! ! Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana ! University Research and Technology ! Corporation. All rights reserved. ! Copyright (c) 2006 Cisco Systems, Inc. All rights reserved. ! ! Simple ring test program ! program ring use mpi implicit none integer :: rank, size, tag, next, from, message, ierr call MPI_INIT(ierr) call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr) call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr) tag = 201 next = mod((rank + 1), size) from = mod((rank + size - 1), size) if (rank .eq. 0) then message = 10 print *, 'Process 0 sending ', message, ' to ', next call MPI_SEND(message, 1, MPI_INTEGER, next, tag, MPI_COMM_WORLD, ierr) endif 10 call MPI_RECV(message, 1, MPI_INTEGER, from, tag, MPI_COMM_WORLD, & MPI_STATUS_IGNORE, ierr) if (rank .eq. 0) then message = message - 1 print *, 'Process 0 decremented num' endif call MPI_SEND(message, 1, MPI_INTEGER, next, tag, MPI_COMM_WORLD, ierr) if (message .eq. 0) then print *, 'Process ', rank, ' exiting' goto 20 endif goto 10 20 if (rank .eq. 0) then call MPI_RECV(message, 1, MPI_INTEGER, from, tag, MPI_COMM_WORLD, & MPI_STATUS_IGNORE, ierr) endif call MPI_FINALIZE(ierr) end program