Lorentzian1DParam.h

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// # Lorentzian1DParam.h:  Parameter handling for one-dimensional Lorentzian class
// # Copyright (C) 2001,2002,2005
// # 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: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef SCIMATH_LORENTZIAN1DPARAM_H
#define SCIMATH_LORENTZIAN1DPARAM_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/BasicSL/String.h>
#include <casacore/scimath/Functionals/Function1D.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward declarations
 
// <summary>  Parameter handling for one dimensional Lorentzian class.</summary>
 
// <use visibility=local>
 
// <reviewed reviewer="tcornwel" date="1996/02/22" tests="tLorentzian1D"
// demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class="FunctionParam">FunctionParam</linkto> class
//   <li> <linkto class="Function1D">Function1D</linkto> class
// </prerequisite>
 
// <etymology>
// A 1-dimensional Lorentzian's parameters.
// </etymology>
 
// <synopsis>
// A <src>Lorentzian1D</src> is described by a height, center, and width.
// The parameters (height, center and width) may be changed at run time.
//
// The width of the Lorentzian (for the constructors or the <src>setWidth
// </src> function) is always specified in terms of the full width at half
// maximum (FWHM). It is always positive and attempts to set a non-positive
// width will throw an assertion when in debug mode.
//
// The peak height of the Lorentzian can be specified at construction time or
// by using the <src> setHeight </src> function. Alternatively the <src>
// setFlux </src> function can be used to implicitly set the peak height by
// specifying the integrated area under the Lorentzian. The height (or flux)
// can be positive, negative or zero, as this class makes no assumptions on
// what quantity the height represents.
//
// <note role=tip> Changing the width of the Lorentzian will not affect
// its peak height but will change its flux. So you should always set the
// width before setting the flux. </note>
//
// The parameter interface (see
// <linkto class="FunctionParam">FunctionParam</linkto> class),
// is used to provide an interface to the
// <linkto module="Fitting">Fitting</linkto> classes.
//
// There are 3 parameters that are used to describe the Lorentzian:
// <ol>
// <li> The height of the Lorentzian. This is identical to the value
//      returned using the <src>height()</src> member function.
// <li> The center of the Lorentzian in the x direction. This is identical to
//      the value returned using the <src>center()</src> member function.
// <li> The width (FWHM) of the Lorentzian. To aid convergence of
//      the non-linear fitting routines this parameter is allowed to be
//      negative. This does not affect the shape of the Lorentzian as the
//  square of the width is used when evaluating the function.
// </ol>
//
// An enumeration for the <src>HEIGHT</src>, <src>WIDTH</src> and
// <src>CENTER</src> parameter index is provided, enabling the setting
// and reading of parameters with the <src>[]</src> operator. The
// <src>mask()</src> methods can be used to check and set the parameter masks.
//
// This class is in general used implicitly by the <src>Lorentzian1D</src>
// class only.
// </synopsis>
 
// <example>
// <srcblock>
//    Lorentzian1D<Double> gf(5.0, 25.0, 7);
//    gf(25);            // = 5.0
//    gf.setHeight(1.0);
//    gf[WIDTH](2.0);
//    gf[CENTER](0.0);
//    gf(1);             // = 0.5*height = 0.5
// </srcblock>
// </example>
 
// <templating arg=T>
//  <li> T should have standard numerical operators and exp() function. Current
//  implementation only tested for real types (and their AutoDiffs).
// </templating>
 
// <thrown>
//    <li> Assertion in debug mode if attempt is made to set a negative width
//    <li> AipsError if incorrect parameter number specified.
// </thrown>
 
// <todo asof="2001/08/19">
//   <li> Lorentzians that know about their DFT's could be required eventually.
// </todo>
 
template <class T>
class Lorentzian1DParam : public Function1D<T> {
 public:
  // # Enumerations
  enum { HEIGHT = 0, CENTER, WIDTH };
 
  // # Constructors
  //  Constructs the one dimensional Lorentzians. Defaults:
  //  height=1, center=0, width(FWHM)=1.
  //  <note role=warning> Could not use default arguments
  //  that worked both with gcc and IRIX and all templates</note>
  //  <group>
  Lorentzian1DParam();
  explicit Lorentzian1DParam(const T &height);
  Lorentzian1DParam(const T &height, const T &center);
  Lorentzian1DParam(const T &height, const T &center, const T &width);
  // </group>
 
  // Copy constructor (deep copy)
  // <group>
  Lorentzian1DParam(const Lorentzian1DParam<T> &other);
  template <class W>
  Lorentzian1DParam(const Lorentzian1DParam<W> &other)
      : Function1D<T>(other), fwhm2int(T(1.0) / T(2.0)) {}
  // </group>
  // Copy assignment (deep copy)
  Lorentzian1DParam<T> &operator=(const Lorentzian1DParam<T> &other);
 
  // Destructor
  virtual ~Lorentzian1DParam();
 
  // # Operators
 
  // # Member functions
  //  Give name of function
  virtual const String &name() const {
    static String x("lorentzian1d");
    return x;
  };
 
  // Get or set the peak height of the Lorentzian
  // <group>
  T height() const { return param_p[HEIGHT]; };
  void setHeight(const T &height) { param_p[HEIGHT] = height; };
  // </group>
 
  // Get or set the analytical integrated area underneath the Lorentzian.
  // Use these functions as an alternative to the height functions.
  // <group>
  T flux() const;
  void setFlux(const T &flux);
  // </group>
 
  // Get or set the center ordinate of the Lorentzian
  // <group>
  T center() const { return param_p[CENTER]; };
  void setCenter(const T &cnter) { param_p[CENTER] = cnter; };
  // </group>
 
  // Get or set the FWHM of the Lorentzian.
  // <group>
  T width() const { return param_p[WIDTH]; };
  void setWidth(const T &width) { param_p[WIDTH] = width; };
  // </group>
 
 protected:
  // Constant to scale halfwidth at 1/e to FWHM
  T fwhm2int;
 
  // # Make members of parent classes known.
 protected:
  using Function1D<T>::param_p;
 
 public:
  using Function1D<T>::nparameters;
};
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include "Lorentzian1DParam.tcc"
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif