2.2 Comparision with Matrix Addition Execution Time, C (gcc)

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//gcc 7.4.0
#include <stdio.h>
#include <omp.h>
#include <stdlib.h>
#include <time.h>
#import <math.h>
int main(void)
{
 int r=7000;
 int c=7000;

// Taking Input for 2 arrays -
 int *arr1[r];
 int *arr2[r];
 for(int i=0;i<r;i++){
 arr1[i]=(int *)malloc(c*sizeof(int));
 }
 for(int i=0;i<r;i++){
 arr2[i]=(int *)malloc(c*sizeof(int));
 }
 for(int i=0;i<r;i++){
 for(int j=0;j<c;j++){
 arr1[i][j]=rand();
 }
 }
 for(int i=0;i<r;i++){
 for(int j=0;j<c;j++){
 arr2[i][j]=rand();
 }
 }
 printf("\nSequential Time: \n");
 int *arr3[r];
 for(int i=0;i<r;i++){
 arr3[i]=(int *)malloc(c*sizeof(int));
 }
 double start=omp_get_wtime();
 for(int i=0;i<r;i++){
 for(int j=0;j<c;j++){
 arr3[i][j]=arr1[i][j]+arr2[i][j];
 }
 }
 double end=omp_get_wtime();
 printf("Execution Time : %f\n",end-start);

// Starting parallel construct
 printf("\nParallel Time: \n");
 int *arr4[r];
 for(int i=0;i<r;i++){
 arr4[i]=(int *)malloc(c*sizeof(int));
 }
 double start1=omp_get_wtime();
 int i=0;
 int j=0;
 #pragma omp parallel for private(j)
 for(i=0;i<r;i++){
 for(j=0;j<c;j++){
 arr4[i][j]=arr1[i][j]+arr2[i][j];
 }
 }
 double end1=omp_get_wtime();
 printf("Execution Time : %f\n",end1-start1);
 for(int i=0;i<r;i++){
 free(arr1[i]);
 free(arr2[i]);
 free(arr3[i]);
 free(arr4[i]);
 }
 return 0;
}

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Compilation time: 0.12 sec, absolute running time: 1.58 sec, cpu time: 2.16 sec, memory peak: 750 Mb, absolute service time: 1,86 sec