mirror of
https://gitcode.com/gh_mirrors/ope/OpenFace.git
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558 lines
14 KiB
C++
558 lines
14 KiB
C++
// Copyright (C) 2007 Davis E. King (davis@dlib.net)
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// License: Boost Software License See LICENSE.txt for the full license.
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#ifndef DLIB_SVm_KERNEL
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#define DLIB_SVm_KERNEL
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#include "kernel_abstract.h"
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#include <cmath>
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#include <limits>
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#include <sstream>
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#include "../matrix.h"
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#include "../algs.h"
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#include "../serialize.h"
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namespace dlib
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{
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// ----------------------------------------------------------------------------------------
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template < typename kernel_type > struct kernel_derivative;
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// ----------------------------------------------------------------------------------------
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template <
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typename T
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>
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struct radial_basis_kernel
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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radial_basis_kernel(const scalar_type g) : gamma(g) {}
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radial_basis_kernel() : gamma(0.1) {}
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radial_basis_kernel(
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const radial_basis_kernel& k
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) : gamma(k.gamma) {}
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const scalar_type gamma;
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scalar_type operator() (
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const sample_type& a,
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const sample_type& b
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) const
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{
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const scalar_type d = trans(a-b)*(a-b);
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return std::exp(-gamma*d);
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}
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radial_basis_kernel& operator= (
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const radial_basis_kernel& k
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)
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{
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const_cast<scalar_type&>(gamma) = k.gamma;
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return *this;
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}
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bool operator== (
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const radial_basis_kernel& k
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) const
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{
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return gamma == k.gamma;
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}
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};
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template <
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typename T
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>
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void serialize (
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const radial_basis_kernel<T>& item,
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std::ostream& out
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)
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{
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try
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{
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serialize(item.gamma, out);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while serializing object of type radial_basis_kernel");
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}
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}
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template <
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typename T
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>
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void deserialize (
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radial_basis_kernel<T>& item,
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std::istream& in
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)
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{
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typedef typename T::type scalar_type;
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try
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{
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deserialize(const_cast<scalar_type&>(item.gamma), in);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while deserializing object of type radial_basis_kernel");
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}
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}
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template <
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typename T
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>
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struct kernel_derivative<radial_basis_kernel<T> >
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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kernel_derivative(const radial_basis_kernel<T>& k_) : k(k_){}
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const sample_type& operator() (const sample_type& x, const sample_type& y) const
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{
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// return the derivative of the rbf kernel
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temp = 2*k.gamma*(x-y)*k(x,y);
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return temp;
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}
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const radial_basis_kernel<T>& k;
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mutable sample_type temp;
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};
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// ----------------------------------------------------------------------------------------
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template <
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typename T
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>
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struct polynomial_kernel
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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polynomial_kernel(const scalar_type g, const scalar_type c, const scalar_type d) : gamma(g), coef(c), degree(d) {}
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polynomial_kernel() : gamma(1), coef(0), degree(1) {}
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polynomial_kernel(
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const polynomial_kernel& k
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) : gamma(k.gamma), coef(k.coef), degree(k.degree) {}
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typedef T type;
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const scalar_type gamma;
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const scalar_type coef;
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const scalar_type degree;
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scalar_type operator() (
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const sample_type& a,
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const sample_type& b
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) const
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{
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return std::pow(gamma*(trans(a)*b) + coef, degree);
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}
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polynomial_kernel& operator= (
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const polynomial_kernel& k
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)
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{
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const_cast<scalar_type&>(gamma) = k.gamma;
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const_cast<scalar_type&>(coef) = k.coef;
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const_cast<scalar_type&>(degree) = k.degree;
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return *this;
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}
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bool operator== (
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const polynomial_kernel& k
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) const
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{
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return (gamma == k.gamma) && (coef == k.coef) && (degree == k.degree);
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}
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};
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template <
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typename T
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>
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void serialize (
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const polynomial_kernel<T>& item,
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std::ostream& out
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)
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{
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try
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{
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serialize(item.gamma, out);
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serialize(item.coef, out);
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serialize(item.degree, out);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while serializing object of type polynomial_kernel");
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}
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}
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template <
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typename T
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>
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void deserialize (
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polynomial_kernel<T>& item,
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std::istream& in
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)
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{
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typedef typename T::type scalar_type;
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try
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{
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deserialize(const_cast<scalar_type&>(item.gamma), in);
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deserialize(const_cast<scalar_type&>(item.coef), in);
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deserialize(const_cast<scalar_type&>(item.degree), in);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while deserializing object of type polynomial_kernel");
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}
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}
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template <
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typename T
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>
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struct kernel_derivative<polynomial_kernel<T> >
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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kernel_derivative(const polynomial_kernel<T>& k_) : k(k_){}
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const sample_type& operator() (const sample_type& x, const sample_type& y) const
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{
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// return the derivative of the rbf kernel
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temp = k.degree*k.gamma*x*std::pow(k.gamma*(trans(x)*y) + k.coef, k.degree-1);
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return temp;
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}
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const polynomial_kernel<T>& k;
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mutable sample_type temp;
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};
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// ----------------------------------------------------------------------------------------
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template <
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typename T
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>
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struct sigmoid_kernel
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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sigmoid_kernel(const scalar_type g, const scalar_type c) : gamma(g), coef(c) {}
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sigmoid_kernel() : gamma(0.1), coef(-1.0) {}
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sigmoid_kernel(
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const sigmoid_kernel& k
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) : gamma(k.gamma), coef(k.coef) {}
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typedef T type;
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const scalar_type gamma;
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const scalar_type coef;
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scalar_type operator() (
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const sample_type& a,
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const sample_type& b
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) const
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{
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return std::tanh(gamma*(trans(a)*b) + coef);
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}
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sigmoid_kernel& operator= (
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const sigmoid_kernel& k
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)
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{
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const_cast<scalar_type&>(gamma) = k.gamma;
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const_cast<scalar_type&>(coef) = k.coef;
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return *this;
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}
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bool operator== (
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const sigmoid_kernel& k
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) const
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{
