From 6ccd6e1cf4dbd865e7855498ea410b75c8c51b6f Mon Sep 17 00:00:00 2001
From: bolero-MURAKAMI <bolero.murakami@gmail.com>
Date: Sat, 5 May 2012 18:50:17 +0900
Subject: [PATCH] add sprout::cbrt, hypot, fmax, fmin, fdim fix sprout::pow
 case x==0

---
 sprout/math/cbrt.hpp              | 47 +++++++++++++++++++++++++++++
 sprout/math/constants.hpp         | 33 +++++++++++++--------
 sprout/math/{abs.hpp => fabs.hpp} |  6 ++--
 sprout/math/fdim.hpp              | 48 ++++++++++++++++++++++++++++++
 sprout/math/fmax.hpp              | 48 ++++++++++++++++++++++++++++++
 sprout/math/fmin.hpp              | 48 ++++++++++++++++++++++++++++++
 sprout/math/hypot.hpp             | 49 +++++++++++++++++++++++++++++++
 sprout/math/operations.hpp        |  5 +++-
 sprout/math/pow.hpp               |  4 ++-
 sprout/math/power.hpp             |  2 ++
 10 files changed, 273 insertions(+), 17 deletions(-)
 create mode 100644 sprout/math/cbrt.hpp
 rename sprout/math/{abs.hpp => fabs.hpp} (90%)
 create mode 100644 sprout/math/fdim.hpp
 create mode 100644 sprout/math/fmax.hpp
 create mode 100644 sprout/math/fmin.hpp
 create mode 100644 sprout/math/hypot.hpp

diff --git a/sprout/math/cbrt.hpp b/sprout/math/cbrt.hpp
new file mode 100644
index 00000000..4bcb6a6c
--- /dev/null
+++ b/sprout/math/cbrt.hpp
@@ -0,0 +1,47 @@
+#ifndef SPROUT_MATH_CBRT_HPP
+#define SPROUT_MATH_CBRT_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/pow.hpp>
+#include <sprout/math/constants.hpp>
+#include <sprout/utility/enabler_if.hpp>
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	include <cmath>
+#endif
+
+namespace sprout {
+	namespace math {
+		namespace detail {
+			template<
+				typename FloatType,
+				typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR FloatType
+			cbrt(FloatType x) {
+				return x < 0 ? -sprout::math::detail::pow(-x, sprout::math::third<FloatType>())
+					: sprout::math::detail::pow(x, sprout::math::third<FloatType>())
+					;
+			}
+
+			template<
+				typename IntType,
+				typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR double
+			cbrt(IntType x) {
+				return sprout::math::detail::cbrt(static_cast<double>(x));
+			}
+		}	// namespace detail
+
+#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+		using std::cbrt;
+#	else
+		using sprout::math::detail::cbrt;
+#	endif
+	}	// namespace math
+
+	using sprout::math::cbrt;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_CBRT_HPP
diff --git a/sprout/math/constants.hpp b/sprout/math/constants.hpp
index 272b1418..1a258c64 100644
--- a/sprout/math/constants.hpp
+++ b/sprout/math/constants.hpp
@@ -7,35 +7,46 @@ namespace sprout {
 	namespace math {
 		//
 		// pi
+		// half_pi
+		// quarter_pi
 		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T pi() {
 			return 3.141592653589793238462643383279502884197169399375105820974944L;
 		}
-		//
-		// half_pi
-		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T half_pi() {
 			return 1.570796326794896619231321691639751442098584699687552910487472L;
 		}
-		//
-		// quarter_pi
-		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T quarter_pi() {
 			return 0.785398163397448309615660845819875721049292349843776455243736L;
 		}
 		//
+		// half
+		// third
+		// twothirds
+		//
+		template<typename T>
+		inline SPROUT_CONSTEXPR T half() {
+			return 0.5L;
+		}
+		template<typename T>
+		inline SPROUT_CONSTEXPR T third() {
+			return 0.3333333333333333333333333333333333333333333333333333333333333333333333L;
+		}
+		template<typename T>
+		inline SPROUT_CONSTEXPR T twothirds() {
+			return 0.6666666666666666666666666666666666666666666666666666666666666666666666L;
+		}
+		//
 		// root_two
+		// half_root_two
 		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T root_two() {
 			return 1.414213562373095048801688724209698078569671875376948073L;
 		}
-		//
-		// half_root_two
-		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T half_root_two() {
 			return 0.70710678118654752440084436210484903928483593756084L;
@@ -49,14 +60,12 @@ namespace sprout {
 		}
 		//
 		// ln_ten
+		// ln_two
 		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T ln_ten() {
 			return 2.302585092994045684017991454684364207601101488628772976L;
 		}
-		//
-		// ln_two
-		//
 		template<typename T>
 		inline SPROUT_CONSTEXPR T ln_two() {
 			return 0.693147180559945309417232121458176568075500134360255254L;
diff --git a/sprout/math/abs.hpp b/sprout/math/fabs.hpp
similarity index 90%
rename from sprout/math/abs.hpp
rename to sprout/math/fabs.hpp
index fcc5ed71..606ed855 100644
--- a/sprout/math/abs.hpp
+++ b/sprout/math/fabs.hpp
@@ -1,5 +1,5 @@
-#ifndef SPROUT_MATH_ABS_HPP
-#define SPROUT_MATH_ABS_HPP
+#ifndef SPROUT_MATH_FABS_HPP
+#define SPROUT_MATH_FABS_HPP
 
 #include <type_traits>
 #include <sprout/config.hpp>
@@ -64,4 +64,4 @@ namespace sprout {
 	using sprout::math::fabs;
 }	// namespace sprout
 
-#endif	// #ifndef SPROUT_MATH_ABS_HPP
+#endif	// #ifndef SPROUT_MATH_FABS_HPP
diff --git a/sprout/math/fdim.hpp b/sprout/math/fdim.hpp
new file mode 100644
index 00000000..c995f8f3
--- /dev/null
+++ b/sprout/math/fdim.hpp
@@ -0,0 +1,48 @@
+#ifndef SPROUT_MATH_FDIM_HPP
+#define SPROUT_MATH_FDIM_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/float_promote.hpp>
+#include <sprout/utility/enabler_if.hpp>
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	include <cmath>
+#endif
+
+namespace sprout {
+	namespace math {
+		namespace detail {
+			template<
+				typename FloatType,
+				typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR FloatType
+			fdim(FloatType x, FloatType y) {
+				return x > y ? x - y : 0;
+			}
+
+			template<
+				typename ArithmeticType1,
+				typename ArithmeticType2,
+				typename sprout::enabler_if<
+					std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
+				>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type
+			fdim(ArithmeticType1 x, ArithmeticType2 y) {
+				typedef typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type type;
+				return sprout::math::detail::fdim(static_cast<type>(x), static_cast<type>(y));
+			}
+		}	// namespace detail
+
+#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+		using std::fdim;
+#	else
+		using sprout::math::detail::fdim;
+#	endif
+	}	// namespace math
+
+	using sprout::math::fdim;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_FDIM_HPP
diff --git a/sprout/math/fmax.hpp b/sprout/math/fmax.hpp
new file mode 100644
index 00000000..7b06755d
--- /dev/null
+++ b/sprout/math/fmax.hpp
@@ -0,0 +1,48 @@
+#ifndef SPROUT_MATH_FMAX_HPP
+#define SPROUT_MATH_FMAX_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/float_promote.hpp>
+#include <sprout/utility/enabler_if.hpp>
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	include <cmath>
+#endif
+
+namespace sprout {
+	namespace math {
+		namespace detail {
+			template<
+				typename FloatType,
+				typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR FloatType
+			fmax(FloatType x, FloatType y) {
+				return x < y ? y : x;
+			}
+
+			template<
+				typename ArithmeticType1,
+				typename ArithmeticType2,
+				typename sprout::enabler_if<
+					std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
+				>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type
+			fmax(ArithmeticType1 x, ArithmeticType2 y) {
+				typedef typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type type;
+				return sprout::math::detail::fmax(static_cast<type>(x), static_cast<type>(y));
+			}
+		}	// namespace detail
+
+#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+		using std::fmax;
+#	else
+		using sprout::math::detail::fmax;
+#	endif
+	}	// namespace math
+
+	using sprout::math::fmax;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_FMAX_HPP
diff --git a/sprout/math/fmin.hpp b/sprout/math/fmin.hpp
new file mode 100644
index 00000000..0fb53263
--- /dev/null
+++ b/sprout/math/fmin.hpp
@@ -0,0 +1,48 @@
+#ifndef SPROUT_MATH_FMIN_HPP
+#define SPROUT_MATH_FMIN_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/float_promote.hpp>
+#include <sprout/utility/enabler_if.hpp>
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	include <cmath>
+#endif
+
+namespace sprout {
+	namespace math {
+		namespace detail {
+			template<
+				typename FloatType,
+				typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR FloatType
+			fmin(FloatType x, FloatType y) {
+				return x > y ? y : x;
+			}
+
+			template<
+				typename ArithmeticType1,
+				typename ArithmeticType2,
+				typename sprout::enabler_if<
+					std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
+				>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type
+			fmin(ArithmeticType1 x, ArithmeticType2 y) {
+				typedef typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type type;
+				return sprout::math::detail::fmin(static_cast<type>(x), static_cast<type>(y));
+			}
+		}	// namespace detail
+
+#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+		using std::fmin;
+#	else
+		using sprout::math::detail::fmin;
+#	endif
+	}	// namespace math
+
+	using sprout::math::fmin;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_FMIN_HPP
diff --git a/sprout/math/hypot.hpp b/sprout/math/hypot.hpp
new file mode 100644
index 00000000..12967e1a
--- /dev/null
+++ b/sprout/math/hypot.hpp
@@ -0,0 +1,49 @@
+#ifndef SPROUT_MATH_HYPOT_HPP
+#define SPROUT_MATH_HYPOT_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/float_promote.hpp>
+#include <sprout/math/sqrt.hpp>
+#include <sprout/utility/enabler_if.hpp>
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	include <cmath>
+#endif
+
+namespace sprout {
+	namespace math {
+		namespace detail {
+			template<
+				typename FloatType,
+				typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR FloatType
+			hypot(FloatType x, FloatType y) {
+				return sprout::math::detail::sqrt(x * x + y * y);
+			}
+
+			template<
+				typename ArithmeticType1,
+				typename ArithmeticType2,
+				typename sprout::enabler_if<
+					std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
+				>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type
+			hypot(ArithmeticType1 x, ArithmeticType2 y) {
+				typedef typename sprout::math::float_promote<ArithmeticType1, ArithmeticType2>::type type;
+				return sprout::math::detail::hypot(static_cast<type>(x), static_cast<type>(y));
+			}
+		}	// namespace detail
+
+#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+		using std::hypot;
+#	else
+		using sprout::math::detail::hypot;
+#	endif
+	}	// namespace math
+
+	using sprout::math::hypot;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_HYPOT_HPP
diff --git a/sprout/math/operations.hpp b/sprout/math/operations.hpp
index b8ae419d..df845bd9 100644
--- a/sprout/math/operations.hpp
+++ b/sprout/math/operations.hpp
@@ -1,6 +1,9 @@
 #ifndef SPROUT_MATH_OPERATIONS_HPP
 #define SPROUT_MATH_OPERATIONS_HPP
 
