CombiFunction.h

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// # CombiFunction.h: Form a linear combination of Functions
// # 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_COMBIFUNCTION_H
#define SCIMATH_COMBIFUNCTION_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/scimath/Functionals/CombiParam.h>
#include <casacore/scimath/Mathematics/AutoDiff.h>
#include <casacore/scimath/Mathematics/AutoDiffMath.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward declarations
 
// <summary>
// Form a linear combination of function objects.
// </summary>
//
// <use visibility=export>
//
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tCombiFunction" demos="">
// </reviewed>
//
// <prerequisite>
//   <li> <linkto class="Function">Function</linkto> class
// </prerequisite>
//
// <synopsis>
// Given N function objects, the class describes a linear combination of the
// form:
// <srcblock>
// f(x) = a(0)*f(0)(x) + a(1)*f(1)(x) + ... + a(N-1)*f(N-1)(x)
// </srcblock>
// where a = {a(n)} are parameters. If the combi function is used in
// a functional fitting process (see
// <linkto class=LinearFit>LinearFit</linkto>) these parameters canm be
// solved for. In all aspects they behave as
// <linkto class=FunctionParam>FunctionParam</linkto> values.
//
// Member functions are added with the <src>addFunction()</src> method.
//
// <note role=tip>
// Check <linkto class=CompoundFunction>CompoundFunction</linkto> class
// for a combination of functions behaving as one object. </note>
// </synopsis>
//
// <example>
// In the following example a second order polynomial is built from 3 separate
// polynomials.
// <srcblock>
// Polynomial<Double> constant(0);
// Polynomial<Double> linear(1);
// Polynomial<Double> square(2);
//
// constant.setCoefficient(0, 1.0);   // 1
// linear.setCoefficient(1, 1.0);     // x
// square[2] = 1.0;     // x^2
//
// CombiFunction<Double> combination;
//
// // form function, e0 + e1*x + e2*x^2
// combination.addFunction(constant);
// combination.addFunction(linear);
// combination.addFunction(square);
// </srcblock>
// </example>
 
// <templating arg=T>
//  <li> T should have standard numerical operators and exp() function. Current
//  implementation only tested for real types.
//  <li> To obtain derivatives, the derivatives should be defined.
// </templating>
 
// <thrown>
// <li> AipsError in debug mode if incorrect function index
// </thrown>
//
// <motivation>
// This class was created to allow specialization of the evaluation in
// a simple way.
// </motivation>
//
// <todo asof="2001/10/22">
// <li> Nothing I know of
// </todo>
 
template <class T>
class CombiFunction : public CombiParam<T> {
 public:
  // # Constructors
  //  The default constructor -- no functions, no parameters, nothing, the
  //  function operator returns a 0.
  CombiFunction() : CombiParam<T>() {}
  // Make this object a (deep) copy of other.
  // <group>
  CombiFunction(const CombiFunction<T> &other) : CombiParam<T>(other) {}
  CombiFunction(const CombiFunction<T> &other, Bool) : CombiParam<T>(other, True) {}
  template <class W>
  CombiFunction(const CombiFunction<W> &other) : CombiParam<T>(other) {}
  template <class W>
  CombiFunction(const CombiFunction<W> &other, Bool) : CombiParam<T>(other, True) {}
  // </group>
  // Make this object a (deep) copy of other.
  CombiFunction<T> &operator=(const CombiFunction<T> &other) {
    CombiParam<T>::operator=(other);
    return *this;
  }
 
  // Destructor
  virtual ~CombiFunction() {}
 
  // # Operators
  //  Evaluate the function at <src>x</src>.
  virtual T eval(typename Function<T>::FunctionArg x) const;
 
  // # Member functions
  //  Return a copy of this object from the heap. The caller is responsible for
  //  deleting the pointer.
  //  <group>
  virtual Function<T> *clone() const { return new CombiFunction<T>(*this); }
  virtual Function<typename FunctionTraits<T>::DiffType> *cloneAD() const {
    return new CombiFunction<typename FunctionTraits<T>::DiffType>(*this);
  }
  virtual Function<typename FunctionTraits<T>::BaseType> *cloneNonAD() const {
    return new CombiFunction<typename FunctionTraits<T>::BaseType>(*this, True);
  }
  // </group>
 
  // # Make members of parent classes known.
 public:
  using CombiParam<T>::nparameters;
};
 
#define CombiFunction_PS CombiFunction
 
// <summary> Partial specialization of CombiFunction for <src>AutoDiff</src>
// </summary>
 
// <synopsis>
// <note role=warning> The name <src>CombiFunction_PS</src> is only for cxx2html
// documentation problems. Use <src>CombiFunction</src> in your code.</note>
// </synopsis>
 
template <class T>
class CombiFunction_PS<AutoDiff<T>> : public CombiParam<AutoDiff<T>> {
 public:
  // # Constructors
  //  The default constructor -- no functions, no parameters, nothing, the
  //  function operator returns a 0.
  CombiFunction_PS() : CombiParam<AutoDiff<T>>() {}
  // Make this object a (deep) copy of other.
  // <group>
  CombiFunction_PS(const CombiFunction_PS<AutoDiff<T>> &other) : CombiParam<AutoDiff<T>>(other) {}
  template <class W>
  CombiFunction_PS(const CombiFunction_PS<W> &other) : CombiParam<AutoDiff<T>>(other) {}
  // </group>
  // Make this object a (deep) copy of other.
  CombiFunction_PS<AutoDiff<T>> &operator=(const CombiFunction_PS<AutoDiff<T>> &other) {
    CombiParam<AutoDiff<T>>::operator=(other);
    return *this;
  }
 
  // Destructor
  virtual ~CombiFunction_PS() {}
 
  // # Operators
  //  Evaluate the function and its derivatives at <src>x</src> <em>wrt</em>
  //  to the coefficients.
  virtual AutoDiff<T> eval(typename Function<AutoDiff<T>>::FunctionArg x) const;
 
  // # Member functions
  //  Return a copy of this object from the heap. The caller is responsible for
  //  deleting the pointer.
  //  <group>
  virtual Function<AutoDiff<T>> *clone() const { return new CombiFunction_PS<AutoDiff<T>>(*this); }
  virtual Function<typename FunctionTraits<AutoDiff<T>>::DiffType> *cloneAD() const {
    return new CombiFunction<typename FunctionTraits<AutoDiff<T>>::DiffType>(*this);
  }
  virtual Function<typename FunctionTraits<AutoDiff<T>>::BaseType> *cloneNonAD() const {
    return new CombiFunction<typename FunctionTraits<AutoDiff<T>>::BaseType>(*this, True);
  }
  // </group>
 
  // # Make members of parent classes known.
 public:
  using CombiParam<AutoDiff<T>>::nparameters;
};
 
#undef CombiFunction_PS
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/scimath/Functionals/CombiFunction.tcc>
#include <casacore/scimath/Functionals/Combi2Function.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif