parallelrandMatrices.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include<sys/time.h>
#define MIN(X, Y) (((X) < (Y)) ? (X) : (Y))


//how many threads am i using? how does that improve my speed up.
int main(int argc, char *argv[])
{
	//command line arguments start
	if( argc != 5 ) 
	{
		printf("Invaild number of Arguments entered \n");
		return -1;
	}

	int k, c, r;
	r = atoi(argv[1]);
	c = atoi(argv[2]);
	k = atoi(argv[3]);

	if(!(r > 0 && r <= 100000) || !(c > 0 && c <= 100000) || !(k >= 2 && k <= MIN(r, c)/10))
	{
		printf("inputs not in range\n");
		return -1;
	}

	srand( time(NULL) );


	void fill_random(int **, int , int , int );
	void writeToFile(FILE*, int**, int, int);

	//to calculate executiontime
	struct timeval start, end;
	//start of execution
	gettimeofday(&start, NULL);

	FILE *outFPtr = fopen(argv[4], "w");


	int **matrix = (int**)malloc(r*sizeof(int*));
		for(int i = 0; i < r; i++)
			matrix[i] = malloc(sizeof(int)*c);

	//parallelise calling functions although not needed in this case
	{
	#pragma omp parallel
	{
		#pragma omp sections 
		{
			#pragma omp section
			fill_random(matrix,r,c,k);
			#pragma omp section
			writeToFile(outFPtr,matrix, r, c);
		}
	}
	}
	
	//end of execution
	gettimeofday(&end, NULL);



	
	for (int i = 0; i < r; i++)
	free(matrix[i]);
	free(matrix);

	float exec_time = ((end.tv_sec * 1000000 + end.tv_usec) - (start.tv_sec * 1000000 + start.tv_usec));
	exec_time /= 1000000;
	printf("Time taken to execute: %fs\n\n", exec_time);

	return 0;
}

void fill_random(int **matrix, int r, int c, int k)
{
	int seed1,seed2;

	//thread 1
	rand_r(&seed1);
	//thread 2
	rand_r(&seed2);

	// loop directive contains a collapse clause as there is more than one associated loop
	#pragma omp parallel
	{
		#pragma omp parallel for collapse(2)
		for (int i = 0; i < r; i++)
			for(int j = 0; j < c; j++)
				matrix[i][j] = ((rand_r(&seed1) % k) + 1);
	}
}

void writeToFile(FILE *outFPtr, int **matrix, int r, int c)
{
	for(int i = 0; i < r; i++)
	{
		for(int j = 0; j < c; j++)
			fprintf(outFPtr, "%d ", matrix[i][j]);

		fprintf(outFPtr, "\n");
	}
	printf("\n");
}