ElementId< VolumeDim > Class Template Reference

An ElementId uniquely labels an Element. More...

#include <ElementId.hpp>

Public Member Functions
	ElementId () noexcept=default
	Default constructor needed for Charm++ serialization.
	ElementId (const ElementId &) noexcept=default
ElementId &	operator= (const ElementId &) noexcept=default
	ElementId (ElementId &&) noexcept=default
ElementId &	operator= (ElementId &&) noexcept=default
	ElementId (size_t block_id, size_t grid_index=0) noexcept
	Create the ElementId of the root Element of a Block.
	ElementId (size_t block_id, std::array< SegmentId, VolumeDim > segment_ids, size_t grid_index=0) noexcept
	Create an arbitrary ElementId.
ElementId< VolumeDim >	id_of_child (size_t dim, Side side) const noexcept
ElementId< VolumeDim >	id_of_parent (size_t dim) const noexcept
size_t	block_id () const noexcept
size_t	grid_index () const noexcept
std::array< SegmentId, VolumeDim >	segment_ids () const noexcept
SegmentId	segment_id (const size_t dim) const noexcept

Static Public Member Functions
static ElementId< VolumeDim >	external_boundary_id () noexcept
	Returns an ElementId meant for identifying data on external boundaries, which should never correspond to the Id of an actual element.

Static Public Attributes
static constexpr size_t	block_id_bits = 24
static constexpr size_t	grid_index_bits = 8
static constexpr size_t	refinement_bits = 4
static constexpr size_t	max_refinement_level = 16
static constexpr size_t	padding = 4
static constexpr size_t	volume_dim = VolumeDim

Detailed Description

template<size_t VolumeDim>
class ElementId< VolumeDim >

An ElementId uniquely labels an Element.

It is constructed from the BlockId of the Block to which the Element belongs and the VolumeDim SegmentIds that label the segments of the Block that the Element covers. An optional grid_index identifies elements with the same BlockId and SegmentIds across multiple grids.

Details

The ElementId serves as an index that is compatible with Charm++ and therefore must adhere to the restrictions imposed by Charm++. These are:

• ElementId must satisfy std::is_pod
• ElementId must not be larger than the size of three ints, i.e. sizeof(ElementId) <= 3 * sizeof(int)

The latter restriction can be relaxed with a special compilation flag to Charm++, but we have not yet needed more elements than can be accounted for by densely packing bits together. SegmentId is responsible for handling the low-level bit manipulations to create an index that satisfies the size constraints.