||
c = 8.45062911510467529297e-01, /* (float)0.84506291151 */
|
||||
/*
|
||||
* Coefficients for approximation to erf in [0,0.84375]
|
||||
*/
|
||||
p0t8 = 1.02703333676410051049867154944018394163280,
|
||||
p0 = 1.283791670955125638123339436800229927041e-0001,
|
||||
p1 = -3.761263890318340796574473028946097022260e-0001,
|
||||
p2 = 1.128379167093567004871858633779992337238e-0001,
|
||||
p3 = -2.686617064084433642889526516177508374437e-0002,
|
||||
p4 = 5.223977576966219409445780927846432273191e-0003,
|
||||
p5 = -8.548323822001639515038738961618255438422e-0004,
|
||||
p6 = 1.205520092530505090384383082516403772317e-0004,
|
||||
p7 = -1.492214100762529635365672665955239554276e-0005,
|
||||
p8 = 1.640186161764254363152286358441771740838e-0006,
|
||||
p9 = -1.571599331700515057841960987689515895479e-0007,
|
||||
p10= 1.073087585213621540635426191486561494058e-0008;
|
||||
/*
|
||||
* Coefficients for approximation to erf in [0.84375,1.25]
|
||||
*/
|
||||
static double
|
||||
pa0 = -2.362118560752659485957248365514511540287e-0003,
|
||||
pa1 = 4.148561186837483359654781492060070469522e-0001,
|
||||
pa2 = -3.722078760357013107593507594535478633044e-0001,
|
||||
pa3 = 3.183466199011617316853636418691420262160e-0001,
|
||||
pa4 = -1.108946942823966771253985510891237782544e-0001,
|
||||
pa5 = 3.547830432561823343969797140537411825179e-0002,
|
||||
pa6 = -2.166375594868790886906539848893221184820e-0003,
|
||||
qa1 = 1.064208804008442270765369280952419863524e-0001,
|
||||
qa2 = 5.403979177021710663441167681878575087235e-0001,
|
||||
qa3 = 7.182865441419627066207655332170665812023e-0002,
|
||||
qa4 = 1.261712198087616469108438860983447773726e-0001,
|
||||
qa5 = 1.363708391202905087876983523620537833157e-0002,
|
||||
qa6 = 1.198449984679910764099772682882189711364e-0002;
|
||||
/*
|
||||
* log(sqrt(pi)) for large x expansions.
|
||||
* The tail (lsqrtPI_lo) is included in the rational
|
||||
* approximations.
|
||||
*/
|
||||
static double
|
||||
lsqrtPI_hi = .5723649429247000819387380943226;
|
||||
/*
|
||||
* lsqrtPI_lo = .000000000000000005132975581353913;
|
||||
*
|
||||
* Coefficients for approximation to erfc in [2, 4]
|
||||
*/
|
||||
static double
|
||||
rb0 = -1.5306508387410807582e-010, /* includes lsqrtPI_lo */
|
||||
rb1 = 2.15592846101742183841910806188e-008,
|
||||
rb2 = 6.24998557732436510470108714799e-001,
|
||||
rb3 = 8.24849222231141787631258921465e+000,
|
||||
rb4 = 2.63974967372233173534823436057e+001,
|
||||
rb5 = 9.86383092541570505318304640241e+000,
|
||||
rb6 = -7.28024154841991322228977878694e+000,
|
||||
rb7 = 5.96303287280680116566600190708e+000,
|
||||
rb8 = -4.40070358507372993983608466806e+000,
|
||||
rb9 = 2.39923700182518073731330332521e+000,
|
||||
rb10 = -6.89257464785841156285073338950e-001,
|
||||
sb1 = 1.56641558965626774835300238919e+001,
|
||||
sb2 = 7.20522741000949622502957936376e+001,
|
||||
sb3 = 9.60121069770492994166488642804e+001;
|
||||
/*
|
||||
* Coefficients for approximation to erfc in [1.25, 2]
|
||||
*/
|
||||
static double
|
||||
rc0 = -2.47925334685189288817e-007, /* includes lsqrtPI_lo */
|
||||
rc1 = 1.28735722546372485255126993930e-005,
|
||||
rc2 = 6.24664954087883916855616917019e-001,
|
||||
rc3 = 4.69798884785807402408863708843e+000,
|
||||
rc4 = 7.61618295853929705430118701770e+000,
|
||||
rc5 = 9.15640208659364240872946538730e-001,
|
||||
rc6 = -3.59753040425048631334448145935e-001,
|
||||
rc7 = 1.42862267989304403403849619281e-001,
|
||||
rc8 = -4.74392758811439801958087514322e-002,
|
||||
rc9 = 1.09964787987580810135757047874e-002,
|
||||
rc10 = -1.28856240494889325194638463046e-003,
|
||||
sc1 = 9.97395106984001955652274773456e+000,
|
||||
sc2 = 2.80952153365721279953959310660e+001,
|
||||
sc3 = 2.19826478142545234106819407316e+001;
|
||||
/*
|
||||
* Coefficients for approximation to erfc in [4,28]
|
||||
*/
|
||||
static double
|
||||
rd0 = -2.1491361969012978677e-016, /* includes lsqrtPI_lo */
|
||||
rd1 = -4.99999999999640086151350330820e-001,
|
||||
rd2 = 6.24999999772906433825880867516e-001,
|
||||
rd3 = -1.54166659428052432723177389562e+000,
|
||||
rd4 = 5.51561147405411844601985649206e+000,
|
||||
rd5 = -2.55046307982949826964613748714e+001,
|
||||
rd6 = 1.43631424382843846387913799845e+002,
|
||||
rd7 = -9.45789244999420134263345971704e+002,
|
||||
rd8 = 6.94834146607051206956384703517e+003,
|
||||
rd9 = -5.27176414235983393155038356781e+004,
|
||||
rd10 = 3.68530281128672766499221324921e+005,
|
||||
rd11 = -2.06466642800404317677021026611e+006,
|
||||
rd12 = 7.78293889471135381609201431274e+006,
|
||||
rd13 = -1.42821001129434127360582351685e+007;
|
||||
|
||||
double erf(x)
|
||||
double x;
|
||||
{
|
||||
if (!finite(x)) {
|
||||
if (isnan(x)) return x; /* erf(NaN) = NaN */
|
||||
return (x>0 ? 1.0 : -1.0); /* erf(+-inf) = +-1.0 */
|
||||
double R,S,P,Q,ax,s,y,z,r,fabs(),exp();
|
||||
if(!finite(x)) { /* erf(nan)=nan */
|
||||
if (isnan(x))
|
||||
return(x);
|
||||
return (x > 0 ? one : -one); /* erf(+/-inf)= +/-1 */
|
||||
}
|
||||
if (x >= 0) return p_gamma(0.5, x * x, LOG_PI_OVER_2);
|
||||
else return - p_gamma(0.5, x * x, LOG_PI_OVER_2);
|
||||
if ((ax = x) < 0)
|
||||
ax = - ax;
|
||||
if (ax < .84375) {
|
||||
if (ax < 3.7e-09) {
|
||||
if (ax < 1.0e-308)
|
||||
return 0.125*(8.0*x+p0t8*x); /*avoid underflow */
|
||||
return x + p0*x;
|
||||
}
|
||||
y = x*x;
|
||||
r = y*(p1+y*(p2+y*(p3+y*(p4+y*(p5+
|
||||
y*(p6+y*(p7+y*(p8+y*(p9+y*p10)))))))));
|
||||
return x + x*(p0+r);
|
||||
}
|
||||
if (ax < 1.25) { /* 0.84375 <= |x| < 1.25 */
|
||||
s = fabs(x)-one;
|
||||
P = pa0+s*(pa1+s*(pa2+s*(pa3+s*(pa4+s*(pa5+s*pa6)))));
|
||||
Q = one+s*(qa1+s*(qa2+s*(qa3+s*(qa4+s*(qa5+s*qa6)))));
|
||||
if (x>=0)
|
||||
return (c + P/Q);
|
||||
else
|
||||
return (-c - P/Q);
|
||||
}
|
||||
if (ax >= 6.0) { /* inf>|x|>=6 */
|
||||
if (x >= 0.0)
|
||||
return (one-tiny);
|
||||
else
|
||||
return (tiny-one);
|
||||
}
|
||||
/* 1.25 <= |x| < 6 */
|
||||
z = -ax*ax;
|
||||
s = -one/z;
|
||||
if (ax < 2.0) {
|
||||
R = rc0+s*(rc1+s*(rc2+s*(rc3+s*(rc4+s*(rc5+
|
||||
s*(rc6+s*(rc7+s*(rc8+s*(rc9+s*rc10)))))))));
|
||||
S = one+s*(sc1+s*(sc2+s*sc3));
|
||||
} else {
|
||||
R = rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(rb5+
