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

#include <SkyJones.h>

Inheritance diagram for casa::SkyJones:

Public Types
enum	Type { E, T, F, D }
	Allowed types of VisJones matrices. More...

enum	SizeType { COMPOSITE, POWEROF2, ANY }

Public Member Functions
	SkyJones ()

virtual	~SkyJones ()
	Destructor. More...

virtual casacore::ImageInterface < casacore::Complex > &	apply (const casacore::ImageInterface< casacore::Complex > &in, casacore::ImageInterface< casacore::Complex > &out, const VisBuffer &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 VisBuffer &vb, casacore::Int row)=0

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

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

virtual SkyComponent &	applySquare (SkyComponent &in, SkyComponent &out, const VisBuffer &vb, casacore::Int row, casacore::Bool fullspectrum=false)=0

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

virtual casacore::Bool	changedBuffer (const VisBuffer &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 VisBuffer &vb, casacore::Int row)=0
	Assure. More...

virtual casacore::Bool	change (const VisBuffer &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 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 VisBuffer &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::Bool	solve (SkyEquation &se)=0
	Solve. More...

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

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

virtual casacore::String	telescope ()=0

virtual casacore::Int	support (const VisBuffer &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 172 of file SkyJones.h.

Member Enumeration Documentation

enum casa::SkyJones::SizeType

Enumerator
COMPOSITE
POWEROF2
ANY

Definition at line 178 of file SkyJones.h.

enum casa::SkyJones::Type

Allowed types of VisJones matrices.

Enumerator
E
T
F
D

Definition at line 176 of file SkyJones.h.

Constructor & Destructor Documentation

casa::SkyJones::SkyJones ( )

virtual casa::SkyJones::~SkyJones ( )

virtual

Destructor.

Member Function Documentation

virtual void casa::SkyJones::addGradients	(	const VisBuffer &	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.

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes