Read a checkpoint back. More...

#include <CheckpointReader.h>

Collaboration diagram for exahype2::CheckpointReader:

[legend]

Public Member Functions
	CheckpointReader (const std::string &indexFileName, double timeStamp, int haloWidth, const tarch::la::Vector< Dimensions, double > &domainOffset, const tarch::la::Vector< Dimensions, double > &domainSize)

const std::vector< peano4::grid::GridControlEvent > &	getRefinementEvents () const
	Refinement events which reconstruct the checkpoint's mesh.

bool	readPatch (const tarch::la::Vector< Dimensions, double > &cellCentre, const tarch::la::Vector< Dimensions, double > &cellH, int numberOfEntries, double *patchWithHalo) const
	Copy the data of a cell's patch including its halo.

const std::string &	getMetaData () const
	Content of the meta-data block of the dataset's files, i.e.

double	getTimeStamp () const
	Time stamp of the dataset as given in the index file.

int	getNumberOfPatches () const

Static Public Member Functions
static CheckpointReader &	getInstance (const std::string &indexFileName, double timeStamp, int haloWidth, const tarch::la::Vector< Dimensions, double > &domainOffset, const tarch::la::Vector< Dimensions, double > &domainSize)
	Reader of a checkpoint dataset.

static void	release (const std::string &indexFileName)
	Free the reader of an index file, if there is one.

Private Types
using	Key = std::array< long long, Dimensions+1 >
	Integer index of the cell per axis, followed by its level.

Private Member Functions
Key	toKey (const tarch::la::Vector< Dimensions, double > &cellOffset, const tarch::la::Vector< Dimensions, double > &cellH) const
	Level and integer index of a cell within the regular grid of its level.

std::vector< std::string >	readIndexFile (const std::string &indexFileName, double timeStamp)
	Files of the selected dataset in the index file.

void	readPatchFile (const std::string &fileName)

void	createRefinementEvents ()

Private Attributes
const int	_haloWidth

const tarch::la::Vector< Dimensions, double >	_domainOffset

const tarch::la::Vector< Dimensions, double >	_domainSize

double	_timeStamp

std::string	_metaData

std::vector< std::vector< double > >	_patchData

std::map< Key, int >	_patchIndex

std::vector< peano4::grid::GridControlEvent >	_refinementEvents

Static Private Attributes
static tarch::logging::Log	_log

static tarch::multicore::BooleanSemaphore	_semaphore

static std::map< std::string, std::unique_ptr< CheckpointReader > >	_instances

Detailed Description

Read a checkpoint back.

A checkpoint is a set of Peano patch files as written by exahype2.api.fv.WriteCheckpoint or exahype2.api.rkfd4.WriteCheckpoint: An index file lists one dataset per checkpoint, and each dataset includes one patch file per spacetree. Every patch holds the data of one mesh cell plus its halo, written over the cell's box enlarged by the halo. The meta-data block in the header of each file holds the solver's state (exahype2::Solver::toCheckpointMetaData()).

File formats

The files are either ASCII or binary files. The reader is format-agnostic: It looks at the header of each patch file (tarch::reader::PeanoTextPatchFileReader::readHeader()), instantiates the matching reader from tarch::reader and lets it parse the file. This class only maps the patches that come back onto the cells of the mesh.

The reader parses all files of one dataset. It then

yields refinement events which reconstruct the checkpoint's mesh (getRefinementEvents()),
hands out the data of the patch belonging to a cell (readPatch()), and
provides the solver state (getMetaData()).

Matching patches and cells

The reader identifies each patch by the level and the integer index of its cell within the regular grid of that level, both derived from the domain's offset and size. The index is the rounded quotient of the cell's offset and size, i.e. there is no tolerance involved, and a coarse cell and the fine cell in its centre never get mixed up.

Reconstructing the mesh

Peano refines a cell if it overlaps a refinement event, and if it is at least as big as the event's mesh size. For every cell of the checkpoint on level two or higher, the reader hence yields one event which covers the middle third of the cell's parent, with the parent's size as mesh size. This event refines the parent and all of its ancestors, but none of the parent's neighbours. Cells on level one result from the refinement of the root, which Peano always carries out. Events of cells with the same parent are identical, so the reader yields each one only once.

Parallelisation

Every rank reads all files of the dataset. The memory footprint per rank hence is the size of the whole checkpoint.

Definition at line 72 of file CheckpointReader.h.

Member Typedef Documentation

◆ Key

using exahype2::CheckpointReader::Key = std::array<long long, Dimensions + 1>

private

Integer index of the cell per axis, followed by its level.

Definition at line 158 of file CheckpointReader.h.

Constructor & Destructor Documentation

◆ CheckpointReader()

exahype2::CheckpointReader::CheckpointReader	(	const std::string &	indexFileName,
		double	timeStamp,
		int	haloWidth,
		const tarch::la::Vector< Dimensions, double > &	domainOffset,
		const tarch::la::Vector< Dimensions, double > &	domainSize
	)

Member Function Documentation

◆ createRefinementEvents()

void exahype2::CheckpointReader::createRefinementEvents ( )

private

◆ getInstance()

static CheckpointReader & exahype2::CheckpointReader::getInstance	(	const std::string &	indexFileName,
		double	timeStamp,
		int	haloWidth,
		const tarch::la::Vector< Dimensions, double > &	domainOffset,
		const tarch::la::Vector< Dimensions, double > &	domainSize
	)

static

Reader of a checkpoint dataset.

