第5回　タスク並列とデータ並列の違い

//#include <iostream>
//#include <iterator>
#include <vector>
#include <cmath>
#include <boost/thread.hpp>
#include <boost/progress.hpp>

class PrimeCalc
{
private:
    int m_start_index;
    int m_end_index;
    std::vector<int> & m_prime_vector;

public:
    PrimeCalc(int start_index, int end_index, std::vector<int> & prime_vector)
            : m_start_index(start_index), m_end_index(end_index),
                m_prime_vector(prime_vector) {}
    ~PrimeCalc() {}
    void operator () (void)
    {
        for (int i = m_start_index; i <= m_end_index; i += 2)
        {
            bool prime_flag = true;
            int square_root = static_cast <int> (sqrt(i));
            for (int j = 3; j <= square_root; j += 2)
            {
                if (0 == (i % j))
                {
                    prime_flag = false;
                    break;
                }
            }
            if (true == prime_flag)
            {
                m_prime_vector.push_back(i);
            }
        }
    }
};

int main(void)
{
    std::vector < int > v0;     /* prime vector */
    std::vector < int > v1;     /* prime vector */

    PrimeCalc pc0(3,   499999, v0);
    PrimeCalc pc1(500001, 999999, v1);

    {
        boost::progress_timer pt;

        boost::thread th0(pc0);
        boost::thread th1(pc1);

        th0.join();
        th1.join();
    }

    //std::copy(v0.begin(), v0.end(), std::ostream_iterator<int>(std::cout, " "));
    //std::copy(v1.begin(), v1.end(), std::ostream_iterator<int>(std::cout, " "));
    //std::cout << std::endl;

    return 0;
}