EvenPolynomialParam.h

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// # EvenPolynomialParam.h: Parameter handling for even polynomials
// # Copyright (C) 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_EVENPOLYNOMIALPARAM_H
#define SCIMATH_EVENPOLYNOMIALPARAM_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Arrays/ArrayFwd.h>
#include <casacore/scimath/Functionals/Function1D.h>
#include <casacore/casa/Utilities/Assert.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary>  Parameter handling for even polynomials
// </summary>
 
// <reviewed reviewer="tcornwel" date="1996/02/22" tests="tSpecialPolynomial"
// demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class="FunctionParam">FunctionParam</linkto> class
//   <li> <linkto class=Function1D>Function1D</linkto>
// </prerequisite>
 
// <etymology>
// A 1-dimensional EvenPolynomial's parameters.
// </etymology>
//
// <synopsis>
// An <src>EvenPolynomial</src> is described by a set of coefficients;
// its fundamental operation is evaluating itself at some "x".
// The number of coefficients is the order of the polynomial divided
// by two, plus one.
//
// Since the <src>EvenPolynomial</src> is a <src>Function</src>,
// the derivatives can be obtained as well.
//
// 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>EvenPolynomial</src>
// class only.
// </synopsis>
//
// <example>
// <srcblock>
//  EvenPolynomial<Float> pf(3);  // Second order polynomial - coeffs 0 by default
//  pf.setCoefficient(0, 1.0);
//  pf[1] = 2.0;        // 2x^2 + 1x^0
//  pf(2); // == 8
// </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>
 
// <todo asof="2002/02/26">
//   <li> Nothing I know of
// </todo>
 
template <class T>
class EvenPolynomialParam : public Function1D<T> {
 public:
  // # Constructors
  //  Constructs a zero'th order polynomial, with a coeficcient of 0.0.
  EvenPolynomialParam();
 
  // Makes a polynomial of the given order, with all coeficcients set to
  // zero.
  explicit EvenPolynomialParam(uInt order);
 
  // Make this a copy of other (deep copy).
  // <group>
  EvenPolynomialParam(const EvenPolynomialParam<T> &other);
  template <class W>
  EvenPolynomialParam(const EvenPolynomialParam<W> &other) : Function1D<T>(other) {}
  EvenPolynomialParam<T> &operator=(const EvenPolynomialParam<T> &other);
  // </group>
 
  // Destructor
  ~EvenPolynomialParam();
 
  // # Operators
  //  Comparisons.
  //  EvenPolynomials are equal if they are the same order
  //  <group>
  Bool operator==(const EvenPolynomialParam<T> &other) const { return (param_p == other.param_p); }
  Bool operator!=(const EvenPolynomialParam<T> &other) const { return (param_p != other.param_p); }
  // </group>
 
  // # Member functions
  //  Give name of function
  virtual const String &name() const {
    static String x("evenpolynomial");
    return x;
  }
 
  // What is the order of the polynomial, i.e. maximum exponent of "x".
  uInt order() const { return 2 * param_p.nelements() - 2; }
 
  // What is the <em>which</em>'th coefficient of the polynomial. For an nth
  // degree polynomial, <em>which</em> varies between zero and n/2.
  T coefficient(uInt which) const {
    DebugAssert(which <= order(), AipsError);
    return param_p[which];
  }
 
  // Return all the coefficients as a vector.
  const Vector<T> &coefficients() const;
 
  // Set the <em>which</em>'th coefficient to <em>value</em>.
  void setCoefficient(uInt which, const T value) {
    DebugAssert(which <= order(), AipsError);
    param_p[which] = value;
  }
 
  // Set all the coefficients at once, throw away all existing coefficients.
  void setCoefficients(const Vector<T> &coefficients);
 
  // # 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 <casacore/scimath/Functionals/EvenPolynomialParam.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif