// C++ Vorlesung  xxx
// C++-17: Threads, execution policies
//   Great web pages, great book by Filipek:   https://www.bfilipek.com/2018/06/parstl-tests.html

/*
 g++ -O3 -std=c++17 main.cpp -ltbb
 g++ -O3 -std=c++17 -pedantic -Weffc++ -Wall -Wextra -pedantic -Wswitch-default -Wfloat-equal -Wundef -Wredundant-decls -Winit-self -Wshadow -Wparentheses -Wshadow -Wunreachable-code -Wuninitialized -Wmaybe-uninitialized main.cpp -ltbb
 ---
 cppcheck --enable=all --inconclusive --std=c++11 --std=posix --suppress=missingIncludeSystem main.cpp
 clang++ -O3 -std=c++17 -ltbb main.cpp
 clang++ -std=c++17 -fsyntax-only -Wdocumentation -Wconversion -Wshadow -Wfloat-conversion -pedantic main.cpp
 clang++ -std=c++17 -Weverything -Wno-c++98-compat -Wno-padded -ltbb main.cpp
 clang++ -cc1 --help
 ---
 icpc -O3 -std=c++17 -ltbb -Wall -Wextra -pedantic main.cpp
*/

#include <algorithm>
#include <chrono>
#include <execution>          // execution policy
#include <iostream>
#include <numeric>            //  accumulate
#include <random>
#include <vector>
using namespace std;
using namespace std::chrono;  // timing

// Great web pages, great book by Filipek
// https://www.bfilipek.com/2018/06/parstl-tests.html
template <typename TFunc> void RunAndMeasure(const char *title, TFunc func)
{
    const auto start = std::chrono::steady_clock::now();
    auto ret = func();
    const auto end = std::chrono::steady_clock::now();
    std::cout << title << ": " <<
              std::chrono::duration <double, std::milli>(end - start).count()
              << " ms, res " << ret << "\n";
}

int main()
{
    //std::vector<double> v(6000000, 0.5);
    std::vector<double> v(1<<30, 0.5);

    RunAndMeasure("std::warm up", [&v]
    {
        return std::reduce(std::execution::seq, v.begin(), v.end(), 0.0);
    });

    RunAndMeasure("std::accumulate", [&v]
    {
        return std::accumulate(v.begin(), v.end(), 0.0);
    });

    RunAndMeasure("std::reduce, seq", [&v]
    {
        return std::reduce(std::execution::seq, v.begin(), v.end(), 0.0);
    });

    RunAndMeasure("std::reduce, par", [&v]
    {
        return std::reduce(std::execution::par, v.begin(), v.end(), 0.0);
    });

    RunAndMeasure("std::reduce, par_unseq", [&v]
    {
        return std::reduce(std::execution::par_unseq, v.begin(), v.end(), 0.0);
    });

    RunAndMeasure("std::find, seq", [&v]
    {
        auto res = std::find(std::execution::seq, std::begin(v), std::end(v), 0.6);
        return res == std::end(v) ? 0.0 : 1.0;
    });

    RunAndMeasure("std::find, par", [&v]
    {
        auto res = std::find(std::execution::par, std::begin(v), std::end(v), 0.6);
        return res == std::end(v) ? 0.0 : 1.0;
    });

    return 0;
}