wip

Python/mpipi.py → Python/mpipi2.py

 #
-# mpipi.py
+# mpipi2.py
 # Neil Gershenfeld 2/6/20
 # calculation of pi by an MPI Numba sum
 # pi = 3.14159265358979323846 
@@ -9,6 +9,13 @@ import time
 from numba import jit
 from mpi4py import MPI
 
+NPTS = 1000000000
+NLOOP = 10
+
+comm = MPI.COMM_WORLD
+rank = comm.Get_rank()
+nproc = comm.Get_size()
+
 @jit(nopython=True)
 def calc(istart,iend):
    sum = 0.0
@@ -16,22 +23,26 @@ def calc(istart,iend):
       sum += 0.5/((i-0.75)*(i-0.25))
    return sum
 
-NPTS = 100000000000
-comm = MPI.COMM_WORLD
-rank = comm.Get_rank()
-nproc = comm.Get_size()
 if (rank == 0):
+   istart = 1+rank*NPTS;
+   iend = (rank+1)*NPTS;
+   max = 0
+   for j in range(NLOOP):
+      comm.Barrier()
       start_time = time.time()
-   istart = int(1 + NPTS*((rank+0)/nproc))
-   iend = int(NPTS*((rank+1)/nproc))
-   pi = calc(istart,iend)
-   comm.reduce(pi,op=MPI.SUM,root=0)
+      sum = 0.0;
+      sum = calc(istart,iend)
+      pi = comm.reduce(sum,op=MPI.SUM,root=0)
       end_time = time.time()
-   mflops = NPTS*5.0/(1.0e6*(end_time-start_time))
-   print("NPTS = %d, pi = %f"%(NPTS,pi))
-   print("time = %f, estimated MFlops = %f"%(end_time-start_time,mflops))
+      mflops = nproc*NPTS*5.0/(1.0e6*(end_time-start_time))
+      print("processes = %d, NPTS = %d, pi = %f"%(nproc,NPTS,pi))
+      if (mflops > max):
+         max = mflops
+      print("time = %f, estimated MFlops = %f, max = %f"%(end_time-start_time,mflops,max))
 else:
-   istart = int(1 + NPTS*((rank+0)/nproc))
-   iend = int(NPTS*((rank+1)/nproc))
-   pi = calc(istart,iend)
-   comm.reduce(pi,op=MPI.SUM,root=0)
+   istart = 1+rank*NPTS
+   iend = (rank+1)*NPTS
+   for j in range(NLOOP):
+      comm.Barrier()
+      sum = calc(istart,iend)
+      comm.reduce(sum,op=MPI.SUM,root=0)