Sky Jones: Model sky-plane instrumental effects for the SkyEquation. More...

#include <SkyJones.h>

Inheritance diagram for casa::refim::SkyJones:

Public Member Functions
	SkyJones ()
	Allowed types of VisJones matrices enum Type{E,T,F,D}; More...

virtual	~SkyJones ()
	Destructor. More...

virtual casacore::ImageInterface < casacore::Complex > &	apply (const casacore::ImageInterface< casacore::Complex > &in, casacore::ImageInterface< casacore::Complex > &out, const vi::VisBuffer2 &vb, casacore::Int row, casacore::Bool forward=true)=0
	Apply Jones matrix to an image (and adjoint) More...

virtual casacore::ImageInterface < casacore::Float > &	apply (const casacore::ImageInterface< casacore::Float > &in, casacore::ImageInterface< casacore::Float > &out, const vi::VisBuffer2 &vb, casacore::Int row)=0

virtual casacore::ImageInterface < casacore::Float > &	applySquare (const casacore::ImageInterface< casacore::Float > &in, casacore::ImageInterface< casacore::Float > &out, const vi::VisBuffer2 &vb, casacore::Int row)=0

virtual SkyComponent &	apply (SkyComponent &in, SkyComponent &out, const vi::VisBuffer2 &vb, casacore::Int row, casacore::Bool forward=true)=0
	Apply Jones matrix to a sky component (and adjoint) More...

virtual SkyComponent &	applySquare (SkyComponent &in, SkyComponent &out, const vi::VisBuffer2 &vb, casacore::Int row)=0

virtual casacore::Bool	changed (const vi::VisBuffer2 &vb, casacore::Int row)=0
	Has this operator changed since the last application? More...

virtual casacore::Bool	changedBuffer (const vi::VisBuffer2 &vb, casacore::Int row1, casacore::Int &row2)=0
	Does this operator changed in this VisBuffer, starting with row1? If yes, we return in row2, the last row that has the same SkyJones as row1. More...

virtual void	reset ()=0
	Reset. More...

virtual void	assure (const vi::VisBuffer2 &vb, casacore::Int row)=0
	Assure. More...

virtual casacore::Bool	change (const vi::VisBuffer2 &vb)=0
	Does the operator change in this visbuffer or since the last call? I'm not sure this is useful – come back to it m.a.h. More...

virtual ::casa::SkyJones::Type	type ()=0
	Return the type of this Jones matrix (actual type of derived class). More...

virtual casacore::ImageInterface < casacore::Complex > &virtual SkyComponent &virtual casacore::Bool	isSolveable ()=0
	Apply gradient. More...

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

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

virtual void	addGradients (const vi::VisBuffer2 &vb, casacore::Int row, const casacore::Float sumwt, const casacore::Float chisq, const casacore::Matrix< casacore::Complex > &c, const casacore::Matrix< casacore::Float > &f)=0
	Add to Gradient Chisq. More...

virtual casacore::ImageRegion *	extent (const casacore::ImageInterface< casacore::Complex > &im, const vi::VisBuffer2 &vb, const casacore::Int irow=-1, const casacore::Float fPad=1.2, const casacore::Int iChan=0, const casa::SkyJones::SizeType sizeType=casa::SkyJones::COMPOSITE)=0
	Solve virtual casacore::Bool solve (SkyEquation& se) = 0; More...

virtual casacore::ImageRegion *	extent (const casacore::ImageInterface< casacore::Float > &im, const vi::VisBuffer2 &vb, const casacore::Int irow=-1, const casacore::Float fPad=1.2, const casacore::Int iChan=0, const casa::SkyJones::SizeType sizeType=casa::SkyJones::COMPOSITE)=0

virtual casacore::String	telescope ()=0

virtual casacore::Int	support (const vi::VisBuffer2 &vb, const casacore::CoordinateSystem &cs)=0

virtual void	setThreshold (const casacore::Float t)

virtual casacore::Float	threshold ()

Protected Member Functions
virtual casacore::String	typeName ()
	Could be over-ridden if necessary. More...

Protected Attributes
casacore::Float	threshold_p

Detailed Description

Sky Jones: Model sky-plane instrumental effects for the SkyEquation.

