The base class to compute convolution functions for convolutional gridding. More...

#include <ConvolutionFunction.h>

Inheritance diagram for casa::ConvolutionFunction:

Public Member Functions
	ConvolutionFunction ()
	ConvolutionFunction (Int dim)
virtual	~ConvolutionFunction ()
virtual void	setDimension (Int n)
	Set the dimention of the convolution function.
virtual CF_TYPE	getValue (Vector< CF_TYPE > &, Vector< CF_TYPE > &)
	Given the pixel co-ordinates and an offset values, this returns the value of the convolution function.
virtual int	getVisParams (const VisBuffer &vb, const CoordinateSystem &skyCoord=CoordinateSystem())=0
	A support function which, for now, returns and integer ID corresponding to the on-sky frequency of the supplied VisBuffer.
virtual void	makeConvFunction (const ImageInterface< Complex > &image, const VisBuffer &vb, const Int wConvSize, const CountedPtr< PolOuterProduct > &pop, const Float pa, const Float dpa, const Vector< Double > &uvScale, const Vector< Double > &uvOffset, const Matrix< Double > &vbFreqSelection, CFStore2 &cfs, CFStore2 &cfwts)=0
	This method computes the convolution function and the convolution function used for gridding the weights (typically these are the same) and returns them in the cfs and cfwts parameters.
virtual Bool	makeAverageResponse (const VisBuffer &vb, const ImageInterface< Complex > &image, ImageInterface< Float > &theavgPB, Bool reset=True)=0
	This method computes the average response function.
virtual Bool	makeAverageResponse (const VisBuffer &vb, const ImageInterface< Complex > &image, ImageInterface< Complex > &theavgPB, Bool reset=True)=0
virtual void	setPolMap (const Vector< Int > &polMap)=0
virtual void	setSpwSelection (const Cube< Int > &spwChanSelFlag)
virtual void	setSpwFreqSelection (const Matrix< Double > &spwFreqSel)
virtual void	setRotateCF (const Double &computeCFAngleRad, const Double &rotateOTF)
virtual Bool	findSupport (Array< Complex > &func, Float &threshold, Int &origin, Int &R)=0
	virtual void setFeedStokes(const Vector<Int>& feedStokes) = 0;
virtual Vector< Double >	findPointingOffset (const ImageInterface< Complex > &image, const VisBuffer &vb)=0
virtual void	prepareConvFunction (const VisBuffer &vb, VBRow2CFBMapType &theMap)=0
	virtual void setParams(const Vector<Int>& polMap, const Vector<Int>& feedStokes) {setPolMap(polMap); setFeedStokes(feedStokes);};
virtual Matrix< Int >	makeBaselineList (const Vector< Int > &antList)
virtual Int	mapAntIDToAntType (const Int &)
virtual void	setMiscInfo (const RecordInterface &)
Protected Member Functions
LogIO &	logIO ()
Protected Attributes
LogIO	logIO_p
Cube< Int >	spwChanSelFlag_p
Matrix< Double >	spwFreqSelection_p
Double	computeCFAngleRad_p
Double	rotateCFOTFAngleRad_p
Private Attributes
Int	nDim

Detailed Description

The base class to compute convolution functions for convolutional gridding.

Intended use:

Public interface

Etymology

Class to encapsulate the convolution function for convolutional gridding.

Synopsis

Standard method of re-sampling data to or from a

regular grid is done by convolutional gridding. This requires a convolution function which a finte support size and well behaved function in the Fourier domain. For standard gridding, the Prolate Spheroidal function are used. Convolution functions used in Projection algorithms (like W-Projection, A-Projection, etc. and their combinations) each require potentially different mechanisms to compute. These are implemented in separate classes in the Synthesis module. Since these are used in common framework for gridding and de-gridding, these are all derived from a common base class. ConvolutionFunction (this class) is that base class.

Most of the methods in this base class are pure virtual. I.e., only surviving offsprings (derived classes) of this class will be those that will have the wisdom that they methods represent.

Definition at line 76 of file ConvolutionFunction.h.

Constructor & Destructor Documentation

casa::ConvolutionFunction::ConvolutionFunction ( ) [inline]

Definition at line 79 of file ConvolutionFunction.h.

casa::ConvolutionFunction::ConvolutionFunction ( Int dim ) [inline]

Definition at line 80 of file ConvolutionFunction.h.

