math.c   [plain text]

```/**********************************************************************

math.c -

\$Author: shyouhei \$
\$Date: 2008-07-02 18:26:29 +0900 (Wed, 02 Jul 2008) \$
created at: Tue Jan 25 14:12:56 JST 1994

**********************************************************************/

#include "ruby.h"
#include <math.h>
#include <errno.h>

VALUE rb_mMath;

#define Need_Float(x) (x) = rb_Float(x)
#define Need_Float2(x,y) do {\
Need_Float(x);\
Need_Float(y);\
} while (0)

static void
domain_check(x, msg)
double x;
char *msg;
{
while(1) {
if (errno) {
rb_sys_fail(msg);
}
if (isnan(x)) {
#if defined(EDOM)
errno = EDOM;
#elif defined(ERANGE)
errno = ERANGE;
#endif
continue;
}
break;
}
}

/*
*  call-seq:
*     Math.atan2(y, x)  => float
*
*  Computes the arc tangent given <i>y</i> and <i>x</i>. Returns
*  -PI..PI.
*
*/

static VALUE
math_atan2(obj, y, x)
VALUE obj, x, y;
{
Need_Float2(y, x);
return rb_float_new(atan2(RFLOAT(y)->value, RFLOAT(x)->value));
}

/*
*  call-seq:
*     Math.cos(x)    => float
*
*  Computes the cosine of <i>x</i> (expressed in radians). Returns
*  -1..1.
*/

static VALUE
math_cos(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(cos(RFLOAT(x)->value));
}

/*
*  call-seq:
*     Math.sin(x)    => float
*
*  Computes the sine of <i>x</i> (expressed in radians). Returns
*  -1..1.
*/

static VALUE
math_sin(obj, x)
VALUE obj, x;
{
Need_Float(x);

return rb_float_new(sin(RFLOAT(x)->value));
}

/*
*  call-seq:
*     Math.tan(x)    => float
*
*  Returns the tangent of <i>x</i> (expressed in radians).
*/

static VALUE
math_tan(obj, x)
VALUE obj, x;
{
Need_Float(x);

return rb_float_new(tan(RFLOAT(x)->value));
}

/*
*  call-seq:
*     Math.acos(x)    => float
*
*  Computes the arc cosine of <i>x</i>. Returns 0..PI.
*/

static VALUE
math_acos(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = acos(RFLOAT(x)->value);
domain_check(d, "acos");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.asin(x)    => float
*
*  Computes the arc sine of <i>x</i>. Returns -{PI/2} .. {PI/2}.
*/

static VALUE
math_asin(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = asin(RFLOAT(x)->value);
domain_check(d, "asin");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.atan(x)    => float
*
*  Computes the arc tangent of <i>x</i>. Returns -{PI/2} .. {PI/2}.
*/

static VALUE
math_atan(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(atan(RFLOAT(x)->value));
}

#ifndef HAVE_COSH
double
cosh(x)
double x;
{
return (exp(x) + exp(-x)) / 2;
}
#endif

/*
*  call-seq:
*     Math.cosh(x)    => float
*
*  Computes the hyperbolic cosine of <i>x</i> (expressed in radians).
*/

static VALUE
math_cosh(obj, x)
VALUE obj, x;
{
Need_Float(x);

return rb_float_new(cosh(RFLOAT(x)->value));
}

#ifndef HAVE_SINH
double
sinh(x)
double x;
{
return (exp(x) - exp(-x)) / 2;
}
#endif

/*
*  call-seq:
*     Math.sinh(x)    => float
*
*  Computes the hyperbolic sine of <i>x</i> (expressed in
*/

static VALUE
math_sinh(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(sinh(RFLOAT(x)->value));
}

#ifndef HAVE_TANH
double
tanh(x)
double x;
{
return sinh(x) / cosh(x);
}
#endif

/*
*  call-seq:
*     Math.tanh()    => float
*
*  Computes the hyperbolic tangent of <i>x</i> (expressed in
*/

static VALUE
math_tanh(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(tanh(RFLOAT(x)->value));
}

/*
*  call-seq:
*     Math.acosh(x)    => float
*
*  Computes the inverse hyperbolic cosine of <i>x</i>.
*/

static VALUE
math_acosh(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = acosh(RFLOAT(x)->value);
domain_check(d, "acosh");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.asinh(x)    => float
*
*  Computes the inverse hyperbolic sine of <i>x</i>.
*/

static VALUE
math_asinh(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(asinh(RFLOAT(x)->value));
}

/*
*  call-seq:
*     Math.atanh(x)    => float
*
*  Computes the inverse hyperbolic tangent of <i>x</i>.
*/

static VALUE
math_atanh(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = atanh(RFLOAT(x)->value);
domain_check(d, "atanh");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.exp(x)    => float
*
*  Returns e**x.
*/

static VALUE
math_exp(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(exp(RFLOAT(x)->value));
}

#if defined __CYGWIN__
# include <cygwin/version.h>
# if CYGWIN_VERSION_DLL_MAJOR < 1005
#  define nan(x) nan()
# endif
# define log(x) ((x) < 0.0 ? nan("") : log(x))
# define log10(x) ((x) < 0.0 ? nan("") : log10(x))
#endif

/*
*  call-seq:
*     Math.log(numeric)    => float
*
*  Returns the natural logarithm of <i>numeric</i>.
