diff --git a/sprout/array/hash.hpp b/sprout/array/hash.hpp
index 7eefce86..1f59c2db 100644
--- a/sprout/array/hash.hpp
+++ b/sprout/array/hash.hpp
@@ -2,6 +2,7 @@
 #define SPROUT_ARRAY_HASH_HPP
 
 #include <cstddef>
+#include <functional>
 #include <sprout/config.hpp>
 #include <sprout/array/array.hpp>
 #include <sprout/functional/hash.hpp>
@@ -17,4 +18,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T, std::size_t N>
+	struct hash<sprout::array<T, N> >
+		: public sprout::hash<sprout::array<T, N> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_ARRAY_HASH_HPP
diff --git a/sprout/bitset/hash.hpp b/sprout/bitset/hash.hpp
index 2178dc72..8632660a 100644
--- a/sprout/bitset/hash.hpp
+++ b/sprout/bitset/hash.hpp
@@ -18,4 +18,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<std::size_t N>
+	struct hash<sprout::bitset<N> >
+		: public sprout::hash<sprout::bitset<N> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_BITSET_HASH_HPP
diff --git a/sprout/complex/hash.hpp b/sprout/complex/hash.hpp
index dcfc4f89..1218477c 100644
--- a/sprout/complex/hash.hpp
+++ b/sprout/complex/hash.hpp
@@ -17,4 +17,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T>
+	struct hash<sprout::complex<T> >
+		: public sprout::hash<sprout::complex<T> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_COMPLEX_HASH_HPP
diff --git a/sprout/detail/pow.hpp b/sprout/detail/pow.hpp
index 41a90e8d..4f32f190 100644
--- a/sprout/detail/pow.hpp
+++ b/sprout/detail/pow.hpp
@@ -1,7 +1,11 @@
 #ifndef SPROUT_DETAIL_POW_HPP
 #define SPROUT_DETAIL_POW_HPP
 
+#include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/type_traits/is_int.hpp>
+#include <sprout/type_traits/is_uint.hpp>
+#include <sprout/type_traits/enabler_if.hpp>
 
 namespace sprout {
 	namespace detail {
@@ -17,21 +21,35 @@ namespace sprout {
 			return x * x * x;
 		}
 
-		template<typename T>
+		template<typename T, typename IntType>
 		inline SPROUT_CONSTEXPR T
-		pow_n_impl(T const& x, int n) {
+		pow_n_impl(T const& x, IntType n) {
 			return n == 1 ? x
 				: n % 2 ? x * sprout::detail::pow2(sprout::detail::pow_n_impl(x, n / 2))
 				: sprout::detail::pow2(sprout::detail::pow_n_impl(x, n / 2))
 				;
 		}
-		template<typename T>
+		template<
+			typename T, typename UIntType,
+			typename sprout::enabler_if<sprout::is_uint<UIntType>::value>::type = sprout::enabler
+		>
 		inline SPROUT_CONSTEXPR T
-		pow_n(T const& x, int n) {
+		pow_n(T const& x, UIntType n) {
 			return n == 0 ? T(1)
 				: sprout::detail::pow_n_impl(x, n)
 				;
 		}
+		template<
+			typename T, typename IntType,
+			typename sprout::enabler_if<sprout::is_int<IntType>::value>::type = sprout::enabler
+		>
+		inline SPROUT_CONSTEXPR T
+		pow_n(T const& x, IntType n) {
+			return n == 0 ? T(1)
+				: n > 0 ? sprout::detail::pow_n_impl(x, n)
+				: T(1) / sprout::detail::pow_n_impl(x, -n)
+				;
+		}
 	}	// namespace detail
 }	// namespace sprout
 
diff --git a/sprout/logic/tribool/hash.hpp b/sprout/logic/tribool/hash.hpp
index 66119f8a..ea91a4d9 100644
--- a/sprout/logic/tribool/hash.hpp
+++ b/sprout/logic/tribool/hash.hpp
@@ -25,4 +25,18 @@ namespace sprout {
 	}	// namespace logic
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<>
+	struct hash<sprout::logic::indeterminate_keyword_t>
+		: public sprout::hash<sprout::logic::indeterminate_keyword_t>
+	{};
+	template<>
+	struct hash<sprout::logic::tribool>
+		: public sprout::hash<sprout::logic::tribool>
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_LOGIC_TRIBOOL_HASH_HPP
diff --git a/sprout/math/exponential.hpp b/sprout/math/exponential.hpp
index 95602a4f..54c9e7a4 100644
--- a/sprout/math/exponential.hpp
+++ b/sprout/math/exponential.hpp
@@ -10,5 +10,8 @@
 #include <sprout/math/log10.hpp>
 #include <sprout/math/log2.hpp>
 #include <sprout/math/log1p.hpp>
+#include <sprout/math/ldexp.hpp>
+#include <sprout/math/scalbn.hpp>
+#include <sprout/math/scalbln.hpp>
 
 #endif	// #ifndef SPROUT_MATH_EXPONENTIAL_HPP
diff --git a/sprout/math/ldexp.hpp b/sprout/math/ldexp.hpp
new file mode 100644
index 00000000..55c31fcd
--- /dev/null
+++ b/sprout/math/ldexp.hpp
@@ -0,0 +1,38 @@
+#ifndef SPROUT_MATH_LDEXP_HPP
+#define SPROUT_MATH_LDEXP_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
+#include <sprout/detail/pow.hpp>
+#include <sprout/type_traits/enabler_if.hpp>
+
+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
+			ldexp(FloatType x, int exp) {
+				return static_cast<FloatType>(x * sprout::detail::pow_n(FloatType(2), exp));
+			}
+
+			template<
+				typename IntType,
+				typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR double
+			ldexp(IntType x, int exp) {
+				return sprout::math::detail::ldexp(static_cast<double>(x), exp);
+			}
+		}	// namespace detail
+
+		using NS_SPROUT_MATH_DETAIL::ldexp;
+	}	// namespace math
+
+	using sprout::math::ldexp;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_LDEXP_HPP
diff --git a/sprout/math/log.hpp b/sprout/math/log.hpp
index 09731056..ee2969b7 100644
--- a/sprout/math/log.hpp
+++ b/sprout/math/log.hpp
@@ -42,7 +42,8 @@ namespace sprout {
 				typedef double type;
 				return x == 0 ? std::numeric_limits<FloatType>::quiet_NaN()
 					: !(x > 0) ? -std::numeric_limits<FloatType>::infinity()
-					: static_cast<FloatType>(sprout::math::detail::log_impl(x))
+					: x < 1 ? static_cast<FloatType>(-sprout::math::detail::log_impl(type(1) / static_cast<type>(x)))
+					: static_cast<FloatType>(sprout::math::detail::log_impl(static_cast<type>(x)))
 					;
 			}
 
diff --git a/sprout/math/scalbln.hpp b/sprout/math/scalbln.hpp
new file mode 100644
index 00000000..7f30a3d9
--- /dev/null
+++ b/sprout/math/scalbln.hpp
@@ -0,0 +1,39 @@
+#ifndef SPROUT_MATH_SCALBLN_HPP
+#define SPROUT_MATH_SCALBLN_HPP
+
+#include <cfloat>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
+#include <sprout/detail/pow.hpp>
+#include <sprout/type_traits/enabler_if.hpp>
+
+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
+			scalbln(FloatType x, long exp) {
+				return static_cast<FloatType>(x * sprout::detail::pow_n(FloatType(FLT_RADIX), exp));
+			}
+
+			template<
+				typename IntType,
+				typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR double
+			scalbln(IntType x, long exp) {
+				return sprout::math::detail::scalbln(static_cast<double>(x), exp);
+			}
+		}	// namespace detail
+
+		using NS_SPROUT_MATH_DETAIL::scalbln;
+	}	// namespace math
+
+	using sprout::math::scalbln;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_SCALBLN_HPP
diff --git a/sprout/math/scalbn.hpp b/sprout/math/scalbn.hpp
new file mode 100644
index 00000000..f56737ca
--- /dev/null
+++ b/sprout/math/scalbn.hpp
@@ -0,0 +1,39 @@
+#ifndef SPROUT_MATH_SCALBN_HPP
+#define SPROUT_MATH_SCALBN_HPP
+
+#include <cfloat>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
+#include <sprout/detail/pow.hpp>
+#include <sprout/type_traits/enabler_if.hpp>
+
+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
+			scalbn(FloatType x, int exp) {
+				return static_cast<FloatType>(x * sprout::detail::pow_n(FloatType(FLT_RADIX), exp));
+			}
+
+			template<
+				typename IntType,
+				typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
+			>
+			inline SPROUT_CONSTEXPR double
+			scalbn(IntType x, int exp) {
+				return sprout::math::detail::scalbn(static_cast<double>(x), exp);
+			}
+		}	// namespace detail
+
+		using NS_SPROUT_MATH_DETAIL::scalbn;
+	}	// namespace math
+
+	using sprout::math::scalbn;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_MATH_SCALBN_HPP
diff --git a/sprout/optional/hash.hpp b/sprout/optional/hash.hpp
index d20a8313..f5437df6 100644
--- a/sprout/optional/hash.hpp
+++ b/sprout/optional/hash.hpp
@@ -19,4 +19,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T>
+	struct hash<sprout::optional<T> >
+		: public sprout::hash<sprout::optional<T> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_OPTIONAL_HASH_HPP
diff --git a/sprout/pit/hash.hpp b/sprout/pit/hash.hpp
index 5963844e..9fb0c57b 100644
--- a/sprout/pit/hash.hpp
+++ b/sprout/pit/hash.hpp
@@ -17,4 +17,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename Container>
+	struct hash<sprout::pit<Container> >
+		: public sprout::hash<sprout::pit<Container> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_PIT_HASH_HPP
diff --git a/sprout/rational/hash.hpp b/sprout/rational/hash.hpp
index e9368f32..e02234a0 100644
--- a/sprout/rational/hash.hpp
+++ b/sprout/rational/hash.hpp
@@ -17,4 +17,14 @@ namespace sprout {
 	}
 } // namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T>
+	struct hash<sprout::rational<T> >
+		: public sprout::hash<sprout::rational<T> >
+	{};
+}	// namespace std
+
 #endif	// SPROUT_RATIONAL_HASH_HPP
diff --git a/sprout/string/hash.hpp b/sprout/string/hash.hpp
index 2a5d9301..07bb94be 100644
--- a/sprout/string/hash.hpp
+++ b/sprout/string/hash.hpp
@@ -17,4 +17,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T, std::size_t N, typename Traits>
+	struct hash<sprout::basic_string<T, N, Traits> >
+		: public sprout::hash<sprout::basic_string<T, N, Traits> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_STRING_HASH_HPP
diff --git a/sprout/sub_array/hash.hpp b/sprout/sub_array/hash.hpp
index 056b3007..a6fd250b 100644
--- a/sprout/sub_array/hash.hpp
+++ b/sprout/sub_array/hash.hpp
@@ -16,4 +16,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename Container>
+	struct hash<sprout::sub_array<Container> >
+		: public sprout::hash<sprout::sub_array<Container> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_SUB_ARRAY_HASH_HPP
diff --git a/sprout/tuple/tuple/hash.hpp b/sprout/tuple/tuple/hash.hpp
index 14baf391..4c243f56 100644
--- a/sprout/tuple/tuple/hash.hpp
+++ b/sprout/tuple/tuple/hash.hpp
@@ -31,4 +31,14 @@ namespace sprout {
 	}	// namespace tuples
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename... Types>
+	struct hash<sprout::tuples::tuple<Types...> >
+		: public sprout::hash<sprout::tuples::tuple<Types...> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_TUPLE_TUPLE_HASH_HPP
diff --git a/sprout/utility/pair/hash.hpp b/sprout/utility/pair/hash.hpp
index a3d94a8b..e070e16c 100644
--- a/sprout/utility/pair/hash.hpp
+++ b/sprout/utility/pair/hash.hpp
@@ -17,4 +17,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T1, typename T2>
+	struct hash<sprout::pair<T1, T2> >
+		: public sprout::hash<sprout::pair<T1, T2> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_UTILITY_PAIR_HASH_HPP
diff --git a/sprout/utility/value_holder/hash.hpp b/sprout/utility/value_holder/hash.hpp
index 4bcd301a..2ea7d574 100644
--- a/sprout/utility/value_holder/hash.hpp
+++ b/sprout/utility/value_holder/hash.hpp
@@ -25,4 +25,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename T>
+	struct hash<sprout::value_holder<T> >
+		: public sprout::hash<sprout::value_holder<T> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_UTILITY_VALUE_HOLDER_HASH_HPP
diff --git a/sprout/uuid/hash.hpp b/sprout/uuid/hash.hpp
index f674df3a..1e515c66 100644
--- a/sprout/uuid/hash.hpp
+++ b/sprout/uuid/hash.hpp
@@ -16,4 +16,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<>
+	struct hash<sprout::uuids::uuid>
+		: public sprout::hash<sprout::uuids::uuid>
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_UUID_HASH_HPP
diff --git a/sprout/variant/hash.hpp b/sprout/variant/hash.hpp
index 66db3172..8aa5d325 100644
--- a/sprout/variant/hash.hpp
+++ b/sprout/variant/hash.hpp
@@ -33,4 +33,14 @@ namespace sprout {
 	}
 }	// namespace sprout
 
+namespace std {
+	//
+	// hash
+	//
+	template<typename... Types>
+	struct hash<sprout::variant<Types...> >
+		: public sprout::hash<sprout::variant<Types...> >
+	{};
+}	// namespace std
+
 #endif	// #ifndef SPROUT_VARIANT_HASH_HPP