casa::SkyComponent Class Reference

A component of a model of the sky. More...

#include <SkyComponent.h>

Inheritance diagram for casa::SkyComponent:

Public Member Functions
	SkyComponent ()
	The default SkyComponent is a point source with a constant spectrum.
	SkyComponent (const ComponentType::Shape &shape)
	Construct a SkyCompRep of the specified shape.
	SkyComponent (const ComponentType::Shape &shape, const ComponentType::SpectralShape &spectralModel)
	Construct a SkyCompRep with the user specified model for the shape and spectrum.
	SkyComponent (const Flux< Double > &flux, const ComponentShape &shape, const SpectralModel &spectrum)
	Construct a SkyComponent with a fully specified model for the shape, spectrum and flux.
	SkyComponent (const SkyComponent &other)
	The copy Constructor uses reference semantics.
virtual	~SkyComponent ()
	the destructor does nothing obvious (its all done by the CountedPtr)
SkyComponent &	operator= (const SkyComponent &other)
	The assignment operator uses reference semantics.
virtual Flux< Double > &	flux ()
	See the corresponding functions in the SkyCompBase class for a description of these functions.
virtual const Flux< Double > &	flux () const
	return a reference to the flux of the component.
virtual const ComponentShape &	shape () const
	See the corresponding functions in the SkyCompBase class for a description of these functions.
virtual ComponentShape &	shape ()
virtual void	setShape (const ComponentShape &newShape)
virtual const SpectralModel &	spectrum () const
	See the corresponding functions in the SkyCompBase class for a description of these functions.
virtual SpectralModel &	spectrum ()
virtual void	setSpectrum (const SpectralModel &newSpectrum)
virtual String &	label ()
	See the corresponding functions in the SkyCompBase class for a description of these functions.
virtual const String &	label () const
virtual Vector< Double > &	optionalParameters ()
	See the corresponding functions in the SkyCompBase class for a description of these functions.
virtual const Vector< Double > &	optionalParameters () const
virtual Bool	isPhysical () const
	See the corresponding function in the SkyCompBase class for a description of this function.
virtual Flux< Double >	sample (const MDirection &direction, const MVAngle &pixelLatSize, const MVAngle &pixelLongSize, const MFrequency &centerFrequency) const
	See the corresponding functions in the SkyCompBase class for a description of this function.
virtual void	sample (Cube< Double > &samples, const Unit &reqUnit, const Vector< MVDirection > &directions, const MeasRef< MDirection > &dirRef, const MVAngle &pixelLatSize, const MVAngle &pixelLongSize, const Vector< MVFrequency > &frequencies, const MeasRef< MFrequency > &freqRef) const
	See the corresponding function in the SkyCompBase class for a description of this function.
virtual Flux< Double >	visibility (const Vector< Double > &uvw, const Double &frequency) const
	See the corresponding function in the SkyCompBase class for a description of this function.
virtual void	visibility (Cube< DComplex > &visibilities, const Matrix< Double > &uvws, const Vector< Double > &frequencies) const
	See the corresponding function in the SkyCompBase class for a description of this function.
virtual Bool	fromRecord (String &errorMessage, const RecordInterface &record)
	See the corresponding functions in the SkyCompBase class for a description of these functions.
virtual Bool	toRecord (String &errorMessage, RecordInterface &record) const
SkyComponent	copy () const
	Return a distinct copy of this component.
Bool	ok () const
	See the corresponding functions in the SkyCompBase class for a description of this function.
Vector< Double >	toPixel (const Unit &brightnessUnitIn, const GaussianBeam &restoringBeam, const CoordinateSystem &cSys, Stokes::StokesTypes stokes) const
	Convert from and to pixel vectors.
void	fromPixel (Double &fluxRatio, const Vector< Double > &parameters, const Unit &brightnessUnitIn, const GaussianBeam &restoringBeam, const CoordinateSystem &cSys, ComponentType::Shape componentShape, Stokes::StokesTypes stokes)
virtual String	summarize (const DirectionCoordinate *const &dc=0, Bool longErrOnGreatCircle=False) const
	Get a nicely formatted string summarizing the component.
String	positionToString (const DirectionCoordinate *const &dc=0, Bool longErrOnGreatCircle=False) const
	If the `dc` parameter is specified, also return the corresponding world coordinates.
Static Private Member Functions
static std::pair< String, String >	_axisLabels (const DirectionCoordinate *const &dc)
Private Attributes
CountedPtr< SkyCompRep >	itsCompPtr

Detailed Description

A component of a model of the sky.

Intended use:

Public interface

Review Status

Date Reviewed:: yyyy/mm/dd

Prerequisite

Synopsis

This class is concrete implementation of a class that represents a component of a model of the sky brightness.

The base class ( SkyCompBase ) contains a description of components and all the member functions used to manipulate them and hence will not be discussed here. But the base class does not include any constructors or a description of the copy semantics. This will be discussed below.

A SkyComponent is an "envelope" class in the sense that it can contain one of a variety of different component shapes and spectral models. It is necessary to specify the which shape and spectral model you want at construction time. This can be done either with enumerators or by constructing the classes derived from ComponentShape & SpectralModel and supplying them as construction arguments.

This class uses reference semantics for both the copy constructor and the assignment operator. Becuase of this the only way to make a true copy of a SkyComponent is to use the copy member function.

Example

These examples are coded in the tSkyCompRep.h file.

Example 1:

In this example a SkyCompRep object is created and used to calculate the ..\.

Motivation

Model fitting is an important part of astronomical data reduction/interpretation. This class defines a model component. Many components can be strung together (using the ComponentList class) to construct a model. It is expected that this class will eventually allow you to solve for parameters of the model.

Thrown Exceptions

AipsError - If an internal inconsistancy is detected, when compiled in debug mode only.

To Do

Add time variability
Add the ability to solve for component parameters.

Definition at line 126 of file SkyComponent.h.

Constructor & Destructor Documentation

casa::SkyComponent::SkyComponent ( )

The default SkyComponent is a point source with a constant spectrum.

See the default constructors in the PointShape, ConstantSpectrum and Flux classes for the default values for the flux, shape and spectrum.

casa::SkyComponent::SkyComponent ( const ComponentType::Shape & shape )

Construct a SkyCompRep of the specified shape.

The resultant component has a constant spectrum and a shape given by the default constructor of the specified ComponentShape class.

casa::SkyComponent::SkyComponent	(	const ComponentType::Shape &	shape,
		const ComponentType::SpectralShape &	spectralModel
	)

Construct a SkyCompRep with the user specified model for the shape and spectrum.

The resultant component has a shape given by the default constructor of the specified ComponentShape class and a spectrum given by the default constructor of the specified SpectralModel class

casa::SkyComponent::SkyComponent	(	const Flux< Double > &	flux,
		const ComponentShape &	shape,
		const SpectralModel &	spectrum
	)

Construct a SkyComponent with a fully specified model for the shape, spectrum and flux.

casa::SkyComponent::SkyComponent ( const SkyComponent & other )

The copy Constructor uses reference semantics.

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

the destructor does nothing obvious (its all done by the CountedPtr)

Member Function Documentation

static std::pair<String, String> casa::SkyComponent::_axisLabels ( const DirectionCoordinate *const & dc ) [static, private]

SkyComponent casa::SkyComponent::copy ( ) const

Return a distinct copy of this component.

As both the assignment operator and the copy constructor use reference semantics this is the only way to get a real copy.

virtual const Flux<Double>& casa::SkyComponent::flux ( ) const [virtual]

return a reference to the flux of the component.

Because this is a reference, manipulation of the flux values is performed through the functions in the Flux class. eg., comp.flux().setValue(newVal). If the component flux varies with frequency then the flux set using this function is the value at the reference frequency.

void casa::SkyComponent::fromPixel	(	Double &	fluxRatio,
		const Vector< Double > &	parameters,
		const Unit &	brightnessUnitIn,
		const GaussianBeam &	restoringBeam,
		const CoordinateSystem &	cSys,
		ComponentType::Shape	componentShape,
		Stokes::StokesTypes	stokes
	)

virtual Bool casa::SkyComponent::fromRecord	(	String &	errorMessage,
		const RecordInterface &	record
	)			`[virtual]`

String casa::SkyComponent::positionToString	(	const DirectionCoordinate *const &	dc = `0`,
		Bool	longErrOnGreatCircle = `False`
	)			const

virtual void casa::SkyComponent::sample	(	Cube< Double > &	samples,
		const Unit &	reqUnit,
		const Vector< MVDirection > &	directions,
		const MeasRef< MDirection > &	dirRef,
		const MVAngle &	pixelLatSize,
		const MVAngle &	pixelLongSize,
		const Vector< MVFrequency > &	frequencies,
		const MeasRef< MFrequency > &	freqRef
	)			const `[virtual]`

virtual Flux<Double> casa::SkyComponent::sample	(	const MDirection &	direction,
		const MVAngle &	pixelLatSize,
		const MVAngle &	pixelLongSize,
		const MFrequency &	centerFrequency
	)			const `[virtual]`

virtual String casa::SkyComponent::summarize	(	const DirectionCoordinate *const &	dc = `0`,
		Bool	longErrOnGreatCircle = `False`
	)			const `[virtual]`

Vector<Double> casa::SkyComponent::toPixel	(	const Unit &	brightnessUnitIn,
		const GaussianBeam &	restoringBeam,
		const CoordinateSystem &	cSys,
		Stokes::StokesTypes	stokes
	)			const

virtual Bool casa::SkyComponent::toRecord	(	String &	errorMessage,
		RecordInterface &	record
	)			const `[virtual]`

virtual void casa::SkyComponent::visibility	(	Cube< DComplex > &	visibilities,
		const Matrix< Double > &	uvws,
		const Vector< Double > &	frequencies
	)			const `[virtual]`

virtual Flux<Double> casa::SkyComponent::visibility	(	const Vector< Double > &	uvw,
		const Double &	frequency
	)			const `[virtual]`