Non-busy-waiting synchronization for fdm computation

main.f90

@@ -20,6 +20,8 @@ program x_code
 
   integer :: n
   character :: sym
+  logical :: flag
+  real*8 :: dummy
 
   call m_timing_init   ! Setting the time zero
   call m_openmpi_init
@@ -134,6 +136,16 @@ program x_code
             call gather_4
             if (myid.eq.master) then
                call fdm_exe
+               do id_to=1,numprocs-1
+                 call MPI_Isend (dummy, 1, MPI_REAL, id_to, 0, MPI_COMM_TASK, mpi_request, mpi_err)
+               end do
+            else
+               call MPI_Irecv (dummy, 1, MPI_REAL, master, 0, MPI_COMM_TASK, mpi_request, mpi_err)
+               do
+                 call MPI_Test(mpi_request, flag, mpi_status, mpi_err)
+                 if (flag) exit
+                 call SLEEPQQ (200)
+               end do
             end if
             call MPI_BARRIER(MPI_COMM_TASK, mpi_err)
         endif