1: ! Synchronized printing: Fortran Example
  2: #include <petsc/finclude/petscsys.h>
  3: program main
  4:   use petscsys

  6:   implicit none
  7:   PetscErrorCode                    :: ierr
  8:   PetscMPIInt                       :: rank, size
  9:   character(len=PETSC_MAX_PATH_LEN) :: outputString

 11:   ! Every PETSc program should begin with the PetscInitialize() routine.

 13:   PetscCallA(PetscInitialize(ierr))

 15:   ! The following MPI calls return the number of processes
 16:   ! being used and the rank of this process in the group

 18:   PetscCallMPIA(MPI_Comm_size(MPI_COMM_WORLD, size, ierr))
 19:   PetscCallMPIA(MPI_Comm_rank(MPI_COMM_WORLD, rank, ierr))

 21:   ! Here we would like to print only one message that represents
 22:   ! all the processes in the group
 23:   write (outputString, *) 'No of Processors = ', size, ', rank = ', rank, '\n'
 24:   PetscCallA(PetscPrintf(PETSC_COMM_WORLD, outputString, ierr))

 26:   write (outputString, *) rank, 'Synchronized Hello World\n'
 27:   PetscCallA(PetscSynchronizedPrintf(PETSC_COMM_WORLD, outputString, ierr))

 29:   write (outputString, *) rank, 'Synchronized Hello World - Part II\n'
 30:   PetscCallA(PetscSynchronizedPrintf(PETSC_COMM_WORLD, outputString, ierr))
 31:   PetscCallA(PetscSynchronizedFlush(PETSC_COMM_WORLD, PETSC_STDOUT, ierr))

 33:   ! Here a barrier is used to separate the two program states.
 34:   PetscCallMPIA(MPI_Barrier(PETSC_COMM_WORLD, ierr))

 36:   write (outputString, *) rank, 'Jumbled Hello World\n'
 37:   PetscCallA(PetscPrintf(PETSC_COMM_SELF, outputString, ierr))

 39:   PetscCallA(PetscFinalize(ierr))
 40: end program main

 42: !/*TEST
 43: !
 44: !   test:
 45: !
 46: !TEST*/