VLAT is the Visibility LookAhead Thread. This thread advances a visibility iterator and fills the data indicated by the visibility iterator into the VlaData buffer ring. More...

#include <VLAT.h>

Inheritance diagram for casa::asyncio::VLAT:

Classes
class	FillerDictionary

class	SweepTerminated

Public Member Functions
	VLAT (AsynchronousInterface *)

	~VLAT ()

void	clearFillTerminationRequest ()

void	initialize (const ROVisibilityIterator &rovi)

void	initialize (const casacore::Block< casacore::MeasurementSet > &mss, const casacore::Block< casacore::Int > &sortColumns, casacore::Bool addDefaultSortCols, casacore::Double timeInterval, casacore::Bool writable)

casacore::Bool	isTerminated () const

void	setModifiers (RoviaModifiers &modifiers)

void	setPrefetchColumns (const PrefetchColumns &prefetchColumns)

void	requestSweepTermination ()

void	terminate ()

Public Member Functions inherited from casa::async::Thread
	Thread ()

virtual	~Thread ()

pthread_t	getId () const

pid_t	gettid () const

bool	isTerminationRequested () const

void *	join ()

void	startThread ()

Protected Types
typedef std::vector < VlatFunctor * >	Fillers

Protected Member Functions
void	applyModifiers (ROVisibilityIterator rovi, VisibilityIterator vi)

void	alignWriteIterator (SubChunkPair subchunk)

void	checkFiller (VisBufferComponents::EnumType id)

void	createFillerDictionary ()

void	fillDatum (VlaDatum *datum)

void	fillDatumMiscellanyAfter (VlaDatum *datum)

void	fillDatumMiscellanyBefore (VlaDatum *datum)

void	fillLsrInfo (VlaDatum *datum)

void	flushWrittenData ()

void	handleWrite ()

void *	run ()

casacore::Bool	sweepTerminationRequested () const

void	sweepVi ()

void	throwIfSweepTerminated ()

casacore::Bool	waitForViReset ()

void	waitUntilFillCanStart ()

Protected Member Functions inherited from casa::async::Thread
bool	isStarted () const

Private Attributes
const InterfaceController *	controller_p
	class NullaryPredicate { public: More...

FillerDictionary	fillerDictionary_p

Fillers	fillers_p

AsynchronousInterface *	interface_p

casacore::Block < casacore::MeasurementSet >	measurementSets_p

SubChunkPair	readSubchunk_p

RoviaModifiers	roviaModifiers_p

volatile casacore::Bool	sweepTerminationRequested_p

casacore::Bool	threadTerminated_p

ROVisibilityIterator *	visibilityIterator_p

VlaData *	vlaData_p

VisibilityIterator *	writeIterator_p

SubChunkPair	writeSubchunk_p

Additional Inherited Members
Public Types inherited from casa::async::Thread
typedef void (	ThreadFunction )(void *)

Static Protected Member Functions inherited from casa::async::Thread
static void *	threadFunction (void *)

Detailed Description

VLAT is the Visibility LookAhead Thread. This thread advances a visibility iterator and fills the data indicated by the visibility iterator into the VlaData buffer ring.

Intended use:

Internal

Review Status

Date Reviewed:: yyyy/mm/dd

Prerequisite

VisBuffer
VisBufferAsync
ROVisibilityIteratorAsync
VlaData
VLAT

Etymology

VLAT is the Visibility LookAhead Thread. It is not related to the more common NRAO acronym VLA.

Synopsis

The VLAT is a thread object that buffers up data from successive visibility iterator positions in a MeasurementSet. It is part of the backend to a ROVisibilityIteratorAsync (ROVIA) object used by the main thread to replace the normal, synchronous ROVisibilityIterator. When the user creates a ROVIA object the information normally used to create a ROVisibilityIterator is passed to the VLAT which uses it to create a ROVisibilityIterator local to itself. The VLAT then uses this ROVisibilityIterator to fill buffers in the VlaData-managed buffer ring (this interaction is described in VlaData). Filling consists of attaching VLAT's ROVisibilityIterator to the VisBufferAsync object associated with a buffer and then calling the fill operations for the data items (e.g., visCube, Ant1, etc.) which the user has requested be prefetched. The fill operations will likely result in synchronous I/O operations being performed by the column access methods related to the casacore::Table system (memory-resident tables, columns, etc., may be able to satisfy a fill operation without performing I/O).

The thread may be terminated by calling the terminate method. This will cause the VLAT to terminate when it notices the termination request. The termination may not be immediate since the VLAT may be engaged in a syncrhonous I/O operation and is uanble to detect the termination request until that I/O has completed.

Normally the VLAT sweeps the VI to the end of the measurement set and then awaits further instructions. The main thread may stop the sweep early by calling VlaData::terminateSweep which will eventually be detected by the VLAT and result in a coordinated reset of the sweep. When the sweep reset is applied the VLAT will also detect visibility iterator modification requests (e.g., setRowBlocking, selectChannel, setInterval, etc.) that were queued up in VlaData; for the set of available VI modification requests supported see ROVisibilityIteratorAsync.

Example

Motivation

Thrown Exceptions

casacore::AipsError for unrecoverable errors. These will not be caught (in C++ anyway) and cause application termination.

Definition at line 219 of file VLAT.h.

Member Typedef Documentation

typedef std::vector<VlatFunctor *> casa::asyncio::VLAT::Fillers

protected

Definition at line 254 of file VLAT.h.

