dlib C++ Library - one_vs_all_decision_function.h

    // Copyright (C) 2010  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_ONE_VS_ALL_DECISION_FUnCTION_Hh_
    #define DLIB_ONE_VS_ALL_DECISION_FUnCTION_Hh_

    #include "one_vs_all_decision_function_abstract.h"

    #include "../serialize.h"
    #include "../type_safe_union.h"
    #include <sstream>
    #include <map>
    #include "../any.h"
    #include "null_df.h"

    namespace dlib
    {

    // ----------------------------------------------------------------------------------------

        template <
            typename one_vs_all_trainer,
            typename DF1 = null_df, typename DF2 = null_df, typename DF3 = null_df,
            typename DF4 = null_df, typename DF5 = null_df, typename DF6 = null_df,
            typename DF7 = null_df, typename DF8 = null_df, typename DF9 = null_df,
            typename DF10 = null_df
            >
        class one_vs_all_decision_function
        {
        public:

            typedef typename one_vs_all_trainer::label_type result_type;
            typedef typename one_vs_all_trainer::sample_type sample_type;
            typedef typename one_vs_all_trainer::scalar_type scalar_type;
            typedef typename one_vs_all_trainer::mem_manager_type mem_manager_type;

            typedef std::map<result_type, any_decision_function<sample_type, scalar_type> > binary_function_table;

            one_vs_all_decision_function() :num_classes(0) {}

            explicit one_vs_all_decision_function(
                const binary_function_table& dfs_
            ) : dfs(dfs_)
            {
                num_classes = dfs.size();
            }

            const binary_function_table& get_binary_decision_functions (
            ) const
            {
                return dfs;
            }

            const std::vector<result_type> get_labels (
            ) const
            {
                std::vector<result_type> temp;
                temp.reserve(dfs.size());
                for (typename binary_function_table::const_iterator i = dfs.begin(); i != dfs.end(); ++i)
                {
                    temp.push_back(i->first);
                }
                return temp;
            }

            template <
                typename df1, typename df2, typename df3, typename df4, typename df5,
                typename df6, typename df7, typename df8, typename df9, typename df10
                >
            one_vs_all_decision_function (
                const one_vs_all_decision_function<one_vs_all_trainer,
                                                   df1, df2, df3, df4, df5,
                                                   df6, df7, df8, df9, df10>& item
            ) : dfs(item.get_binary_decision_functions()), num_classes(item.number_of_classes()) {}

            unsigned long number_of_classes (
            ) const
            {
                return num_classes;
            }

            std::pair<result_type, scalar_type> predict (
                const sample_type& sample
            ) const
            {
                DLIB_ASSERT(number_of_classes() != 0,
                    "\t pair<result_type,scalar_type> one_vs_all_decision_function::predict()"
                    << "\n\t You can't make predictions with an empty decision function."
                    << "\n\t this: " << this
                    );

                result_type best_label = result_type();
                scalar_type best_score = -std::numeric_limits<scalar_type>::infinity();

                // run all the classifiers over the sample and find the best one
                for(typename binary_function_table::const_iterator i = dfs.begin(); i != dfs.end(); ++i)
                {
                    const scalar_type score = i->second(sample);

                    if (score > best_score)
                    {
                        best_score = score;
                        best_label = i->first;
                    }
                }

                return std::make_pair(best_label, best_score);
            }

            result_type operator() (
                const sample_type& sample
            ) const
            {
                DLIB_ASSERT(number_of_classes() != 0,
                    "\t result_type one_vs_all_decision_function::operator()"
                    << "\n\t You can't make predictions with an empty decision function."
                    << "\n\t this: " << this
                    );

                return predict(sample).first;
            }

        private:
            binary_function_table dfs;
            unsigned long num_classes;

        };

    // ----------------------------------------------------------------------------------------

        template <
            typename T,
            typename DF1, typename DF2, typename DF3,
            typename DF4, typename DF5, typename DF6,
            typename DF7, typename DF8, typename DF9,
            typename DF10
            >
        void serialize(
            const one_vs_all_decision_function<T,DF1,DF2,DF3,DF4,DF5,DF6,DF7,DF8,DF9,DF10>& item,
            std::ostream& out
        )
        {
            try
            {
                type_safe_union<DF1,DF2,DF3,DF4,DF5,DF6,DF7,DF8,DF9,DF10> temp;
                typedef typename T::label_type result_type;
                typedef typename T::sample_type sample_type;
                typedef typename T::scalar_type scalar_type;
                typedef std::map<result_type, any_decision_function<sample_type, scalar_type> > binary_function_table;

                const unsigned long version = 1;
                serialize(version, out);

                const unsigned long size = item.get_binary_decision_functions().size();
                serialize(size, out);

                for(typename binary_function_table::const_iterator i = item.get_binary_decision_functions().begin();
                    i != item.get_binary_decision_functions().end(); ++i)
                {
                    serialize(i->first, out);

                    if      (i->second.template contains<DF1>()) temp.template get<DF1>() = any_cast<DF1>(i->second);
                    else if (i->second.template contains<DF2>()) temp.template get<DF2>() = any_cast<DF2>(i->second);
                    else if (i->second.template contains<DF3>()) temp.template get<DF3>() = any_cast<DF3>(i->second);
                    else if (i->second.template contains<DF4>()) temp.template get<DF4>() = any_cast<DF4>(i->second);
                    else if (i->second.template contains<DF5>()) temp.template get<DF5>() = any_cast<DF5>(i->second);
                    else if (i->second.template contains<DF6>()) temp.template get<DF6>() = any_cast<DF6>(i->second);
                    else if (i->second.template contains<DF7>()) temp.template get<DF7>() = any_cast<DF7>(i->second);
                    else if (i->second.template contains<DF8>()) temp.template get<DF8>() = any_cast<DF8>(i->second);
                    else if (i->second.template contains<DF9>()) temp.template get<DF9>() = any_cast<DF9>(i->second);
                    else if (i->second.template contains<DF10>()) temp.template get<DF10>() = any_cast<DF10>(i->second);
                    else throw serialization_error("Can't serialize one_vs_all_decision_function.  Not all decision functions defined.");

                    serialize(temp,out);
                }
            }
            catch (serialization_error& e)
            {
                throw serialization_error(e.info + "\n   while serializing an object of type one_vs_all_decision_function");
            }

        }

    // ----------------------------------------------------------------------------------------

        namespace impl_ova
        {
            template <typename sample_type, typename scalar_type>
            struct copy_to_df_helper
            {
                copy_to_df_helper(any_decision_function<sample_type, scalar_type>& target_) : target(target_) {}

                any_decision_function<sample_type, scalar_type>& target;

                template <typename T>
                void operator() (
                    const T& item
                ) const
                {
                    target = item;
                }
            };
        }

        template <
            typename T,
            typename DF1, typename DF2, typename DF3,
            typename DF4, typename DF5, typename DF6,
            typename DF7, typename DF8, typename DF9,
            typename DF10
            >
        void deserialize(
            one_vs_all_decision_function<T,DF1,DF2,DF3,DF4,DF5,DF6,DF7,DF8,DF9,DF10>& item,
            std::istream& in
        )
        {
            try
            {
                type_safe_union<DF1,DF2,DF3,DF4,DF5,DF6,DF7,DF8,DF9,DF10> temp;
                typedef typename T::label_type result_type;
                typedef typename T::sample_type sample_type;
                typedef typename T::scalar_type scalar_type;
                typedef impl_ova::copy_to_df_helper<sample_type, scalar_type> copy_to;

                unsigned long version;
                deserialize(version, in);

                if (version != 1)
                    throw serialization_error("Can't deserialize one_vs_all_decision_function.  Wrong version.");

                unsigned long size;
                deserialize(size, in);

                typedef std::map<result_type, any_decision_function<sample_type, scalar_type> > binary_function_table;
                binary_function_table dfs;

                result_type l;
                for (unsigned long i = 0; i < size; ++i)
                {
                    deserialize(l, in);
                    deserialize(temp, in);
                    if (temp.template contains<null_df>())
                        throw serialization_error("A sub decision function of unknown type was encountered.");

                    temp.apply_to_contents(copy_to(dfs[l]));
                }

                item = one_vs_all_decision_function<T,DF1,DF2,DF3,DF4,DF5,DF6,DF7,DF8,DF9,DF10>(dfs);
            }
            catch (serialization_error& e)
            {
                throw serialization_error(e.info + "\n   while deserializing an object of type one_vs_all_decision_function");
            }
        }

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_ONE_VS_ALL_DECISION_FUnCTION_Hh_