tpf_chrono_random.hpp

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#ifndef _TPF_CHRONO_RANDOM_HPP
#define _TPF_CHRONO_RANDOM_HPP
 
#ifndef NOMINMAX
#define NOMINMAX
#endif
 
#ifdef _MSVC_LANG  
    #if _MSVC_LANG < 201703L
        #error This libary requires C++17 Standard (Visual Studio 2017).
    #endif
#else
 
    #if __cplusplus < 201703
        #error This library requires C++17 Standard (GNU g++ version 8.0 or clang++ version 8.0 above)
    #endif // end of __cplusplus 
 
#endif // end of _MSVC_LANG
 
#include <tpf_types.hpp>
#include <tpf_conversion.hpp>
 
#include <chrono>
#include <ratio>
#include <random>
#include <iostream>
#include <sstream>
#include <vector>
#include <numeric>
#include <algorithm>
#include <execution>
 
namespace tpf
{
    namespace chrono_random
    {
        using nano_t = std::nano;
        using micro_t = std::micro;
        using milli_t = std::milli;
        using second_t = std::ratio<1>;
        using minute_t = std::ratio<60>;
        using hour_t = std::ratio<3600>;
 
        template<typename TimeUnit>
        using duration_t = std::chrono::duration<double, TimeUnit>;
        
        using nanoseconds_t = duration_t<nano_t>;
        using microseconds_t = duration_t<micro_t>;
        using milliseconds_t = duration_t<milli_t>;
        using seconds_t = duration_t<second_t>;
        using minutes_t = duration_t<minute_t>;
        using hours_t = duration_t<hour_t>;
       
        using high_resolution_clock_t = std::chrono::high_resolution_clock;
        using time_point_t = std::chrono::time_point<high_resolution_clock_t>;
        auto& now = high_resolution_clock_t::now;
 
        inline unsigned int seed() 
            { return high_resolution_clock_t::now().time_since_epoch().count(); }
 
        // used to initialize random engine
        unsigned int get_current_tick()
        {
            using std::chrono::duration;
            using std::chrono::duration_cast;
 
            auto current = 
                duration_cast<std::chrono::milliseconds>(now().time_since_epoch());
            
            return current.count();
        }
 
        // to convert time (in TimeUnit) to type double
        template<typename TimeUnit>
        double time_difference_in_unit(
            const time_point_t& start_time,
            const time_point_t& end_time)
        {
            using std::chrono::duration;
            using std::chrono::duration_cast;
 
            if constexpr(std::is_same_v<TimeUnit, second_t>)
            {
                auto period_of_time =
                    duration_cast<std::chrono::duration<double, second_t>>(end_time - start_time);
                return period_of_time.count();
            }
            else
            {
                auto period_of_time =
                    duration_cast<std::chrono::duration<double, TimeUnit>>(end_time - start_time);
                
                return period_of_time.count();
            }            
        }
        
        using random_engine_t = std::default_random_engine;
 
        template<typename IntegralType, 
            typename Type = std::enable_if_t<types::is_integral_v<IntegralType>>>
        using random_uniform_integral_distribution =
            std::uniform_int_distribution<IntegralType>;
 
        template<typename RealType,
            typename Type = std::enable_if_t<types::is_real_number_v<RealType>>>
        using random_uniform_real_distribution = 
            std::uniform_real_distribution<RealType>;
 
        class stop_watch
        {
            private:
                mutable high_resolution_clock_t m_clock;
                mutable time_point_t m_start_time;
            
            public:
                stop_watch(): m_start_time{now()}
                { }
 
                void reset() const { this->m_start_time = now(); }
 
                template<typename TimeUnit = milli_t>
                auto elapsed(bool bReset = true) const
                {
                    auto rlt = time_difference_in_unit<TimeUnit>(this->m_start_time, now());
                    if(bReset) reset(); 
                    return rlt;
                }
 
                template<typename TimeUnit = milli_t>
                std::string elapsed_time(bool bReset = true, TimeUnit dummy_time = TimeUnit{}) const
                {
                    std::ostringstream os;
 