The routine reads the files once and hands out the same reader to all later calls with the same index file, until release() frees it. It is thread-safe.

Parameters

indexFileName	Index file of the checkpoint, i.e. the file checkpoint-SolverName.peano-patch-file. The paths of the patch files in there are relative to the directory of the index file.
timeStamp	Time stamp of the dataset to read. If it is negative, the reader reads the latest dataset. Otherwise, it reads the dataset whose time stamp is closest to timeStamp. Datasets without files are ignored.
haloWidth	Number of volumes or grid cells of the halo per side, i.e. the difference between the number of entries per axis in the file and in the solver's patch, divided by two.
domainOffset	Offset of the computational domain.
domainSize	Size of the computational domain.

◆ getMetaData()

const std::string & exahype2::CheckpointReader::getMetaData ( ) const

Content of the meta-data block of the dataset's files, i.e.

the solver's state (exahype2::Solver::fromCheckpointMetaData()). One key-value pair per line, without indentation.

◆ getNumberOfPatches()

int exahype2::CheckpointReader::getNumberOfPatches ( ) const

◆ getRefinementEvents()

const std::vector< peano4::grid::GridControlEvent > & exahype2::CheckpointReader::getRefinementEvents ( ) const

Refinement events which reconstruct the checkpoint's mesh.

◆ getTimeStamp()

double exahype2::CheckpointReader::getTimeStamp ( ) const

Time stamp of the dataset as given in the index file.

◆ readIndexFile()

std::vector< std::string > exahype2::CheckpointReader::readIndexFile	(	const std::string &	indexFileName,
		double	timeStamp
	)

private

Files of the selected dataset in the index file.

◆ readPatch()

bool exahype2::CheckpointReader::readPatch	(	const tarch::la::Vector< Dimensions, double > &	cellCentre,
		const tarch::la::Vector< Dimensions, double > &	cellH,
		int	numberOfEntries,
		double *	patchWithHalo
	)		const

Copy the data of a cell's patch including its halo.

Parameters

cellCentre	Centre of the cell, i.e. marker.x().
cellH	Size of the cell, i.e. marker.h().
numberOfEntries	Number of doubles the patch with halo holds, i.e. the number of unknowns times the number of entries per axis to the power of Dimensions. The routine checks it against the file.
patchWithHalo	Destination.

Returns: Whether the checkpoint holds a patch for the cell. If not, the routine leaves patchWithHalo unchanged.

◆ readPatchFile()

void exahype2::CheckpointReader::readPatchFile ( const std::string & fileName )

private

◆ release()

static void exahype2::CheckpointReader::release ( const std::string & indexFileName )

static

Free the reader of an index file, if there is one.

◆ toKey()

Key exahype2::CheckpointReader::toKey	(	const tarch::la::Vector< Dimensions, double > &	cellOffset,
		const tarch::la::Vector< Dimensions, double > &	cellH
	)		const

private

Level and integer index of a cell within the regular grid of its level.

Field Documentation

◆ _domainOffset

const tarch::la::Vector<Dimensions, double> exahype2::CheckpointReader::_domainOffset

private

Definition at line 166 of file CheckpointReader.h.

◆ _domainSize

const tarch::la::Vector<Dimensions, double> exahype2::CheckpointReader::_domainSize

private

Definition at line 167 of file CheckpointReader.h.

◆ _haloWidth

const int exahype2::CheckpointReader::_haloWidth

private

Definition at line 165 of file CheckpointReader.h.

◆ _instances

std::map<std::string, std::unique_ptr<CheckpointReader> > exahype2::CheckpointReader::_instances

staticprivate

Definition at line 163 of file CheckpointReader.h.

◆ _log

tarch::logging::Log exahype2::CheckpointReader::_log

staticprivate

Definition at line 160 of file CheckpointReader.h.

◆ _metaData

std::string exahype2::CheckpointReader::_metaData

private

Definition at line 170 of file CheckpointReader.h.

◆ _patchData

std::vector<std::vector<double> > exahype2::CheckpointReader::_patchData

private

Definition at line 171 of file CheckpointReader.h.

◆ _patchIndex

std::map<Key, int> exahype2::CheckpointReader::_patchIndex

private

Definition at line 172 of file CheckpointReader.h.

◆ _refinementEvents

std::vector<peano4::grid::GridControlEvent> exahype2::CheckpointReader::_refinementEvents

private

Definition at line 173 of file CheckpointReader.h.

◆ _semaphore

tarch::multicore::BooleanSemaphore exahype2::CheckpointReader::_semaphore

staticprivate

Definition at line 162 of file CheckpointReader.h.

◆ _timeStamp

double exahype2::CheckpointReader::_timeStamp

private

Definition at line 169 of file CheckpointReader.h.

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

src/exahype2/CheckpointReader.h

Public Member Functions

Static Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

File formats

Matching patches and cells

Reconstructing the mesh

Parallelisation

Member Typedef Documentation

◆ Key

Constructor & Destructor Documentation

◆ CheckpointReader()

Member Function Documentation

◆ createRefinementEvents()

◆ getInstance()

◆ getMetaData()

◆ getNumberOfPatches()

◆ getRefinementEvents()

◆ getTimeStamp()

◆ readIndexFile()

◆ readPatch()

◆ readPatchFile()

◆ release()

◆ toKey()

Field Documentation

◆ _domainOffset

◆ _domainSize

◆ _haloWidth

◆ _instances

◆ _log

◆ _metaData

◆ _patchData

◆ _patchIndex

◆ _refinementEvents

◆ _semaphore

◆ _timeStamp