OpenMP.c

/*
 * A simple OpenMP implementation of the Matrix-Vector multiplication
 * 
 * Author: Petros Anastasiadis(panastas@cslab.ece.ntua.gr) 
 *
 * For more info about OpenMP programming see http://bisqwit.iki.fi/story/howto/openmp/
 */

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <omp.h>
/* Need to include External_Functions for these */
#include "matrix_op.h"
#include "util.h"
#include "input.h"


int main(int argc, char **argv)
{
	/* Initializations */
	int i, j, k, n, m;
	double timer;

	if (argc < 3) error("Usage: ./Program N M");
	else if ( argc == 3) { /*./Program N M */
		n = atoi(argv[1]);
		m = atoi(argv[2]);		
	}
	else error("Too many Arguments");

	/* Allocate space */
	double *x 			= (double *) malloc(m * sizeof(*x));
	double *y	= (double *) malloc(n * sizeof(*y));
	double **M 			= (double **) malloc(n * sizeof(*M));
	for( i=0 ; i<n ; ++i) M[i] = (double *) calloc(m, sizeof(double));
	if( !y || !x || !M ) error("memory allocation failed");

	/* Initialize matrices */
	matrix_init_rand(M,n,m,1.0); /* Normal matrices generated randomly */

	/* Initialize vectors */
	vec_init_rand(x, m, 1.0);
	vec_init(y, n, 0.0);
	

	/* OpenMP Kernel */
	printf("OpenMP Version(N=%d, M=%d, Threads=%s): ", n, m, getenv("OMP_NUM_THREADS"));
	timer = csecond();
	for (i = 0; i < NR_ITER; ++i){
		register double	yi = 0;
		#pragma omp parallel for private(j,yi) shared(n,m,M,y) schedule(dynamic)
		for (k = 0; k < n; ++k) {
        	yi = 0.0;
        	for (j = 0; j < m; ++j) yi += M[k][j]*x[j];
        	y[k] = yi;
    	}
	}
	timer = csecond() - timer;

#ifdef _DEBUG_
	/* Output y vector to a file for debugging */
    FILE * fp;
	char * filename = "OpenMP.debug" ;
	if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
    for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
	fclose(fp) ;
#endif
	report_results(timer);

	return 0;
}