Detailed Description

Data packing/unpacking for ghost layer based communication of a field.

Encapsulate information on how to extract data from blocks that should be communicated to neighboring blocks (see packData()) and how to inject this data in a receiving block (see unpackData()). This involves a memory buffer and two memory copy operations.

A special method exists for communication between two blocks which are allocated on the same process (see communicateLocal()). In this case the data does not have be communicated via a buffer, but can be copied directly.

Data that is packed in direction "dir" at one block is unpacked in direction "stencil::inverseDir[dir]" at the neighboring block. This behavior must be implemented in communicateLocal()!

#include <UniformPackInfo.h>

Inheritance diagram for walberla::communication::UniformPackInfo:

Construction & Destruction
std::map< const IBlock *, std::map< stencil::Direction, size_t > >	bufferSize_

	UniformPackInfo ()=default

virtual	~UniformPackInfo ()=default

virtual bool	constantDataExchange () const =0
	Should return true if the amount of data that is packed for a given block in direction "dir" is guaranteed to remain constant over time.

virtual bool	threadsafeReceiving () const =0
	Must return false if calling unpackData and/or communicateLocal is not thread-safe.

void	packData (const IBlock *sender, stencil::Direction dir, mpi::SendBuffer &buffer) const
	Pack data from a block into a send buffer.

virtual void	unpackData (IBlock *receiver, stencil::Direction dir, mpi::RecvBuffer &buffer)=0
	Unpack received Data.

virtual void	communicateLocal (const IBlock sender, IBlock receiver, stencil::Direction dir)=0
	Copy data from one local block to another local block.

virtual void	beforeStartCommunication ()
	This function is called once before the communication is started by the UniformBufferedScheme.

virtual void	afterStartCommunication ()
	This function is called once after the communication has been started by the UniformBufferedScheme.

virtual void	beforeWait ()
	This function is called once before the UniformBufferedScheme waits for the communication to finish.

virtual void	afterWait ()
	This function is called once after the communication has been finished by the UniformBufferedScheme.

virtual void	packDataImpl (const IBlock *sender, stencil::Direction dir, mpi::SendBuffer &buffer) const =0
	Pack data from a block into a send buffer.

Constructor & Destructor Documentation

◆ UniformPackInfo()

walberla::communication::UniformPackInfo::UniformPackInfo ( )

default

◆ ~UniformPackInfo()

virtual walberla::communication::UniformPackInfo::~UniformPackInfo ( )

virtualdefault

Member Function Documentation

◆ afterStartCommunication()

virtual void walberla::communication::UniformPackInfo::afterStartCommunication ( )

inlinevirtual

This function is called once after the communication has been started by the UniformBufferedScheme.

◆ afterWait()

virtual void walberla::communication::UniformPackInfo::afterWait ( )

inlinevirtual

This function is called once after the communication has been finished by the UniformBufferedScheme.

◆ beforeStartCommunication()

virtual void walberla::communication::UniformPackInfo::beforeStartCommunication ( )

inlinevirtual

This function is called once before the communication is started by the UniformBufferedScheme.

◆ beforeWait()

virtual void walberla::communication::UniformPackInfo::beforeWait ( )

inlinevirtual

This function is called once before the UniformBufferedScheme waits for the communication to finish.

◆ communicateLocal()

virtual void walberla::communication::UniformPackInfo::communicateLocal	(	const IBlock *	sender,
		IBlock *	receiver,
		stencil::Direction	dir )

pure virtual

Copy data from one local block to another local block.

Both blocks are allocated on the current process. If NOT thread-safe, threadsafeReceiving must return false!

