Date: 2026-03-31T05:46:26+00:00

Actual source code: ex6f.F90

      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, parameter :: n = 128

     30:   PetscCallA(PetscInitialize(ierr))
     31:   ctxF%lambda = 3.14_PETSC_REAL_KIND
     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*/