Added src/math.c. Also, edited src/init.c in order to load the Math module.

2 files changed, 752 insertions, 1 deletions

diff --git a/src/init.c b/src/init.c
index 347c6919f..d61c5514a 100644
--- a/src/init.c
+++ b/src/init.c
@@ -32,6 +32,7 @@ void Init_var_tables(mrb_state *mrb);
 void Init_version(mrb_state *mrb);
 void mrb_init_print(mrb_state *mrb);
 void mrb_init_mrblib(mrb_state *mrb);
+void mrb_init_math(mrb_state *mrb);
 
 #define MANDEL
 #ifdef MANDEL
@@ -99,7 +100,7 @@ mrb_init_core(mrb_state *mrb)
   mrb_init_exception(mrb);
   mrb_init_print(mrb);
   mrb_init_time(mrb);
-
+  mrb_init_math(mrb);
 #ifdef MANDEL
   mrb_define_method(mrb, mrb->kernel_module, "pow", mpow, ARGS_REQ(2));
   mrb_define_method(mrb, mrb->kernel_module, "sqrt", msqrt, ARGS_REQ(1));
diff --git a/src/math.c b/src/math.c
new file mode 100644
index 000000000..f58538cba
--- /dev/null
+++ b/src/math.c
@@ -0,0 +1,750 @@
+/*
+** math.c - Math module
+**
+** See Copyright Notice in mruby.h
+*/
+
+#include "mruby.h"
+
+#include <ctype.h>
+#include <math.h>
+#include <stdio.h>
+
+#if defined(__FreeBSD__) && __FreeBSD__ < 4
+#include <floatingpoint.h>
+#endif
+
+#ifdef HAVE_FLOAT_H
+#include <float.h>
+#endif
+
+#ifdef HAVE_IEEEFP_H
+#include <ieeefp.h>
+#endif
+
+#define SIGNED_VALUE intptr_t
+
+#ifdef MRB_USE_FLOAT
+#define floor(f) floorf(f)
+#define ceil(f) ceilf(f)
+#define floor(f) floorf(f)
+#define fmod(x,y) fmodf(x,y)
+#endif
+
+#define numberof(array) (int)(sizeof(array) / sizeof((array)[0]))
+
+#define domain_error(msg) \
+    mrb_raise(mrb, E_RANGE_ERROR, "Numerical argument is out of domain - " #msg);
+
+
+mrb_value
+mrb_assoc_new(mrb_state *mrb, mrb_value car, mrb_value cdr);
+
+/*
+  TRIGONOMETRIC FUNCTIONS
+*/
+
+/*
+ *  call-seq:
+ *     Math.sin(x)    -> float
+ *
+ *  Computes the sine of <i>x</i> (expressed in radians). Returns
+ *  -1..1.
+ */
+static mrb_value
+math_sin(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = sin(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.cos(x)    -> float
+ *
+ *  Computes the cosine of <i>x</i> (expressed in radians). Returns
+ *  -1..1.
+ */
+static mrb_value
+math_cos(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = cos(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.tan(x)    -> float
+ *
+ *  Returns the tangent of <i>x</i> (expressed in radians).
+ */
+static mrb_value
+math_tan(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = tan(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+  INVERSE TRIGONOMETRIC FUNCTIONS
+*/
+
+/*
+ *  call-seq:
+ *     Math.asin(x)    -> float
+ *
+ *  Computes the arc sine of <i>x</i>. Returns -{PI/2} .. {PI/2}.
+ */
+static mrb_value
+math_asin(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = asin(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.acos(x)    -> float
+ *
+ *  Computes the arc cosine of <i>x</i>. Returns 0..PI.
+ */
+static mrb_value
+math_acos(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = acos(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.atan(x)    -> float
+ *
+ *  Computes the arc tangent of <i>x</i>. Returns -{PI/2} .. {PI/2}.
+ */
+static mrb_value
+math_atan(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = atan(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.atan2(y, x)  -> float
+ *
+ *  Computes the arc tangent given <i>y</i> and <i>x</i>. Returns
+ *  -PI..PI.
