govno_mochi

#include <iostream>
#include <stdlib.h>
#include <time.h>
#include <chrono>
#include <omp.h>

double fRand(double fMin, double fMax)
{
    double f = (double)rand() / RAND_MAX;
    return fMin + f * (fMax - fMin);
}

void delMatr(double** matr, int n)
{
    for (int i = 0; i < n; i++)
    {
        delete[] matr[i];
    }
    delete[] matr;
}

int main ()
{
    srand(time (0));
    int  i, j, k, r;

    std::chrono::time_point<std::chrono::system_clock> start, end;

    std :: cin >> r;

    double** a = new double* [r];
    double** b = new double* [r];
    double** c = new double* [r];

    for (i=0; i<r; i++)
      {
        a[i] = new double [r];
        b[i] = new double [r];
        c[i] = new double [r];
      }

    for (i=0;i<r;i++)
      {
        for (j=0;j<r;j++)
         {
           a[i][j] = 0;
           b[i][j] = fRand(-999.999,999.999);
           c[i][j] = fRand(-999.999,999.999);
         }
      }


    start = std::chrono::system_clock::now();
        #pragma omp parallel
    {
       #pragma omp for
       for (i=0;i<r;i++)
        for (k=0;k<r;k++)
          for (j=0;j<r;j++)
            a[i][j]+=b[i][k] * c[k][j];
    }
    end = std::chrono::system_clock::now();

        std::chrono::duration<double> sec = end - start;

    std::cout << "Elapsed time: " << sec.count() << "\n";


    /* for (i=0;i<r;i++)
      {
        for (j=0;j<r;j++)
         {
           a[i][j] = 0;
         }
      }

    start = std::chrono::system_clock::now();
    for (i=0;i<r;i++)
      for (k=0;k<r;k++)
        for (j=0;j<r;++)
          a[i][j]+=b[i][k] * c[k][j];
    end = std::chrono::system_clock::now();

        sec = end - start;

    std::cout << "Elapsed time: " << sec.count() << "\n";
    */
    delMatr(a, r); delMatr(b, r); delMatr(c, r);
    return 0;
}