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//
//
// $Id$
//
// Hadronic Process: Nuclear De-excitations
// by V. Lara

#ifndef G4Solver_h
#define G4Solver_h 1

#include "globals.hh"

#include <cmath>

#define DefaultTolerance 5.0e-14

template <class Function> class G4Solver 
{
public:
    enum {DefaultMaxIter = 100};
	
    // default constructor
    G4Solver() : MaxIter(DefaultMaxIter), tolerance(DefaultTolerance),
		 a(0.0), b(0.0), root(0.0) {};
	
    G4Solver(const G4int iterations, const G4double tol) :
	MaxIter(iterations), tolerance(tol),
	a(0.0), b(0.0), root(0.0) {};

    // copy constructor	
    G4Solver(const G4Solver & right);

    // destructor
    ~G4Solver() {};
	
    // operators
    G4Solver & operator=(const G4Solver & right);
    G4bool operator==(const G4Solver & right) const;
    G4bool operator!=(const G4Solver & right) const;
		
    G4int GetMaxIterations(void) const {return MaxIter;}
    void SetMaxIterations(const G4int iterations) {MaxIter=iterations;}
	
    G4double GetTolerance(void) const {return tolerance;}
    void SetTolerance(const G4double epsilon) {tolerance = epsilon;}
	
	
    G4double GetIntervalLowerLimit(void) const {return a;}
    G4double GetIntervalUpperLimit(void) const {return b;}
	
    void SetIntervalLimits(const G4double Limit1, const G4double Limit2);
    
    G4double GetRoot(void) const {return root;}
    
    // Calculates the root by the Bisection method
    G4bool Bisection(Function & theFunction);	
	
    // Calculates the root by the Regula-Falsi method
    G4bool RegulaFalsi(Function & theFunction);
	
	
    // Calculates the root by the Brent's method
    G4bool Brent(Function & theFunction);

    // Calculates the root by the Inverse Parabolic Interpolation method 
    // due to Jack Crenshaw
    G4bool Crenshaw(Function & theFunction);
	
private:

    // Maximum number of iterations
    G4int MaxIter;

    // 
    G4double tolerance;

    // interval limits [a,b] which should bracket the root
    G4double a;
    G4double b;

    // The root
    G4double root;

};

#include "G4Solver.icc"

#endif