+ *
+ *    Math.atan2(-0.0, -1.0) #=> -3.141592653589793
+ *    Math.atan2(-1.0, -1.0) #=> -2.356194490192345
+ *    Math.atan2(-1.0, 0.0)  #=> -1.5707963267948966
+ *    Math.atan2(-1.0, 1.0)  #=> -0.7853981633974483
+ *    Math.atan2(-0.0, 1.0)  #=> -0.0
+ *    Math.atan2(0.0, 1.0)   #=> 0.0
+ *    Math.atan2(1.0, 1.0)   #=> 0.7853981633974483
+ *    Math.atan2(1.0, 0.0)   #=> 1.5707963267948966
+ *    Math.atan2(1.0, -1.0)  #=> 2.356194490192345
+ *    Math.atan2(0.0, -1.0)  #=> 3.141592653589793
+ *
+ */
+static mrb_value
+math_atan2(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x, y;
+
+  mrb_get_args(mrb, "ff", &x, &y);
+  x = atan2(x, y);
+
+  return mrb_float_value(x);
+}
+
+
+
+/*
+  HYPERBOLIC TRIG FUNCTIONS
+*/
+#ifndef HAVE_SINH
+double
+sinh(double x)
+{
+    return (exp(x) - exp(-x)) / 2;
+}
+#endif
+
+#ifndef HAVE_TANH
+double
+tanh(double x)
+{
+    return sinh(x) / cosh(x);
+}
+#endif
+
+/*
+ *  call-seq:
+ *     Math.sinh(x)    -> float
+ *
+ *  Computes the hyperbolic sine of <i>x</i> (expressed in
+ *  radians).
+ */
+static mrb_value
+math_sinh(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = sinh(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.cosh(x)    -> float
+ *
+ *  Computes the hyperbolic cosine of <i>x</i> (expressed in radians).
+ */
+static mrb_value
+math_cosh(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = cosh(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.tanh()    -> float
+ *
+ *  Computes the hyperbolic tangent of <i>x</i> (expressed in
+ *  radians).
+ */
+static mrb_value
+math_tanh(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = tanh(x);
+
+  return mrb_float_value(x);
+}
+
+
+/*
+  INVERSE HYPERBOLIC TRIG FUNCTIONS
+*/
+
+/*
+ *  call-seq:
+ *     Math.asinh(x)    -> float
+ *
+ *  Computes the inverse hyperbolic sine of <i>x</i>.
+ */
+static mrb_value
+math_asinh(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = asinh(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.acosh(x)    -> float
+ *
+ *  Computes the inverse hyperbolic cosine of <i>x</i>.
+ */
+static mrb_value
+math_acosh(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = acosh(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.atanh(x)    -> float
+ *
+ *  Computes the inverse hyperbolic tangent of <i>x</i>.
+ */
+static mrb_value
+math_atanh(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = atanh(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+  EXPONENTIALS AND LOGARITHMS
+*/
+#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
+
+#ifndef log2
+#ifndef HAVE_LOG2
+double
+log2(double x)
+{
+    return log10(x)/log10(2.0);
+}
+#else
+extern double log2(double);
+#endif
+#endif
+
+/*
+ *  call-seq:
+ *     Math.exp(x)    -> float
+ *
+ *  Returns e**x.
+ *
+ *    Math.exp(0)       #=> 1.0
+ *    Math.exp(1)       #=> 2.718281828459045
+ *    Math.exp(1.5)     #=> 4.4816890703380645
+ *
+ */
+static mrb_value
+math_exp(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = exp(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.log(numeric)    -> float
+ *     Math.log(num,base)   -> float
+ *
+ *  Returns the natural logarithm of <i>numeric</i>.
+ *  If additional second argument is given, it will be the base
+ *  of logarithm.
+ *
+ *    Math.log(1)          #=> 0.0
+ *    Math.log(Math::E)    #=> 1.0
+ *    Math.log(Math::E**3) #=> 3.0
+ *    Math.log(12,3)       #=> 2.2618595071429146
+ *
+ */
+static mrb_value
+math_log(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = log(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.log2(numeric)    -> float
+ *
+ *  Returns the base 2 logarithm of <i>numeric</i>.
+ *
+ *    Math.log2(1)      #=> 0.0
+ *    Math.log2(2)      #=> 1.0
+ *    Math.log2(32768)  #=> 15.0
+ *    Math.log2(65536)  #=> 16.0
+ *
+ */
+static mrb_value
+math_log2(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = log2(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.log10(numeric)    -> float
+ *
+ *  Returns the base 10 logarithm of <i>numeric</i>.
+ *
+ *    Math.log10(1)       #=> 0.0
+ *    Math.log10(10)      #=> 1.0
+ *    Math.log10(10**100) #=> 100.0
+ *
+ */
+static mrb_value
+math_log10(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = log10(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  call-seq:
+ *     Math.cbrt(numeric)    -> float
+ *
+ *  Returns the cube root of <i>numeric</i>.
+ *
+ *    -9.upto(9) {|x|
+ *      p [x, Math.cbrt(x), Math.cbrt(x)**3]
+ *    }
+ *    #=>
+ *    [-9, -2.0800838230519, -9.0]
+ *    [-8, -2.0, -8.0]
+ *    [-7, -1.91293118277239, -7.0]
+ *    [-6, -1.81712059283214, -6.0]
+ *    [-5, -1.7099759466767, -5.0]
+ *    [-4, -1.5874010519682, -4.0]
+ *    [-3, -1.44224957030741, -3.0]
+ *    [-2, -1.25992104989487, -2.0]
+ *    [-1, -1.0, -1.0]
+ *    [0, 0.0, 0.0]
+ *    [1, 1.0, 1.0]
+ *    [2, 1.25992104989487, 2.0]
+ *    [3, 1.44224957030741, 3.0]
+ *    [4, 1.5874010519682, 4.0]
+ *    [5, 1.7099759466767, 5.0]
+ *    [6, 1.81712059283214, 6.0]
+ *    [7, 1.91293118277239, 7.0]
+ *    [8, 2.0, 8.0]
+ *    [9, 2.0800838230519, 9.0]
+ *
+ */
+static mrb_value
+math_cbrt(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = cbrt(x);
+
+  return mrb_float_value(x);
+}
+
+
+/*
+ *  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 mrb_value
+math_frexp(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+  int exp;
+  
+  mrb_get_args(mrb, "f", &x);
+  x = frexp(x, &exp);
+
+  return mrb_assoc_new(mrb, mrb_float_value(x), mrb_fixnum_value(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 mrb_value
+math_ldexp(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+  mrb_int   i;
+
+  mrb_get_args(mrb, "fi", &x, &i);
+  x = ldexp(x, i);
+
+  return mrb_float_value(x);
+}
+
+/*
+ *  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 mrb_value
+math_hypot(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x, y;
+
+  mrb_get_args(mrb, "ff", &x, &y);
+  x = hypot(x, y);
+
+  return mrb_float_value(x);
+}
+
+/*
+ * call-seq:
+ *    Math.erf(x)  -> float
+ *
+ *  Calculates the error function of x.
+ */
+static mrb_value
+math_erf(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = erf(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ * call-seq:
+ *    Math.erfc(x)  -> float
+ *
+ *  Calculates the complementary error function of x.
+ */
+static mrb_value
+math_erfc(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+
+  mrb_get_args(mrb, "f", &x);
+  x = erfc(x);
+
+  return mrb_float_value(x);
+}
+
+/*
+ * call-seq:
+ *    Math.gamma(x)  -> float
+ *
+ *  Calculates the gamma function of x.
+ *
+ *  Note that gamma(n) is same as fact(n-1) for integer n > 0.
+ *  However gamma(n) returns float and can be an approximation.
+ *
+ *   def fact(n) (1..n).inject(1) {|r,i| r*i } end
+ *   1.upto(26) {|i| p [i, Math.gamma(i), fact(i-1)] }
+ *   #=> [1, 1.0, 1]
+ *   #   [2, 1.0, 1]
+ *   #   [3, 2.0, 2]
+ *   #   [4, 6.0, 6]
+ *   #   [5, 24.0, 24]
+ *   #   [6, 120.0, 120]
+ *   #   [7, 720.0, 720]
+ *   #   [8, 5040.0, 5040]
+ *   #   [9, 40320.0, 40320]
+ *   #   [10, 362880.0, 362880]
+ *   #   [11, 3628800.0, 3628800]
+ *   #   [12, 39916800.0, 39916800]
+ *   #   [13, 479001600.0, 479001600]
+ *   #   [14, 6227020800.0, 6227020800]
+ *   #   [15, 87178291200.0, 87178291200]
+ *   #   [16, 1307674368000.0, 1307674368000]
+ *   #   [17, 20922789888000.0, 20922789888000]
+ *   #   [18, 355687428096000.0, 355687428096000]
+ *   #   [19, 6.402373705728e+15, 6402373705728000]
+ *   #   [20, 1.21645100408832e+17, 121645100408832000]
+ *   #   [21, 2.43290200817664e+18, 2432902008176640000]
+ *   #   [22, 5.109094217170944e+19, 51090942171709440000]
+ *   #   [23, 1.1240007277776077e+21, 1124000727777607680000]
+ *   #   [24, 2.5852016738885062e+22, 25852016738884976640000]
+ *   #   [25, 6.204484017332391e+23, 620448401733239439360000]
+ *   #   [26, 1.5511210043330954e+25, 15511210043330985984000000]
+ *
+ */
+static mrb_value
+math_gamma(mrb_state *mrb, mrb_value obj)
+{
+    static const double fact_table[] = {
+        /* fact(0) */ 1.0,
+        /* fact(1) */ 1.0,
+        /* fact(2) */ 2.0,
+        /* fact(3) */ 6.0,
+        /* fact(4) */ 24.0,
+        /* fact(5) */ 120.0,
+        /* fact(6) */ 720.0,
+        /* fact(7) */ 5040.0,
+        /* fact(8) */ 40320.0,
+        /* fact(9) */ 362880.0,
+        /* fact(10) */ 3628800.0,
+        /* fact(11) */ 39916800.0,
+        /* fact(12) */ 479001600.0,
+        /* fact(13) */ 6227020800.0,
+        /* fact(14) */ 87178291200.0,
+        /* fact(15) */ 1307674368000.0,
+        /* fact(16) */ 20922789888000.0,
+        /* fact(17) */ 355687428096000.0,
+        /* fact(18) */ 6402373705728000.0,
+        /* fact(19) */ 121645100408832000.0,
+        /* fact(20) */ 2432902008176640000.0,
+        /* fact(21) */ 51090942171709440000.0,
+        /* fact(22) */ 1124000727777607680000.0,
+        /* fact(23)=25852016738884976640000 needs 56bit mantissa which is
+         * impossible to represent exactly in IEEE 754 double which have
+         * 53bit mantissa. */
+    };
+    double intpart, fracpart;
+    mrb_float x;
+    mrb_get_args(mrb, "f", &x);
+    
+    /* check for domain error */
+    if (isinf(x) && signbit(x)) domain_error("gamma");
+    fracpart = modf(x, &intpart);
+    if (fracpart == 0.0) {
+	    if (intpart < 0) domain_error("gamma");
+	    if (0 < intpart &&
+	      intpart - 1 < (double)numberof(fact_table)) {
+	    return mrb_float_value(fact_table[(int)intpart - 1]);
+	    }
+    }
+    return mrb_float_value(tgamma(x));
+}
+
+
+/*
+ * call-seq:
+ *    Math.lgamma(x)  -> [float, -1 or 1]
+ *
+ *  Calculates the logarithmic gamma of x and
+ *  the sign of gamma of x.
