int main(int argc, char **argv)
{
Mat A;
KSP ksp;
DM shell;
Vec *left, *right;
MPI_Comm c;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc, &argv, NULL, NULL);if (ierr) return ierr;
c = PETSC_COMM_WORLD;
ierr = MatCreate(c, &A); CHKERRQ(ierr);
ierr = MatSetSizes(A, 1, 1, PETSC_DECIDE, PETSC_DECIDE); CHKERRQ(ierr);
ierr = MatSetFromOptions(A); CHKERRQ(ierr);
ierr = MatSetUp(A); CHKERRQ(ierr);
ierr = KSPCreate(c, &ksp); CHKERRQ(ierr);
ierr = KSPSetOperators(ksp, A, A); CHKERRQ(ierr);
ierr = KSPSetFromOptions(ksp); CHKERRQ(ierr);
ierr = DMShellCreate(c, &shell); CHKERRQ(ierr);
ierr = DMSetFromOptions(shell); CHKERRQ(ierr);
ierr = DMSetUp(shell); CHKERRQ(ierr);
ierr = KSPSetDM(ksp, shell); CHKERRQ(ierr);
ierr = KSPCreateVecs(ksp, 1, &right, 1, &left); CHKERRQ(ierr);
ierr = VecView(right[0], PETSC_VIEWER_STDOUT_(c));CHKERRQ(ierr);
ierr = VecDestroyVecs(1,&right); CHKERRQ(ierr);
ierr = VecDestroyVecs(1,&left); CHKERRQ(ierr);
ierr = DMDestroy(&shell); CHKERRQ(ierr);
ierr = KSPDestroy(&ksp); CHKERRQ(ierr);
ierr = MatDestroy(&A); CHKERRQ(ierr);
PetscFinalize();
return 0;
}
PetscErrorCode DMCreateSubDM_Shell(DM dm, PetscInt numFields, PetscInt fields[], IS *is, DM *subdm)
{
PetscErrorCode ierr;
PetscFunctionBegin;
if (subdm) {ierr = DMShellCreate(PetscObjectComm((PetscObject) dm), subdm);CHKERRQ(ierr);}
ierr = DMCreateSubDM_Section_Private(dm, numFields, fields, is, subdm);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/*@
KSPGetDM - Gets the DM that may be used by some preconditioners
Not Collective
Input Parameter:
. ksp - the preconditioner context
Output Parameter:
. dm - the dm
Level: intermediate
.seealso: KSPSetDM(), KSPSetDMActive()
@*/
PetscErrorCode KSPGetDM(KSP ksp,DM *dm)
{
PetscErrorCode ierr;
PetscFunctionBegin;
PetscValidHeaderSpecific(ksp,KSP_CLASSID,1);
if (!ksp->dm) {
ierr = DMShellCreate(PetscObjectComm((PetscObject)ksp),&ksp->dm);CHKERRQ(ierr);
ksp->dmAuto = PETSC_TRUE;
}
*dm = ksp->dm;
PetscFunctionReturn(0);
}
static PetscErrorCode MyDMShellCreate(MPI_Comm comm,DM da,DM *shell)
{
PetscErrorCode ierr;
ierr = DMShellCreate(comm,shell);CHKERRQ(ierr);
ierr = DMShellSetContext(*shell,da);CHKERRQ(ierr);
ierr = DMShellSetCreateMatrix(*shell,CreateMatrix);CHKERRQ(ierr);
ierr = DMShellSetCreateGlobalVector(*shell,CreateGlobalVector);CHKERRQ(ierr);
ierr = DMShellSetCreateLocalVector(*shell,CreateLocalVector);CHKERRQ(ierr);
ierr = DMShellSetRefine(*shell,Refine);CHKERRQ(ierr);
ierr = DMShellSetCoarsen(*shell,Coarsen);CHKERRQ(ierr);
ierr = DMShellSetCreateInterpolation(*shell,CreateInterpolation);CHKERRQ(ierr);
ierr = DMShellSetCreateRestriction(*shell,CreateRestriction);CHKERRQ(ierr);
return 0;
}