Module MeasurementComponents

Description (classes)

Prerequisite

• MeasurementEquations

Etymology

Synopsis

Synthesis calibration and imaging is accomplished using the modules MeasurementEquations to control the form of the equations to be solved, and MeasurementComponents to encapsulate different types of physical effects.

An example may help. Standard antenna-based gain calibration is accomplished using a class GJones (derived from VisJones) that applies antenna based gains indexed by time, antenna id (of course), and spectral window. All calibration can proceed using this class plugged into the MeasurementEquations. Solution for the parameters of the GJones class is accomplished using a generic solver that calls methods of the MeasurementEquations. Suppose that we want to elaborate the model for the antenna gains by insisting that antenna phases be given by a polynomial function of position across the array (useful for compact synthesis arrays). We then derive another class e.g. SpatialGJones, that internally is parametrized in terms of antenna position. All calibration and imaging can proceed with the new class in place of GJones. Solution for the phase screen is accomplished using the same services of the MeasurementEquations but the gradients of chi-squared are used internally by SpatialGJones to calculate coefficients of the polynomial. When the apply method of the SpatialGJones is called, it calculates the phase screen as appropriate.

It is expected that some degree of caching will be implemented by most MeasurementComponents in order that efficient processing is possible.

• VisJones encapsulates pure visibility-based gain effects as antenna gains
• SkyJones encapsulates pure image plane-based gain effects such as the primary beam
• MJones encapsulates multiplicative correlator-related visibility-based effects
• ACoh encapsulates additive correlator-related visibility-based effects
• XCorr encapsulates non-linear correlator-related visibility-based effects
• FTMachine encapsulates Fourier transform machines
• SkyModel encapsulates models of the sky brightness such as images or discrete components

Example

    // Make a MeasurementComponent that applies antenna-based gain
    // to a coherence sample
    VisSet vs("3c84.MS");
    GJones gain(vs, 30);

    // Write original and corrupted coherences
    ROVisIter vi(vs->iter());
    VisBuffer vb(vi);
    for (vi.origin(); vi.more(); vi++) {
       cout<<"Original value "<<vb.visibility()<<" becomes "
	     <<apply(vb).correctedVisibility()<<endl;
    }

Motivation

To Do

Classes

ACoh -- ACoh: Model additive errors for the VisEquation. (full description)

Atmosphere -- Basic class for atmospheric calculation wrapping the fortran code of IRAM for ATM model. Fortran code written by J. Cernicharo which interpolate atmospheric model between summer and winter at a latitude of 45 Only Oxygen and water vapor is modelled (full description)

BJones -- (full description)

BJonesPoly -- A bandpass visibility Jones matrix of polynomial form (full description)

BeamSkyJones -- beam-like sky-plane effects for the SkyEquation (full description)

BeamSquint -- encapsulates beam squint (RR and LL beams at different directions) (full description)

CEMemImageSkyModel -- Image Sky Model for the Cornwell-Evens maximum entropy algorithm (full description)

CJones -- Model configuration matrix corrections for the VisEquation (full description)

CSCleanImageSkyModel -- CS Image Sky Model: Image Sky Model implementing the Cotton-Schwab Clean algorithm (full description)

Calibrater -- Controls the solution of calibration components (Jones Matrices) (full description)

ClarkCleanAlgorithm -- (full description)

ClarkCleanImageSkyModel -- Clark Image Sky Model: Image Sky Model implementing the Clark Clean algorithm (full description)

CleanImageSkyModel -- Image Sky Model: Image-based Model for the Sky Brightness (full description)

ComponentFTMachine -- ComponentFTMachine: a abstract base class defining the interface for a Fourier Transform Machine to be used in the SkyEquation for the transformation of SkyComponents (full description)

DBeamSkyJones -- Model the polarization leakage in the Sky Jones Matrices (full description)

DJones -- DJones: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

EVisJones -- EVisJones: Model Gain Curve corrections for the VisEquation (full description)

FTMachine -- defines interface for the Fourier Transform Machine (full description)

FVisJones -- FVisJones: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

GJones -- GJones: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

GJonesDSB -- A GJones matrix containing a sideband gain ratio (full description)

GJonesDelayRateSB -- GJonesDelayRateSB: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

GJonesPoly -- Electronic gain Jones matrix as a polynomial over time (full description)

GJonesSpline -- Electronic gain Jones matrix as spline polynomial over time (full description)

GridBoth -- An FTMachine for Gridding Single Dish data (full description)

GridFT -- An FTMachine for Gridded Fourier transforms (full description)

HogbomCleanImageSkyModel -- Hogbom Clean Image Sky Model: Image Sky Model implementing the Hogbom Clean algorithm (full description)

ImageSkyModel -- Image Sky Model: Image-based Model for the Sky Brightness (full description)

MFCEMemImageSkyModel -- MF CE Mem Image Sky Model: Image Sky Model implementing the MF Mem algorithm (full description)

MFCleanImageSkyModel -- MF Image Sky Model: Image Sky Model implementing the MF Clean algorithm (full description)

MFMSCleanImageSkyModel -- Image Sky Model implementing the MultiScale, MultiField Clean algorithm (full description)