|
||||
s*(rb6+s*(rb7+s*(rb8+s*(rb9+s*rb10)))))))));
|
||||
S = one+s*(sb1+s*(sb2+s*sb3));
|
||||
}
|
||||
y = (R/S -.5*s) - lsqrtPI_hi;
|
||||
z += y;
|
||||
z = exp(z)/ax;
|
||||
if (x >= 0)
|
||||
return (one-z);
|
||||
else
|
||||
return (z-one);
|
||||
}
|
||||
|
||||
double erfc(x)
|
||||
double x;
|
||||
{
|
||||
double R,S,P,Q,s,ax,y,z,r,fabs(),__exp__D();
|
||||
if (!finite(x)) {
|
||||
if (isnan(x)) return x; /* erfc(NaN) = NaN */
|
||||
return (x>0 ? 0.0 : 2.0); /* erfc(+-inf) = 0.0, 2.0 */
|
||||
if (isnan(x)) /* erfc(NaN) = NaN */
|
||||
return(x);
|
||||
else if (x > 0) /* erfc(+-inf)=0,2 */
|
||||
return 0.0;
|
||||
else
|
||||
return 2.0;
|
||||
}
|
||||
if (x >= 0) return q_gamma(0.5, x * x, LOG_PI_OVER_2);
|
||||
else return 1 + p_gamma(0.5, x * x, LOG_PI_OVER_2);
|
||||
if ((ax = x) < 0)
|
||||
ax = -ax;
|
||||
if (ax < .84375) { /* |x|<0.84375 */
|
||||
if (ax < 1.38777878078144568e-17) /* |x|<2**-56 */
|
||||
return one-x;
|
||||
y = x*x;
|
||||
r = y*(p1+y*(p2+y*(p3+y*(p4+y*(p5+
|
||||
y*(p6+y*(p7+y*(p8+y*(p9+y*p10)))))))));
|
||||
if (ax < .0625) { /* |x|<2**-4 */
|
||||
return (one-(x+x*(p0+r)));
|
||||
} else {
|
||||
r = x*(p0+r);
|
||||
r += (x-half);
|
||||
return (half - r);
|
||||
}
|
||||
}
|
||||
if (ax < 1.25) { /* 0.84375 <= |x| < 1.25 */
|
||||
s = ax-one;
|
||||
P = pa0+s*(pa1+s*(pa2+s*(pa3+s*(pa4+s*(pa5+s*pa6)))));
|
||||
Q = one+s*(qa1+s*(qa2+s*(qa3+s*(qa4+s*(qa5+s*qa6)))));
|
||||
if (x>=0) {
|
||||
z = one-c; return z - P/Q;
|
||||
} else {
|
||||
z = c+P/Q; return one+z;
|
||||
}
|
||||
}
|
||||
if (ax >= 28) /* Out of range */
|
||||
if (x>0)
|
||||
return (tiny*tiny);
|
||||
else
|
||||
return (two-tiny);
|
||||
z = ax;
|
||||
TRUNC(z);
|
||||
y = z - ax; y *= (ax+z);
|
||||
z *= -z; /* Here z + y = -x^2 */
|
||||
s = one/(-z-y); /* 1/(x*x) */
|
||||
if (ax >= 4) { /* 6 <= ax */
|
||||
R = s*(rd1+s*(rd2+s*(rd3+s*(rd4+s*(rd5+
|
||||
s*(rd6+s*(rd7+s*(rd8+s*(rd9+s*(rd10
|
||||
+s*(rd11+s*(rd12+s*rd13))))))))))));
|
||||
y += rd0;
|
||||
} else if (ax >= 2) {
|
||||
R = rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(rb5+
|
||||
s*(rb6+s*(rb7+s*(rb8+s*(rb9+s*rb10)))))))));
|
||||
S = one+s*(sb1+s*(sb2+s*sb3));
|
||||
y += R/S;
|
||||
R = -.5*s;
|
||||
} else {
|
||||
R = rc0+s*(rc1+s*(rc2+s*(rc3+s*(rc4+s*(rc5+
|
||||
s*(rc6+s*(rc7+s*(rc8+s*(rc9+s*rc10)))))))));
|
||||
S = one+s*(sc1+s*(sc2+s*sc3));
|
||||
y += R/S;
|
||||
R = -.5*s;
|
||||
}
|
||||
/* return exp(-x^2 - lsqrtPI_hi + R + y)/x; */
|
||||
s = ((R + y) - lsqrtPI_hi) + z;
|
||||
y = (((z-s) - lsqrtPI_hi) + R) + y;
|
||||
r = __exp__D(s, y)/x;
|
||||
if (x>0)
|
||||
return r;
|
||||
else
|
||||
return two-r;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -13,11 +13,7 @@
|
|||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by the University of
|
||||
* California, Berkeley and its contributors.
|
||||
* 4. Neither the name of the University nor the names of its contributors
|
||||
* 3. Neither the name of the University nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
|
|
|
|||
Loading…
Reference in a new issue