*/

static VALUE
math_log(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = log(RFLOAT(x)->value);
domain_check(d, "log");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.log10(numeric)    => float
*
*  Returns the base 10 logarithm of <i>numeric</i>.
*/

static VALUE
math_log10(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = log10(RFLOAT(x)->value);
domain_check(d, "log10");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.sqrt(numeric)    => float
*
*  Returns the non-negative square root of <i>numeric</i>.
*/

static VALUE
math_sqrt(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = sqrt(RFLOAT(x)->value);
domain_check(d, "sqrt");
return rb_float_new(d);
}

/*
*  call-seq:
*     Math.frexp(numeric)    => [ fraction, exponent ]
*
*  Returns a two-element array containing the normalized fraction (a
*  <code>Float</code>) and exponent (a <code>Fixnum</code>) of
*  <i>numeric</i>.
*
*     fraction, exponent = Math.frexp(1234)   #=> [0.6025390625, 11]
*     fraction * 2**exponent                  #=> 1234.0
*/

static VALUE
math_frexp(obj, x)
VALUE obj, x;
{
double d;
int exp;

Need_Float(x);

d = frexp(RFLOAT(x)->value, &exp);
return rb_assoc_new(rb_float_new(d), INT2NUM(exp));
}

/*
*  call-seq:
*     Math.ldexp(flt, int) -> float
*
*  Returns the value of <i>flt</i>*(2**<i>int</i>).
*
*     fraction, exponent = Math.frexp(1234)
*     Math.ldexp(fraction, exponent)   #=> 1234.0
*/

static VALUE
math_ldexp(obj, x, n)
VALUE obj, x, n;
{
Need_Float(x);
return rb_float_new(ldexp(RFLOAT(x)->value, NUM2INT(n)));
}

/*
*  call-seq:
*     Math.hypot(x, y)    => float
*
*  Returns sqrt(x**2 + y**2), the hypotenuse of a right-angled triangle
*  with sides <i>x</i> and <i>y</i>.
*
*     Math.hypot(3, 4)   #=> 5.0
*/

static VALUE
math_hypot(obj, x, y)
VALUE obj, x, y;
{
Need_Float2(x, y);
return rb_float_new(hypot(RFLOAT(x)->value, RFLOAT(y)->value));
}

/*
* call-seq:
*    Math.erf(x)  => float
*
*  Calculates the error function of x.
*/

static VALUE
math_erf(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(erf(RFLOAT(x)->value));
}

/*
* call-seq:
*    Math.erfc(x)  => float
*
*  Calculates the complementary error function of x.
*/

static VALUE
math_erfc(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(erfc(RFLOAT(x)->value));
}

/*
*  The <code>Math</code> module contains module functions for basic
*  trigonometric and transcendental functions. See class
*  <code>Float</code> for a list of constants that
*  define Ruby's floating point accuracy.
*/

void
Init_Math()
{
rb_mMath = rb_define_module("Math");

#ifdef M_PI
rb_define_const(rb_mMath, "PI", rb_float_new(M_PI));
#else
rb_define_const(rb_mMath, "PI", rb_float_new(atan(1.0)*4.0));
#endif

#ifdef M_E
rb_define_const(rb_mMath, "E", rb_float_new(M_E));
#else
rb_define_const(rb_mMath, "E", rb_float_new(exp(1.0)));
#endif

rb_define_module_function(rb_mMath, "atan2", math_atan2, 2);
rb_define_module_function(rb_mMath, "cos", math_cos, 1);
rb_define_module_function(rb_mMath, "sin", math_sin, 1);
rb_define_module_function(rb_mMath, "tan", math_tan, 1);

rb_define_module_function(rb_mMath, "acos", math_acos, 1);
rb_define_module_function(rb_mMath, "asin", math_asin, 1);
rb_define_module_function(rb_mMath, "atan", math_atan, 1);

rb_define_module_function(rb_mMath, "cosh", math_cosh, 1);
rb_define_module_function(rb_mMath, "sinh", math_sinh, 1);
rb_define_module_function(rb_mMath, "tanh", math_tanh, 1);

rb_define_module_function(rb_mMath, "acosh", math_acosh, 1);
rb_define_module_function(rb_mMath, "asinh", math_asinh, 1);
rb_define_module_function(rb_mMath, "atanh", math_atanh, 1);

rb_define_module_function(rb_mMath, "exp", math_exp, 1);
rb_define_module_function(rb_mMath, "log", math_log, 1);
rb_define_module_function(rb_mMath, "log10", math_log10, 1);
rb_define_module_function(rb_mMath, "sqrt", math_sqrt, 1);

rb_define_module_function(rb_mMath, "frexp", math_frexp, 1);
rb_define_module_function(rb_mMath, "ldexp", math_ldexp, 2);

rb_define_module_function(rb_mMath, "hypot", math_hypot, 2);

rb_define_module_function(rb_mMath, "erf",  math_erf,  1);
rb_define_module_function(rb_mMath, "erfc", math_erfc, 1);
}
```