Sky Model: Model the Sky Brightness for the SkyEquation. More...

#include <SkyModel.h>

Inheritance diagram for casa::SkyModel:

Public Types
enum	PolRep { CIRCULAR, LINEAR }

Public Member Functions
	SkyModel ()

virtual casacore::Int	numberOfModels ()=0
	Number of models contained. More...

virtual casacore::Int	numberOfTaylorTerms ()=0
	MFS : Number of taylor terms per model. More...

virtual casacore::Double	getReferenceFrequency ()=0
	MFS : Reference Frequency. More...

virtual casacore::Int	getTaylorIndex (casacore::Int index=0)=0
	MFS : Index of Taylor term in array of nmodels x ntaylorterms. More...

virtual casacore::Bool	isSolveable (casacore::Int model=0)=0
	Is this SkyModel solveable? More...

virtual casacore::Bool	doFluxScale (casacore::Int model=0)=0
	Is there a flux scale image associated with this model? More...

virtual void	initializeGradients ()=0
	Initialize for gradient search. More...

virtual void	finalizeGradients ()=0
	Finalize for gradient search. More...

virtual ComponentList &	componentList ()=0
	Return the component list. More...

virtual casacore::Bool	hasComponentList ()=0
	Return the component list. More...

virtual casacore::ImageInterface < casacore::Float > &	image (casacore::Int model=0)=0
	Image interface for this model (casacore::Stokes representation) More...

virtual casacore::ImageInterface < casacore::Float > &	deltaImage (casacore::Int model=0)=0
	Increment in the image. More...

virtual casacore::ImageInterface < casacore::Complex > &	cImage (casacore::Int model=0)=0
	casacore::Complex image (needed for e.g. More...

virtual casacore::ImageInterface < casacore::Complex > &	XFR (casacore::Int model=0, casacore::Int numXFR=0)=0
	casacore::Complex XFR More...

virtual casacore::Bool	hasXFR (casacore::Int model=0)=0

virtual casacore::ImageInterface < casacore::Float > &	PSF (casacore::Int model=0)=0
	PSF. More...

virtual casacore::ImageInterface < casacore::Float > &	gS (casacore::Int model=0)=0
	Gradient of chi-squared wrt pixels. More...

virtual casacore::ImageInterface < casacore::Float > &	ggS (casacore::Int model=0)=0
	Grad Grad chi-squared wrt pixels (diagonal elements only) More...

virtual casacore::ImageInterface < casacore::Float > &	fluxScale (casacore::Int model=0)=0
	FluxScale image: image * fluxScale => true brightness distribution. More...

virtual casacore::ImageInterface < casacore::Float > &	work (casacore::Int model=0)=0
	Work image. More...

virtual void	addStatistics (casacore::Float sumwt, casacore::Float chisq)=0
	Add to Sum weights, Chi-Squared. More...

virtual casacore::Matrix < casacore::Float > &	weight (casacore::Int model=0)=0
	Weight per model (channels, polarizations) More...

virtual casacore::Bool	solve (SkyEquation &se)=0
	Solve for this SkyModel. More...

virtual casacore::Bool	isEmpty (casacore::Int model=0)=0
	Is this model empty. More...

virtual casacore::Int	getModelIndex (casacore::uInt field=0, casacore::uInt taylor=0)=0

void	setAlgorithm (const casacore::String &alg)
	set Algorithm (e.g clean, mem, nnls) More...

const casacore::String	getAlgorithm ()
	get Algorithm More...

void	setSubAlgorithm (const casacore::String &alg)
	set Sub Algorithm More...

const casacore::String	getSubAlgorithm ()
	get Sub Algorithm More...

void	setImageRegion (casacore::ImageRegion &ir)
	Set the imageregion that will be used for the next XFR generation. More...

void	unsetImageRegion ()
	use the default shape More...

