1! Introductory example that illustrates printing: Fortran Example 2 3program main 4#include <petsc/finclude/petscsys.h> 5 use petscsys 6 7 implicit none 8 PetscErrorCode :: ierr 9 PetscMPIInt :: rank,size 10 character(len=80) :: outputString 11 12 ! Every PETSc routine should begin with the PetscInitialize() routine. 13 PetscCallA(PetscInitialize(ierr)) 14 15 ! We can now change the communicator universe for PETSc 16 PetscCallMPIA(MPI_Comm_size(PETSC_COMM_WORLD,size,ierr)) 17 PetscCallMPIA(MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)) 18 19 ! Here we would like to print only one message that represents all the processes in the group 20 ! We use PetscPrintf() with the 21 ! communicator PETSC_COMM_WORLD. Thus, only one message is 22 ! printed representng PETSC_COMM_WORLD, i.e., all the processors. 23 24 write(outputString,*) 'No of Processors = ', size, ', rank = ',rank,'\n' 25 PetscCallA(PetscPrintf(PETSC_COMM_WORLD,outputString,ierr)) 26 27 ! Here a barrier is used to separate the two program states. 28 PetscCallMPIA(MPI_Barrier(PETSC_COMM_WORLD,ierr)) 29 30 ! Here we simply use PetscPrintf() with the communicator PETSC_COMM_SELF, 31 ! where each process is considered separately and prints independently 32 ! to the screen. Thus, the output from different processes does not 33 ! appear in any particular order. 34 35 write(outputString,*) rank,'Jumbled Hello World\n' 36 PetscCallA(PetscPrintf(PETSC_COMM_SELF,outputString,ierr)) 37 38 ! Always call PetscFinalize() before exiting a program. This routine 39 ! - finalizes the PETSc libraries as well as MPI 40 ! - provides summary and diagnostic information if certain runtime 41 ! options are chosen (e.g., -log_view). See PetscFinalize() 42 ! manpage for more information. 43 44 PetscCallA(PetscFinalize(ierr)) 45 46end program main 47!/*TEST 48! 49! test: 50! 51!TEST*/ 52