Move a Misc/NEWS entry to right section.
[python.git] / Include / pymath.h
blobdc2c42794475d46c6ba8979d1ada7a8bb8c0c44e
1 #ifndef Py_PYMATH_H
2 #define Py_PYMATH_H
4 #include "pyconfig.h" /* include for defines */
6 /**************************************************************************
7 Symbols and macros to supply platform-independent interfaces to mathematical
8 functions and constants
9 **************************************************************************/
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.
15 *Note: PC/pyconfig.h defines copysign as _copysign
17 #ifndef HAVE_COPYSIGN
18 extern double copysign(double, double);
19 #endif
21 #ifndef HAVE_ROUND
22 extern double round(double);
23 #endif
25 #ifndef HAVE_ACOSH
26 extern double acosh(double);
27 #endif
29 #ifndef HAVE_ASINH
30 extern double asinh(double);
31 #endif
33 #ifndef HAVE_ATANH
34 extern double atanh(double);
35 #endif
37 #ifndef HAVE_LOG1P
38 extern double log1p(double);
39 #endif
41 #ifndef HAVE_HYPOT
42 extern double hypot(double, double);
43 #endif
45 /* extra declarations */
46 #ifndef _MSC_VER
47 #ifndef __STDC__
48 extern double fmod (double, double);
49 extern double frexp (double, int *);
50 extern double ldexp (double, int);
51 extern double modf (double, double *);
52 extern double pow(double, double);
53 #endif /* __STDC__ */
54 #endif /* _MSC_VER */
56 #ifdef _OSF_SOURCE
57 /* OSF1 5.1 doesn't make these available with XOPEN_SOURCE_EXTENDED defined */
58 extern int finite(double);
59 extern double copysign(double, double);
60 #endif
62 /* High precision defintion of pi and e (Euler)
63 * The values are taken from libc6's math.h.
65 #ifndef Py_MATH_PIl
66 #define Py_MATH_PIl 3.1415926535897932384626433832795029L
67 #endif
68 #ifndef Py_MATH_PI
69 #define Py_MATH_PI 3.14159265358979323846
70 #endif
72 #ifndef Py_MATH_El
73 #define Py_MATH_El 2.7182818284590452353602874713526625L
74 #endif
76 #ifndef Py_MATH_E
77 #define Py_MATH_E 2.7182818284590452354
78 #endif
80 /* On x86, Py_FORCE_DOUBLE forces a floating-point number out of an x87 FPU
81 register and into a 64-bit memory location, rounding from extended
82 precision to double precision in the process. On other platforms it does
83 nothing. */
85 /* we take double rounding as evidence of x87 usage */
86 #ifndef Py_FORCE_DOUBLE
87 # ifdef X87_DOUBLE_ROUNDING
88 PyAPI_FUNC(double) _Py_force_double(double);
89 # define Py_FORCE_DOUBLE(X) (_Py_force_double(X))
90 # else
91 # define Py_FORCE_DOUBLE(X) (X)
92 # endif
93 #endif
95 #ifdef HAVE_GCC_ASM_FOR_X87
96 PyAPI_FUNC(unsigned short) _Py_get_387controlword(void);
97 PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
98 #endif
100 /* Py_IS_NAN(X)
101 * Return 1 if float or double arg is a NaN, else 0.
102 * Caution:
103 * X is evaluated more than once.
104 * This may not work on all platforms. Each platform has *some*
105 * way to spell this, though -- override in pyconfig.h if you have
106 * a platform where it doesn't work.
107 * Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
109 #ifndef Py_IS_NAN
110 #if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
111 #define Py_IS_NAN(X) isnan(X)
112 #else
113 #define Py_IS_NAN(X) ((X) != (X))
114 #endif
115 #endif
117 /* Py_IS_INFINITY(X)
118 * Return 1 if float or double arg is an infinity, else 0.
119 * Caution:
120 * X is evaluated more than once.
121 * This implementation may set the underflow flag if |X| is very small;
122 * it really can't be implemented correctly (& easily) before C99.
