Include/pymath.h

   1 #ifndef Py_PYMATH_H
   2 #define Py_PYMATH_H
   3
   4 #include "pyconfig.h" /* include for defines */
   5
   6 #ifdef HAVE_STDINT_H
   7 #include <stdint.h>
   8 #endif
   9
  10 /**************************************************************************
  11 Symbols and macros to supply platform-independent interfaces to mathematical
  12 functions and constants
  13 **************************************************************************/
  14
  15 /* Python provides implementations for copysign, acosh, asinh, atanh,
  16  * log1p and hypot in Python/pymath.c just in case your math library doesn't
  17  * provide the functions.
  18  *
  19  *Note: PC/pyconfig.h defines copysign as _copysign
  20  */
  21 #ifndef HAVE_COPYSIGN
  22 extern double copysign(double, double);
  23 #endif
  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 #ifndef HAVE_HYPOT
  42 extern double hypot(double, double);
  43 #endif
  44
  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 */
  55
  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
  61
  62 /* High precision defintion of pi and e (Euler)
  63  * The values are taken from libc6's math.h.
  64  */
  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
  71
  72 #ifndef Py_MATH_El
  73 #define Py_MATH_El 2.7182818284590452353602874713526625L
  74 #endif
  75
  76 #ifndef Py_MATH_E
  77 #define Py_MATH_E 2.7182818284590452354
  78 #endif
  79
  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. */
  84
  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
  94
  95 /* Py_IS_NAN(X)
  96  * Return 1 if float or double arg is a NaN, else 0.
  97  * Caution:
  98  *     X is evaluated more than once.
  99  *     This may not work on all platforms.  Each platform has *some*
 100  *     way to spell this, though -- override in pyconfig.h if you have
 101  *     a platform where it doesn't work.
 102  * Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
 103  */
 104 #ifndef Py_IS_NAN
 105 #if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
 106 #define Py_IS_NAN(X) isnan(X)
 107 #else
 108 #define Py_IS_NAN(X) ((X) != (X))
 109 #endif
 110 #endif
 111
 112 /* Py_IS_INFINITY(X)
 113  * Return 1 if float or double arg is an infinity, else 0.
 114  * Caution:
 115  *    X is evaluated more than once.
 116  *    This implementation may set the underflow flag if |X| is very small;
 117  *    it really can't be implemented correctly (& easily) before C99.
 118  *    Override in pyconfig.h if you have a better spelling on your platform.
 119  *  Py_FORCE_DOUBLE is used to avoid getting false negatives from a
 120  *    non-infinite value v sitting in an 80-bit x87 register such that
 121  *    v becomes infinite when spilled from the register to 64-bit memory.
 122  * Note: PC/pyconfig.h defines Py_IS_INFINITY as _isinf
 123  */
 124 #ifndef Py_IS_INFINITY
 125 #  if defined HAVE_DECL_ISINF && HAVE_DECL_ISINF == 1
 126 #    define Py_IS_INFINITY(X) isinf(X)
 127 #  else
 128 #    define Py_IS_INFINITY(X) ((X) &&                                   \
 129                                (Py_FORCE_DOUBLE(X)*0.5 == Py_FORCE_DOUBLE(X)))
 130 #  endif
 131 #endif
 132
 133 /* Py_IS_FINITE(X)
 134  * Return 1 if float or double arg is neither infinite nor NAN, else 0.
 135  * Some compilers (e.g. VisualStudio) have intrisics for this, so a special
 136  * macro for this particular test is useful
 137  * Note: PC/pyconfig.h defines Py_IS_FINITE as _finite
 138  */
 139 #ifndef Py_IS_FINITE
 140 #if defined HAVE_DECL_ISFINITE && HAVE_DECL_ISFINITE == 1
 141 #define Py_IS_FINITE(X) isfinite(X)
 142 #elif defined HAVE_FINITE
 143 #define Py_IS_FINITE(X) finite(X)
 144 #else
 145 #define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
 146 #endif
 147 #endif
 148
 149 /* HUGE_VAL is supposed to expand to a positive double infinity.  Python
 150  * uses Py_HUGE_VAL instead because some platforms are broken in this
 151  * respect.  We used to embed code in pyport.h to try to worm around that,
 152  * but different platforms are broken in conflicting ways.  If you're on
 153  * a platform where HUGE_VAL is defined incorrectly, fiddle your Python
 154  * config to #define Py_HUGE_VAL to something that works on your platform.
 155  */
 156 #ifndef Py_HUGE_VAL
 157 #define Py_HUGE_VAL HUGE_VAL
 158 #endif
 159
 160 /* Py_NAN
 161  * A value that evaluates to a NaN. On IEEE 754 platforms INF*0 or
 162  * INF/INF works. Define Py_NO_NAN in pyconfig.h if your platform
 163  * doesn't support NaNs.
 164  */
 165 #if !defined(Py_NAN) && !defined(Py_NO_NAN)
 166 #define Py_NAN (Py_HUGE_VAL * 0.)
 167 #endif
 168
 169 /* Py_OVERFLOWED(X)
 170  * Return 1 iff a libm function overflowed.  Set errno to 0 before calling
 171  * a libm function, and invoke this macro after, passing the function
 172  * result.
 173  * Caution:
 174  *    This isn't reliable.  C99 no longer requires libm to set errno under
 175  *        any exceptional condition, but does require +- HUGE_VAL return
 176  *        values on overflow.  A 754 box *probably* maps HUGE_VAL to a
 177  *        double infinity, and we're cool if that's so, unless the input
 178  *        was an infinity and an infinity is the expected result.  A C89
 179  *        system sets errno to ERANGE, so we check for that too.  We're
 180  *        out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
 181  *        if the returned result is a NaN, or if a C89 box returns HUGE_VAL
 182  *        in non-overflow cases.
 183  *    X is evaluated more than once.
 184  * Some platforms have better way to spell this, so expect some #ifdef'ery.
 185  *
 186  * OpenBSD uses 'isinf()' because a compiler bug on that platform causes
 187  * the longer macro version to be mis-compiled. This isn't optimal, and
 188  * should be removed once a newer compiler is available on that platform.
 189  * The system that had the failure was running OpenBSD 3.2 on Intel, with
 190  * gcc 2.95.3.
 191  *
 192  * According to Tim's checkin, the FreeBSD systems use isinf() to work
 193  * around a FPE bug on that platform.
 194  */
 195 #if defined(__FreeBSD__) || defined(__OpenBSD__)
 196 #define Py_OVERFLOWED(X) isinf(X)
 197 #else
 198 #define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE ||    \
 199                                          (X) == Py_HUGE_VAL || \
 200                                          (X) == -Py_HUGE_VAL))
 201 #endif
 202
 203 #endif /* Py_PYMATH_H */