e$B$D$$$G$Ke(B 3e$B>h:,$Ne(B Math.cbrt
e$B$b:n$C$?$s$G$9$,$I$&$G$7$g$&$+!#e(B
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Index: math.c
— math.c (revision 15410)
+++ math.c (working copy)
@@ -402,6 +402,20 @@ math_sqrt(VALUE obj, VALUE x)
/*
- call-seq:
-
-
Math.cbrt(numeric) => float
-
-
-
- Returns the cube root of numeric.
- */
+static VALUE
+math_cbrt(VALUE obj, VALUE x)
+{
- Need_Float(x);
- return DOUBLE2NUM(cbrt(RFLOAT_VALUE(x)));
+}
+/*
-
- call-seq:
-
Math.frexp(numeric) => [ fraction, exponent ] - Returns a two-element array containing the normalized fraction (a
@@ -603,6 +617,7 @@ Init_Math(void)
rb_define_module_function(rb_mMath, “log2”, math_log2, 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, “cbrt”, math_cbrt, 1);
rb_define_module_function(rb_mMath, “frexp”, math_frexp, 1);
rb_define_module_function(rb_mMath, “ldexp”, math_ldexp, 2);
Index: configure.in
===================================================================
— configure.in (revision 15410)
+++ configure.in (working copy)
@@ -649,7 +649,7 @@ esac
AC_FUNC_MEMCMP
AC_REPLACE_FUNCS(dup2 memmove strerror strftime
strchr strstr crypt flock vsnprintf\
-
isnan finite isinf hypot acosh erf tgamma lgamma_r \
-
isnan finite isinf hypot acosh erf tgamma lgamma_r cbrt \ strlcpy strlcat)
AC_CHECK_FUNCS(fmod killpg wait4 waitpid fork spawnv syscall chroot
fsync getcwd eaccess
truncate chsize times utimes utimensat fcntl lockf lstat
Index: missing/cbrt.c
— missing/cbrt.c (revision 0)
+++ missing/cbrt.c (revision 0)
@@ -0,0 +1,10 @@
+#include <math.h>
+
+double cbrt(double x)
+{
- if (x < 0)
-
return -pow(-x, 1/3.0); - else
-
return pow(x, 1/3.0);
+}
+