casa6

//# ResidualEquation.h: this defines ResidualEquation

//# Copyright (C) 1996,1997,1999,2000

//# Associated Universities, Inc. Washington DC, USA.

//#

//# This library is free software; you can redistribute it and/or modify it

//# under the terms of the GNU Library General Public License as published by

//# the Free Software Foundation; either version 2 of the License, or (at your

//# option) any later version.

//#

//# This library is distributed in the hope that it will be useful, but WITHOUT

//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public

//# License for more details.

//#

//# You should have received a copy of the GNU Library General Public License

//# along with this library; if not, write to the Free Software Foundation,

//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.

//#

//# Correspondence concerning AIPS++ should be addressed as follows:

//#        Internet email: aips2-request@nrao.edu.

//#        Postal address: AIPS++ Project Office

//#                        National Radio Astronomy Observatory

//#                        520 Edgemont Road

//#                        Charlottesville, VA 22903-2475 USA

//#

//#

//#

//# $Id$

​

#ifndef SYNTHESIS_RESIDUALEQUATION_H

#define SYNTHESIS_RESIDUALEQUATION_H

​

#include <casa/aips.h>

#include <synthesis/MeasurementEquations/LinearModel.h>

​

namespace casa { //# NAMESPACE CASA - BEGIN

​

template<class Domain> class LinearModel;

​

// <summary>Interface class containing functions returning "Domain" type</summary>

​

// <use visibility=local>

​

// <reviewed reviewer="" date="yyyy/mm/dd" tests="" demos="">

// </reviewed>

​

// <prerequisite>

//   This class should be read in conjunction with:

//   <li> <linkto class="LinearModel">LinearModel</linkto>

//   <li> <linkto class="LinearEquation">LinearEquation</linkto>

// </prerequisite>

//

// <etymology>

// ResidualEquation reflects the fact that the residual() function was the

// first, and perhaps most important member of the class.

// </etymology>

//

// <synopsis>

// ResidualEquation is an abstract interface class into the more extensive

// LinearEquation class. It is composed of the subset of functions from

// LinearEquation which return objects of the "Domain", type. These objects

// can be used by the solve() function in the LinearModel to determine a new

// model. The separation of the ResidualEquation functions isolates the

// model, of type "Domain" from knowing what the data "Range", used by the

// LinearEquation class is. 

// </synopsis>

//

// <example>

// Suppose we have a simple class that has a vector model and knows (using

// the solve() function) how to update this vector if it is told the error

// betweeen the measured data and a model of the data produced using the

// current vector. 

// <srcblock> 

// SimpleModel< casacore::Vector<casacore::Float> > simplemodel;

// </srcblock> 

// 

// Suppose we also have a big complicated equation that does

// the forward modelling from vectors to some arbitrary class;

//

// <srcblock> 

// FancyEquation<casacore::Vector<casacore::Float>, VisibilitySet> eqn;

// </srcblock> 

//

// Then Simplemodel class does not need to know anything about the

// VisibilitySet class as it knows that the FancyEquation class will have 

// (via inheritence) a ResidualEquation interface which returns vectors,

// so that it can use code like:

// <srcblock> 

// casacore::Vector<casacore::Float> error;

// if (eqn.residual(*this, error)){ 

//   use the error to determine a new model