fv_communication.hpp File Reference

Ghost layer communication for scalar finite volume (FV) fields on the shell grid. More...

#include <algorithm>
#include <tuple>
#include <vector>
#include <mpi.h>
#include "grid/grid_types.hpp"
#include "grid/shell/spherical_shell.hpp"
#include "mpi/mpi.hpp"

Go to the source code of this file.

Classes
class	terra::communication::shell::FVGhostLayerBuffers< ScalarType >
	Pre-allocated send/recv buffers and sorted face-pair lists for FV ghost layer comm. More...
struct	terra::communication::shell::FVGhostLayerBuffers< ScalarType >::FacePair
	All metadata needed to drive communication for one subdomain face. More...
class	terra::communication::shell::FVGhostLayerVecBuffers< ScalarType, VecDim >
	Pre-allocated send/recv buffers for vector-valued FV ghost layer communication. More...
struct	terra::communication::shell::FVGhostLayerVecBuffers< ScalarType, VecDim >::FacePair

Namespaces
namespace	terra
namespace	terra::communication
namespace	terra::communication::shell
namespace	terra::communication::shell::fv_detail

Functions
template<typename ScalarType >
void	terra::communication::shell::fv_detail::pack_inner_cells (const grid::Grid2DDataScalar< ScalarType > &buffer, const grid::Grid4DDataScalar< ScalarType > &data, const int local_subdomain_id, const grid::BoundaryFace face)
	Packs the innermost real-cell layer adjacent to face into buffer.
template<typename ScalarType >
void	terra::communication::shell::fv_detail::unpack_to_ghost (const grid::Grid2DDataScalar< ScalarType > &buffer, const grid::Grid4DDataScalar< ScalarType > &data, const int local_subdomain_id, const grid::BoundaryFace face, const grid::BoundaryDirection dir0, const grid::BoundaryDirection dir1)
	Writes buffer into the ghost cell layer at face.
template<typename ScalarType >
void	terra::communication::shell::update_fv_ghost_layers (const grid::shell::DistributedDomain &domain, const grid::Grid4DDataScalar< ScalarType > &data, FVGhostLayerBuffers< ScalarType > &bufs)
	Fills all ghost layers of a scalar FV field from neighbouring subdomains.
template<typename ScalarType >
void	terra::communication::shell::update_fv_ghost_layers (const grid::shell::DistributedDomain &domain, const grid::Grid4DDataScalar< ScalarType > &data)
	Convenience overload — allocates temporary buffers internally.
template<typename ScalarType , int VecDim>
void	terra::communication::shell::fv_detail::pack_inner_cells_vec (const grid::Grid3DDataScalar< ScalarType > &buffer, const grid::Grid4DDataVec< ScalarType, VecDim > &data, const int local_subdomain_id, const grid::BoundaryFace face)
	Packs the innermost real-cell layer adjacent to face into buffer for a vector field.
template<typename ScalarType , int VecDim>
void	terra::communication::shell::fv_detail::unpack_to_ghost_vec (const grid::Grid3DDataScalar< ScalarType > &buffer, const grid::Grid4DDataVec< ScalarType, VecDim > &data, const int local_subdomain_id, const grid::BoundaryFace face, const grid::BoundaryDirection dir0, const grid::BoundaryDirection dir1)
	Writes buffer into the ghost cell layer at face for a vector field.
template<typename ScalarType , int VecDim>
void	terra::communication::shell::update_fv_ghost_layers (const grid::shell::DistributedDomain &domain, const grid::Grid4DDataVec< ScalarType, VecDim > &data, FVGhostLayerVecBuffers< ScalarType, VecDim > &bufs)
	Fills all ghost layers of a vector-valued FV field from neighbouring subdomains.
template<typename ScalarType , int VecDim>
void	terra::communication::shell::update_fv_ghost_layers (const grid::shell::DistributedDomain &domain, const grid::Grid4DDataVec< ScalarType, VecDim > &data)
	Convenience overload for vector fields — allocates temporary buffers internally.

Variables
constexpr int	terra::communication::shell::MPI_TAG_FV_GHOST_LAYERS = 200
	MPI tag for FV ghost layer messages (distinct from MPI_TAG_BOUNDARY_DATA = 100).
constexpr int	terra::communication::shell::MPI_TAG_FV_VEC_GHOST_LAYERS = 201
	MPI tag for vector-valued FV ghost layer messages.

Detailed Description

Ghost layer communication for scalar finite volume (FV) fields on the shell grid.

FV cells are owned exclusively by one subdomain. Each cell array has a one-cell-wide ghost layer on every side so that operator stencils can read neighbour values without extra index checks. Unlike the FE communication in communication.hpp — which adds contributions from shared nodes — here we simply copy the innermost real cells of the neighbour into our ghost cells (no reduction required).

Layout reminder (Grid4DDataScalar, shape [n_subdomains, N_lat+1, N_lat+1, N_rad+1]):

• Real cells: indices [1, N_lat-1] × [1, N_lat-1] × [1, N_rad-1]
• Ghost cells: index 0 and index N (for each axis, N = last extent index)

Only face-to-face communication is implemented here. A 6-neighbour cell stencil (±x, ±y, ±r) never touches edge or vertex ghost cells, so face communication is sufficient.

Typical usage (operator that is applied repeatedly):

// Construct once (allocates Kokkos views for send/recv buffers):
FVGhostLayerBuffers<double> ghost_bufs(domain);
 
// Call every time the field changes (no allocation, just pack/MPI/unpack):
update_fv_ghost_layers(domain, field, ghost_bufs);