1: !
  2: !     Demonstrates use of MatShellSetContext() and MatShellGetContext()
  3: !
  4: !     Contributed by:  Samuel Lanthaler
  5: !
  6: #include "petsc/finclude/petscmat.h"
  7: module solver_context_ex6f
  8:   use petscsys
  9:   implicit none
 10:   type :: MatCtx
 11:     PetscReal :: lambda, kappa
 12:     PetscReal :: h
 13:   end type MatCtx
 14: end module solver_context_ex6f

 16: ! ----------------------------------------------------
 17: !                    main program
 18: ! ----------------------------------------------------
 19: program main
 20:   use petscmat
 21:   use solver_context_ex6f
 22:   implicit none

 24:   Mat :: F
 25:   type(MatCtx) :: ctxF
 26:   type(MatCtx), pointer :: ctxF_pt
 27:   PetscErrorCode :: ierr
 28:   PetscInt :: n = 128

 30:   PetscCallA(PetscInitialize(ierr))
 31:   ctxF%lambda = 3.14d0
 32:   PetscCallA(MatCreateShell(PETSC_COMM_WORLD, n, n, n, n, ctxF, F, ierr))
 33:   PetscCallA(MatShellSetContext(F, ctxF, ierr))
 34:   print *, 'ctxF%lambda = ', ctxF%lambda

 36:   PetscCallA(MatShellGetContext(F, ctxF_pt, ierr))
 37:   print *, 'ctxF_pt%lambda = ', ctxF_pt%lambda

 39:   PetscCallA(MatDestroy(F, ierr))
 40:   PetscCallA(PetscFinalize(ierr))
 41: end program main

 43: !/*TEST
 44: !
 45: !     build:
 46: !       requires: double
 47: !
 48: !     test:
 49: !
 50: !TEST*/