123 * Override in pyconfig.h if you have a better spelling on your platform.
124 * Py_FORCE_DOUBLE is used to avoid getting false negatives from a
125 * non-infinite value v sitting in an 80-bit x87 register such that
126 * v becomes infinite when spilled from the register to 64-bit memory.
127 * Note: PC/pyconfig.h defines Py_IS_INFINITY as _isinf
129 #ifndef Py_IS_INFINITY
130 # if defined HAVE_DECL_ISINF && HAVE_DECL_ISINF == 1
131 # define Py_IS_INFINITY(X) isinf(X)
132 # else
133 # define Py_IS_INFINITY(X) ((X) && \
134 (Py_FORCE_DOUBLE(X)*0.5 == Py_FORCE_DOUBLE(X)))
135 # endif
136 #endif
138 /* Py_IS_FINITE(X)
139 * Return 1 if float or double arg is neither infinite nor NAN, else 0.
140 * Some compilers (e.g. VisualStudio) have intrisics for this, so a special
141 * macro for this particular test is useful
142 * Note: PC/pyconfig.h defines Py_IS_FINITE as _finite
144 #ifndef Py_IS_FINITE
145 #if defined HAVE_DECL_ISFINITE && HAVE_DECL_ISFINITE == 1
146 #define Py_IS_FINITE(X) isfinite(X)
147 #elif defined HAVE_FINITE
148 #define Py_IS_FINITE(X) finite(X)
149 #else
150 #define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
151 #endif
152 #endif
154 /* HUGE_VAL is supposed to expand to a positive double infinity. Python
155 * uses Py_HUGE_VAL instead because some platforms are broken in this
156 * respect. We used to embed code in pyport.h to try to worm around that,
157 * but different platforms are broken in conflicting ways. If you're on
158 * a platform where HUGE_VAL is defined incorrectly, fiddle your Python
159 * config to #define Py_HUGE_VAL to something that works on your platform.
161 #ifndef Py_HUGE_VAL
162 #define Py_HUGE_VAL HUGE_VAL
163 #endif
165 /* Py_NAN
166 * A value that evaluates to a NaN. On IEEE 754 platforms INF*0 or
167 * INF/INF works. Define Py_NO_NAN in pyconfig.h if your platform
168 * doesn't support NaNs.
170 #if !defined(Py_NAN) && !defined(Py_NO_NAN)
171 #define Py_NAN (Py_HUGE_VAL * 0.)
172 #endif
174 /* Py_OVERFLOWED(X)
175 * Return 1 iff a libm function overflowed. Set errno to 0 before calling
176 * a libm function, and invoke this macro after, passing the function
177 * result.
178 * Caution:
179 * This isn't reliable. C99 no longer requires libm to set errno under
180 * any exceptional condition, but does require +- HUGE_VAL return
181 * values on overflow. A 754 box *probably* maps HUGE_VAL to a
182 * double infinity, and we're cool if that's so, unless the input
183 * was an infinity and an infinity is the expected result. A C89
184 * system sets errno to ERANGE, so we check for that too. We're
185 * out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
186 * if the returned result is a NaN, or if a C89 box returns HUGE_VAL
187 * in non-overflow cases.
188 * X is evaluated more than once.
189 * Some platforms have better way to spell this, so expect some #ifdef'ery.
191 * OpenBSD uses 'isinf()' because a compiler bug on that platform causes
192 * the longer macro version to be mis-compiled. This isn't optimal, and
193 * should be removed once a newer compiler is available on that platform.
194 * The system that had the failure was running OpenBSD 3.2 on Intel, with
195 * gcc 2.95.3.
197 * According to Tim's checkin, the FreeBSD systems use isinf() to work
198 * around a FPE bug on that platform.
200 #if defined(__FreeBSD__) || defined(__OpenBSD__)
201 #define Py_OVERFLOWED(X) isinf(X)
202 #else
203 #define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE || \
204 (X) == Py_HUGE_VAL || \
205 (X) == -Py_HUGE_VAL))
206 #endif
208 #endif /* Py_PYMATH_H */