MIfr -- MIfr: Model solvable, time-variable diagonal multiplicative errors for the VisEquation (full description)

MJones -- MJones: Model multiplicative errors for the VisEquation (full description)

MSCalEnums -- MSCalEnums: Field name dictionary for MeasurementSet and calibration tables (full description)

MSCleanImageSkyModel -- MS Clean Image Sky Model: Image Sky Model implementing the MS Clean algorithm (full description)

MakeApproxPSFAlgorithm -- Parallelized version of approximate PSF formation (full description)

MosaicFT -- An FTMachine for Gridded Fourier transforms (full description)

NNLSImageSkyModel -- Briggs' Non-Negative Least Squares deconvolution algorithm (full description)

NewSimDJones -- Model multiplicative gain errors for the VisEquation (full description)

NewSimGJones -- Model multiplicative gain errors for the VisEquation (full description)

NewSimTimeDepVisJones -- Model multiplicative gain errors for the VisEquation (full description)

NewSimVisJones -- Model multiplicative gain errors for the VisEquation (full description)

PBMath -- Primary beam envelope class, derived from PBMathInterface (full description)

PBMath1D -- base class for 1D PBMath objects (full description)

PBMath1DAiry -- PBMath1DAiry is a 1-D Airy Disk voltage pattern & Primary Beam (full description)

PBMath1DCosPoly -- PBMath1DCosPoly is a 1-D Polynomial Cosine Expansion for a Primary Beam (full description)

PBMath1DGauss -- PBMath1DGauss is a 1-D Gaussian Primary Beam (full description)

PBMath1DIPoly -- PBMath1DIPoly is a 1-D Inverse Polynomial Expansion for a Primary Beam (full description)

PBMath1DNumeric -- 1-D Numeric Primary Beam Model (full description)

PBMath1DPoly -- PBMath1DPoly is a 1-D Polynomial Expansion for a Primary Beam (full description)

PBMath2D -- base class for 1D PBMath objects (full description)

PBMath2DImage -- 2-D Image Primary Beam Model (full description)

PBMathInterface -- Virtual base class defining the Primary Beam interface (full description)

PClarkCleanImageSkyModel -- Clark Image Sky Model: Image Sky Model implementing the Clark Clean algorithm (full description)

PJones -- Model parallactic angle corrections for the VisEquation (full description)

PWFCleanImageSkyModel -- Parallelized version of class WFCleanImageSkyModel (full description)

PredictAlgorithm -- Parallel model visibility prediction (full description)

ReadMSAlgorithm -- (full description)

ResidualAlgorithm -- Parallel residual image formation (full description)

SDGrid -- An FTMachine for Gridding Single Dish data (full description)

SimACoh -- SimACoh: Model additive noise errors for the VisEquation (full description)

SimACohCalc -- SimACohCalc: Model additive noise errors for the VisEquation (full description)

SimAntGainCache -- A container for antenna gains (full description)

SimDJones -- Model multiplicative gain errors for the VisEquation (full description)

SimGJones -- Model multiplicative gain errors for the VisEquation (full description)

SimVisJones -- Model multiplicative gain errors for the VisEquation (full description)

SimpComponentGridMachine -- SimpComponentFTMachine: does the simplest Fourier transform on SkyComponents. (full description)

SimpleComponentFTMachine -- does the simplest Fourier transform on SkyComponents (full description)

SimpleComponentGridMachine -- does the simplest Fourier transform on SkyComponents (full description)

SkyJones -- Sky Jones: Model sky-plane instrumental effects for the SkyEquation (full description)

SkyModel -- Sky Model: Model the Sky Brightness for the SkyEquation (full description)

SolvableMJones -- Model solvable, time-variable multiplicative errors for the VisEquation (full description)

SolvableVisJones -- SolvableVisJones: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

StokesConverter -- StokesConverter converts any set of polarizations into any other one (full description)

TJones -- TJones: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

TJonesPoly -- Atmospheric gain Jones matrix as a polynomial over time (full description)

TJonesSpline -- Atmospheric gain Jones matrix as spline polynomial over time (full description)

TOpac -- TOpac: Model solvable, time-variable multiplicative errors for the VisEquation (full description)

TimeVarMJones -- Model baseline-related multiplicative errors for the VisEquation (full description)

TimeVarVisJones -- Model time-variable multiplicative errors for the VisEquation (full description)

VPSkyJones -- Model the diagonal elements of the Voltage Pattern Sky Jones Matrices (full description)

VisJones -- VisJones: Model multiplicative errors for the VisEquation (full description)

WFCleanImageSkyModel -- WF Image Sky Model: Image Sky Model implementing the WF Clean algorithm (full description)

WFGridFT -- (full description)

WProjectFT -- An FTMachine for Gridded Fourier transforms (full description)

XCorr -- Model non-linear correlator function for the VisEquation (full description)

atmosphere -- atmosphere: atmosphere class, the basis for atmospheric calcultions based on atmospheric models for mm radio observations (full description)

atmosphereFactory -- (full description)

calibrater -- calibrater: Calibrater class, forming the basis of the calibrater DO (full description)

calibraterFactory -- (full description)