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return (gamma == k.gamma) && (coef == k.coef);
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}
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};
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template <
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typename T
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>
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void serialize (
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const sigmoid_kernel<T>& item,
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std::ostream& out
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)
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{
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try
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{
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serialize(item.gamma, out);
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serialize(item.coef, out);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while serializing object of type sigmoid_kernel");
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}
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}
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template <
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typename T
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>
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void deserialize (
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sigmoid_kernel<T>& item,
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std::istream& in
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)
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{
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typedef typename T::type scalar_type;
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try
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{
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deserialize(const_cast<scalar_type&>(item.gamma), in);
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deserialize(const_cast<scalar_type&>(item.coef), in);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while deserializing object of type sigmoid_kernel");
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}
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}
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template <
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typename T
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>
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struct kernel_derivative<sigmoid_kernel<T> >
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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kernel_derivative(const sigmoid_kernel<T>& k_) : k(k_){}
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const sample_type& operator() (const sample_type& x, const sample_type& y) const
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{
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// return the derivative of the rbf kernel
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temp = k.gamma*x*(1-std::pow(k(x,y),2));
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return temp;
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}
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const sigmoid_kernel<T>& k;
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mutable sample_type temp;
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};
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// ----------------------------------------------------------------------------------------
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template <typename T>
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struct linear_kernel
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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scalar_type operator() (
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const sample_type& a,
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const sample_type& b
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) const
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{
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return trans(a)*b;
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}
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bool operator== (
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const linear_kernel&
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) const
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{
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return true;
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}
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};
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template <
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typename T
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>
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void serialize (
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const linear_kernel<T>& ,
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std::ostream&
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){}
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template <
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typename T
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>
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void deserialize (
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linear_kernel<T>& ,
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std::istream&
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){}
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template <
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typename T
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>
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struct kernel_derivative<linear_kernel<T> >
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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kernel_derivative(const linear_kernel<T>& k_) : k(k_){}
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const sample_type& operator() (const sample_type& x, const sample_type& ) const
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{
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return x;
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}
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const linear_kernel<T>& k;
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};
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// ----------------------------------------------------------------------------------------
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template <typename T>
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struct histogram_intersection_kernel
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{
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typedef typename T::type scalar_type;
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typedef T sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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scalar_type operator() (
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const sample_type& a,
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const sample_type& b
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) const
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{
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scalar_type temp = 0;
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for (long i = 0; i < a.size(); ++i)
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{
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temp += std::min(a(i), b(i));
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}
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return temp;
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}
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bool operator== (
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const histogram_intersection_kernel&
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) const
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{
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return true;
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}
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};
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template <
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typename T
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>
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void serialize (
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const histogram_intersection_kernel<T>& ,
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std::ostream&
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){}
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template <
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typename T
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>
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void deserialize (
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histogram_intersection_kernel<T>& ,
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std::istream&
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){}
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// ----------------------------------------------------------------------------------------
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template <typename T>
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struct offset_kernel
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{
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typedef typename T::scalar_type scalar_type;
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typedef typename T::sample_type sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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offset_kernel(const T& k, const scalar_type& offset_
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) : kernel(k), offset(offset_) {}
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offset_kernel() : kernel(T()), offset(0.01) {}
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offset_kernel(
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const offset_kernel& k
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) : kernel(k.kernel), offset(k.offset) {}
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const T kernel;
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const scalar_type offset;
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scalar_type operator() (
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const sample_type& a,
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const sample_type& b
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) const
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{
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return kernel(a,b) + offset;
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}
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offset_kernel& operator= (
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const offset_kernel& k
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)
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{
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const_cast<T&>(kernel) = k.kernel;
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const_cast<scalar_type&>(offset) = k.offset;
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return *this;
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}
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bool operator== (
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const offset_kernel& k
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) const
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{
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return k.kernel == kernel && offset == k.offset;
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}
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};
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template <
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typename T
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>
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void serialize (
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const offset_kernel<T>& item,
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std::ostream& out
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)
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{
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try
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{
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serialize(item.offset, out);
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serialize(item.kernel, out);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while serializing object of type offset_kernel");
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}
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}
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template <
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typename T
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>
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void deserialize (
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offset_kernel<T>& item,
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std::istream& in
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)
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{
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typedef typename offset_kernel<T>::scalar_type scalar_type;
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try
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{
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deserialize(const_cast<scalar_type&>(item.offset), in);
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deserialize(const_cast<T&>(item.kernel), in);
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}
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catch (serialization_error& e)
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{
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throw serialization_error(e.info + "\n while deserializing object of type offset_kernel");
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}
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}
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template <
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typename T
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>
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struct kernel_derivative<offset_kernel<T> >
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{
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typedef typename T::scalar_type scalar_type;
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typedef typename T::sample_type sample_type;
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typedef typename T::mem_manager_type mem_manager_type;
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kernel_derivative(const offset_kernel<T>& k) : der(k.kernel){}
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const sample_type operator() (const sample_type& x, const sample_type& y) const
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{
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return der(x,y);
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}
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kernel_derivative<T> der;
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};
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// ----------------------------------------------------------------------------------------
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}
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#endif // DLIB_SVm_KERNEL
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