#include <sys/cdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: s_erff.c,v 1.6 1999/07/02 15:37:42 simonb Exp $");
#endif
#include "math.h"
#include "math_private.h"
static const float
tiny = 1e-30,
half= 5.0000000000e-01,
one = 1.0000000000e+00,
two = 2.0000000000e+00,
erx = 8.4506291151e-01,
efx = 1.2837916613e-01,
efx8= 1.0270333290e+00,
pp0 = 1.2837916613e-01,
pp1 = -3.2504209876e-01,
pp2 = -2.8481749818e-02,
pp3 = -5.7702702470e-03,
pp4 = -2.3763017452e-05,
qq1 = 3.9791721106e-01,
qq2 = 6.5022252500e-02,
qq3 = 5.0813062117e-03,
qq4 = 1.3249473704e-04,
qq5 = -3.9602282413e-06,
pa0 = -2.3621185683e-03,
pa1 = 4.1485610604e-01,
pa2 = -3.7220788002e-01,
pa3 = 3.1834661961e-01,
pa4 = -1.1089469492e-01,
pa5 = 3.5478305072e-02,
pa6 = -2.1663755178e-03,
qa1 = 1.0642088205e-01,
qa2 = 5.4039794207e-01,
qa3 = 7.1828655899e-02,
qa4 = 1.2617121637e-01,
qa5 = 1.3637083583e-02,
qa6 = 1.1984500103e-02,
ra0 = -9.8649440333e-03,
ra1 = -6.9385856390e-01,
ra2 = -1.0558626175e+01,
ra3 = -6.2375331879e+01,
ra4 = -1.6239666748e+02,
ra5 = -1.8460508728e+02,
ra6 = -8.1287437439e+01,
ra7 = -9.8143291473e+00,
sa1 = 1.9651271820e+01,
sa2 = 1.3765776062e+02,
sa3 = 4.3456588745e+02,
sa4 = 6.4538726807e+02,
sa5 = 4.2900814819e+02,
sa6 = 1.0863500214e+02,
sa7 = 6.5702495575e+00,
sa8 = -6.0424413532e-02,
rb0 = -9.8649431020e-03,
rb1 = -7.9928326607e-01,
rb2 = -1.7757955551e+01,
rb3 = -1.6063638306e+02,
rb4 = -6.3756646729e+02,
rb5 = -1.0250950928e+03,
rb6 = -4.8351919556e+02,
sb1 = 3.0338060379e+01,
sb2 = 3.2579251099e+02,
sb3 = 1.5367296143e+03,
sb4 = 3.1998581543e+03,
sb5 = 2.5530502930e+03,
sb6 = 4.7452853394e+02,
sb7 = -2.2440952301e+01;
#define __ieee754_expf expf
float erff(float x)
{
int32_t hx,ix,i;
float R,S,P,Q,s,y,z,r;
GET_FLOAT_WORD(hx,x);
ix = hx&0x7fffffff;
if(ix>=0x7f800000) {
i = ((u_int32_t)hx>>31)<<1;
return (float)(1-i)+one/x;
}
if(ix < 0x3f580000) {
if(ix < 0x31800000) {
if (ix < 0x04000000)
return (float)0.125*((float)8.0*x+efx8*x);
return x + efx*x;
}
z = x*x;
r = pp0+z*(pp1+z*(pp2+z*(pp3+z*pp4)));
s = one+z*(qq1+z*(qq2+z*(qq3+z*(qq4+z*qq5))));
y = r/s;
return x + x*y;
}
if(ix < 0x3fa00000) {
s = fabsf(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(hx>=0) return erx + P/Q; else return -erx - P/Q;
}
if (ix >= 0x40c00000) {
if(hx>=0) return one-tiny; else return tiny-one;
}
x = fabsf(x);
s = one/(x*x);
if(ix< 0x4036DB6E) {
R=ra0+s*(ra1+s*(ra2+s*(ra3+s*(ra4+s*(
ra5+s*(ra6+s*ra7))))));
S=one+s*(sa1+s*(sa2+s*(sa3+s*(sa4+s*(
sa5+s*(sa6+s*(sa7+s*sa8)))))));
} else {
R=rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(
rb5+s*rb6)))));
S=one+s*(sb1+s*(sb2+s*(sb3+s*(sb4+s*(
sb5+s*(sb6+s*sb7))))));
}
GET_FLOAT_WORD(ix,x);
SET_FLOAT_WORD(z,ix&0xfffff000);
r = __ieee754_expf(-z*z-(float)0.5625)*__ieee754_expf((z-x)*(z+x)+R/S);
if(hx>=0) return one-r/x; else return r/x-one;
}
float erfcf(float x)
{
int32_t hx,ix;
float R,S,P,Q,s,y,z,r;
GET_FLOAT_WORD(hx,x);
ix = hx&0x7fffffff;
if(ix>=0x7f800000) {
return (float)(((u_int32_t)hx>>31)<<1)+one/x;
}
if(ix < 0x3f580000) {
if(ix < 0x23800000)
return one-x;
z = x*x;
r = pp0+z*(pp1+z*(pp2+z*(pp3+z*pp4)));
s = one+z*(qq1+z*(qq2+z*(qq3+z*(qq4+z*qq5))));
y = r/s;
if(hx < 0x3e800000) {
return one-(x+x*y);
} else {
r = x*y;
r += (x-half);
return half - r ;
}
}
if(ix < 0x3fa00000) {
s = fabsf(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(hx>=0) {
z = one-erx; return z - P/Q;
} else {
z = erx+P/Q; return one+z;
}
}
if (ix < 0x41e00000) {
x = fabsf(x);
s = one/(x*x);
if(ix< 0x4036DB6D) {
R=ra0+s*(ra1+s*(ra2+s*(ra3+s*(ra4+s*(
ra5+s*(ra6+s*ra7))))));
S=one+s*(sa1+s*(sa2+s*(sa3+s*(sa4+s*(
sa5+s*(sa6+s*(sa7+s*sa8)))))));
} else {
if(hx<0&&ix>=0x40c00000) return two-tiny;
R=rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(
rb5+s*rb6)))));
S=one+s*(sb1+s*(sb2+s*(sb3+s*(sb4+s*(
sb5+s*(sb6+s*sb7))))));
}
GET_FLOAT_WORD(ix,x);
SET_FLOAT_WORD(z,ix&0xfffff000);
r = __ieee754_expf(-z*z-(float)0.5625)*
__ieee754_expf((z-x)*(z+x)+R/S);
if(hx>0) return r/x; else return two-r/x;
} else {
if(hx>0) return tiny*tiny; else return two-tiny;
}
}