                    os << time_difference_in_unit<TimeUnit>(this->m_start_time, now());
 
                    if constexpr(std::is_same_v<TimeUnit, nano_t>)
                        os << " nano-seconds";
                    else if constexpr(std::is_same_v<TimeUnit, micro_t>)
                        os << " micro-seconds";
                    else if constexpr(std::is_same_v<TimeUnit, milli_t>)
                        os << " milli-seconds";
                    else if constexpr(std::is_same_v<TimeUnit, second_t>)
                        os << " seconds";
                    else if constexpr(std::is_same_v<TimeUnit, minute_t>)
                        os << " minutes";
                    else if constexpr(std::is_same_v<TimeUnit, hour_t>)
                        os << " hours";
 
                    if(bReset) reset(); 
                    return os.str();            
                }        
        };
 
        template<typename Type,
            typename = std::enable_if_t<tpf::types::is_integral_v<Type>>>
        class fair_dice
        {
            private:
            
                std::random_device m_rd;
                std::mt19937 m_randomizer;
                typename std::vector<Type>::iterator m_next;
                std::vector<Type> m_array;
 
            public:
                // [start, end)
                fair_dice(Type start, Type end, Type instance = 1): 
                    m_array((end-start)*instance), m_rd{}, m_randomizer{ m_rd() }
                {
                    auto diff = end - start;
 
                    for(size_t i = 0; i < m_array.size(); ++i )
                        m_array[i] = (i % diff) + start;
                    
                    shuffle();               
                }
 
                typename std::vector<Type>::iterator begin() { return this->m_array.begin(); };
                typename std::vector<Type>::iterator end() { return this->m_array.end(); };
                typename std::vector<Type>::iterator next() { return this->m_next; };
 
                size_t size() { return m_array.size(); }
 
                void shuffle()
                {
                    std::shuffle(m_array.begin(), m_array.end(), m_randomizer);
                    this->m_next = m_array.begin();
                }
 
                Type operator()()
                {
                    if(this->m_next == m_array.end())
                        shuffle();
                        
                    Type v = *this->m_next;
                    ++this->m_next;
                    return v;
                }
 
                const std::vector<Type>& array()
                {
                    return this->m_array;
                }
        };
 
        template<typename Type,
                typename DistributionType, typename EngineType>
        class random_t
        {
            public:
                using engine_type = EngineType;
                using distribution_type = DistributionType;
            private:
                mutable Type m_range_start;
                mutable Type m_range_end;
                mutable engine_type m_engine;
                mutable distribution_type m_distribution;
              
            public:
                random_t(Type range_start = Type{}, 
                    Type range_end = Type{100}, 
                    unsigned int seed = 0): 
                    m_range_start{range_start},
                    m_range_end{range_end},
                    m_engine{seed == 0 ? get_current_tick(): seed},
                    m_distribution{range_start, range_end} {}
 
                random_t(const random_t&) = default;
                random_t& operator=(const random_t&) = default;
                
                Type operator()() const
                {
                    return m_distribution(m_engine);
                }
 
                template<typename SizeType>
                auto clone(SizeType size) const;
 
                template<typename SizeType>
                auto clone_pair(SizeType size) const;
        };
 
        template<typename IntegralType,
            typename Type = std::enable_if_t<types::is_integral_v<IntegralType>>>
        using random_uniform_integer_t = random_t<IntegralType, 
                random_uniform_integral_distribution<IntegralType>, random_engine_t>;
                
        template<typename RealType,
            typename Type = std::enable_if_t<types::is_real_number_v<RealType>>>
        using random_uniform_real_t = random_t<RealType, 
                random_uniform_real_distribution<RealType>, random_engine_t>;
 
        template<typename ValueType, typename RangeType1, typename RangeType2>
            auto random_generator(RangeType1 range_start, RangeType2 range_end)
        {
            if constexpr(tpf::types::is_integral_v<ValueType>)
            {
                random_uniform_integer_t<ValueType> 
                    random_generator{(ValueType)range_start, (ValueType)range_end};
                