Parameters

sender	id of block where the data should be copied from
receiver	id of block where the data should be copied to
dir	the direction of the communication ( from sender to receiver )

Implemented in walberla::boundary::HandlingPackInfo< Handling_T >, walberla::field::communication::PackInfo< GhostLayerField_T >, walberla::field::communication::PackInfo< GhostLayerField< BubbleID, 1 > >, walberla::field::communication::StencilRestrictedPackInfo< GhostLayerField_T, Stencil_T >, walberla::field::communication::UniformPullReductionPackInfo< ReduceOperation, GhostLayerField_T >, walberla::free_surface::bubble_model::BubbleIDFieldPackInfo< Stencil_T >, walberla::gpu::communication::GPUPackInfo< GPUField_T >, walberla::lbm::CombinedInPlaceCpuPackInfo< EvenPackInfo, OddPackInfo >, walberla::lbm::SparsePdfFieldPackInfo< LatticeModel_T, FlagField_T >, and walberla::lbm_generated::CombinedInPlaceCpuPackInfo< LatticeStorageSpecification_T, EvenPackInfo, OddPackInfo >.

◆ constantDataExchange()

virtual bool walberla::communication::UniformPackInfo::constantDataExchange ( ) const

pure virtual

Should return true if the amount of data that is packed for a given block in direction "dir" is guaranteed to remain constant over time.

False otherwise. If you are not sure what to return, return false! Returning false is always safe. Falsely returning true will lead to errors! However, if the data can be guaranteed to remain constant over time, returning true enables performance optimizations during the communication.

Implemented in walberla::boundary::HandlingPackInfo< Handling_T >, walberla::field::communication::PackInfo< GhostLayerField_T >, walberla::field::communication::PackInfo< GhostLayerField< BubbleID, 1 > >, walberla::field::communication::StencilRestrictedPackInfo< GhostLayerField_T, Stencil_T >, walberla::field::communication::UniformPullReductionPackInfo< ReduceOperation, GhostLayerField_T >, walberla::gpu::communication::GPUPackInfo< GPUField_T >, walberla::lbm::CombinedInPlaceCpuPackInfo< EvenPackInfo, OddPackInfo >, walberla::lbm::SparsePdfFieldPackInfo< LatticeModel_T, FlagField_T >, walberla::lbm_generated::CombinedInPlaceCpuPackInfo< LatticeStorageSpecification_T, EvenPackInfo, OddPackInfo >, and walberla::lbm_generated::UniformGeneratedPdfPackInfo< PdfField_T >.

◆ packData()

void walberla::communication::UniformPackInfo::packData	(	const IBlock *	sender,
		stencil::Direction	dir,
		mpi::SendBuffer &	buffer ) const

inline

Pack data from a block into a send buffer.

Must be thread-safe! Calls packDataImpl.

Parameters

sender	the block whose data should be packed into a buffer
dir	pack data for neighbor in this direction
buffer	buffer for writing the data into

◆ packDataImpl()

virtual void walberla::communication::UniformPackInfo::packDataImpl	(	const IBlock *	sender,
		stencil::Direction	dir,
		mpi::SendBuffer &	buffer ) const

protectedpure virtual

Pack data from a block into a send buffer.

Must be thread-safe!

Implementations must reserve extra space and advance the send buffer pointer according to the alignment of the ghost layer data type! The buffer is char-aligned.

Parameters

sender	the block whose data should be packed into a buffer
dir	pack data for neighbor in this direction
buffer	buffer for writing the data into

Implemented in walberla::boundary::HandlingPackInfo< Handling_T >, walberla::field::communication::PackInfo< GhostLayerField_T >, walberla::field::communication::PackInfo< GhostLayerField< BubbleID, 1 > >, walberla::field::communication::StencilRestrictedPackInfo< GhostLayerField_T, Stencil_T >, walberla::field::communication::UniformPullReductionPackInfo< ReduceOperation, GhostLayerField_T >, walberla::gpu::communication::GPUPackInfo< GPUField_T >, walberla::lbm::CombinedInPlaceCpuPackInfo< EvenPackInfo, OddPackInfo >, walberla::lbm::SparsePdfFieldPackInfo< LatticeModel_T, FlagField_T >, and walberla::lbm_generated::CombinedInPlaceCpuPackInfo< LatticeStorageSpecification_T, EvenPackInfo, OddPackInfo >.

◆ threadsafeReceiving()

virtual bool walberla::communication::UniformPackInfo::threadsafeReceiving ( ) const

pure virtual

Must return false if calling unpackData and/or communicateLocal is not thread-safe.

True otherwise. If you are not sure what to return, return false! Returning false is always safe. Falsely returning true will most likely lead to errors! However, if both unpackData AND communicateLocal are thread-safe, returning true can lead to performance improvements.

Implemented in walberla::boundary::HandlingPackInfo< Handling_T >, walberla::field::communication::PackInfo< GhostLayerField_T >, walberla::field::communication::PackInfo< GhostLayerField< BubbleID, 1 > >, walberla::field::communication::StencilRestrictedPackInfo< GhostLayerField_T, Stencil_T >, walberla::field::communication::UniformPullReductionPackInfo< ReduceOperation, GhostLayerField_T >, walberla::free_surface::bubble_model::BubbleIDFieldPackInfo< Stencil_T >, walberla::gpu::communication::GPUPackInfo< GPUField_T >, walberla::lbm::CombinedInPlaceCpuPackInfo< EvenPackInfo, OddPackInfo >, walberla::lbm::SparsePdfFieldPackInfo< LatticeModel_T, FlagField_T >, walberla::lbm_generated::CombinedInPlaceCpuPackInfo< LatticeStorageSpecification_T, EvenPackInfo, OddPackInfo >, and walberla::lbm_generated::UniformGeneratedPdfPackInfo< PdfField_T >.

◆ unpackData()

virtual void walberla::communication::UniformPackInfo::unpackData	(	IBlock *	receiver,
		stencil::Direction	dir,
		mpi::RecvBuffer &	buffer )

pure virtual

Unpack received Data.

If NOT thread-safe, threadsafeReceiving must return false!

Implementations must reserve extra space and advance the send buffer pointer according to the alignment of the ghost layer data type! The buffer is char-aligned.

Parameters

receiver	the block where the unpacked data should be stored into
dir	receive data from neighbor in this direction
buffer	buffer for reading the data from

Implemented in walberla::boundary::HandlingPackInfo< Handling_T >, walberla::field::communication::PackInfo< GhostLayerField_T >, walberla::field::communication::PackInfo< GhostLayerField< BubbleID, 1 > >, walberla::field::communication::StencilRestrictedPackInfo< GhostLayerField_T, Stencil_T >, walberla::field::communication::UniformPullReductionPackInfo< ReduceOperation, GhostLayerField_T >, walberla::free_surface::bubble_model::BubbleIDFieldPackInfo< Stencil_T >, walberla::gpu::communication::GPUPackInfo< GPUField_T >, walberla::lbm::CombinedInPlaceCpuPackInfo< EvenPackInfo, OddPackInfo >, walberla::lbm::SparsePdfFieldPackInfo< LatticeModel_T, FlagField_T >, and walberla::lbm_generated::CombinedInPlaceCpuPackInfo< LatticeStorageSpecification_T, EvenPackInfo, OddPackInfo >.

Member Data Documentation

◆ bufferSize_

std::map< const IBlock *, std::map< stencil::Direction, size_t > > walberla::communication::UniformPackInfo::bufferSize_

mutableprotected

The documentation for this class was generated from the following file:

/builds/administration/walberla-website/walberla/src/communication/UniformPackInfo.h

Detailed Description

Construction & Destruction

Constructor & Destructor Documentation

◆ UniformPackInfo()

◆ ~UniformPackInfo()

Member Function Documentation

◆ afterStartCommunication()

◆ afterWait()

◆ beforeStartCommunication()

◆ beforeWait()

◆ communicateLocal()

◆ constantDataExchange()

◆ packData()

◆ packDataImpl()

◆ threadsafeReceiving()

◆ unpackData()

Member Data Documentation

◆ bufferSize_