PetscErrorCode DMDAGetElements(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
{
DM_DA *da = (DM_DA*)dm->data;
PetscErrorCode ierr;
PetscFunctionBegin;
if (da->dim==-1) {
*nel = 0; *nen = 0; *e = PETSC_NULL;
} else if (da->dim==1) {
ierr = DMDAGetElements_1D(dm,nel,nen,e);CHKERRQ(ierr);
} else if (da->dim==2) {
ierr = DMDAGetElements_2D(dm,nel,nen,e);CHKERRQ(ierr);
} else if (da->dim==3) {
ierr = DMDAGetElements_3D(dm,nel,nen,e);CHKERRQ(ierr);
} else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"DMDA dimension not 1, 2, or 3, it is %D\n",da->dim);
PetscFunctionReturn(0);
}
/*@C
DMDAGetElements - Gets an array containing the indices (in local coordinates)
of all the local elements
Not Collective
Input Parameter:
. dm - the DM object
Output Parameters:
+ nel - number of local elements
. nen - number of element nodes
- e - the local indices of the elements' vertices
Level: intermediate
Notes:
Call DMDARestoreElements() once you have finished accessing the elements.
Each process uniquely owns a subset of the elements. That is no element is owned by two or more processes.
If on each process you integrate over its owned elements and use ADD_VALUES in Vec/MatSetValuesLocal() then you'll obtain the correct result.
.seealso: DMDAElementType, DMDASetElementType(), VecSetValuesLocal(), MatSetValuesLocal(), DMGlobalToLocalBegin(), DMLocalToGlobalBegin()
@*/
PetscErrorCode DMDAGetElements(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
{
PetscInt dim;
PetscErrorCode ierr;
DM_DA *dd = (DM_DA*)dm->data;
PetscFunctionBegin;
if (dd->stencil_type == DMDA_STENCIL_STAR) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"DMDAGetElement() requires you use a stencil type of DMDA_STENCIL_BOX");
ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
if (dim==-1) {
*nel = 0; *nen = 0; *e = NULL;
} else if (dim==1) {
ierr = DMDAGetElements_1D(dm,nel,nen,e);CHKERRQ(ierr);
} else if (dim==2) {
ierr = DMDAGetElements_2D(dm,nel,nen,e);CHKERRQ(ierr);
} else if (dim==3) {
ierr = DMDAGetElements_3D(dm,nel,nen,e);CHKERRQ(ierr);
} else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"DMDA dimension not 1, 2, or 3, it is %D\n",dim);
PetscFunctionReturn(0);
}