                return random_generator;
            }
            else if constexpr(tpf::types::is_real_number_v<ValueType>)
            {
                random_uniform_real_t<ValueType> 
                    random_generator{(ValueType)range_start, (ValueType)range_end};
 
                return random_generator;
            }
        }
 
        template<typename Type,
                typename DistributionType, typename EngineType>
        template<typename SizeType>
        auto random_t<Type, DistributionType, EngineType>::clone(SizeType size) const
        {
            using random_type = 
                random_t<Type, DistributionType, EngineType>;
            
            std::vector<random_type> randoms;
            randoms.reserve((size_t)size);
 
            auto generator = 
                random_generator<unsigned>((unsigned)1, 
                    std::numeric_limits<unsigned>::max());
            
            std::set<unsigned> seeds;
            while(seeds.size() != (size_t)size)
            {
                seeds.insert(generator());
            }
 
            for(auto seed: seeds)
                randoms.emplace_back(random_type{this->m_range_start,
                    this->m_range_end, seed});
 
            return randoms;
        } 
 
        template<typename Type,
                typename DistributionType, typename EngineType>
        template<typename SizeType>
        auto random_t<Type, DistributionType, EngineType>::clone_pair(SizeType size) const
        {
            using random_type = 
                random_t<Type, DistributionType, EngineType>;
            using random_pair = std::pair<size_t, random_type>;
 
            std::vector<random_pair> randoms;
            randoms.reserve((size_t)size);
 
            auto generator = 
                random_generator<unsigned>((unsigned)1, 
                    std::numeric_limits<unsigned>::max());
            
            std::set<unsigned> seeds;
            while(seeds.size() != (size_t)size)
            {
                seeds.insert(generator());
            }
 
            size_t index{};
 
            for(auto seed: seeds)
                randoms.emplace_back(index++, random_type{this->m_range_start,
                    this->m_range_end, seed});
 
            return randoms;
        }
 
        template<template<typename, typename...> class ContainerType,
            typename Type, typename RType, typename... Types,
            template<typename, typename...> class RandomGeneratorType, typename... RTypes>
        void random_fill(ContainerType<Type, Types...>& container,
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            if(container.empty())
                return;
                
            for(auto& e: container)
                e = (Type)random_generator();    
        }
 
        template<typename Type, std::size_t N, typename RandomGeneratorType>
        void random_fill( Type(&container)[N], RandomGeneratorType const& random_generator)
        {
            for(auto& e: container)
                e = (Type)random_generator();    
        }
 
        template<typename Type, std::size_t M, std::size_t N, typename RandomGeneratorType>
        void random_fill( Type(&container)[M][N], RandomGeneratorType const& random_generator)
        {
            using array_t = Type[M * N];
            auto& array = (array_t&)container[0][0];
 
            random_fill(array, random_generator);
        }
 
        template<typename Type, std::size_t L, std::size_t M, std::size_t N, typename RandomGeneratorType>
        void random_fill( Type(&container)[L][M][N], RandomGeneratorType const& random_generator)
        {
            using array_t = Type[L * M * N];
            auto& array = (array_t&)container[0][0];
 
            random_fill(array, random_generator);
        }
 
        template<template<typename, std::size_t> class ContainerType,
            typename Type, std::size_t N, typename RType,
            template<typename, typename...> class RandomGeneratorType, typename... RTypes>
        void random_fill(ContainerType<Type, N>& container,
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            if(container.empty())
                return;
                
            for(auto& e: container)
                e = (Type)random_generator();    
        }
 
        template<template<typename, typename...> class ContainerType,
            typename Type, typename... Types, typename RandomGeneratorType>
        void random_fill(ContainerType<Type, Types...>& container,
            RandomGeneratorType&& random_generator)
        {
            if(container.empty())
                return;
                
            for(auto& e: container)
                e = (Type) random_generator();    
        }
       
