Regular decomposition cell system. More...

#include <RegularDecomposition.hpp>

Inheritance diagram for RegularDecomposition:

Collaboration diagram for RegularDecomposition:

Public Member Functions
	RegularDecomposition (boost::mpi::communicator comm, double range, BoxGeometry const &box_geo, LocalBox const &local_geo, std::optional< std::pair< int, int > > fully_connected)

GhostCommunicator const &	exchange_ghosts_comm () const override

GhostCommunicator const &	collect_ghost_force_comm () const override

std::span< Cell *const >	local_cells () const override

std::span< Cell *const >	ghost_cells () const override

auto const &	get_local_cells () const

auto const &	get_ghost_cells () const

Cell *	particle_to_cell (Particle const &p) override

Cell const *	particle_to_cell (Particle const &p) const override

void	resort (bool global, std::vector< ParticleChange > &diff) override

Utils::Vector3d	max_cutoff () const override

Utils::Vector3d	max_range () const override

auto	fully_connected_boundary () const

std::optional< BoxGeometry >	minimum_image_distance () const override

BoxGeometry const &	box () const override

Public Member Functions inherited from ParticleDecomposition
virtual	~ParticleDecomposition ()=default

Public Attributes
Utils::Vector3i	cell_grid = {}
	Grid dimensions per node.

Utils::Vector3d	cell_size = {}
	Cell size.

Utils::Vector3i	cell_offset = {}
	Offset in global grid.

Utils::Vector3i	ghost_cell_grid = {}
	linked cell grid with ghost frame.

Utils::Vector3d	inv_cell_size = {}
	inverse cell_size.

boost::mpi::communicator	m_comm

BoxGeometry const &	m_box

LocalBox	m_local_box

std::optional< std::pair< int, int > >	m_fully_connected_boundary = {}

std::vector< Cell >	cells

std::vector< Cell * >	m_local_cells

std::vector< Cell * >	m_ghost_cells

GhostCommunicator	m_exchange_ghosts_comm

GhostCommunicator	m_collect_ghost_force_comm

Detailed Description

Regular decomposition cell system.

The domain of a node is split into a 3D cell grid with dimension cell_grid. Together with one ghost cell layer on each side the overall dimension of the ghost cell grid is ghost_cell_grid. The regular decomposition enables the use of the linked cell algorithm which is in turn used for setting up the Verlet list for the system. You can see a 2D graphical representation of the linked cell grid below.

Linked cells structure

2D representation of a linked cell grid: cell_grid = {4,4}, ghost_cell_grid = {6,6}

Each cell has \( 3^D \) neighbor cells. Since we deal with pair forces, it is sufficient to calculate only half of the interactions (Newton's law: action = reaction). We have chosen the upper half e.g. all neighbor cells with a higher linear index (for cell 14 they are marked in light blue). Caution: This implementation needs double sided ghost communication! For single sided ghost communication one would need some ghost-ghost cell interaction as well, which we do not need!

Definition at line 67 of file RegularDecomposition.hpp.

Constructor & Destructor Documentation

◆ RegularDecomposition()

RegularDecomposition::RegularDecomposition	(	boost::mpi::communicator	comm,
		double	range,
		BoxGeometry const &	box_geo,
		LocalBox const &	local_geo,
		std::optional< std::pair< int, int > >	fully_connected
	)