Intended use:

Public interface

Prerequisite

SkyEquation class

Etymology

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

Synopsis

A SkyJones implements the instrumental effect of some sky-plane based calibration effect. It conceptually applies an image of Jones matrices to an image. For example, it takes an image of the sky brightness and applies the complex primary beam for a given interferometer. Only the interface is defined here in the Abstract Base Class. Actual concrete classes must be derived from SkyJones. Some (most) SkyJones are solvable: the SkyEquation can be used by the SkyJones to return gradients with respect to itself (via the image interface). Thus for a SkyJones to solve for itself, it calls the SkyEquation methods to get gradients of chi-squared with respect to the image pixel values. The SkyJones then uses these gradients as appropriate to update itself.

The following examples illustrate how a SkyJones can be used:

Mosaicing: one SkyJones for the primary beam. For efficiency the image must be cached and the VisSet iteration order set to minimize the number of recalculations.

Example

// Low level code example:
casacore::MeasurementSet ms("imagertest/3C273XC1.ms", casacore::Table::Update);
VPSkyJones  unsquintedVPSJ(ms);
VPSkyJones  squintedVPSJ(ms, true, casacore::Quantity(5.0, "deg"), BeamSquint::GOFIGURE);
unsquintedVPSJ.reset();
squintedVPSJ.reset();
casacore::PagedImage<casacore::Complex> imageIn;
casacore::PagedImage<casacore::Complex> imageOut;  // in reality, this ouwld need more construction with coords and shapes
VisSet vs(ms,bi,chanSelection,interval);
casacore::Int row = 0;
VisIter &vi = vs.iter();
VisBuffer vb(vi);
for (vi.originChunks();vi.moreChunks();vi.nextChunk()) {
cout << "This is integration: " << nChunks++ << endl;
for (vi.origin();vi.more();vi++) {
if (myVPSJ.change(vb)) { 
cout << "State has changed: " << endl;
squintedVPSJ.showState(os);
squintedVPSJ.apply(imageIn, imageOut, vb, row);
}
}
}
// High Level Code Example:
// Create an ImageSkyJones from an image on disk
ImageSkyModel ism(casacore::PagedImage<casacore::Float>("3C273XC1.modelImage"));
// Make an FTMachine: here we use a simple Grid and FT.
GridFT ft;
SkyEquation se(ism, vs, ft);
// Make a Primary Beam Sky Model
VPSkyJones pbsj(ms);
// Add it to the SkyEquation
se.setSkyJones(pbsj);
// Predict the visibility set
se.predict();
// Read some other data
VisSet othervs("3c84.MS.Otherdata");
// Make a Clean Image and write it out
HogbomCleanImageSkyJones csm(ism);
if (csm.solve(othervs)) {
casacore::PagedImage<casacore::Float> cleanImage=csm.image(0);
cleanImage.setName("3c84.cleanImage");
}

Motivation

The properties of sky-plane based calibration effects must be described for the SkyEquation

To Do

There are no Concrete Classes derived from SkyJones!
Solvable part needs implementation: we need to derive an image of gradients of the elements of the Jones matrix. See VisJones for how to do this.

Definition at line 174 of file SkyJones.h.

Constructor & Destructor Documentation

casa::refim::SkyJones::SkyJones ( )

Allowed types of VisJones matrices

enum Type{E,T,F,D};

enum SizeType{COMPOSITE, POWEROF2, ANY};

virtual casa::refim::SkyJones::~SkyJones ( )

virtual

Destructor.

Member Function Documentation

virtual void casa::refim::SkyJones::addGradients	(	const vi::VisBuffer2 &	vb,
		casacore::Int	row,
		const casacore::Float	sumwt,
		const casacore::Float	chisq,
		const casacore::Matrix< casacore::Complex > &	c,
		const casacore::Matrix< casacore::Float > &	f
	)

pure virtual

Add to Gradient Chisq.

