dolittle.cpp

#include<bits/stdc++.h>
#include<omp.h>
#define ld long double
#define n 2000
#define chunk 10
#include <sys/types.h>
#include <sys/times.h>
#include <sys/time.h>
#include <time.h>

using namespace std;
 
ld a[n][n],lwr[n][n],upr[n][n];
int main(){
	struct timeval start, stop;  /* Elapsed times using gettimeofday() */
  struct timezone tz;
  clock_t start2, stop2;  /* Elapsed times using times() */
  unsigned long long usecstart, usecstop ;
  struct tms cputstart, cputstop;  /* CPU times for processes */
	int i,j,k,nthreads,tid;
	//double start,end;      // for measuring time
	//cout<<"enter order of matrix : ";
	//cin>>n;

	/*----------------------------Initalization of matrix-------------------------------*/
	srand(time(NULL));
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{
			a[i][j]=1+rand()%1000;
//			cin>>a[i][j];
		}
	}
	
	/*----------------------------Parallel run of algorithm-----------------------------*/
	printf("\nStarting clock for parallel algorithm.\n");
  	gettimeofday(&start, &tz);
  	start2 = times(&cputstart);
	//start=omp_get_wtime();
	//start = clock_t
	#pragma omp parallel shared(lwr,upr,a,nthreads) private(tid,i,k,j)
	{
		tid=omp_get_thread_num();
		if(tid==0)
		nthreads=omp_get_num_threads();

		for(k=0;k<n;k++)
		{
			lwr[k][k]=1;
			#pragma omp for schedule(static,chunk)
			for(j=k;j<n;j++)
			{
				ld sum=0;
				for(int s=0;s<=k-1;s++)
				{
					sum+=lwr[k][s]*upr[s][j];
				}
				upr[k][j]=a[k][j]-sum;
			}
			#pragma omp for schedule(static,chunk)
			for(i=k+1;i<n;i++)
			{
				ld sum=0;
				for(int s=0;s<=k-1;s++)
				{
					sum+=lwr[i][s]*upr[s][k];
				}
				lwr[i][k]=(a[i][k]-sum)/upr[k][k];
			}
		}	
	}
	//end=omp_get_wtime();
	//printf("time for parallel run : %lf\n",end-start);
	
	gettimeofday(&stop, &tz);
  stop2 = times(&cputstop);
  printf("Stopped clock.\n");
  usecstart = (unsigned long long)start.tv_sec * 1000000 + start.tv_usec;
  usecstop = (unsigned long long)stop.tv_sec * 1000000 + stop.tv_usec;

  	printf("Total elapsed time = %g ms.\n",(float)(usecstop-usecstart)/(float)CLOCKS_PER_SEC * 1000) ;
  printf("Total elapsed time by system in calling and executing = %g ms.\n",(float)(stop2-start2) / (float)CLOCKS_PER_SEC * 1000) ;
  printf("My total CPU time for parent = %g ms.\n", (float)( (cputstop.tms_utime + cputstop.tms_stime) - (cputstart.tms_utime + cputstart.tms_stime) ) /(float)CLOCKS_PER_SEC * 1000);
  printf("My total CPU time for child processes = %g ms.\n", (float)( (cputstop.tms_cutime + cputstop.tms_cstime) - (cputstart.tms_cutime + cputstart.tms_cstime) ) / (float)CLOCKS_PER_SEC * 1000);
  printf("--------------------------------------------\n");

	/*----------------------------Sequential run of algorithm-----------------------------*/
	//start=omp_get_wtime();
	printf("\nStarting clock for sequential algorithm.\n");
  	gettimeofday(&start, &tz);
  	start2 = times(&cputstart);
	for(k=0;k<n;k++)
	{
		lwr[k][k]=1;
		for(j=k;j<n;j++)
		{
			ld sum=0;
			for(int s=0;s<=k-1;s++)
			{
				sum+=lwr[k][s]*upr[s][j];
			}
			upr[k][j]=a[k][j]-sum;
		}
		for(i=k+1;i<n;i++)
		{
			ld sum=0;
			for(int s=0;s<=k-1;s++)
			{
				sum+=lwr[i][s]*upr[s][k];
			}
			lwr[i][k]=(a[i][k]-sum)/upr[k][k];
		}
	}
	
	gettimeofday(&stop, &tz);
  stop2 = times(&cputstop);
  printf("Stopped clock.\n");
  usecstart = (unsigned long long)start.tv_sec * 1000000 + start.tv_usec;
  usecstop = (unsigned long long)stop.tv_sec * 1000000 + stop.tv_usec;

  	printf("Total elapsed time = %g ms.\n",(float)(usecstop-usecstart)/(float)CLOCKS_PER_SEC * 1000) ;
  printf("Total elapsed time by system in calling and executing = %g ms.\n",(float)(stop2-start2) / (float)CLOCKS_PER_SEC * 1000) ;
  printf("My total CPU time for parent = %g ms.\n", (float)( (cputstop.tms_utime + cputstop.tms_stime) - (cputstart.tms_utime + cputstart.tms_stime) ) /(float)CLOCKS_PER_SEC * 1000);
  printf("My total CPU time for child processes = %g ms.\n", (float)( (cputstop.tms_cutime + cputstop.tms_cstime) - (cputstart.tms_cutime + cputstart.tms_cstime) ) / (float)CLOCKS_PER_SEC * 1000);
  printf("--------------------------------------------\n");
	//end=omp_get_wtime();
	//printf("\ntime for sequential run : %lf\n",end-start);
	/*for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{
			cout<<lwr[i][j]<<" ";
		}
		cout<<endl;
	}*/
	/*for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{
			cout<<upr[i][j]<<" ";
		}
		cout<<endl;
	}*/
}