ConstantNDParam.h

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// # HyperPlaneParam.h: Parameters For 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
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// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef SCIMATH_CONSTANTNDPARAM_H
#define SCIMATH_CONSTANTNDPARAM_H
 
#include <casacore/casa/aips.h>
#include <casacore/scimath/Functionals/Function.h>
#include <casacore/casa/BasicSL/String.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary> Parameter handling for a constant function in a space of arbitrary dimensionality.
// </summary>
//
// <use visibility=local>
// <reviewed reviewer="" date="" tests="tConstant" demos="">
// </reviewed>
//
// <prerequisite>
//   <li> <linkto class="FunctionParam">FunctionParam</linkto> class
//   <li> <linkto class="Function">Function</linkto> class
// </prerequisite>
//
// <synopsis>
// This class forms a function of the form
// f(x<sub>0</sub>,x<sub>1</sub>,..,x<sub>m-1</sub>) = constant
// in an m-dimensional parameter space where
// x<sub>i</sub> are independent arguments.
//
// Since the <src>Constant</src> is a <src>Function</src>, the derivatives
// can be obtained as well (and in fact are 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 a constant function in 4-D space
//  Constant<Double> constant(4); // constant in 4-D param space
//  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 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>
 
// <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 ConstantNDParam : public Function<T> {
 public:
  // # Constructors
  //  Construct a constant in m-dimensional space.  By
  //  default, the constant value is initialized to zero.
  //  <group>
  explicit ConstantNDParam(uInt m = 0);
  // </group>
 
  // Copy constructor (deep copy)
  // <group>
  ConstantNDParam(const ConstantNDParam &other);
  template <class W>
  ConstantNDParam(const ConstantNDParam<W> &other) : Function<T>(other), _ndim(other.ndim()) {}
  // </group>
 
  // Copy assignment (deep copy)
  ConstantNDParam<T> &operator=(const ConstantNDParam<T> &other);
 
  // Destructor
  virtual ~ConstantNDParam();
 
  // # Operators
  //  Comparisons.
  //  HyperPlanes are equal if they are of the same order and have the same
  //  parameters
  //  <group>
  Bool operator==(const ConstantNDParam<T> &other) const {
    return (this->param_p == other.param_p);
  };
  Bool operator!=(const ConstantNDParam<T> &other) const {
    return (this->param_p != other.param_p);
  };
  // </group>
 
  // # Member functions
  //  Give name of function
  virtual const String &name() const {
    static String x("constant");
    return x;
  };
 
  // What is the dimension of the parameter list
  virtual uInt ndim() const { return _ndim; };
 
  // # Make members of parent classes known.
 protected:
  using Function<T>::param_p;
 
 public:
  using Function<T>::nparameters;
 
 private:
  uInt _ndim;
};
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/scimath/Functionals/ConstantNDParam.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif