Re-added Math finctions not supported under MSVC, and added preprocessor...

Re-added Math finctions not supported under MSVC, and added preprocessor directives to support these functions under MSVC too

src/math.c

@@ -10,6 +10,39 @@
 #define domain_error(msg) \
     mrb_raise(mrb, E_RANGE_ERROR, "Numerical argument is out of domain - " #msg);
 
+/* math functions not provided under Microsoft Visual C++ */
+#ifdef _MSC_VER
+#define asinh(x) log(x + sqrt(pow(x,2.0) + 1))
+#define acosh(x) log(x + sqrt(pow(x,2.0) - 1))
+#define atanh(x) (log(1+x) - log(1-x))/2.0
+#define cbrt(x)  pow(x,1.0/3.0)
+
+
+double erf(double x)
+{
+    // constants
+    double a1 =  0.254829592;
+    double a2 = -0.284496736;
+    double a3 =  1.421413741;
+    double a4 = -1.453152027;
+    double a5 =  1.061405429;
+    double p  =  0.3275911;
+
+    // Save the sign of x
+    int sign = 1;
+    if (x < 0)
+        sign = -1;
+    x = fabs(x);
+
+    // A&S formula 7.1.26
+    double t = 1.0/(1.0 + p*x);
+    double y = 1.0 - (((((a5*t + a4)*t) + a3)*t + a2)*t + a1)*t*exp(-x*x);
+
+    return sign*y;
+}
+
+#endif
+
 
 mrb_value
 mrb_assoc_new(mrb_state *mrb, mrb_value car, mrb_value cdr);
@@ -215,6 +248,62 @@ math_tanh(mrb_state *mrb, mrb_value obj)
 }
 
 
+/*
+  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
 */
@@ -332,6 +421,49 @@ math_log10(mrb_state *mrb, mrb_value obj)
   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 ]
@@ -396,6 +528,43 @@ math_hypot(mrb_state *mrb, mrb_value obj)
   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);
+}
+
+
+#ifndef _MSC_VER
+/*
+ * 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);
+}
+#endif
+
 /* ------------------------------------------------------------------------*/
 void
 mrb_init_math(mrb_state *mrb)
@@ -428,13 +597,23 @@ mrb_init_math(mrb_state *mrb)
   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);
+#ifndef _MSC_VER
+  mrb_define_class_method(mrb, mrb_math, "erfc", math_erfc, 1);
+#endif
 }