double
sqrt(double x)
{
int exponent;
double val;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (x <= 0) {
if (x < 0) errno = EDOM;
return 0;
}
if (x > DBL_MAX) return x; /* for infinity */
val = frexp(x, &exponent);
if (exponent & 1) {
exponent--;
val *= 2;
}
val = ldexp(val + 1.0, exponent/2 - 1);
/* was: val = (val + 1.0)/2.0; val = ldexp(val, exponent/2); */
for (exponent = NITER - 1; exponent >= 0; exponent--) {
val = (val + x / val) / 2.0;
}
return val;
}
double
atan(double x)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double p[] = {
-0.13688768894191926929e+2,
-0.20505855195861651981e+2,
-0.84946240351320683534e+1,
-0.83758299368150059274e+0
};
static double q[] = {
0.41066306682575781263e+2,
0.86157349597130242515e+2,
0.59578436142597344465e+2,
0.15024001160028576121e+2,
1.0
};
static double a[] = {
0.0,
0.52359877559829887307710723554658381, /* pi/6 */
M_PI_2,
1.04719755119659774615421446109316763 /* pi/3 */
};
int neg = x < 0;
int n;
double g;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (neg) {
x = -x;
}
if (x > 1.0) {
x = 1.0/x;
n = 2;
}
else n = 0;
if (x > 0.26794919243112270647) { /* 2-sqtr(3) */
n = n + 1;
x = (((0.73205080756887729353*x-0.5)-0.5)+x)/
(1.73205080756887729353+x);
}
/* ??? avoid underflow ??? */
g = x * x;
x += x * g * POLYNOM3(g, p) / POLYNOM4(g, q);
if (n > 1) x = -x;
x += a[n];
return neg ? -x : x;
}
double
exp(double x)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double p[] = {
0.25000000000000000000e+0,
0.75753180159422776666e-2,
0.31555192765684646356e-4
};
static double q[] = {
0.50000000000000000000e+0,
0.56817302698551221787e-1,
0.63121894374398503557e-3,
0.75104028399870046114e-6
};
double xn, g;
int n;
int negative = x < 0;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (x < M_LN_MIN_D) {
errno = ERANGE;
return 0.0;
}
if (x > M_LN_MAX_D) {
errno = ERANGE;
return HUGE_VAL;
}
if (negative) x = -x;
/* ??? avoid underflow ??? */
n = x * M_LOG2E + 0.5; /* 1/ln(2) = log2(e), 0.5 added for rounding */
xn = n;
{
double x1 = (long) x;
double x2 = x - x1;
g = ((x1-xn*0.693359375)+x2) - xn*(-2.1219444005469058277e-4);
}
if (negative) {
g = -g;
n = -n;
}
xn = g * g;
x = g * POLYNOM2(xn, p);
n += 1;
return (ldexp(0.5 + x/(POLYNOM3(xn, q) - x), n));
}
static double
asin_acos(double x, int cosfl)
{
int negative = x < 0;
int i;
double g;
static double p[] = {
-0.27368494524164255994e+2,
0.57208227877891731407e+2,
-0.39688862997540877339e+2,
0.10152522233806463645e+2,
-0.69674573447350646411e+0
};
static double q[] = {
-0.16421096714498560795e+3,
0.41714430248260412556e+3,
-0.38186303361750149284e+3,
0.15095270841030604719e+3,
-0.23823859153670238830e+2,
1.0
};
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (negative) {
x = -x;
}
if (x > 0.5) {
i = 1;
if (x > 1) {
errno = EDOM;
return 0;
}
g = 0.5 - 0.5 * x;
x = - sqrt(g);
x += x;
}
else {
/* ??? avoid underflow ??? */
i = 0;
g = x * x;
}
x += x * g * POLYNOM4(g, p) / POLYNOM5(g, q);
if (cosfl) {
if (! negative) x = -x;
}
if ((cosfl == 0) == (i == 1)) {
x = (x + M_PI_4) + M_PI_4;
}
else if (cosfl && negative && i == 1) {
x = (x + M_PI_2) + M_PI_2;
}
if (! cosfl && negative) x = -x;
return x;
}
static double
sinh_cosh(double x, int cosh_flag)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double p[] = {
-0.35181283430177117881e+6,
-0.11563521196851768270e+5,
-0.16375798202630751372e+3,
-0.78966127417357099479e+0
};
static double q[] = {
-0.21108770058106271242e+7,
0.36162723109421836460e+5,
-0.27773523119650701167e+3,
1.0
};
int negative = x < 0;
double y = negative ? -x : x;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (! cosh_flag && y <= 1.0) {
/* ??? check for underflow ??? */
y = y * y;
return x + x * y * POLYNOM3(y, p)/POLYNOM3(y,q);
}
if (y >= M_LN_MAX_D) {
/* exp(y) would cause overflow */
#define LNV 0.69316101074218750000e+0
#define VD2M1 0.52820835025874852469e-4
double w = y - LNV;
if (w < M_LN_MAX_D+M_LN2-LNV) {
x = exp(w);
x += VD2M1 * x;
}
else {
errno = ERANGE;
x = HUGE_VAL;
}
}
else {
double z = exp(y);
x = 0.5 * (z + (cosh_flag ? 1.0 : -1.0)/z);
}
return negative ? -x : x;
}
double
log(double x)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double a[] = {
-0.64124943423745581147e2,
0.16383943563021534222e2,
-0.78956112887491257267e0
};
static double b[] = {
-0.76949932108494879777e3,
0.31203222091924532844e3,
-0.35667977739034646171e2,
1.0
};
double znum, zden, z, w;
int exponent;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (x < 0) {
errno = EDOM;
return -HUGE_VAL;
}
else if (x == 0) {
errno = ERANGE;
return -HUGE_VAL;
}
if (x <= DBL_MAX) {
}
else return x; /* for infinity and Nan */
x = frexp(x, &exponent);
if (x > M_1_SQRT2) {
znum = (x - 0.5) - 0.5;
zden = x * 0.5 + 0.5;
}
else {
znum = x - 0.5;
zden = znum * 0.5 + 0.5;
exponent--;
}
z = znum/zden; w = z * z;
x = z + z * w * (POLYNOM2(w,a)/POLYNOM3(w,b));
z = exponent;
x += z * (-2.121944400546905827679e-4);
return x + z * 0.693359375;
}
double
ldexp(double fl, int exp)
{
int sign = 1;
int currexp;
if (__IsNan(fl)) {
errno = EDOM;
return fl;
}
if (fl == 0.0) return 0.0;
if (fl<0) {
fl = -fl;
sign = -1;
}
if (fl > DBL_MAX) { /* for infinity */
errno = ERANGE;
return sign * fl;
}
fl = frexp(fl,&currexp);
exp += currexp;
if (exp > 0) {
if (exp > DBL_MAX_EXP) {
errno = ERANGE;
return sign * HUGE_VAL;
}
while (exp>30) {
fl *= (double) (1L << 30);
exp -= 30;
}
fl *= (double) (1L << exp);
}
else {
/* number need not be normalized */
if (exp < DBL_MIN_EXP - DBL_MANT_DIG) {
return 0.0;
}
while (exp<-30) {
fl /= (double) (1L << 30);
exp += 30;
}
fl /= (double) (1L << -exp);
}
return sign * fl;
}
double
tanh(double x)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double p[] = {
-0.16134119023996228053e+4,
-0.99225929672236083313e+2,
-0.96437492777225469787e+0
};
static double q[] = {
0.48402357071988688686e+4,
0.22337720718962312926e+4,
0.11274474380534949335e+3,
1.0
};
int negative = x < 0;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (negative) x = -x;
if (x >= 0.5*M_LN_MAX_D) {
x = 1.0;
}
#define LN3D2 0.54930614433405484570e+0 /* ln(3)/2 */
else if (x > LN3D2) {
x = 0.5 - 1.0/(exp(x+x)+1.0);
x += x;
}
else {
/* ??? avoid underflow ??? */
double g = x*x;
x += x * g * POLYNOM2(g, p)/POLYNOM3(g, q);
}
return negative ? -x : x;
}
static double
sinus(double x, int cos_flag)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double r[] = {
-0.16666666666666665052e+0,
0.83333333333331650314e-2,
-0.19841269841201840457e-3,
0.27557319210152756119e-5,
-0.25052106798274584544e-7,
0.16058936490371589114e-9,
-0.76429178068910467734e-12,
0.27204790957888846175e-14
};
double y;
int neg = 1;
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (x < 0) {
x = -x;
neg = -1;
}
if (cos_flag) {
neg = 1;
y = M_PI_2 + x;
}
else y = x;
/* ??? avoid loss of significance, if y is too large, error ??? */
y = y * M_1_PI + 0.5;
if (y >= DBL_MAX/M_PI) return 0.0;
/* Use extended precision to calculate reduced argument.
Here we used 12 bits of the mantissa for a1.
Also split x in integer part x1 and fraction part x2.
*/
#define A1 3.1416015625
#define A2 -8.908910206761537356617e-6
{
double x1, x2;
modf(y, &y);
if (modf(0.5*y, &x1)) neg = -neg;
if (cos_flag) y -= 0.5;
x2 = modf(x, &x1);
x = x1 - y * A1;
x += x2;
x -= y * A2;
#undef A1
#undef A2
}
if (x < 0) {
neg = -neg;
x = -x;
}
/* ??? avoid underflow ??? */
y = x * x;
x += x * y * POLYNOM7(y, r);
return neg==-1 ? -x : x;
}
double
tan(double x)
{
/* Algorithm and coefficients from:
"Software manual for the elementary functions"
by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
int negative = x < 0;
int invert = 0;
double y;
static double p[] = {
1.0,
-0.13338350006421960681e+0,
0.34248878235890589960e-2,
-0.17861707342254426711e-4
};
static double q[] = {
1.0,
-0.46671683339755294240e+0,
0.25663832289440112864e-1,
-0.31181531907010027307e-3,
0.49819433993786512270e-6
};
if (__IsNan(x)) {
errno = EDOM;
return x;
}
if (negative) x = -x;
/* ??? avoid loss of significance, error if x is too large ??? */
y = x * M_2_PI + 0.5;
if (y >= DBL_MAX/M_PI_2) return 0.0;
/* Use extended precision to calculate reduced argument.
Here we used 12 bits of the mantissa for a1.
Also split x in integer part x1 and fraction part x2.
*/
#define A1 1.57080078125
#define A2 -4.454455103380768678308e-6
{
double x1, x2;
modf(y, &y);
if (modf(0.5*y, &x1)) invert = 1;
x2 = modf(x, &x1);
x = x1 - y * A1;
x += x2;
x -= y * A2;
#undef A1
#undef A2
}
/* ??? avoid underflow ??? */
y = x * x;
x += x * y * POLYNOM2(y, p+1);
y = POLYNOM4(y, q);
if (negative) x = -x;
return invert ? -y/x : x/y;
}