diff options
Diffstat (limited to 'math.c')
| -rw-r--r-- | math.c | 82 |
1 files changed, 50 insertions, 32 deletions
@@ -170,6 +170,12 @@ math_tan(VALUE unused_obj, VALUE x) return DBL2NUM(tan(Get_Double(x))); } +#define math_arc(num, func) \ + double d; \ + d = Get_Double((num)); \ + domain_check_range(d, -1.0, 1.0, #func); \ + return DBL2NUM(func(d)); + /* * call-seq: * Math.acos(x) -> float @@ -190,11 +196,7 @@ math_tan(VALUE unused_obj, VALUE x) static VALUE math_acos(VALUE unused_obj, VALUE x) { - double d; - - d = Get_Double(x); - domain_check_range(d, -1.0, 1.0, "acos"); - return DBL2NUM(acos(d)); + math_arc(x, acos) } /* @@ -217,11 +219,7 @@ math_acos(VALUE unused_obj, VALUE x) static VALUE math_asin(VALUE unused_obj, VALUE x) { - double d; - - d = Get_Double(x); - domain_check_range(d, -1.0, 1.0, "asin"); - return DBL2NUM(asin(d)); + math_arc(x, asin) } /* @@ -476,7 +474,6 @@ math_exp(VALUE unused_obj, VALUE x) # define M_LN10 2.30258509299404568401799145468436421 #endif -static double math_log1(VALUE x); FUNC_MINIMIZED(static VALUE math_log(int, const VALUE *, VALUE)); /* @@ -511,20 +508,6 @@ math_log(int argc, const VALUE *argv, VALUE unused_obj) return rb_math_log(argc, argv); } -VALUE -rb_math_log(int argc, const VALUE *argv) -{ - VALUE x, base; - double d; - - rb_scan_args(argc, argv, "11", &x, &base); - d = math_log1(x); - if (argc == 2) { - d /= math_log1(base); - } - return DBL2NUM(d); -} - static double get_double_rshift(VALUE x, size_t *pnumbits) { @@ -543,16 +526,51 @@ get_double_rshift(VALUE x, size_t *pnumbits) } static double -math_log1(VALUE x) +math_log_split(VALUE x, size_t *numbits) { - size_t numbits; - double d = get_double_rshift(x, &numbits); + double d = get_double_rshift(x, numbits); domain_check_min(d, 0.0, "log"); - /* check for pole error */ - if (d == 0.0) return -HUGE_VAL; + return d; +} + +#if defined(log2) || defined(HAVE_LOG2) +# define log_intermediate log2 +#else +# define log_intermediate log10 +double log2(double x); +#endif - return log(d) + numbits * M_LN2; /* log(d * 2 ** numbits) */ +VALUE +rb_math_log(int argc, const VALUE *argv) +{ + VALUE x, base; + double d; + size_t numbits; + + argc = rb_scan_args(argc, argv, "11", &x, &base); + d = math_log_split(x, &numbits); + if (argc == 2) { + size_t numbits_2; + double b = math_log_split(base, &numbits_2); + /* check for pole error */ + if (d == 0.0) { + // Already DomainError if b < 0.0 + return b ? DBL2NUM(-HUGE_VAL) : DBL2NUM(NAN); + } + else if (b == 0.0) { + return DBL2NUM(-0.0); + } + d = log_intermediate(d) / log_intermediate(b); + d += (numbits - numbits_2) / log2(b); + } + else { + /* check for pole error */ + if (d == 0.0) return DBL2NUM(-HUGE_VAL); + d = log(d); + d += numbits * M_LN2; + } + return DBL2NUM(d); } #ifndef log2 @@ -713,7 +731,7 @@ rb_math_sqrt(VALUE x) * cbrt(1.0) # => 1.0 * cbrt(0.0) # => 0.0 * cbrt(1.0) # => 1.0 - cbrt(2.0) # => 1.2599210498948732 + * cbrt(2.0) # => 1.2599210498948732 * cbrt(8.0) # => 2.0 * cbrt(27.0) # => 3.0 * cbrt(INFINITY) # => Infinity |