See below for an overview of the classes in this module.
Measurement Components represent components of the Measurement Equation
The Measurement Equation is expressed in terms of Measurement Components such as gain matrices, additive errors, Fourier transform machines, etc. MeasurementComponents typically take as arguments a VisBuffer that holds the original, model and corrected visibility plus the information needed for the correction (e.g. time, uvw, antenna ids, etc) and returns the modified VisBuffer .
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.
// 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; }
To encapsulate behavior of components of the MeasurementEquation.
Modules | |
| MeasurementComponents_internal_classes | |
| Internal MeasurementComponents classes and functions. | |
Classes | |
| class | casa::BeamSkyJones |
| beam-like sky-plane effects for the SkyEquation More... | |
| class | casa::BeamSquint |
| encapsulates beam squint (RR and LL beams at different directions) More... | |
| class | casa::Calibrater |
| Controls the solution of calibration components (Jones Matrices). More... | |
| class | casa::CEMemImageSkyModel |
| Image Sky Model for the Cornwell-Evens maximum entropy algorithm. More... | |
| class | casa::ClarkCleanImageSkyModel |
| Clark Image Sky Model: Image Sky Model implementing the Clark Clean algorithm. More... | |
| class | casa::ConvFuncDiskCache |
| An object to manage the caches of pre-computed convolution functions on the disk and in the memory. More... | |
| class | casa::CSCleanImageSkyModel |
| CS Image Sky Model: Image Sky Model implementing the CS Clean algorithm. More... | |
| class | casa::DBeamSkyJones |
| Model the polarization leakage in the Sky Jones Matrices. More... | |
| class | casa::FTMachine |
| defines interface for the Fourier Transform Machine More... | |
| class | casa::GridFT |
| An FTMachine for Gridded Fourier transforms. More... | |
| class | casa::HogbomCleanImageSkyModel |
| Hogbom Clean Image Sky Model: Image Sky Model implementing the Hogbom Clean algorithm. More... | |
| class | casa::ImageSkyModel |
| Image Sky Model: Image-based Model for the Sky Brightness. More... | |
| class | casa::MakeApproxPSFAlgorithm |
| Parallelized version of approximate PSF formation. More... | |
| class | casa::MFCEMemImageSkyModel |
| MF CE Mem Image Sky Model: Image Sky Model implementing the MF Mem algorithm. More... | |
| class | casa::MFCleanImageSkyModel |
| MF Image Sky Model: Image Sky Model implementing the MF Clean algorithm. More... | |
| class | casa::MFMSCleanImageSkyModel |
| Image Sky Model implementing the MultiScale, MultiField Clean algorithm. More... | |
| class | casa::MSCleanImageSkyModel |
| MS Clean Image Sky Model: Image Sky Model implementing the MS Clean algorithm. More... | |
| class | casa::NNLSImageSkyModel |
| Briggs' Non-Negative Least Squares deconvolution algorithm. More... | |
| class | casa::PBMath |
| Primary beam envelope class, derived from PBMathInterface. More... | |
| class | casa::PBMath1D |
| base class for 1D PBMath objects More... | |
| class | casa::PBMath1DAiry |
| PBMath1DAiry is a 1-D Airy Disk voltage pattern & Primary Beam. More... | |
| class | casa::PBMath1DCosPoly |
| PBMath1DCosPoly is a 1-D Polynomial Cosine Expansion for a Primary Beam. More... | |
| class | casa::PBMath1DGauss |
| PBMath1DGauss is a 1-D Gaussian Primary Beam. More... | |
| class | casa::PBMath1DIPoly |
| PBMath1DIPoly is a 1-D Inverse Polynomial Expansion for a Primary Beam. More... | |
| class | casa::PBMath1DNumeric |
| 1-D Numeric Primary Beam Model More... | |
| class | casa::PBMath1DPoly |
| More... | |
| class | casa::PBMath2D |
| base class for 1D PBMath objects More... | |
| class | casa::PBMath2DImage |
| 2-D Image Primary Beam Model More... | |
| class | casa::PBMathInterface |
| Virtual base class defining the Primary Beam interface. More... | |
| class | casa::PClarkCleanImageSkyModel |
| Clark Image Sky Model: Image Sky Model implementing the Clark Clean algorithm. More... | |
| class | casa::PredictAlgorithm |
| Parallel model visibility prediction. More... | |
| class | casa::PWFCleanImageSkyModel |
| Parallelized version of class WFCleanImageSkyModel. More... | |
| class | casa::ResidualAlgorithm |
| Parallel residual image formation. More... | |
| class | casa::SDGrid |
| An FTMachine for Gridding Single Dish data. More... | |
| class | casa::SimACoh |
| SimACoh: Model additive noise errors for the VisEquation . More... | |
| class | casa::SimACohCalc |
| SimACohCalc: Model additive noise errors for the VisEquation. More... | |
| class | casa::SimpComponentGridMachine |
| SimpComponentFTMachine: does the simplest Fourier transform on SkyComponents. More... | |
| class | casa::SkyJones |
| Sky Jones: Model sky-plane instrumental effects for the SkyEquation. More... | |
| class | casa::SkyModel |
| Sky Model: Model the Sky Brightness for the SkyEquation. More... | |
| class | casa::SynthesisError |
| class | casa::SynthesisFTMachineError |
| Error thrown by the classes in the Synthesis module. More... | |
| class | casa::UVMod |
| VisCal: Model multiplicative errors for the VisEquation . More... | |
| class | casa::VisCalSolver |
| VisCalSolver: Default solver for calibration using visibility data. More... | |
| class | casa::VPSkyJones |
| Model the diagonal elements of the Voltage Pattern Sky Jones Matrices. More... | |
| class | casa::WBCleanImageSkyModel |
| WB Clean Image Sky Model: Image Sky Model implementing a Wide-Band multi frequency synthesis algorithm. More... | |
| class | casa::WFCleanImageSkyModel |
| WF Image Sky Model: Image Sky Model implementing the WF Clean algorithm. More... | |
| class | casa::WProjectFT |
| An FTMachine for Gridded Fourier transforms. More... | |
| class | casa::XCorr |
| Model non-linear correlator function for the VisEquation. More... | |
1.5.1