        template<template<typename, typename...> class ContainerType,
            typename Type, typename... Types, typename RType,
            template<typename, typename...> class RandomGeneratorType, typename... RTypes>
        void random_parallel_fill(ContainerType<Type, Types...>& container,
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            if(container.empty()) return;
                
            size_t container_size = container.size();
            size_t generator_size = std::thread::hardware_concurrency();
            size_t span = container_size / generator_size;
 
            if(span < 100) 
            {
                random_fill(container, random_generator); 
                return;
            }
            
            if(container_size % generator_size ) ++generator_size;
 
            auto generator_pairs = 
                random_generator.clone_pair(generator_size);          
 
            std::for_each(std::execution::par, 
                generator_pairs.begin(), generator_pairs.end(),
                [&](auto& pair)
                {
                    auto index_start = pair.first * span;
                    auto index_end = index_start + span;
 
                    if(index_end > container_size) index_end = container_size;
 
                    for(size_t i = index_start; i < index_end; ++i)
                        container[i] = (Type)pair.second();
                });
        }
 
        template<typename Type, std::size_t N, 
            template<typename, typename...> class RandomGeneratorType, typename RType, typename... RTypes>
        void random_parallel_fill( Type( &container )[N],
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            size_t container_size = N;
            size_t generator_size = std::thread::hardware_concurrency();
            size_t span = container_size / generator_size;
 
            if(span < 100) 
            {
                random_fill(container, random_generator); 
                return;
            }
            
            if(container_size % generator_size ) ++generator_size;
 
            auto generator_pairs = 
                random_generator.clone_pair(generator_size);          
 
            std::for_each(std::execution::par, 
                generator_pairs.begin(), generator_pairs.end(),
                [&](auto& pair)
                {
                    auto index_start = pair.first * span;
                    auto index_end = index_start + span;
 
                    if(index_end > container_size) index_end = container_size;
 
                    for(size_t i = index_start; i < index_end; ++i)
                        container[i] = (Type)pair.second();
                });
        }
 
        template<typename Type, std::size_t M, std::size_t N,
            template<typename, typename...> class RandomGeneratorType, typename RType, typename... RTypes>
        void random_parallel_fill( Type( &container )[M][N],
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            using array_t = Type[M * N];
            auto& array = (array_t&)container[0][0];
 
            random_parallel_fill(array, random_generator);
        }
 
        template<typename Type, std::size_t L, std::size_t M, std::size_t N,
            template<typename, typename...> class RandomGeneratorType, typename RType, typename... RTypes>
        void random_parallel_fill( Type( &container )[L][M][N],
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            using array_t = Type[L * M * N];
            auto& array = (array_t&)container[0][0][0];
 
            random_parallel_fill(array, random_generator);
        }
 
 
        template<template<typename, std::size_t> class ContainerType,
            typename Type, std::size_t N, typename RType,
            template<typename, typename...> class RandomGeneratorType, typename... RTypes>
        void random_parallel_fill(ContainerType<Type, N>& container,
            const RandomGeneratorType<RType, RTypes...>& random_generator)
        {
            if(container.empty()) return;
                
            size_t container_size = container.size();
            size_t generator_size = std::thread::hardware_concurrency();
            size_t span = container_size / generator_size;
 
            if(span < 100) 
            {
                random_fill(container, random_generator); 
                return;
            }
            
            if(container_size % generator_size ) ++generator_size;
 
            auto generator_pairs = 
                random_generator.clone_pair(generator_size);          
 
            std::for_each(std::execution::par, 
                generator_pairs.begin(), generator_pairs.end(),
                [&](auto& pair)
                {
                    auto index_start = pair.first * span;
                    auto index_end = index_start + span;
 
                    if(index_end > container_size) index_end = container_size;
 
                    for(size_t i = index_start; i < index_end; ++i)
                        container[i] = (Type)pair.second();
                });
        }
 
        template<template<typename, typename...> class ContainerType,
            typename Type, typename... Types, 
            typename RandomGeneratorType>
        void random_parallel_fill(ContainerType<Type, Types...>& container,
            RandomGeneratorType&& random_generator)
        {
            if(container.empty()) return;
                
