#include <stdio.h>
#include <string.h>
#include "mpi.h"

#include <math.h>

#include <sys/time.h>
//#include <time.h>


int main(int argc, char** argv)
{
    long n, i;
    double total;
    struct timeval tv;
    struct timezone tz;
    long starttimeSec, starttimeMicro;
    long endtimeSec, endtimeMicro;
    long totalSec, totalMicro;
    long starttime, endtime;
    int rank, size;

    MPI_Init( &argc, &argv );
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    if (argc > 1)
       n = atoi(argv[1]);
    else
       n = 1000;


    gettimeofday(&tv, &tz);
    starttimeSec = tv.tv_sec;
    starttimeMicro = tv.tv_usec;
    printf("Start Time process %d =%d sec %d microsec\n",
             rank, starttimeSec, starttimeMicro);

//   starttime = MPI_Wtime();
//   printf("Start time for process %d = %ld\n", rank, starttime);

//    printf("Time(0)=%u\n", time(0));

    total = 0.0;
    for(i = 1; i <= n; i++)
    {
        if(i % 4 == 1)
        {
            total += 1.0 / i;
        }
        else if (i % 4 == 3)
        {
            total -= 1.0 / i;
        }
    }


    gettimeofday(&tv, &tz);
    endtimeSec = tv.tv_sec;
    endtimeMicro = tv.tv_usec;
    printf("End Time for process %d = %d sec %d microsec\n",
            rank, endtimeSec, endtimeMicro);

    if (endtimeSec > starttimeSec)
    {
        totalSec = endtimeSec-starttimeSec;
        totalMicro = endtimeMicro + (1000000 - starttimeMicro);
    }

    else {
        totalSec = 0;
        totalMicro = endtimeMicro - starttimeMicro;
    }

/*
   endtime = MPI_Wtime();
   printf("End time for process %d = %ld\n", rank, endtime);
   printf("Total time for process %d = %ld\n", rank, endtime-starttime);
*/
 //   printf("Time(0)=%u\n", ftime(0));
    printf("Process %d: Pi = %.32f for %d iterations.\n", rank, total * 4, n);
    printf("Process %d: Real PI = %.32lf\n", rank, M_PI);
    printf("Process %d: Percent error = %.32lf\n",
                rank, fabs((total*4)-M_PI)/M_PI * 100);

    printf("Time for process %d: %d sec and %d microsec\n",
             rank, totalSec, totalMicro);
    MPI_Finalize();
    return 0;
}