1: ! Synchronized printing: Fortran Example

  3: program main
  4: #include <petsc/finclude/petscsys.h>
  5:       use petscmpi  ! or mpi or mpi_f08
  6:       use petscsys

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

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

 15:       PetscCallA(PetscInitialize(ierr))

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

 20:       PetscCallMPIA(MPI_Comm_size(MPI_COMM_WORLD,size,ierr))
 21:       PetscCallMPIA(MPI_Comm_rank(MPI_COMM_WORLD,rank,ierr))

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

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

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

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

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

 41:       PetscCallA(PetscFinalize(ierr))
 42: end program main

 44: !/*TEST
 45: !
 46: !   test:
 47: !
 48: !TEST*/