tema1.c

#include <omp.h>
#include <stdio.h>
#include <time.h>

#define N 50  /* dimensiunea vectorilor; experimentati cu diverse valori pentru N */
#define M 40
#define R 60

double a[N][M], b[M][R], c[N][R];

double get_time();

int main (int argc, char *argv[])
{
    int i, j, k, tid, nthreads;

    /* aici puteti initializa vectorii a si b dupa dorinta, prin expresii sau prin citire din fisier */

	srand(time(NULL));
	printf("Generating the elements of the first matrix\n");
	for(i = 0; i < N; i++)
	{
		for(j = 0; j < M; j++)
		{
			a[i][j] = rand() % 100;
		}
	}

	printf("Generating the elements of the second matrix\n");
	for(i = 0; i < M; i++)
	{
		for(j = 0; j < R; j++)
		{
			b[i][j] = rand() % 100;
		}
	}

	display_matrix(a, N, N);
	display_matrix(b, N, N);

	double start_time = omp_get_wtime();
    #pragma omp parallel shared(a,b,c,nthreads)  private(i,tid)
    {
		tid = omp_get_thread_num();
		if (tid == 0)
		{
			nthreads = omp_get_num_threads();
			printf("Number of threads = %d\n", nthreads);
		}

		printf("Thread %d starting...\n",tid);

		for (i=0;i<N;i++)
		{
			for (j=0;j<R;j++)
			{
				#pragma omp for
				for (k=0;k<M;k++)
				{
					c[i][j] += a[i][k] * b[k][j];
					printf("Thread %d: i = %d, j = %d, c[%d][%d] = %f\n", tid, i, j, i, j, c[i][j]);
				}
			}
		}
		/* end of for */
		printf ("Thread %d done!\n", tid);

    }  /* end of parallel region */
	double end = omp_get_wtime();
	double duration = end - start_time;
	//printf("Parallel program duration: %d\n", duration);

	for (i = 0; i < N; i++) {
		for (j = 0; j < R; j++)
			c[i][j] = 0;
	}

	//se poate pune la omp for: schedule(static, 4) nowait - de incercat
	//collapse(n) extinde paralelizarea unei bucle pe mai multe bucle imbricate (asta reprezinta n-ul)
	//tine cont de scheduler - dynamic vs static, valoarea optima a chunk-ului, etc
	double start_time_secv = get_time();
	for (i=0;i<N;i++)
	{
		for (j=0;j<R;j++)
		{
			for (k=0;k<M;k++)
			{
				c[i][j] += a[i][k] * b[k][j];
				printf("i = %d, j = %d, c[%d][%d] = %f\n", i, j, i, j, c[i][j]);
			}
		}
	}
	double end_secv = get_time();
	double duration_secv = end_secv - start_time_secv;

	/*
	input data: a[50][40], b[40][60], c[50][60];

	--paralelizat primul for
	Parallel program duration:   805306368
    Secvential program duration: 2147483648

	Parallel program duration:   1879048192
	Secvential program duration: 1073741824

	Parallel program duration:   939524096
	Secvential program duration: 536870912

	Parallel program duration:   1610612736
	Secvential program duration: 268435456

	Parallel program duration:    671088640
	Secvential program duration:  268435456

	--paralelizat al doilea for

	Parallel program duration:   1207959552
	Secvential program duration: 1610612736

	Parallel program duration:   134217728
	Secvential program duration: 1879048192

	Parallel program duration:   671088640
	Secvential program duration: 1879048192

	Parallel program duration:   402653184
	Secvential program duration: 1610612736

	Parallel program duration:   2013265920
	Secvential program duration: 2147483648

	--paralelizat al treilea for

	Parallel program duration:   1073741824
	Secvential program duration: 1342177280

	*/

	printf("Parallel program duration: %d\n", duration);
	printf("Secvential program duration: %d\n", duration_secv);
    printf("Program end.\n");
}

void display_matrix(long matrix[150][150], int r, int c)
{
	int i, j;
	// Displaying the matrix
    for (i = 0; i < r; i++) {
		for (j = 0; j < c; j++)
			printf("%d\t", matrix[i][j]);
		printf("\n");
	}
}

double get_time()
{
    struct timeval t;
    struct timezone tzp;
    gettimeofday(&t, &tzp);
    return t.tv_sec + t.tv_usec*1e-6;
}