Hi, all,
I am parallelizing a CFD 2D code in FORTRAN+OPENMPI. Suppose that the grid (all triangles) is partitioned among 8 processes using METIS. Each process has different number of neighboring processes. Suppose each process has n elements/faces whose data it needs to sends to corresponding neighboring processes, and it has m number of elements/faces on which it needs to get data from corresponding neighboring processes. Values of n and m are different for each process. Another aim is to hide the communication behind computation. For this I do the following for each process: DO j = 1 to n CALL MPI_ISEND (send_data, num, type, dest(j), tag, MPI_COMM_WORLD, ireq(j), ierr) ENDDO DO k = 1 to m CALL MPI_RECV(recv_data, num, type, source(k), tag, MPI_COMM_WORLD, status, ierr) ENDDO This solves my problem. But it gives memory leakage; RAM gets filled after few thousands of iteration. What is the solution/remedy? How should I tackle this? In another CFD code I removed this problem of memory-filling by following (in that code n=m) : DO j = 1 to n CALL MPI_ISEND (send_data, num, type, dest(j), tag, MPI_COMM_WORLD, ireq(j), ierr) ENDDO CALL MPI_WAITALL(n,ireq,status,ierr) DO k = 1 to n CALL MPI_RECV(recv_data, num, type, source(k), tag, MPI_COMM_WORLD, status, ierr) ENDDO But this is not working in current code; and the previous code was not giving correct results with large number of processes. Please suggest solution. THANKS A LOT FOR YOUR KIND ATTENTION. With best regards, Amjad Ali.
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