Implemented in casa::refim::BeamSkyJones.

virtual casacore::ImageInterface<casacore::Complex>& casa::refim::SkyJones::apply	(	const casacore::ImageInterface< casacore::Complex > &	in,
		casacore::ImageInterface< casacore::Complex > &	out,
		const vi::VisBuffer2 &	vb,
		casacore::Int	row,
		casacore::Bool	forward = `true`
	)

pure virtual

Apply Jones matrix to an image (and adjoint)

Implemented in casa::refim::BeamSkyJones.

virtual casacore::ImageInterface<casacore::Float>& casa::refim::SkyJones::apply	(	const casacore::ImageInterface< casacore::Float > &	in,
		casacore::ImageInterface< casacore::Float > &	out,
		const vi::VisBuffer2 &	vb,
		casacore::Int	row
	)

pure virtual

Implemented in casa::refim::BeamSkyJones.

virtual SkyComponent& casa::refim::SkyJones::apply	(	SkyComponent &	in,
		SkyComponent &	out,
		const vi::VisBuffer2 &	vb,
		casacore::Int	row,
		casacore::Bool	forward = `true`
	)

pure virtual

Apply Jones matrix to a sky component (and adjoint)

Implemented in casa::refim::BeamSkyJones.

virtual casacore::ImageInterface<casacore::Float>& casa::refim::SkyJones::applySquare	(	const casacore::ImageInterface< casacore::Float > &	in,
		casacore::ImageInterface< casacore::Float > &	out,
		const vi::VisBuffer2 &	vb,
		casacore::Int	row
	)

pure virtual

Implemented in casa::refim::BeamSkyJones.

virtual SkyComponent& casa::refim::SkyJones::applySquare	(	SkyComponent &	in,
		SkyComponent &	out,
		const vi::VisBuffer2 &	vb,
		casacore::Int	row
	)

pure virtual

Implemented in casa::refim::BeamSkyJones.

virtual void casa::refim::SkyJones::assure	(	const vi::VisBuffer2 &	vb,
		casacore::Int	row
	)

pure virtual

Assure.

Implemented in casa::refim::BeamSkyJones.

virtual casacore::Bool casa::refim::SkyJones::change ( const vi::VisBuffer2 & vb )

pure virtual

Does the operator change in this visbuffer or since the last call? I'm not sure this is useful – come back to it m.a.h.

Dec 30 1999

Implemented in casa::refim::BeamSkyJones.

virtual casacore::Bool casa::refim::SkyJones::changed	(	const vi::VisBuffer2 &	vb,
		casacore::Int	row
	)

pure virtual

Has this operator changed since the last application?

Implemented in casa::refim::BeamSkyJones.

virtual casacore::Bool casa::refim::SkyJones::changedBuffer	(	const vi::VisBuffer2 &	vb,
		casacore::Int	row1,
		casacore::Int &	row2
	)

pure virtual

Does this operator changed in this VisBuffer, starting with row1? If yes, we return in row2, the last row that has the same SkyJones as row1.

Implemented in casa::refim::BeamSkyJones.

virtual casacore::ImageRegion* casa::refim::SkyJones::extent	(	const casacore::ImageInterface< casacore::Complex > &	im,
		const vi::VisBuffer2 &	vb,
		const casacore::Int	irow = `-1`,
		const casacore::Float	fPad = `1.2`,
		const casacore::Int	iChan = `0`,
		const casa::SkyJones::SizeType	sizeType = `casa::SkyJones::COMPOSITE`
	)

pure virtual

Solve

virtual casacore::Bool solve (SkyEquation& se) = 0;

Get the casacore::ImageRegion of the primary beam on an Image for a given pointing Note: casacore::ImageRegion is not necesarily constrained to lie within the image region (for example, if the pointing center is near the edge of the image). fPad: extra fractional padding beyond the primary beam support (note: we do not properly treat squint yet, this will cover it for now) iChan: frequency channel to take: lowest frequency channel is safe for all SizeType: COMPOSITE = next larger composite number, POWEROF2 = next larger power of 2, ANY = just take what we get!

Potential problem: this casacore::ImageRegion includes all casacore::Stokes and Frequency Channels present in the input image. COMMENTING out for now as this depend on PBMathInterface and which depends back on SkyJones::sizeType

Implemented in casa::refim::BeamSkyJones.

virtual casacore::ImageRegion* casa::refim::SkyJones::extent	(	const casacore::ImageInterface< casacore::Float > &	im,
		const vi::VisBuffer2 &	vb,
		const casacore::Int	irow = `-1`,
		const casacore::Float	fPad = `1.2`,
		const casacore::Int	iChan = `0`,
		const casa::SkyJones::SizeType	sizeType = `casa::SkyJones::COMPOSITE`
	)