ROOT::Math::ModABRootFinder Class Reference

Class for finding the root of a one dimensional function using the ModAB algorithm.

It is based on the Modified Anderson-Björck method (2022 Ganchovski & Traykov) that adaptively switches between bisection and regula-falsi with side-correction, yielding superlinear convergence on well-behaved functions while retaining the robustness of bisection.

Definition at line 37 of file ModABRootFinder.h.

Public Member Functions
int	Iterations () const override
	Return number of iteration used to find minimum.
const char *	Name () const override
	Return name of root finder algorithm ("ModABRootFinder").
double	Root () const override
	Returns root value.
virtual bool	SetFunction (const ROOT::Math::IGenFunction &, double, double)
	Set function to solve and the interval in where to look for the root.
bool	SetFunction (const ROOT::Math::IGenFunction &f, double xlow, double xup) override
	Sets the function for the rest of the algorithms.
virtual bool	SetFunction (const ROOT::Math::IGradFunction &, double)
	Set function to solve and the interval in where to look for the root.
bool	Solve (int maxIter=100, double absTol=1E-8, double relTol=1E-10) override
	Returns the X value corresponding to the function value fy for (xmin<x<xmax).
int	Status () const override
	Returns status of last estimate.
Public Member Functions inherited from ROOT::Math::IRootFinderMethod
	IRootFinderMethod ()
	Default Constructor.
virtual	~IRootFinderMethod ()
	Default Destructor.
virtual int	Iterate ()
	This method is implemented only by the GSLRootFinder and GSLRootFinderDeriv classes and will return an error if it's not one of them.

Private Attributes
const IGenFunction *	fFunction = nullptr
int	fNIter = 0
double	fRoot = 0.
int	fStatus = -1
double	fXMax = 0.
double	fXMin = 0.

#include <Math/ModABRootFinder.h>

Inheritance diagram for ROOT::Math::ModABRootFinder:

Member Function Documentation

Iterations()

int ROOT::Math::ModABRootFinder::Iterations ( ) const

inlineoverridevirtual

Return number of iteration used to find minimum.

Reimplemented from ROOT::Math::IRootFinderMethod.

Definition at line 65 of file ModABRootFinder.h.

Name()

const char * ROOT::Math::ModABRootFinder::Name ( ) const

overridevirtual

Return name of root finder algorithm ("ModABRootFinder").

Implements ROOT::Math::IRootFinderMethod.

Definition at line 38 of file ModABRootFinder.cxx.

Root()

double ROOT::Math::ModABRootFinder::Root ( ) const

inlineoverridevirtual

Returns root value.

Need to call first Solve().

Implements ROOT::Math::IRootFinderMethod.

Definition at line 59 of file ModABRootFinder.h.

SetFunction() [1/3]

virtual bool ROOT::Math::IRootFinderMethod::SetFunction ( const ROOT::Math::IGenFunction & , double , double  )

inlinevirtual

Set function to solve and the interval in where to look for the root.

@param f Function to be minimized. @param xlow Lower bound of the search interval. @param xup Upper bound of the search interval.

Reimplemented from ROOT::Math::IRootFinderMethod.

Definition at line 53 of file IRootFinderMethod.h.

SetFunction() [2/3]

bool ROOT::Math::ModABRootFinder::SetFunction ( const ROOT::Math::IGenFunction & , double , double  )

overridevirtual

Sets the function for the rest of the algorithms.

The parameters set the interval where the root has to be calculated.

Reimplemented from ROOT::Math::IRootFinderMethod.

Definition at line 21 of file ModABRootFinder.cxx.

SetFunction() [3/3]

virtual bool ROOT::Math::IRootFinderMethod::SetFunction ( const ROOT::Math::IGradFunction & , double  )

inlinevirtual

Set function to solve and the interval in where to look for the root.

@param f Function to be minimized. @param xlow Lower bound of the search interval. @param xup Upper bound of the search interval.

Reimplemented from ROOT::Math::IRootFinderMethod.

Definition at line 45 of file IRootFinderMethod.h.

Solve()

bool ROOT::Math::ModABRootFinder::Solve ( int maxIter = 100, double absTol = 1E-8, double relTol = 1E-10 )

overridevirtual

Returns the X value corresponding to the function value fy for (xmin<x<xmax).

Method: Modified Anderson-Björck method is applied on the bracketed interval.

@param maxIter maximum number of iterations. @param absTol desired absolute error in the minimum position. @param relTol desired relative error in the minimum position.

Implements ROOT::Math::IRootFinderMethod.

Definition at line 50 of file ModABRootFinder.cxx.

Status()

int ROOT::Math::ModABRootFinder::Status ( ) const

inlineoverridevirtual

Returns status of last estimate.

If = 0 is OK

Implements ROOT::Math::IRootFinderMethod.

Definition at line 62 of file ModABRootFinder.h.

Member Data Documentation

fFunction

const IGenFunction* ROOT::Math::ModABRootFinder::fFunction = nullptr

private

Definition at line 71 of file ModABRootFinder.h.

fNIter

int ROOT::Math::ModABRootFinder::fNIter = 0

private

Definition at line 72 of file ModABRootFinder.h.

fRoot

double ROOT::Math::ModABRootFinder::fRoot = 0.

private

Definition at line 76 of file ModABRootFinder.h.

fStatus

int ROOT::Math::ModABRootFinder::fStatus = -1

private

Definition at line 73 of file ModABRootFinder.h.

fXMax

double ROOT::Math::ModABRootFinder::fXMax = 0.

private

Definition at line 75 of file ModABRootFinder.h.

fXMin

double ROOT::Math::ModABRootFinder::fXMin = 0.

private

Definition at line 74 of file ModABRootFinder.h.

Libraries for ROOT::Math::ModABRootFinder:

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

• math/mathcore/inc/Math/ModABRootFinder.h
• math/mathcore/src/ModABRootFinder.cxx