EquationSolver.h

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/*                                                                            
                                                                            
Nikolai Amelin, Ludmila Malinina, Timur Pocheptsov (C) JINR/Dubna
amelin@sunhe.jinr.ru, malinina@sunhe.jinr.ru, pocheptsov@sunhe.jinr.ru 
November. 2, 2005                                

*/
//This equation solver class is taken from GEANT4 and modified!!

#ifndef NAEquationSolver_h
#define NAEquationSolver_h 1
#include <Rtypes.h>
#include "MathUtil.h"

#define DefaultTolerance 5.0e-14

template <class Function>
class NAEquationSolver {
public:
  enum { DefaultMaxIter = 100 };

private:
  // Maximum number of iterations
  int fMaxIter;
  double fTolerance;
  // interval limits [a,b] which should bracket the root
  double fA;
  double fB;
  // root
  double fRoot;

public:
  // default constructor
  NAEquationSolver() : fMaxIter(DefaultMaxIter), fTolerance(DefaultTolerance), fA(0.0), fB(0.0), fRoot(0.0){};

  NAEquationSolver(const int iterations, const double tol)
      : fMaxIter(iterations), fTolerance(tol), fA(0.0), fB(0.0), fRoot(0.0){};

  // copy constructor
  NAEquationSolver(const NAEquationSolver& right);

  // destructor
  ~NAEquationSolver(){};

  // operators
  NAEquationSolver& operator=(const NAEquationSolver& right);
  bool operator==(const NAEquationSolver& right) const;
  bool operator!=(const NAEquationSolver& right) const;

  int GetMaxIterations(void) const { return fMaxIter; }
  void SetMaxIterations(const int iterations) { fMaxIter = iterations; }

  double GetTolerance(void) const { return fTolerance; }
  void SetTolerance(const double epsilon) { fTolerance = epsilon; }

  double GetIntervalLowerLimit(void) const { return fA; }
  double GetIntervalUpperLimit(void) const { return fB; }

  void SetIntervalLimits(const double Limit1, const double Limit2);

  double GetRoot(void) const { return fRoot; }

  // Calculates the root by the Brent's method
  bool Brent(Function& theFunction);
};

#include "GeneratorInterface/Hydjet2Interface/interface/EquationSolver.icc"

#endif