ConstantND.h

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// # HyperPlane.h: Form a hyper plane function
// # Copyright (C) 2001,2002,2004,2005
// # 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_CONSTANT_H
#define SCIMATH_CONSTANT_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/scimath/Functionals/ConstantNDParam.h>
#include <casacore/scimath/Functionals/Function.h>
#include <casacore/scimath/Mathematics/AutoDiff.h>
#include <casacore/scimath/Mathematics/AutoDiffMath.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary> A constant function.
// </summary>
//
// <use visibility=export>
// <reviewed reviewer="" date="" tests="tConstant" demos="">
// </reviewed>
//
// <prerequisite>
//   <li> <linkto class=Function>Function</linkto>
// </prerequisite>
//
// <synopsis>
// This class represents a constant function in a space
// of arbitrary dimension
// f(x<sub>0</sub>,x<sub>1</sub>,..,x<sub>m-1</sub>) = constant
// where x<sub>i</sub>
// are independent arguments and m is the number of dimensions of the space.
//
//
// Since the <src>Constant</src> is a <src>Function</src>, the derivatives
// can be obtained as well (and are in fact 0 of course).
//
// The parameter interface (see
// <linkto class="FunctionParam">FunctionParam</linkto> class),
// is used to provide an interface to the
// <linkto module="Fitting">Fitting</linkto> classes.
//
// This class is in general used implicitly by the <src>Constant</src>
// class only.
// </synopsis>
//
// <example>
// <srcblock>
// // form the constant function in 4-D space
//  Constant<Double> constant(4); // 4-dim hyperplane
//  constant.parameters()[0] = 22;
//  // Evaluate at x0=5, x3=7
//  Vector<Double> x(4);
//  x=0; x[0]=5; x[3]=7;
//  cout << "constant value: " << constant(x) << endl;
//  constant value: 22
// </srcblock>
// </example>
 
// <templating arg=T>
//  <li> T should have standard numerical operators. Current
//  implementation only tested for real types (and their AutoDiffs).
// </templating>
 
// <thrown>
//    <li> Assertion in debug mode if attempt is made to address incorrect
//     coefficients
// </thrown>
 
// <motivation>
// This class was created because HyperPlane does not support a constant
// offset and modifying that class really required an interface change
// (ie that the constant offset be at the beginning of the parameter vector
// and that the parameter vector increase by one) so rather than breaking
// any code that already used HyperPlane I simply made a trivial Constant
// class.
// </motivation>
//
// <todo asof="2011/07/01">
//  <li> Nothing I know of
// </todo>
 
template <class T>
class ConstantND : public ConstantNDParam<T> {
 public:
  // # Constructors
  //  Construct a constant in an a space of dimensionality <src>m</src>.  By
  //  default, the constant value is initialised to zero, and <src>m=0</src>
  explicit ConstantND(const uInt m = 0) : ConstantNDParam<T>(m) { ; };
  // Copy constructor/assignment (deep copy)
  // <group>
  ConstantND(const ConstantND<T> &other) : ConstantNDParam<T>(other) {};
  template <class W>
  ConstantND(const ConstantND<W> &other) : ConstantNDParam<T>(other) {}
  ConstantND<T> &operator=(const ConstantND<T> &other) {
    ConstantNDParam<T>::operator=(other);
    return *this;
  };
  // </group>
 
  // Destructor
  virtual ~ConstantND() {};
 
  // # Operators
  //  Evaluate the hyper plane function at
  //  (x<sub>0</sub>,x<sub>1</sub>,..,x<sub>m-1</sub>).
  virtual T eval(typename Function<T>::FunctionArg x) const;
 
  // 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 ConstantND<T>(*this); };
  virtual Function<typename FunctionTraits<T>::DiffType> *cloneAD() const {
    return new ConstantND<typename FunctionTraits<T>::DiffType>(*this);
  };
  virtual Function<typename FunctionTraits<T>::BaseType> *cloneNonAD() const {
    return new ConstantND<typename FunctionTraits<T>::BaseType>(*this);
  };
  // </group>
 
  // # Make members of parent classes known.
 protected:
  using ConstantNDParam<T>::param_p;
 
 public:
  using ConstantNDParam<T>::nparameters;
};
 
#define ConstantND_PS ConstantND
 
// <summary> Partial specialization of ConstantND for <src>AutoDiff</src>
// </summary>
 
// <synopsis>
// <note role=warning> The name <src>HyperPlane_PS</src> is only for cxx2html
// documentation problems. Use <src>HyperPlane</src> in your code.</note>
// </synopsis>
 
template <class T>
class ConstantND_PS<AutoDiff<T>> : public ConstantNDParam<AutoDiff<T>> {
 public:
  // # Construct
  //  Constructors a constant in a space of dimensionality <src>m</src>.  By
  //  default, the coefficients are initialized to zero, and <src>m=0</src>
  explicit ConstantND_PS(const uInt m = 0) : ConstantNDParam<AutoDiff<T>>(m) {};
  // Copy constructor/assignment (deep copy)
  // <group>
  ConstantND_PS(const ConstantND_PS<AutoDiff<T>> &other) : ConstantNDParam<AutoDiff<T>>(other) {};
  template <class W>
  ConstantND_PS(const ConstantND_PS<W> &other) : ConstantNDParam<AutoDiff<T>>(other) {}
  ConstantND_PS<AutoDiff<T>> &operator=(const ConstantND_PS<AutoDiff<T>> &other) {
    ConstantNDParam<AutoDiff<T>>::operator=(other);
    return *this;
  };
  // </group>
 
  // Destructor
  virtual ~ConstantND() {};
 
  // # Operators
  //  Evaluate the constant function at
  //  (x<sub>0</sub>,x<sub>1</sub>,..,x<sub>m-1</sub>).
  virtual AutoDiff<T> eval(typename Function<AutoDiff<T>>::FunctionArg x) const;
 
  // 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 ConstantND_PS<AutoDiff<T>>(*this); };
  virtual Function<typename FunctionTraits<AutoDiff<T>>::DiffType> *cloneAD() const {
    return new ConstantND<typename FunctionTraits<AutoDiff<T>>::DiffType>(*this);
  };
  virtual Function<typename FunctionTraits<AutoDiff<T>>::BaseType> *cloneNonAD() const {
    return new ConstantND<typename FunctionTraits<AutoDiff<T>>::BaseType>(*this);
  };
  // </group>
 
  // # Make members of parent classes known.
 protected:
  using ConstantNDParam<AutoDiff<T>>::param_p;
 
 public:
  using ConstantNDParam<AutoDiff<T>>::nparameters;
};
 
#undef ConstantND_PS
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/scimath/Functionals/ConstantND.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif