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| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -8,9 +8,9 @@ Symbols and macros to supply platform-independent interfaces to mathematical | |||
| 8 | 8 | functions and constants | |
| 9 | 9 | **************************************************************************/ | |
| 10 | 10 | ||
| 11 | - /* Python provides implementations for copysign, acosh, asinh, atanh, | ||
| 12 | - * log1p and hypot in Python/pymath.c just in case your math library doesn't | ||
| 13 | - * provide the functions. | ||
| 11 | + /* Python provides implementations for copysign, round and hypot in | ||
| 12 | + * Python/pymath.c just in case your math library doesn't provide the | ||
| 13 | + * functions. | ||
| 14 | 14 | * | |
| 15 | 15 | *Note: PC/pyconfig.h defines copysign as _copysign | |
| 16 | 16 | */ | |
@@ -22,22 +22,6 @@ extern double copysign(double, double); | |||
| 22 | 22 | extern double round(double); | |
| 23 | 23 | #endif | |
| 24 | 24 | ||
| 25 | - #ifndef HAVE_ACOSH | ||
| 26 | - extern double acosh(double); | ||
| 27 | - #endif | ||
| 28 | - | ||
| 29 | - #ifndef HAVE_ASINH | ||
| 30 | - extern double asinh(double); | ||
| 31 | - #endif | ||
| 32 | - | ||
| 33 | - #ifndef HAVE_ATANH | ||
| 34 | - extern double atanh(double); | ||
| 35 | - #endif | ||
| 36 | - | ||
| 37 | - #ifndef HAVE_LOG1P | ||
| 38 | - extern double log1p(double); | ||
| 39 | - #endif | ||
| 40 | - | ||
| 41 | 25 | #ifndef HAVE_HYPOT | |
| 42 | 26 | extern double hypot(double, double); | |
| 43 | 27 | #endif | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -157,7 +157,7 @@ _symtable symtablemodule.c | |||
| 157 | 157 | # Modules that should always be present (non UNIX dependent): | |
| 158 | 158 | ||
| 159 | 159 | #array arraymodule.c # array objects | |
| 160 | - #cmath cmathmodule.c # -lm # complex math library functions | ||
| 160 | + #cmath cmathmodule.c _math.c # -lm # complex math library functions | ||
| 161 | 161 | #math mathmodule.c _math.c # -lm # math library functions, e.g. sin() | |
| 162 | 162 | #_struct _struct.c # binary structure packing/unpacking | |
| 163 | 163 | #time timemodule.c # -lm # time operations and variables | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -1,8 +1,161 @@ | |||
| 1 | 1 | /* Definitions of some C99 math library functions, for those platforms | |
| 2 | 2 | that don't implement these functions already. */ | |
| 3 | 3 | ||
| 4 | + #include "Python.h" | ||
| 4 | 5 | #include <float.h> | |
| 5 | - #include <math.h> | ||
| 6 | + | ||
| 7 | + /* The following copyright notice applies to the original | ||
| 8 | + implementations of acosh, asinh and atanh. */ | ||
| 9 | + | ||
| 10 | + /* | ||
| 11 | + * ==================================================== | ||
| 12 | + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | ||
| 13 | + * | ||
| 14 | + * Developed at SunPro, a Sun Microsystems, Inc. business. | ||
| 15 | + * Permission to use, copy, modify, and distribute this | ||
| 16 | + * software is freely granted, provided that this notice | ||
| 17 | + * is preserved. | ||
| 18 | + * ==================================================== | ||
| 19 | + */ | ||
| 20 | + | ||
| 21 | + static const double ln2 = 6.93147180559945286227E-01; | ||
| 22 | + static const double two_pow_m28 = 3.7252902984619141E-09; /* 2**-28 */ | ||
| 23 | + static const double two_pow_p28 = 268435456.0; /* 2**28 */ | ||
| 24 | + static const double zero = 0.0; | ||
| 25 | + | ||
| 26 | + /* acosh(x) | ||
| 27 | + * Method : | ||
| 28 | + * Based on | ||
| 29 | + * acosh(x) = log [ x + sqrt(x*x-1) ] | ||
| 30 | + * we have | ||
| 31 | + * acosh(x) := log(x)+ln2, if x is large; else | ||
| 32 | + * acosh(x) := log(2x-1/(sqrt(x*x-1)+x)) if x>2; else | ||
| 33 | + * acosh(x) := log1p(t+sqrt(2.0*t+t*t)); where t=x-1. | ||
| 34 | + * | ||
| 35 | + * Special cases: | ||
| 36 | + * acosh(x) is NaN with signal if x<1. | ||
| 37 | + * acosh(NaN) is NaN without signal. | ||
| 38 | + */ | ||
| 39 | + | ||
| 40 | + double | ||
| 41 | + _Py_acosh(double x) | ||
| 42 | + { | ||
| 43 | + if (Py_IS_NAN(x)) { | ||
| 44 | + return x+x; | ||
| 45 | + } | ||
| 46 | + if (x < 1.) { /* x < 1; return a signaling NaN */ | ||
| 47 | + errno = EDOM; | ||
| 48 | + #ifdef Py_NAN | ||
| 49 | + return Py_NAN; | ||
| 50 | + #else | ||
| 51 | + return (x-x)/(x-x); | ||
| 52 | + #endif | ||
| 53 | + } | ||
| 54 | + else if (x >= two_pow_p28) { /* x > 2**28 */ | ||
| 55 | + if (Py_IS_INFINITY(x)) { | ||
| 56 | + return x+x; | ||
| 57 | + } else { | ||
| 58 | + return log(x)+ln2; /* acosh(huge)=log(2x) */ | ||
| 59 | + } | ||
| 60 | + } | ||
| 61 | + else if (x == 1.) { | ||
| 62 | + return 0.0; /* acosh(1) = 0 */ | ||
| 63 | + } | ||
| 64 | + else if (x > 2.) { /* 2 < x < 2**28 */ | ||
| 65 | + double t = x*x; | ||
| 66 | + return log(2.0*x - 1.0 / (x + sqrt(t - 1.0))); | ||
| 67 | + } | ||
| 68 | + else { /* 1 < x <= 2 */ | ||
| 69 | + double t = x - 1.0; | ||
| 70 | + return log1p(t + sqrt(2.0*t + t*t)); | ||
| 71 | + } | ||
| 72 | + } | ||
| 73 | + | ||
| 74 | + | ||
| 75 | + /* asinh(x) | ||
| 76 | + * Method : | ||
| 77 | + * Based on | ||
| 78 | + * asinh(x) = sign(x) * log [ |x| + sqrt(x*x+1) ] | ||
| 79 | + * we have | ||
| 80 | + * asinh(x) := x if 1+x*x=1, | ||
| 81 | + * := sign(x)*(log(x)+ln2)) for large |x|, else | ||
| 82 | + * := sign(x)*log(2|x|+1/(|x|+sqrt(x*x+1))) if|x|>2, else | ||
| 83 | + * := sign(x)*log1p(|x| + x^2/(1 + sqrt(1+x^2))) | ||
| 84 | + */ | ||
| 85 | + | ||
| 86 | + double | ||
| 87 | + _Py_asinh(double x) | ||
| 88 | + { | ||
| 89 | + double w; | ||
| 90 | + double absx = fabs(x); | ||
| 91 | + | ||
| 92 | + if (Py_IS_NAN(x) || Py_IS_INFINITY(x)) { | ||
| 93 | + return x+x; | ||
| 94 | + } | ||
| 95 | + if (absx < two_pow_m28) { /* |x| < 2**-28 */ | ||
| 96 | + return x; /* return x inexact except 0 */ | ||
| 97 | + } | ||
| 98 | + if (absx > two_pow_p28) { /* |x| > 2**28 */ | ||
| 99 | + w = log(absx)+ln2; | ||
| 100 | + } | ||
| 101 | + else if (absx > 2.0) { /* 2 < |x| < 2**28 */ | ||
| 102 | + w = log(2.0*absx + 1.0 / (sqrt(x*x + 1.0) + absx)); | ||
| 103 | + } | ||
| 104 | + else { /* 2**-28 <= |x| < 2= */ | ||
| 105 | + double t = x*x; | ||
| 106 | + w = log1p(absx + t / (1.0 + sqrt(1.0 + t))); | ||
| 107 | + } | ||
| 108 | + return copysign(w, x); | ||
| 109 | + | ||
| 110 | + } | ||
| 111 | + | ||
| 112 | + /* atanh(x) | ||
| 113 | + * Method : | ||
| 114 | + * 1.Reduced x to positive by atanh(-x) = -atanh(x) | ||
| 115 | + * 2.For x>=0.5 | ||
| 116 | + * 1 2x x | ||
| 117 | + * atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------) | ||
| 118 | + * 2 1 - x 1 - x | ||
| 119 | + * | ||
| 120 | + * For x<0.5 | ||
| 121 | + * atanh(x) = 0.5*log1p(2x+2x*x/(1-x)) | ||
| 122 | + * | ||
| 123 | + * Special cases: | ||
| 124 | + * atanh(x) is NaN if |x| >= 1 with signal; | ||
| 125 | + * atanh(NaN) is that NaN with no signal; | ||
| 126 | + * | ||
| 127 | + */ | ||
| 128 | + | ||
| 129 | + double | ||
| 130 | + _Py_atanh(double x) | ||
| 131 | + { | ||
| 132 | + double absx; | ||
| 133 | + double t; | ||
| 134 | + | ||
| 135 | + if (Py_IS_NAN(x)) { | ||
| 136 | + return x+x; | ||
| 137 | + } | ||
| 138 | + absx = fabs(x); | ||
| 139 | + if (absx >= 1.) { /* |x| >= 1 */ | ||
| 140 | + errno = EDOM; | ||
| 141 | + #ifdef Py_NAN | ||
| 142 | + return Py_NAN; | ||
| 143 | + #else | ||
| 144 | + return x/zero; | ||
| 145 | + #endif | ||
| 146 | + } | ||
| 147 | + if (absx < two_pow_m28) { /* |x| < 2**-28 */ | ||
| 148 | + return x; | ||
| 149 | + } | ||
| 150 | + if (absx < 0.5) { /* |x| < 0.5 */ | ||
| 151 | + t = absx+absx; | ||
| 152 | + t = 0.5 * log1p(t + t*absx / (1.0 - absx)); | ||
| 153 | + } | ||
| 154 | + else { /* 0.5 <= |x| <= 1.0 */ | ||
| 155 | + t = 0.5 * log1p((absx + absx) / (1.0 - absx)); | ||
| 156 | + } | ||
| 157 | + return copysign(t, x); | ||
| 158 | + } | ||
| 6 | 159 | ||
| 7 | 160 | /* Mathematically, expm1(x) = exp(x) - 1. The expm1 function is designed | |
| 8 | 161 | to avoid the significant loss of precision that arises from direct | |
@@ -29,3 +182,47 @@ _Py_expm1(double x) | |||
| 29 | 182 | else | |
| 30 | 183 | return exp(x) - 1.0; | |
| 31 | 184 | } | |
| 185 | + | ||
| 186 | + /* log1p(x) = log(1+x). The log1p function is designed to avoid the | ||
| 187 | + significant loss of precision that arises from direct evaluation when x is | ||
| 188 | + small. */ | ||
| 189 | + | ||
| 190 | + double | ||
| 191 | + _Py_log1p(double x) | ||
| 192 | + { | ||
| 193 | + /* For x small, we use the following approach. Let y be the nearest float | ||
| 194 | + to 1+x, then | ||
| 195 | + | ||
| 196 | + 1+x = y * (1 - (y-1-x)/y) | ||
| 197 | + | ||
| 198 | + so log(1+x) = log(y) + log(1-(y-1-x)/y). Since (y-1-x)/y is tiny, the | ||
| 199 | + second term is well approximated by (y-1-x)/y. If abs(x) >= | ||
| 200 | + DBL_EPSILON/2 or the rounding-mode is some form of round-to-nearest | ||
| 201 | + then y-1-x will be exactly representable, and is computed exactly by | ||
| 202 | + (y-1)-x. | ||
| 203 | + | ||
| 204 | + If abs(x) < DBL_EPSILON/2 and the rounding mode is not known to be | ||
| 205 | + round-to-nearest then this method is slightly dangerous: 1+x could be | ||
| 206 | + rounded up to 1+DBL_EPSILON instead of down to 1, and in that case | ||
| 207 | + y-1-x will not be exactly representable any more and the result can be | ||
| 208 | + off by many ulps. But this is easily fixed: for a floating-point | ||
| 209 | + number |x| < DBL_EPSILON/2., the closest floating-point number to | ||
| 210 | + log(1+x) is exactly x. | ||
| 211 | + */ | ||
| 212 | + | ||
| 213 | + double y; | ||
| 214 | + if (fabs(x) < DBL_EPSILON/2.) { | ||
| 215 | + return x; | ||
| 216 | + } else if (-0.5 <= x && x <= 1.) { | ||
| 217 | + /* WARNING: it's possible than an overeager compiler | ||
| 218 | + will incorrectly optimize the following two lines | ||
| 219 | + to the equivalent of "return log(1.+x)". If this | ||
| 220 | + happens, then results from log1p will be inaccurate | ||
| 221 | + for small x. */ | ||
| 222 | + y = 1.+x; | ||
| 223 | + return log(y)-((y-1.)-x)/y; | ||
| 224 | + } else { | ||
| 225 | + /* NaNs and infinities should end up here */ | ||
| 226 | + return log(1.+x); | ||
| 227 | + } | ||
| 228 | + } | ||
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -1,4 +1,32 @@ | |||
| 1 | + double _Py_acosh(double x); | ||
| 2 | + double _Py_asinh(double x); | ||
| 3 | + double _Py_atanh(double x); | ||
| 1 | 4 | double _Py_expm1(double x); | |
| 5 | + double _Py_log1p(double x); | ||
| 6 | + | ||
| 7 | + #ifdef HAVE_ACOSH | ||
| 8 | + #define m_acosh acosh | ||
| 9 | + #else | ||
| 10 | + /* if the system doesn't have acosh, use the substitute | ||
| 11 | + function defined in Modules/_math.c. */ | ||
| 12 | + #define m_acosh _Py_acosh | ||
| 13 | + #endif | ||
| 14 | + | ||
| 15 | + #ifdef HAVE_ASINH | ||
| 16 | + #define m_asinh asinh | ||
| 17 | + #else | ||
| 18 | + /* if the system doesn't have asinh, use the substitute | ||
| 19 | + function defined in Modules/_math.c. */ | ||
| 20 | + #define m_asinh _Py_asinh | ||
| 21 | + #endif | ||
| 22 | + | ||
| 23 | + #ifdef HAVE_ATANH | ||
| 24 | + #define m_atanh atanh | ||
| 25 | + #else | ||
| 26 | + /* if the system doesn't have atanh, use the substitute | ||
| 27 | + function defined in Modules/_math.c. */ | ||
| 28 | + #define m_atanh _Py_atanh | ||
| 29 | + #endif | ||
| 2 | 30 | ||
| 3 | 31 | #ifdef HAVE_EXPM1 | |
| 4 | 32 | #define m_expm1 expm1 | |
@@ -7,3 +35,11 @@ double _Py_expm1(double x); | |||
| 7 | 35 | function defined in Modules/_math.c. */ | |
| 8 | 36 | #define m_expm1 _Py_expm1 | |
| 9 | 37 | #endif | |
| 38 | + | ||
| 39 | + #ifdef HAVE_LOG1P | ||
| 40 | + #define m_log1p log1p | ||
| 41 | + #else | ||
| 42 | + /* if the system doesn't have log1p, use the substitute | ||
| 43 | + function defined in Modules/_math.c. */ | ||
| 44 | + #define m_log1p _Py_log1p | ||
| 45 | + #endif | ||
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -3,6 +3,7 @@ | |||
| 3 | 3 | /* much code borrowed from mathmodule.c */ | |
| 4 | 4 | ||
| 5 | 5 | #include "Python.h" | |
| 6 | + #include "_math.h" | ||
| 6 | 7 | /* we need DBL_MAX, DBL_MIN, DBL_EPSILON, DBL_MANT_DIG and FLT_RADIX from | |
| 7 | 8 | float.h. We assume that FLT_RADIX is either 2 or 16. */ | |
| 8 | 9 | #include <float.h> | |
@@ -149,7 +150,7 @@ c_acos(Py_complex z) | |||
| 149 | 150 | s2.imag = z.imag; | |
| 150 | 151 | s2 = c_sqrt(s2); | |
| 151 | 152 | r.real = 2.*atan2(s1.real, s2.real); | |
| 152 | - r.imag = asinh(s2.real*s1.imag - s2.imag*s1.real); | ||
| 153 | + r.imag = m_asinh(s2.real*s1.imag - s2.imag*s1.real); | ||
| 153 | 154 | } | |
| 154 | 155 | errno = 0; | |
| 155 | 156 | return r; | |
@@ -181,7 +182,7 @@ c_acosh(Py_complex z) | |||
| 181 | 182 | s2.real = z.real + 1.; | |
| 182 | 183 | s2.imag = z.imag; | |
| 183 | 184 | s2 = c_sqrt(s2); | |
| 184 | - r.real = asinh(s1.real*s2.real + s1.imag*s2.imag); | ||
| 185 | + r.real = m_asinh(s1.real*s2.real + s1.imag*s2.imag); | ||
| 185 | 186 | r.imag = 2.*atan2(s1.imag, s2.real); | |
| 186 | 187 | } | |
| 187 | 188 | errno = 0; | |
@@ -238,7 +239,7 @@ c_asinh(Py_complex z) | |||
| 238 | 239 | s2.real = 1.-z.imag; | |
| 239 | 240 | s2.imag = z.real; | |
| 240 | 241 | s2 = c_sqrt(s2); | |
| 241 | - r.real = asinh(s1.real*s2.imag-s2.real*s1.imag); | ||
| 242 | + r.real = m_asinh(s1.real*s2.imag-s2.real*s1.imag); | ||
| 242 | 243 | r.imag = atan2(z.imag, s1.real*s2.real-s1.imag*s2.imag); | |
| 243 | 244 | } | |
| 244 | 245 | errno = 0; | |
@@ -342,7 +343,7 @@ c_atanh(Py_complex z) | |||
| 342 | 343 | errno = 0; | |
| 343 | 344 | } | |
| 344 | 345 | } else { | |
| 345 | - r.real = log1p(4.*z.real/((1-z.real)*(1-z.real) + ay*ay))/4.; | ||
| 346 | + r.real = m_log1p(4.*z.real/((1-z.real)*(1-z.real) + ay*ay))/4.; | ||
| 346 | 347 | r.imag = -atan2(-2.*z.imag, (1-z.real)*(1+z.real) - ay*ay)/2.; | |
| 347 | 348 | errno = 0; | |
| 348 | 349 | } | |
@@ -552,7 +553,7 @@ c_log(Py_complex z) | |||
| 552 | 553 | if (0.71 <= h && h <= 1.73) { | |
| 553 | 554 | am = ax > ay ? ax : ay; /* max(ax, ay) */ | |
| 554 | 555 | an = ax > ay ? ay : ax; /* min(ax, ay) */ | |
| 555 | - r.real = log1p((am-1)*(am+1)+an*an)/2.; | ||
| 556 | + r.real = m_log1p((am-1)*(am+1)+an*an)/2.; | ||
| 556 | 557 | } else { | |
| 557 | 558 | r.real = log(h); | |
| 558 | 559 | } | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -816,18 +816,18 @@ math_2(PyObject *args, double (*func) (double, double), char *funcname) | |||
| 816 | 816 | ||
| 817 | 817 | FUNC1(acos, acos, 0, | |
| 818 | 818 | "acos(x)\n\nReturn the arc cosine (measured in radians) of x.") | |
| 819 | - FUNC1(acosh, acosh, 0, | ||
| 819 | + FUNC1(acosh, m_acosh, 0, | ||
| 820 | 820 | "acosh(x)\n\nReturn the hyperbolic arc cosine (measured in radians) of x.") | |
| 821 | 821 | FUNC1(asin, asin, 0, | |
| 822 | 822 | "asin(x)\n\nReturn the arc sine (measured in radians) of x.") | |
| 823 | - FUNC1(asinh, asinh, 0, | ||
| 823 | + FUNC1(asinh, m_asinh, 0, | ||
| 824 | 824 | "asinh(x)\n\nReturn the hyperbolic arc sine (measured in radians) of x.") | |
| 825 | 825 | FUNC1(atan, atan, 0, | |
| 826 | 826 | "atan(x)\n\nReturn the arc tangent (measured in radians) of x.") | |
| 827 | 827 | FUNC2(atan2, m_atan2, | |
| 828 | 828 | "atan2(y, x)\n\nReturn the arc tangent (measured in radians) of y/x.\n" | |
| 829 | 829 | "Unlike atan(y/x), the signs of both x and y are considered.") | |
| 830 | - FUNC1(atanh, atanh, 0, | ||
| 830 | + FUNC1(atanh, m_atanh, 0, | ||
| 831 | 831 | "atanh(x)\n\nReturn the hyperbolic arc tangent (measured in radians) of x.") | |
| 832 | 832 | ||
| 833 | 833 | static PyObject * math_ceil(PyObject *self, PyObject *number) { | |
@@ -895,7 +895,7 @@ FUNC1A(gamma, m_tgamma, | |||
| 895 | 895 | "gamma(x)\n\nGamma function at x.") | |
| 896 | 896 | FUNC1A(lgamma, m_lgamma, | |
| 897 | 897 | "lgamma(x)\n\nNatural logarithm of absolute value of Gamma function at x.") | |
| 898 | - FUNC1(log1p, log1p, 1, | ||
| 898 | + FUNC1(log1p, m_log1p, 1, | ||
| 899 | 899 | "log1p(x)\n\nReturn the natural logarithm of 1+x (base e).\n" | |
| 900 | 900 | "The result is computed in a way which is accurate for x near zero.") | |
| 901 | 901 | FUNC1(sin, sin, 0, | |
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