wip

MPI/mpipi.c

@@ -8,11 +8,10 @@
 #include <mpi.h>
 #include <sys/time.h>
 
-#define NPTS 100000000
-#define NLOOP 10
+#define NPTS 1000000000
 
 void main(int argc, char** argv) {
-   int rank,nproc,i,istart,iend,loop,N;
+   int rank,nproc,i,istart,iend;
    unsigned long int start_time,end_time;
    struct timeval start,end;
    double sum,pi,mflops;
@@ -25,22 +24,20 @@ void main(int argc, char** argv) {
       istart = 1 + NPTS*((rank+0.0)/nproc);
       iend = NPTS*((rank+1.0)/nproc);
       sum = 0.0;
-      for (loop = 0; loop < NLOOP; ++loop)
       for (i = istart; i <= iend; ++i)
          sum += 0.5/((i-0.75)*(i-0.25));
       MPI_Reduce(&sum,&pi,1,MPI_DOUBLE,MPI_SUM,0,MPI_COMM_WORLD);
       gettimeofday(&end, NULL);
       start_time = start.tv_sec * 1e6 + start.tv_usec;
       end_time = end.tv_sec * 1e6 + end.tv_usec;
-      mflops = NLOOP*(NPTS*(5.0/(end_time-start_time)));
-      printf("processes = %d, NPTS = %d, NLOOP = %d, pi = %f\n",nproc,NPTS,NLOOP,pi/NLOOP);
+      mflops = NPTS*(5.0/(end_time-start_time));
+      printf("processes = %d, NPTS = %d, pi = %f\n",nproc,NPTS,pi);
       printf("time = %f, estimated MFlops = %f\n",(end_time-start_time)/1.0e6,mflops);
       }
    else {
       istart = 1 + NPTS*((rank+0.0)/nproc);
       iend = NPTS*((rank+1.0)/nproc);
       sum = 0.0;
-      for (loop = 0; loop < NLOOP; ++loop)
       for (i = istart; i <= iend; ++i)
          sum += 0.5/((i-0.75)*(i-0.25));
       MPI_Reduce(&sum,&pi,1,MPI_DOUBLE,MPI_SUM,0,MPI_COMM_WORLD);