1! 2! Example usage of Fortran 2003/2008 classes (extended derived types) as 3! user-defined contexts in PETSc. Example contributed by Glenn Hammond. 4! 5module Base_module 6#include "petsc/finclude/petscsnes.h" 7 implicit none 8 private 9 10 type, public :: base_type 11 PetscInt :: A ! junk 12 PetscReal :: I ! junk 13 contains 14 procedure, public :: Print => BasePrint 15 end type base_type 16contains 17subroutine BasePrint(this) 18 implicit none 19 class(base_type) :: this 20 print * 21 print *, 'Base printout' 22 print * 23end subroutine BasePrint 24end module Base_module 25 26module Extended_module 27 use Base_module 28 implicit none 29 private 30 type, public, extends(base_type) :: extended_type 31 PetscInt :: B ! junk 32 PetscReal :: J ! junk 33 contains 34 procedure, public :: Print => ExtendedPrint 35 end type extended_type 36contains 37subroutine ExtendedPrint(this) 38 implicit none 39 class(extended_type) :: this 40 print * 41 print *, 'Extended printout' 42 print * 43end subroutine ExtendedPrint 44end module Extended_module 45 46module Function_module 47 use petscsnes 48 implicit none 49 public :: TestFunction 50 contains 51subroutine TestFunction(snes,xx,r,ctx,ierr) 52 use Base_module 53 implicit none 54 SNES :: snes 55 Vec :: xx 56 Vec :: r 57 class(base_type) :: ctx ! yes, this should be base_type in order to handle all 58 PetscErrorCode :: ierr ! polymorphic extensions 59 call ctx%Print() 60end subroutine TestFunction 61end module Function_module 62 63program ex18f90 64 65 use Base_module 66 use Extended_module 67 use Function_module 68 implicit none 69 70! ifort on windows requires this interface definition 71interface 72 subroutine SNESSetFunction(snes_base,x,TestFunction,base,ierr) 73 use Base_module 74 use petscsnes 75 SNES snes_base 76 Vec x 77 external TestFunction 78 class(base_type) :: base 79 PetscErrorCode ierr 80 end subroutine 81end interface 82 83 PetscMPIInt :: size 84 PetscMPIInt :: rank 85 86 SNES :: snes_base, snes_extended 87 Vec :: x 88 class(base_type), pointer :: base 89 class(extended_type), pointer :: extended 90 PetscErrorCode :: ierr 91 92 print *, 'Start of Fortran2003 test program' 93 94 nullify(base) 95 nullify(extended) 96 allocate(base) 97 allocate(extended) 98 call PetscInitialize(PETSC_NULL_CHARACTER, ierr) 99 if (ierr .ne. 0) then 100 print*,'Unable to initialize PETSc' 101 stop 102 endif 103 call MPI_Comm_size(PETSC_COMM_WORLD,size,ierr);CHKERRA(ierr) 104 call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRA(ierr) 105 106 call VecCreate(PETSC_COMM_WORLD,x,ierr);CHKERRA(ierr) 107 108 ! use the base class as the context 109 print * 110 print *, 'the base class will succeed by printing out Base printout below' 111 call SNESCreate(PETSC_COMM_WORLD,snes_base,ierr);CHKERRA(ierr) 112 call SNESSetFunction(snes_base,x,TestFunction,base,ierr);CHKERRA(ierr) 113 call SNESComputeFunction(snes_base,x,x,ierr);CHKERRA(ierr) 114 call SNESDestroy(snes_base,ierr);CHKERRA(ierr) 115 116 ! use the extended class as the context 117 print *, 'the extended class will succeed by printing out Extended printout below' 118 call SNESCreate(PETSC_COMM_WORLD,snes_extended,ierr);CHKERRA(ierr) 119 call SNESSetFunction(snes_extended,x,TestFunction,extended,ierr);CHKERRA(ierr) 120 call SNESComputeFunction(snes_extended,x,x,ierr);CHKERRA(ierr) 121 call VecDestroy(x,ierr);CHKERRA(ierr) 122 call SNESDestroy(snes_extended,ierr);CHKERRA(ierr) 123 if (associated(base)) deallocate(base) 124 if (associated(extended)) deallocate(extended) 125 call PetscFinalize(ierr) 126 127 print *, 'End of Fortran2003 test program' 128 129end program ex18f90 130 131!/*TEST 132! 133! build: 134! requires: defined(PETSC_USING_F2003) defined(PETSC_USING_F90FREEFORM) 135! test: 136! requires: !pgf90_compiler 137! 138!TEST*/ 139