+ *
+ *  Math.lgamma(x) is same as
+ *   [Math.log(Math.gamma(x).abs), Math.gamma(x) < 0 ? -1 : 1]
+ *  but avoid overflow by Math.gamma(x) for large x.
+ */
+
+// TODO: lgamma_r() is missing
+
+/*
+static mrb_value
+math_lgamma(mrb_state *mrb, mrb_value obj)
+{
+    double d0, d;
+    int sign=1;
+    mrb_float x;
+    mrb_get_args(mrb, "f", &x);
+
+    // check for domain error
+    if (isinf(x)) {
+	    if (signbit(x)) domain_error("lgamma");
+	    return rb_assoc_new(mrb_float_value(INFINITY), mrb_fixnum_value(1));
+    }
+    d = lgamma_r(x, &sign);
+    return mrb_assoc_new(mrb, mrb_float_value(d), mrb_fixnum_value(sign));
+}
+*/
+
+
+
+
+
+/* ------------------------------------------------------------------------*/
+void
+mrb_init_math(mrb_state *mrb)
+{
+  struct RClass *mrb_math;
+  mrb_math = mrb_define_module(mrb, "Math");
+  
+  #ifdef M_PI
+      mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(M_PI));
+  #else
+      mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(atan(1.0)*4.0));
+  #endif
+  
+  #ifdef M_E
+      mrb_define_const(mrb, mrb_math, "E", mrb_float_value(M_E));
+  #else
+      mrb_define_const(mrb, mrb_math, "E", mrb_float_value(exp(1.0)));
+  #endif
+  
+  mrb_define_class_method(mrb, mrb_math, "sin", math_sin, 1);
+  mrb_define_class_method(mrb, mrb_math, "cos", math_cos, 1);
+  mrb_define_class_method(mrb, mrb_math, "tan", math_tan, 1);
+
+  mrb_define_class_method(mrb, mrb_math, "asin", math_asin, 1);
+  mrb_define_class_method(mrb, mrb_math, "acos", math_acos, 1);
+  mrb_define_class_method(mrb, mrb_math, "atan", math_atan, 1);
+  mrb_define_class_method(mrb, mrb_math, "atan2", math_atan2, 2);
+  
+  mrb_define_class_method(mrb, mrb_math, "sinh", math_sinh, 1);
+  mrb_define_class_method(mrb, mrb_math, "cosh", math_cosh, 1);
+  mrb_define_class_method(mrb, mrb_math, "tanh", math_tanh, 1);
+
+  mrb_define_class_method(mrb, mrb_math, "asinh", math_asinh, 1);
+  mrb_define_class_method(mrb, mrb_math, "acosh", math_acosh, 1);
+  mrb_define_class_method(mrb, mrb_math, "atanh", math_atanh, 1);
+
+  mrb_define_class_method(mrb, mrb_math, "exp", math_exp, 1);
+  mrb_define_class_method(mrb, mrb_math, "log", math_log, -1);
+  mrb_define_class_method(mrb, mrb_math, "log2", math_log2, 1);
+  mrb_define_class_method(mrb, mrb_math, "log10", math_log10, 1);
+  mrb_define_class_method(mrb, mrb_math, "cbrt", math_cbrt, 1);
+
+  mrb_define_class_method(mrb, mrb_math, "frexp", math_frexp, 1);
+  mrb_define_class_method(mrb, mrb_math, "ldexp", math_ldexp, 2);
+
+  mrb_define_class_method(mrb, mrb_math, "hypot", math_hypot, 2);
+
+  mrb_define_class_method(mrb, mrb_math, "erf",  math_erf,  1);
+  mrb_define_class_method(mrb, mrb_math, "erfc", math_erfc, 1);
+
+  mrb_define_class_method(mrb, mrb_math, "gamma", math_gamma, 1);
+  // mrb_define_class_method(mrb, mrb_math, "lgamma", math_lgamma, 1);
+}