Constructor & Destructor Documentation

casa::asyncio::VLAT::VLAT ( AsynchronousInterface * )

casa::asyncio::VLAT::~VLAT ( )

Member Function Documentation

void casa::asyncio::VLAT::alignWriteIterator ( SubChunkPair subchunk )

protected

void casa::asyncio::VLAT::applyModifiers	(	ROVisibilityIterator *	rovi,
		VisibilityIterator *	vi
	)

protected

void casa::asyncio::VLAT::checkFiller ( VisBufferComponents::EnumType id )

protected

void casa::asyncio::VLAT::clearFillTerminationRequest ( )

void casa::asyncio::VLAT::createFillerDictionary ( )

protected

void casa::asyncio::VLAT::fillDatum ( VlaDatum * datum )

protected

void casa::asyncio::VLAT::fillDatumMiscellanyAfter ( VlaDatum * datum )

protected

void casa::asyncio::VLAT::fillDatumMiscellanyBefore ( VlaDatum * datum )

protected

void casa::asyncio::VLAT::fillLsrInfo ( VlaDatum * datum )

protected

void casa::asyncio::VLAT::flushWrittenData ( )

protected

void casa::asyncio::VLAT::handleWrite ( )

protected

void casa::asyncio::VLAT::initialize ( const ROVisibilityIterator & rovi )

void casa::asyncio::VLAT::initialize	(	const casacore::Block< casacore::MeasurementSet > &	mss,
		const casacore::Block< casacore::Int > &	sortColumns,
		casacore::Bool	addDefaultSortCols,
		casacore::Double	timeInterval,
		casacore::Bool	writable
	)

casacore::Bool casa::asyncio::VLAT::isTerminated ( ) const

void casa::asyncio::VLAT::requestSweepTermination ( )

void* casa::asyncio::VLAT::run ( )

protectedvirtual

Implements casa::async::Thread.

void casa::asyncio::VLAT::setModifiers ( RoviaModifiers & modifiers )

void casa::asyncio::VLAT::setPrefetchColumns ( const PrefetchColumns & prefetchColumns )

casacore::Bool casa::asyncio::VLAT::sweepTerminationRequested ( ) const

protected

void casa::asyncio::VLAT::sweepVi ( )

protected

void casa::asyncio::VLAT::terminate ( )

virtual

Reimplemented from casa::async::Thread.

void casa::asyncio::VLAT::throwIfSweepTerminated ( )

protected

casacore::Bool casa::asyncio::VLAT::waitForViReset ( )

protected

void casa::asyncio::VLAT::waitUntilFillCanStart ( )

protected

Member Data Documentation

const InterfaceController* casa::asyncio::VLAT::controller_p

private

class NullaryPredicate { public:

virtual ~NullaryPredicate () {} virtual casacore::Bool operator () () const = 0; };

class FillCanStartOrSweepTermination : public NullaryPredicate {

public:

FillCanStartOrSweepTermination (VlaData * vlaData, AsynchronousInterface * interface) : interface_p (interface), vlaData_p (vlaData) {}

casacore::Bool operator() () const { return vlaData_p->fillCanStart () || interface_p->isSweepTerminationRequested (); }

private:

AsynchronousInterface * interface_p; VlaData * vlaData_p; };

class ViResetOrLookaheadTermination : public NullaryPredicate {

public:

ViResetOrLookaheadTermination (AsynchronousInterface * interface) : interface_p (interface) {}

casacore::Bool operator() () const { casacore::Bool viWasReset_p = interface_p->viResetRequested;

return viWasReset_p || interface_p->isLookaheadTerminationRequested (); }

private:

AsynchronousInterface * interface_p; };

Definition at line 324 of file VLAT.h.

FillerDictionary casa::asyncio::VLAT::fillerDictionary_p

private

Definition at line 325 of file VLAT.h.

Fillers casa::asyncio::VLAT::fillers_p

private

Definition at line 326 of file VLAT.h.

AsynchronousInterface* casa::asyncio::VLAT::interface_p

private

Definition at line 327 of file VLAT.h.

casacore::Block<casacore::MeasurementSet> casa::asyncio::VLAT::measurementSets_p

private

Definition at line 328 of file VLAT.h.

SubChunkPair casa::asyncio::VLAT::readSubchunk_p

private

Definition at line 329 of file VLAT.h.

RoviaModifiers casa::asyncio::VLAT::roviaModifiers_p

private

Definition at line 330 of file VLAT.h.

volatile casacore::Bool casa::asyncio::VLAT::sweepTerminationRequested_p

private

Definition at line 331 of file VLAT.h.

casacore::Bool casa::asyncio::VLAT::threadTerminated_p

private

Definition at line 332 of file VLAT.h.

ROVisibilityIterator* casa::asyncio::VLAT::visibilityIterator_p

private

Definition at line 333 of file VLAT.h.

VlaData* casa::asyncio::VLAT::vlaData_p

private

Definition at line 334 of file VLAT.h.

VisibilityIterator* casa::asyncio::VLAT::writeIterator_p

private

Definition at line 335 of file VLAT.h.

SubChunkPair casa::asyncio::VLAT::writeSubchunk_p

private

Definition at line 336 of file VLAT.h.

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

casa/code/msvis/MSVis/VLAT.h

Classes

Public Member Functions

Protected Types

Protected Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Intended use:

Review Status

Prerequisite

Etymology

Synopsis

Example

Motivation

Thrown Exceptions

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation