casa::vi::LayeredVi2Factory Class Reference

A factory for generating ViImplementation2 layers that optionally include calibration (via CalibratingVi2) and time-averaging (via AveragingTvi2). More...

#include <LayeredVi2Factory.h>

Inheritance diagram for casa::vi::LayeredVi2Factory:

List of all members.

Public Member Functions
	LayeredVi2Factory (MeasurementSet ms, IteratingParameters iterpar, AveragingParameters *avepar=0)
	Non-calibrating version.
	LayeredVi2Factory (MeasurementSet ms, IteratingParameters iterpar, const Record &calrec, AveragingParameters *avepar=0)
	Calibrating version, via CalLib Record.
	LayeredVi2Factory (MeasurementSet ms, IteratingParameters iterpar, const String &callib, AveragingParameters *avepar=0)
	Calibrating version, vis CalLib String (filename or String).
	~LayeredVi2Factory ()
vi::ViImplementation2 *	createVi () const
vi::ViImplementation2 *	createVi (vi::ViImplementation2 *) const
Private Attributes
MeasurementSet *	ms_p
vi::IteratingParameters *	iterpar_p
vi::AveragingParameters *	avepar_p
Bool	doCal_p
String	callib_p
Record	calrec_p
Int	nlayer_p
CalibratingVi2FactoryI *	calvi2factory_p

Detailed Description

A factory for generating ViImplementation2 layers that optionally include calibration (via CalibratingVi2) and time-averaging (via AveragingTvi2).

Intended use:

Public interface

Prerequisite

Etymology

Factory for layered ViImplementation2 construction

Synopsis

LayeredVi2Factory generates a Visibility Iterator implementation (ViImplementation2) object that can be plugged into a Visibility Iterator (VisibilityIterator2) object, so that the user can access the data using the Visibility Iterator interface. The ViImplementation2 generated by this factory consists of an underlying VisibilityIteratorImpl2, and (optionally) CalibratingVi2 and AveragingTvi2 ViImplementation2s, thereby supporting these operations in sequence. When both calibration and averaging are invoked, calibration is hard-wired to occur first.

Motivation

This class makes the combination of OTF calibration application and time-averaging portable, and available to all VisibilityIterator2 users.

Example

External usage is quite simple, and compliant with the 'normal' VI/VB framework.

The user first makes objects describing the data iteration, calibration parameters, and averaging parameters:

 IteratingParameters iterpar(60.0);  // 60s chunk interval
 
 Float calfactor(100.0);             // a simple factor with which to multiply the data
 Record calrec;                      //   (in leiu of full VisEquation functionality (TBD)
 calrec.define("calfactor",calfactor); // in a Record   
 
 AveragingParameters avepar(10.0);   // 10s averaging

Then these parameter objects, along with a MeasurementSet pointer, are used to make a factory suitable for the generic VisibilityIterator2 ctor, which is then invoked

 MeasurementSet *ms(....);   // typically from elsewhere, e.g., selected
 LayeredVi2Factory factory(ms,&iterpar,calrec,&avepar);
 vi::VisibilityIterator2 *visIter = new vi::VisibilityIterator2 (factory);
 vi::VisBuffer2 *visBuffer = visIter->getVisBuffer();

Once this is done one can normally iterate and access OTF calibrated and averaged data:

 while (visIter->moreChunks())
 {
 visIter->origin();
 
 while (visIter->more())
 {
 
 // the following will have been calibrated and averaged to 10s
 Vector<Int> ddi = visBuffer->dataDescriptionIds();
 Vector<Int> antenna1 = visBuffer->antenna1();
 Vector<Int> antenna2 = visBuffer->antenna2();
 Cube<Complex> cvis = visBuffer->visCubeCorrected();
 
 visIter->next();
 }
 
 visIter->nextChunk();
 }

Notice that it is the responsibility of the application layer to delete the VisibilityIterator2 pointer returned by the factory method. However the life cycle of the VisBuffer2 object is responsibility of the VisibilityIterator2 object.

 delete visIter;

Definition at line 134 of file LayeredVi2Factory.h.

Constructor & Destructor Documentation

casa::vi::LayeredVi2Factory::LayeredVi2Factory	(	MeasurementSet *	ms,
		IteratingParameters *	iterpar,
		AveragingParameters *	avepar = `0`
	)

Non-calibrating version.

casa::vi::LayeredVi2Factory::LayeredVi2Factory	(	MeasurementSet *	ms,
		IteratingParameters *	iterpar,
		const Record &	calrec,
		AveragingParameters *	avepar = `0`
	)

Calibrating version, via CalLib Record.

casa::vi::LayeredVi2Factory::LayeredVi2Factory	(	MeasurementSet *	ms,
		IteratingParameters *	iterpar,
		const String &	callib,
		AveragingParameters *	avepar = `0`
	)