[OpenMP] pragma omp parallel

// prir lab2.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define LOOPS 50

double** StworzMacierz(int rows, int columns)
{
     double **macierz;
     macierz = (double**)malloc(rows * sizeof(double*));
     for (int i = 0; i < rows; i++)
         macierz[i] = (double*)malloc(columns * sizeof(double));
     return macierz;
}

int _tmain(int argc, _TCHAR* argv[])
{
     double **macierz;
     double *v1, *v2;
     long rows = 5000, columns = 5000;
     time_t begin_t, end_t;
     long i, j, k;

     v1 = (double*)malloc(columns * sizeof(double));
     v2 = (double*)malloc(rows * sizeof(double));

     macierz = StworzMacierz(rows,columns);

     for (i = 0; i < columns; i++)
     {
         v1[i] = (double)(i / 1000.0f);
         v2[i] = (double)(i / 1000.0f);
         for ( j = 0; j < rows; j++ )
             macierz[j][i] = (double)(i * j / 1000.0f);
     }

     begin_t = time(NULL);


     for (k = 0; k < LOOPS; k++)
     {
        #pragma omp parallel for shared(macierz, v1, v2, rows, columns) private(i, j)
         for (i = 0; i < rows; i++)
         {
            // v2[i] = 0.0f;
             for (j = 0; j < columns; j++)
                 v2[i] = macierz[i][j] * v1[j];
         }
     }

      end_t = time(NULL);
      printf("Czas obliczen: %f.\n", difftime(end_t, begin_t));

      free(v1);
      free(v2);
      for (i = 0; i < rows; i++)
          free(macierz[i]);
      free(macierz);


    return 0;
}