G4FunctionSolver< T_Function > Class Template Reference

#include <G4FunctionSolver.hh>

Public Member Functions
	G4FunctionSolver (T_Function *ff, const G4int iterations, const G4double tol)
	G4FunctionSolver (const G4FunctionSolver &right)=delete
	~G4FunctionSolver ()=default
G4FunctionSolver &	operator= (const G4FunctionSolver &right)=delete
G4bool	operator== (const G4FunctionSolver &right) const =delete
G4bool	operator!= (const G4FunctionSolver &right) const =delete
void	SetMaxIterations (const G4int iterations)
void	SetTolerance (const G4double epsilon)
void	SetIntervalLimits (const G4double Limit1, const G4double Limit2)
G4bool	FindRoot (G4double &x)

Detailed Description

template<class T_Function>
class G4FunctionSolver< T_Function >

Definition at line 52 of file G4FunctionSolver.hh.

Constructor & Destructor Documentation

G4FunctionSolver() [1/2]

template<class T_Function>

G4FunctionSolver< T_Function >::G4FunctionSolver ( T_Function * ff, const G4int iterations, const G4double tol )

inline

Definition at line 56 of file G4FunctionSolver.hh.

    : maxIter(iterations), tolerance(tol), tF(ff) {};

Referenced by G4FunctionSolver(), operator!=(), operator=(), and operator==().

G4FunctionSolver() [2/2]

template<class T_Function>

G4FunctionSolver< T_Function >::G4FunctionSolver ( const G4FunctionSolver< T_Function > & right )

delete

~G4FunctionSolver()

template<class T_Function>

G4FunctionSolver< T_Function >::~G4FunctionSolver ( )

default

Member Function Documentation

FindRoot()

template<class T_Function>

G4bool G4FunctionSolver< T_Function >::FindRoot ( G4double & x )

inline

Definition at line 83 of file G4FunctionSolver.hh.

  {
    G4double a = aa;
    G4double b = bb;
 
    // check the interval before the start
    x = std::min(std::max(x, a), b);
 
    // check initial function
    G4double fc = tF->Function(x);
    if (0.0 == fc) { return true; }
 
    // define accuracy in X
    G4double epsX = tolerance*x;
    // define accuracy in Y
    G4double epsY = tolerance*fc;
 
    // the interval is too small
    if (std::abs(a - b) <= epsX)
    {
      x = 0.5*(a + b);
      return true;
    }
 
    // check edges
    G4double fa = tF->Function(a);
    G4double fb = tF->Function(b);
 
    // root should be inside interval
    if (fa*fb >= 0.0)
    {
      x = (std::abs(fa) <= std::abs(fb)) ? a : b;
      return (std::min(std::abs(fa), std::abs(fb)) < epsY);
    }
 
    // fa*fb < 0.0 - finding the root by iterative procedure, 
    // the loop is completed if function is below epsY
    // or if x become close to edges with accuracy epsX 
    for (G4int i = 0; i < maxIter; ++i)
    {
      x = (a*fb - b*fa)/(fb - fa);
      fc = tF->Function(x);
      if (std::abs(fc) < epsY) { return true; }
 
      G4double delta = std::min((x - a), (b - x));
      if (delta < epsX) { return true; }
      else if (fa*fc < 0.0) { b = x; fb = fc; }
      else { a = x; fa = fc; }
    }
    // number of iterations exceed the limit
    return false;
  }

operator!=()

template<class T_Function>

G4bool G4FunctionSolver< T_Function >::operator!= ( const G4FunctionSolver< T_Function > & right ) const

delete

operator=()

template<class T_Function>

G4FunctionSolver & G4FunctionSolver< T_Function >::operator= ( const G4FunctionSolver< T_Function > & right )

delete

operator==()

template<class T_Function>

G4bool G4FunctionSolver< T_Function >::operator== ( const G4FunctionSolver< T_Function > & right ) const

delete

SetIntervalLimits()

template<class T_Function>

void G4FunctionSolver< T_Function >::SetIntervalLimits ( const G4double Limit1, const G4double Limit2 )

inline

Definition at line 76 of file G4FunctionSolver.hh.

  {
    aa = std::min(Limit1, Limit2);
    bb = std::max(Limit1, Limit2);
  }

SetMaxIterations()

template<class T_Function>

void G4FunctionSolver< T_Function >::SetMaxIterations ( const G4int iterations )

inline

Definition at line 70 of file G4FunctionSolver.hh.

  { maxIter = iterations; }

SetTolerance()

template<class T_Function>

void G4FunctionSolver< T_Function >::SetTolerance ( const G4double epsilon )

inline

Definition at line 73 of file G4FunctionSolver.hh.

  { tolerance = epsilon; }

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The documentation for this class was generated from the following file:

• G4FunctionSolver.hh