-#include <sprout/math/abs.hpp>
+#include <sprout/math/fabs.hpp>
+#include <sprout/math/fmax.hpp>
+#include <sprout/math/fmin.hpp>
+#include <sprout/math/fdim.hpp>
 
 #endif	// #ifndef SPROUT_MATH_OPERATIONS_HPP
diff --git a/sprout/math/pow.hpp b/sprout/math/pow.hpp
index 635eb66a..d762787e 100644
--- a/sprout/math/pow.hpp
+++ b/sprout/math/pow.hpp
@@ -21,7 +21,9 @@ namespace sprout {
 			>
 			inline SPROUT_CONSTEXPR FloatType
 			pow(FloatType x, FloatType y) {
-				return sprout::math::detail::exp(y * sprout::math::detail::log(x));
+				return x == 0 && y > 0 ? FloatType(0)
+					: sprout::math::detail::exp(y * sprout::math::detail::log(x))
+					;
 			}
 
 			template<
diff --git a/sprout/math/power.hpp b/sprout/math/power.hpp
index ebcd6e55..4ebd1266 100644
--- a/sprout/math/power.hpp
+++ b/sprout/math/power.hpp
@@ -2,6 +2,8 @@
 #define SPROUT_MATH_POWER_HPP
 
 #include <sprout/math/sqrt.hpp>
+#include <sprout/math/cbrt.hpp>
 #include <sprout/math/pow.hpp>
+#include <sprout/math/hypot.hpp>
 
 #endif	// #ifndef SPROUT_MATH_POWER_HPP