            size_t container_size = container.size();
            size_t generator_size = std::thread::hardware_concurrency();
            size_t span = container_size / generator_size;
 
            if(span < 100) 
            {
                random_fill(container, random_generator); 
                return;
            }
            
            if(container_size % generator_size ) ++generator_size;
 
            auto generator_pairs = 
                random_generator.clone_pair(generator_size);          
 
            std::for_each(std::execution::par, 
                generator_pairs.begin(), generator_pairs.end(),
                [&](auto& pair)
                {
                    auto index_start = pair.first * span;
                    auto index_end = index_start + span;
 
                    if(index_end > container_size) index_end = container_size;
 
                    for(size_t i = index_start; i < index_end; ++i)
                        container[i] = pair.second();
                });
        }
 
        template<template<typename, typename...> class ContainerType,
            typename Type, typename... Types, typename SizeType,
            template<typename, typename...> class RandomGeneratorType, typename... RTypes>
        void random_fill(ContainerType<Type, Types...>& container, 
            const RandomGeneratorType<Type, RTypes...>& random_generator, SizeType size)
        {
            if constexpr (types::is_resize_available_v<ContainerType<Type, Types...>>)
            {
                container.resize((size_t)size);
 
                for(auto& e: container)
                    e = random_generator();
            }
            else
            {
                container.clear();
                
                while(container.size() != size)
                {
                   types::push_back(container, random_generator());
                }
            }
        }
 
        template<typename CharType, size_t Size>
        class random_words
        {
            public:
 
                const CharType* m_alphabet;
                random_uniform_integer_t<size_t> m_character_selector;
                random_uniform_integer_t<size_t> m_length_selector;
                random_uniform_integer_t<size_t> m_wordcount_selector;
                
            public:
                template<typename Type, size_t ArraySize>
                random_words(size_t minimum, size_t maximum, size_t max_words, 
                    const Type(&alphabet)[ArraySize]): 
                    m_alphabet{alphabet}, 
                    m_character_selector{ random_generator<size_t>(size_t{}, ArraySize-2)},
                    m_length_selector{ random_generator<size_t>(minimum, maximum) },
                    m_wordcount_selector{ random_generator<size_t>(1, max_words) } { }
 
                std::basic_string<char> operator()()
                {
                    // Windows codepage character - char
                    if constexpr(std::is_same_v<CharType, char>)
                     {
                        std::basic_ostringstream<CharType> stream;
 
                        auto word_count = m_wordcount_selector();
 
                        for(size_t j = 0; j < word_count; ++j)
                        {
                            auto length = this->m_length_selector();
                            
                            std::basic_string<CharType> text(length, ' ');
 
                            for(size_t i=0; i < length; ++i)
                                text[i] = m_alphabet[m_character_selector()];
 
                            stream << text;
 
                            if(j + 1 != (size_t)word_count) stream <<' ';
                        }
                        return stream.str();
                    }
                    else 
                    {
                        // utf16 - wchar_t == CharType
                        std::basic_ostringstream<CharType> stream;
 
                        auto word_count = m_wordcount_selector();
 
                        for(size_t j = 0; j < word_count; ++j)
                        {
                            auto length = this->m_length_selector();
                            
                            std::basic_string<CharType> text(length, L' ');
 
                            for(size_t i=0; i < length; ++i)
                                text[i] = m_alphabet[m_character_selector()];
 
                            stream << text;
 
                            if(j + 1 != (size_t)word_count) stream << L' ';
                        }
 
                            // UTF16 - utf8 std::string
                            // conversion::wstring_to_string(stream.str());
 
                            // UTF16 - Windows codepage std::string
                        return conversion::wstring_to_string(stream.str(), CP_ACP);
                    }
                }
        };
 
        template<typename Type, size_t ArraySize>
        random_words(int, int, int, const Type(&)[ArraySize]) -> random_words<Type, ArraySize>;
 
 
    } // end of namespace chrono_random
 
} // end of namespace tpf
 
#endif // end of file _TPF_CHRONO_RANDOM_HPP