References nDim.

virtual casa::ConvolutionFunction::~ConvolutionFunction ( ) [virtual]

Member Function Documentation

virtual Vector<Double> casa::ConvolutionFunction::findPointingOffset	(	const ImageInterface< Complex > &	image,
		const VisBuffer &	vb
	)		`[pure virtual]`

Implemented in casa::AWConvFunc, casa::IlluminationConvFunc, and casa::AWConvFuncEPJones.

virtual Bool casa::ConvolutionFunction::findSupport	(	Array< Complex > &	func,
		Float &	threshold,
		Int &	origin,
		Int &	R
	)		`[pure virtual]`

virtual void setFeedStokes(const Vector<Int>& feedStokes) = 0;

Implemented in casa::AWConvFunc, casa::IlluminationConvFunc, casa::VLACalcIlluminationConvFunc, casa::WOnlyConvFunc, casa::WOnlyConvFunc, and casa::EVLAConvFunc.

virtual CF_TYPE casa::ConvolutionFunction::getValue	(	Vector< CF_TYPE > &	,
		Vector< CF_TYPE > &
	)		`[inline, virtual]`

Given the pixel co-ordinates and an offset values, this returns the value of the convolution function.

This is however not used anywhere yet (and is therefore also not a pure virtual function).

Reimplemented in casa::IlluminationConvFunc.

Definition at line 90 of file ConvolutionFunction.h.

virtual int casa::ConvolutionFunction::getVisParams	(	const VisBuffer &	vb,
		const CoordinateSystem &	skyCoord = `CoordinateSystem()`
	)		`[pure virtual]`

A support function which, for now, returns and integer ID corresponding to the on-sky frequency of the supplied VisBuffer.

Implemented in casa::AWConvFunc, casa::IlluminationConvFunc, and casa::PixelatedConvFunc< T >.

LogIO& casa::ConvolutionFunction::logIO ( ) [inline, protected]

Reimplemented in casa::EVLAConvFunc.

Definition at line 150 of file ConvolutionFunction.h.

References logIO_p.

virtual Bool casa::ConvolutionFunction::makeAverageResponse	(	const VisBuffer &	vb,
		const ImageInterface< Complex > &	image,
		ImageInterface< Float > &	theavgPB,
		Bool	reset = `True`
	)		`[pure virtual]`

This method computes the average response function.

This is typically image-plane equivalent of the convolution functions, averaged over various axis. The precise averaging will be implementation dependent in the derived classes.

Implemented in casa::IlluminationConvFunc, casa::VLACalcIlluminationConvFunc, casa::AWConvFunc, casa::WOnlyConvFunc, and casa::WOnlyConvFunc.

virtual Bool casa::ConvolutionFunction::makeAverageResponse	(	const VisBuffer &	vb,
		const ImageInterface< Complex > &	image,
		ImageInterface< Complex > &	theavgPB,
		Bool	reset = `True`
	)		`[pure virtual]`

Implemented in casa::IlluminationConvFunc, casa::AWConvFunc, casa::WOnlyConvFunc, casa::WOnlyConvFunc, and casa::PixelatedConvFunc< T >.

virtual Matrix<Int> casa::ConvolutionFunction::makeBaselineList ( const Vector< Int > & antList ) [virtual]

virtual void casa::ConvolutionFunction::makeConvFunction	(	const ImageInterface< Complex > &	image,
		const VisBuffer &	vb,
		const Int	wConvSize,
		const CountedPtr< PolOuterProduct > &	pop,
		const Float	pa,
		const Float	dpa,
		const Vector< Double > &	uvScale,
		const Vector< Double > &	uvOffset,
		const Matrix< Double > &	vbFreqSelection,
		CFStore2 &	cfs,
		CFStore2 &	cfwts
	)		`[pure virtual]`

This method computes the convolution function and the convolution function used for gridding the weights (typically these are the same) and returns them in the cfs and cfwts parameters.

The required information about the image and visibility parameters is dervided from the given image and VisBuffer objects. wConvSize is the number of w-term planes and pa is the Parallactic Angle in radians for which the convolution function(s) are computed.

Implemented in casa::AWConvFunc, and casa::AWConvFuncEPJones.

virtual Int casa::ConvolutionFunction::mapAntIDToAntType ( const Int & ) [inline, virtual]