void	setImageNormalization (casacore::Bool val)

casacore::Bool	isImageNormalized ()

virtual void	setMemoryUse (casacore::Bool memuse)=0
	set and get memory usage model More...

virtual casacore::Bool	getMemoryUse ()=0

Public Member Functions inherited from casa::Iterate
	Iterate ()
	Constructor. More...

virtual	~Iterate ()

void	setFree ()
	Is this a free variable? More...

void	setNotFree ()

casacore::Bool	free ()

void	setNumberIterations (const casacore::Int n)

void	setGain (const casacore::Float g)

void	setTolerance (const casacore::Float t)

void	setThreshold (const casacore::Float t)

void	setMode (const casacore::String m)

casacore::Int	numberIterations ()

casacore::Float	gain ()

casacore::Float	tolerance ()

virtual casacore::Float	threshold ()

const casacore::String	mode ()

Protected Attributes
casacore::String	itsAlgorithm

casacore::String	itsSubAlgorithm

casacore::ImageRegion *	imageRegion_p
	this casacore::ImageRegion is used to suggest the shape for the XFR. More...

casacore::Bool	isImageNormalized_p

Detailed Description

Sky Model: Model the Sky Brightness for the SkyEquation.

Intended use:

Public interface

Prerequisite

casacore::Matrix module
casacore::Vector module
MeasurementComponents module
VisSet module

Etymology

SkyModel describes an interface for Models to be used in the SkyEquation. It is an Abstract Base Class: most methods must be defined in derived classes.

Synopsis

A SkyModel contains a number of separate models. The interface to SkyEquation is via an image per model. SkyEquation uses this image to calculate Fourier transforms, etc. Some (most) SkyModels are solvable: the SkyEquation can be used by the SkyModel to return gradients with respect to itself (via the image interface). Thus for a SkyModel to solve for itself, it calls the SkyEquation methods to get gradients of chi-squared with respect to the image pixel values (thus returning an image: basically a residual image). The SkyModel then uses these gradients as appropriate to update itself.

The following examples illustrate how a SkyModel can be used:

Simple cleaning: one model. The gradient gives the residual image. A special method gives a PSF.
Cleaning with visibility-based subtraction: one model. The gradient can be calculated as needed (using the SkyEquation) to produce the correct residual image.
Wide-field imaging: one model per patch of the sky that is to be imaged.
Non-coplanar baselines imaging: one model per facet of the polyhedron. At the end of processing all facets are combined into one overall image.
Mosaicing: one model per primary beam pointing. Each model is derived (as needed) by cutting out a patch from the full-field mosaic.

Example

// Read the VisSet from disk
VisSet vs("3c84.MS");
// Create an ImageSkyModel from an image on disk
ImageSkyModel ism(casacore::PagedImage<casacore::Float>("3c84.modelImage"));
// Make an FTMachine: here we use a simple Grid and FT.
GridFT ft;
SkyEquation se(ism, vs, ft);
// Predict the visibility set
se.predict();
// Make a Clean Image and write it out
HogbomCleanImageSkyModel csm(ism);
if (csm.solve()) {
casacore::PagedImage<casacore::Float> cleanImage=csm.image(0);
cleanImage.setName("3c84.cleanImage");
}

Motivation

The properties of a model of the sky must be described for the SkyEquation.

To Do

Multiple images in SkyModel
ComponentModel

Definition at line 132 of file SkyModel.h.

Member Enumeration Documentation

enum casa::SkyModel::PolRep

Enumerator
CIRCULAR
LINEAR

Definition at line 136 of file SkyModel.h.

Constructor & Destructor Documentation

casa::SkyModel::SkyModel ( )

inline

Definition at line 141 of file SkyModel.h.

Member Function Documentation

virtual void casa::SkyModel::addStatistics	(	casacore::Float	sumwt,
		casacore::Float	chisq
	)

pure virtual

Add to Sum weights, Chi-Squared.

Public Types

Public Member Functions

Protected Attributes