This class updates components in UV plane. More...

#include <ComponentUpdate.h>

Public Member Functions
	ComponentUpdate ()
	Default constructor -- update not possible without one or more set() methods.
	ComponentUpdate (const ComponentList &model)
	Construct an update machine for the sources in the given ComponentList, using the 'separate' type of solution, and ILM solve.
	ComponentUpdate (const ComponentList &model, const ComponentUpdate::Solve solve)
	Construct an update machine for the sources in the given ComponentList, using the specified sovables and the separate type.
	ComponentUpdate (const ComponentList &model, const ComponentUpdate::Solve solve, const ComponentUpdate::Type tp)
	Construct an update machine for the sources in the given ComponentList, using the specified type of solution and solvables.
	~ComponentUpdate ()
	Destructor.
void	makeEquations (const Array< DComplex > &deriv, const Vector< DComplex > &data)
	Create the solution equations.
Bool	solve (Matrix< Double > &sol, Matrix< Double > &err)
	Provide the solution (i.e.
Private Types
enum	Type { SEPARATE, COMBINED, CLUSTER, N_Type }
	The different solution types. More...
enum	Solve { ILM, N_Solve }
	The different solvable parameters. More...
Private Member Functions
	ComponentUpdate (const ComponentUpdate &other)
	Copy constructor (not implemented)
ComponentUpdate &	operator= (const ComponentUpdate &other)
	Assignment (not implemented)
void	init ()
	Initialise the list of fitting areas.
void	clean ()
	Empty the list of fitting areas.
Private Attributes
ComponentUpdate::Type	soltp_p
	Type of solution.
ComponentUpdate::Solve	solve_p
	Solvable parameters.
Int	nmodel_p
	Number of sources to fit.
Double *	dt_p
	Work area for expression data.
ComponentList	complist_p
	Component list to solve (note: a pointer to it)
PtrBlock< LSQaips * >	fit_p
	List of solution fitting areas.
Static Private Attributes
static const Int	N_unknown [N_Solve]
	List of number of unknowns for solvables.

Detailed Description

This class updates components in UV plane.

Intended use:

Public interface

 <h3>Review Status</h3><dl><dt>Date Reviewed:<dd>yyyy/mm/dd</dl>

Prerequisite

ComponentModels module

Etymology

Component and Update

Synopsis

This class is an update machine for model components. The updating is done using UV-plane information (and, of course, already available calibration information). In principle all the elements of a component can be updated (like polarisation flux, position, etc), but certain combinations are more useful (and orthogonal enough) to be of practical use.

The update process works by comparing the theoretical UV-plane expectations of a model component, with the actual UV-plane data, and solve, in the least-squares sense) for the component data elements. In practice the full nodel sky, as known, is subtracted from the observed data, after which the solution for for differnces is done. This solution can proceed in a variety of ways:

for all model components to be solved for in one solution. In this case the dependences between the different source components are taken properly into account, but the number of simultaneously to be solved unknowns can be very large.
solve for all model components separately, as if they were the only one producing UV-plane output. In practice this would cause dependencies between sources (e.g. if two components have (almost) the same position, they will both be adjusted e.g, in flux as if they were the only one, resulting in a twice too high adjustment. By using an (estimate of the) synthesised beam, this can be adjusted
a combination of the above two. If components are close together, they will be combined as one source to be solved for, otherwise they will be treated separately.

Non-component sky models (like images) could be adjusted for their overall parameters (integrated flux, position) as well. This could be added at a later stage.

Not all of the different possibilities and adjustable parameters will be implemented initially.

Motivation

To provide an accurate way to adjust model component parameters from the observed data, using all the available data.

To Do

Definition at line 109 of file ComponentUpdate.h.

Member Enumeration Documentation

enum casa::ComponentUpdate::Solve [private]

The different solvable parameters.

Enumerator:

ILM	Solve for I and l,m.
N_Solve	Number of solvable parameters.

Definition at line 122 of file ComponentUpdate.h.

enum casa::ComponentUpdate::Type [private]

The different solution types.

Enumerator:

SEPARATE	Sove each source individually.
COMBINED	Slove in one solution.
CLUSTER	Solve in clusters of sources.
N_Type	Number of options.

Definition at line 111 of file ComponentUpdate.h.

Constructor & Destructor Documentation

casa::ComponentUpdate::ComponentUpdate ( )

Default constructor -- update not possible without one or more set() methods.

casa::ComponentUpdate::ComponentUpdate ( const ComponentList & model ) [explicit]

Construct an update machine for the sources in the given ComponentList, using the 'separate' type of solution, and ILM solve.

Note that the component list must be a writable one to receive the updates.

casa::ComponentUpdate::ComponentUpdate	(	const ComponentList &	model,
		const ComponentUpdate::Solve	solve
	)

Construct an update machine for the sources in the given ComponentList, using the specified sovables and the separate type.

casa::ComponentUpdate::ComponentUpdate	(	const ComponentList &	model,
		const ComponentUpdate::Solve	solve,
		const ComponentUpdate::Type	tp
	)

Construct an update machine for the sources in the given ComponentList, using the specified type of solution and solvables.

casa::ComponentUpdate::~ComponentUpdate ( )

Destructor.

casa::ComponentUpdate::ComponentUpdate ( const ComponentUpdate & other ) [private]

Copy constructor (not implemented)

Member Function Documentation

void casa::ComponentUpdate::clean ( ) [private]

Empty the list of fitting areas.

void casa::ComponentUpdate::init ( ) [private]

Initialise the list of fitting areas.

void casa::ComponentUpdate::makeEquations	(	const Array< DComplex > &	deriv,
		const Vector< DComplex > &	data
	)

Create the solution equations.

For each series of UV points, provide the following information to the engine (we can speed it up later by having raw rather than Array type interface). Needed:

data: a vector(=data) of length equal to the number of UV points provided in one go (nuv) representing the observed residual data
A Cube with dimensions (3, nsource, nuv) (the 3 for the ILM case, but different for other solutions). nsource is the number of sources, and the 3 are the coefficients of the derivatives (in the default case the values provided should be X, 2pi.U.i.X and 2pi.V.i.X (i == sqrt(-1); X == the calculated UV plane value for the source model component). In this we solve dI/I, dl and dm. Order of indices is determined by VectorIterator...

Extra arguments possible: data weight.
Extra calls: Just provide list of data (and weight) and UVW coordinates. Calls to some Skymodel.visibility() and/or .derivative() would then suffice.
Improvements, by providing telescope rather than baseline based data; proper care taken analytically of integration over time and frequency.

ComponentUpdate& casa::ComponentUpdate::operator= ( const ComponentUpdate & other ) [private]

Assignment (not implemented)