Enumerations
enum	GhostTag : int { TAG_POSITION = 100 , TAG_FORCE = 101 , TAG_PARTNUM = 102 , TAG_DEFAULT = 103 , TAG_BONDS = 104 }
	MPI tags for ghost communications. More...

Functions
int	main_tag (unsigned data_parts)

std::span< ParticleList *const >	as_span (std::vector< ParticleList * > const &v)
	View a list of cell pointers as a span for the packing routines.

std::vector< ParticleList * >	region_cells (std::vector< SendRegion > const &send)
	Extract the plain cell pointers from a list of send regions.

void	pack_regions (CommBuf &buf, std::vector< SendRegion > const &regions, BoxGeometry const &box, unsigned data_parts)
	Pack all send regions of one NeighborComm into a single buffer.

void	run_collective (HaloPlan const &plan, BoxGeometry const &box, unsigned data_parts, ExchangeOp op)
	Collective (broadcast/reduce-sum) section.

Enumeration Type Documentation

◆ GhostTag

enum GhostComm::anonymous_namespace{HaloExchange.cpp}::GhostTag : int

MPI tags for ghost communications.

One tag per exchange-kind keeps concurrent exchanges (a future goal) from aliasing: within a single exchange each message is already uniquely matched by (peer, tag). The BONDS transfer needs its own tag because it is sent as a second message to the same peer, mirroring the legacy two-transfer.

Enumerator
TAG_POSITION
TAG_FORCE
TAG_PARTNUM
TAG_DEFAULT
TAG_BONDS

Definition at line 61 of file HaloExchange.cpp.

Function Documentation

◆ as_span()

std::span< ParticleList *const > GhostComm::anonymous_namespace{HaloExchange.cpp}::as_span ( std::vector< ParticleList * > const & v )

View a list of cell pointers as a span for the packing routines.

Definition at line 83 of file HaloExchange.cpp.

References as_span().

Referenced by as_span(), and pack_regions().

◆ main_tag()

int GhostComm::anonymous_namespace{HaloExchange.cpp}::main_tag ( unsigned data_parts )

Definition at line 69 of file HaloExchange.cpp.

References GHOSTTRANS_FORCE, GHOSTTRANS_PARTNUM, GHOSTTRANS_POSITION, main_tag(), TAG_DEFAULT, TAG_FORCE, TAG_PARTNUM, and TAG_POSITION.

Referenced by main_tag().

◆ pack_regions()

void GhostComm::anonymous_namespace{HaloExchange.cpp}::pack_regions	(	CommBuf &	buf,
		std::vector< SendRegion > const &	regions,
		BoxGeometry const &	box,
		unsigned	data_parts
	)

Pack all send regions of one NeighborComm into a single buffer.

All regions are packed with a single pack_cells call so that bonds produce exactly one boost binary archive per neighbor message – matching the single unpack_cells call on the receive side. Concatenating per-region archives would corrupt the bond stream (the second archive header is misread as bond data by the receiver).

Per-region shifts are honored via the common shift. All SendRegion.shift values within a NeighborComm are equal — RegularDecomposition:: make_halo_plan() sets them all to {}. This lets us pack every region's cells in one pack_cells call (a single bond archive, matching the receiver's single unpack_cells).

Note: If a future decomposition (e.g. a Lees-Edwards refactor) ever stores DISTINCT per-region shifts, pack_regions must be generalized to pack each region's non-bond (flat) data with its own shift while still writing all bonds into ONE shared archive — do not simply concatenate per-region archives (that was the bond-corruption bug fixed in commit 314e7c366b).

Definition at line 117 of file HaloExchange.cpp.

References as_span(), Utils::Vector< T, N >::empty(), Utils::Vector< T, N >::front(), GhostComm::pack_cells(), pack_regions(), and region_cells().

Referenced by pack_regions().

◆ region_cells()

std::vector< ParticleList * > GhostComm::anonymous_namespace{HaloExchange.cpp}::region_cells ( std::vector< SendRegion > const & send )

Extract the plain cell pointers from a list of send regions.

Definition at line 88 of file HaloExchange.cpp.

References region_cells().

Referenced by pack_regions(), and region_cells().

◆ run_collective()

void GhostComm::anonymous_namespace{HaloExchange.cpp}::run_collective	(	HaloPlan const &	plan,
		BoxGeometry const &	box,
		unsigned	data_parts,
		ExchangeOp	op
	)

Collective (broadcast/reduce-sum) section.

For each root rank in [0, comm.size()):

Broadcast (Push): root packs its owned cell (cells[root]) and broadcasts the buffer to all ranks; every non-root rank unpacks into cells[root] (their ghost copy of root's data).
ReduceSum (Reduce): every rank packs cells[root] (ghost-force contribution) and reduces to root with std::plus on the raw double buffer; root unpacks into cells[root] (the owned cell, so forces accumulate there).

The legacy code uses one GHOST_BCST (or GHOST_RDCE) step per rank, each step addressing a single cell pointer (ghost_comm.part_lists[0] == &cells.at(n)). We replicate that loop exactly.

Definition at line 155 of file HaloExchange.cpp.

References GhostComm::CommBuf::bonds(), GhostComm::calc_transmit_size(), GhostComm::HaloPlan::collective, GhostComm::HaloPlan::comm, GhostComm::ExchangeOp::direction, GhostComm::None, GhostComm::pack_cells(), GhostComm::Push, GhostComm::CommBuf::resize(), run_collective(), GhostComm::CommBuf::size(), and GhostComm::unpack_cells().

Referenced by run_collective().

Enumerations

Functions