2014-12-27 04:56:41 +00:00
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/*=============================================================================
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2015-01-10 10:13:57 +00:00
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Copyright (c) 2011-2015 Bolero MURAKAMI
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2014-12-27 04:56:41 +00:00
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_MATH_SIGMOID_HPP
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#define SPROUT_MATH_SIGMOID_HPP
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/math/detail/config.hpp>
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#include <sprout/math/detail/float_compute.hpp>
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#include <sprout/math/exp.hpp>
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#include <sprout/type_traits/float_promote.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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namespace sprout {
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namespace math {
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//
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// sigmoid
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//
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namespace detail {
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template<typename T>
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inline SPROUT_CONSTEXPR T
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sigmoid_impl(T x){
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return 1 / (1 + sprout::math::exp(-x));
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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sigmoid_impl(T x, T a){
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return sprout::math::detail::sigmoid_impl(a * x);
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}
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} // namespace detail
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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sigmoid(FloatType x){
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return sprout::math::detail::sigmoid_impl(sprout::math::detail::as_float_compute(x));
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}
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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sigmoid(FloatType x, FloatType a){
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return sprout::math::detail::sigmoid_impl(sprout::math::detail::as_float_compute(x), sprout::math::detail::as_float_compute(a));
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}
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template<
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR double
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sigmoid(IntType x) {
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return sprout::math::sigmoid(static_cast<double>(x));
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}
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template<
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typename ArithmeticType1,
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typename ArithmeticType2,
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typename sprout::enabler_if<
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std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
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>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
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sigmoid(ArithmeticType1 x, ArithmeticType2 a) {
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typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
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return sprout::math::sigmoid(static_cast<type>(x), static_cast<type>(a));
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}
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//
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// d_sigmoid
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//
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namespace detail {
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d_sigmoid_impl_1(T s){
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return s * (1 - s);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d_sigmoid_impl_1(T s, T a){
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return a * s * (1 - s);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d_sigmoid_impl(T x){
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return sprout::math::detail::d_sigmoid_impl_1(sprout::math::sigmoid(x));
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d_sigmoid_impl(T x, T a){
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return sprout::math::detail::d_sigmoid_impl_1(sprout::math::sigmoid(x, a), a);
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}
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} // namespace detail
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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d_sigmoid(FloatType x){
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return sprout::math::detail::d_sigmoid_impl(sprout::math::detail::as_float_compute(x));
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}
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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d_sigmoid(FloatType x, FloatType a){
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return sprout::math::detail::d_sigmoid_impl(sprout::math::detail::as_float_compute(x), sprout::math::detail::as_float_compute(a));
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}
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template<
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR double
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d_sigmoid(IntType x) {
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return sprout::math::d_sigmoid(static_cast<double>(x));
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}
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template<
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typename ArithmeticType1,
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typename ArithmeticType2,
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typename sprout::enabler_if<
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std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
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>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
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d_sigmoid(ArithmeticType1 x, ArithmeticType2 a) {
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typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
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return sprout::math::d_sigmoid(static_cast<type>(x), static_cast<type>(a));
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}
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//
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// d2_sigmoid
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//
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namespace detail {
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d2_sigmoid_impl_1(T s){
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return s * (1 - s) * (1 - 2 * s);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d2_sigmoid_impl_1(T s, T a){
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return a * a * s * (1 - s) * (1 - 2 * s);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d2_sigmoid_impl(T x){
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return sprout::math::detail::d2_sigmoid_impl_1(sprout::math::sigmoid(x));
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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d2_sigmoid_impl(T x, T a){
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return sprout::math::detail::d2_sigmoid_impl_1(sprout::math::sigmoid(x, a), a);
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}
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} // namespace detail
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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d2_sigmoid(FloatType x){
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return sprout::math::detail::d2_sigmoid_impl(sprout::math::detail::as_float_compute(x));
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}
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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d2_sigmoid(FloatType x, FloatType a){
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return sprout::math::detail::d2_sigmoid_impl(sprout::math::detail::as_float_compute(x), sprout::math::detail::as_float_compute(a));
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}
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template<
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR double
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d2_sigmoid(IntType x) {
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return sprout::math::d2_sigmoid(static_cast<double>(x));
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}
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template<
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typename ArithmeticType1,
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typename ArithmeticType2,
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typename sprout::enabler_if<
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std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
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>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
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d2_sigmoid(ArithmeticType1 x, ArithmeticType2 a) {
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typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
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return sprout::math::d2_sigmoid(static_cast<type>(x), static_cast<type>(a));
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}
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} // namespace math
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using sprout::math::sigmoid;
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using sprout::math::d_sigmoid;
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using sprout::math::d2_sigmoid;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_SIGMOID_HPP
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