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);
}
PetscErrorCode DMCreateSubDM_DA(DM dm, PetscInt numFields, PetscInt fields[], IS *is, DM *subdm)
{
DM_DA *da = (DM_DA*) dm->data;
PetscSection section;
PetscErrorCode ierr;
PetscFunctionBegin;
if (subdm) {
PetscSF sf;
Vec coords;
void *ctx;
/* Cannot use DMClone since the dof stuff is mixed in. Ugh
ierr = DMClone(dm, subdm);CHKERRQ(ierr); */
ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
ierr = DMGetPointSF(dm, &sf);CHKERRQ(ierr);
ierr = DMSetPointSF(*subdm, sf);CHKERRQ(ierr);
ierr = DMGetApplicationContext(dm, &ctx);CHKERRQ(ierr);
ierr = DMSetApplicationContext(*subdm, ctx);CHKERRQ(ierr);
ierr = DMGetCoordinatesLocal(dm, &coords);CHKERRQ(ierr);
if (coords) {
ierr = DMSetCoordinatesLocal(*subdm, coords);CHKERRQ(ierr);
} else {
ierr = DMGetCoordinates(dm, &coords);CHKERRQ(ierr);
if (coords) {ierr = DMSetCoordinates(*subdm, coords);CHKERRQ(ierr);}
}
ierr = DMSetType(*subdm, DMDA);CHKERRQ(ierr);
ierr = DMSetDimension(*subdm, dm->dim);CHKERRQ(ierr);
ierr = DMDASetSizes(*subdm, da->M, da->N, da->P);CHKERRQ(ierr);
ierr = DMDASetNumProcs(*subdm, da->m, da->n, da->p);CHKERRQ(ierr);
ierr = DMDASetBoundaryType(*subdm, da->bx, da->by, da->bz);CHKERRQ(ierr);
ierr = DMDASetDof(*subdm, numFields);CHKERRQ(ierr);
ierr = DMDASetStencilType(*subdm, da->stencil_type);CHKERRQ(ierr);
ierr = DMDASetStencilWidth(*subdm, da->s);CHKERRQ(ierr);
ierr = DMDASetOwnershipRanges(*subdm, da->lx, da->ly, da->lz);CHKERRQ(ierr);
}
ierr = DMGetDefaultSection(dm, §ion);CHKERRQ(ierr);
if (section) {
ierr = DMCreateSubDM_Section_Private(dm, numFields, fields, is, subdm);CHKERRQ(ierr);
} else {
if (is) {
PetscInt *indices, cnt = 0, dof = da->w, i, j;
ierr = PetscMalloc1(da->Nlocal*numFields/dof, &indices);CHKERRQ(ierr);
for (i = da->base/dof; i < (da->base+da->Nlocal)/dof; ++i) {
for (j = 0; j < numFields; ++j) {
indices[cnt++] = dof*i + fields[j];
}
}
if (cnt != da->Nlocal*numFields/dof) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Count %d does not equal expected value %d", cnt, da->Nlocal*numFields/dof);
ierr = ISCreateGeneral(PetscObjectComm((PetscObject) dm), cnt, indices, PETSC_OWN_POINTER, is);CHKERRQ(ierr);
}
}
PetscFunctionReturn(0);
}
