Interface (abstract class) defining the function to be minimized, which has to be implemented by the user.

Author: Fred James and Matthias Winkler; modified by Andras Zsenei and Lorenzo Moneta

Definition at line 51 of file FCNBase.h.

Public Member Functions
virtual double	ErrorDef () const
	Error definition of the function.

virtual std::vector< double >	G2 (std::vector< double > const &) const
	return second derivatives (diagonal of the Hessian matrix)

virtual std::vector< double >	Gradient (std::vector< double > const &) const

virtual std::vector< double >	GradientWithPrevResult (std::vector< double > const &parameters, double , double , double *) const

virtual GradientParameterSpace	gradParameterSpace () const

virtual bool	HasG2 () const

virtual bool	HasGradient () const

virtual bool	HasHessian () const

virtual std::vector< double >	Hessian (std::vector< double > const &) const
	return Hessian

double	operator() (std::vector< double > const &v) const override=0
	The meaning of the vector of parameters is of course defined by the user, who uses the values of those parameters to calculate their function Value.

virtual void	SetErrorDef (double)
	add interface to set dynamically a new error definition Re-implement this function if needed.

virtual double	Up () const =0
	Error definition of the function.

Public Member Functions inherited from ROOT::Minuit2::GenericFunction
virtual	~GenericFunction ()

#include <Minuit2/FCNBase.h>

Inheritance diagram for ROOT::Minuit2::FCNBase:

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Member Function Documentation

◆ ErrorDef()

virtual double ROOT::Minuit2::FCNBase::ErrorDef ( ) const

inlinevirtual

Error definition of the function.

MINUIT defines Parameter errors as the change in Parameter Value required to change the function Value by up. Normally, for chisquared fits it is 1, and for negative log likelihood, its Value is 0.5. If the user wants instead the 2-sigma errors for chisquared fits, it becomes 4, as Chi2(x+n*sigma) = Chi2(x) + n*n.

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Definition at line 91 of file FCNBase.h.

◆ G2()

virtual std::vector< double > ROOT::Minuit2::FCNBase::G2 ( std::vector< double > const & ) const

inlinevirtual

return second derivatives (diagonal of the Hessian matrix)

Reimplemented in ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 127 of file FCNBase.h.

◆ Gradient()

virtual std::vector< double > ROOT::Minuit2::FCNBase::Gradient ( std::vector< double > const & ) const

inlinevirtual

Reimplemented in ROOT::Minuit2::FumiliFCNBase, and ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 115 of file FCNBase.h.

◆ GradientWithPrevResult()

virtual std::vector< double > ROOT::Minuit2::FCNBase::GradientWithPrevResult	(	std::vector< double > const &	parameters,
		double *	,
		double *	,
		double *
	)		const

inlinevirtual

Reimplemented in ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 116 of file FCNBase.h.

◆ gradParameterSpace()

virtual GradientParameterSpace ROOT::Minuit2::FCNBase::gradParameterSpace ( ) const

inlinevirtual

Reimplemented in ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 122 of file FCNBase.h.

◆ HasG2()

virtual bool ROOT::Minuit2::FCNBase::HasG2 ( ) const

inlinevirtual

Reimplemented in ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 134 of file FCNBase.h.

◆ HasGradient()

virtual bool ROOT::Minuit2::FCNBase::HasGradient ( ) const

inlinevirtual

Reimplemented in ROOT::Minuit2::FCNGradientBase, ROOT::Minuit2::FCNGradAdapter< Function >, and ROOT::Minuit2::FumiliFCNBase.

Definition at line 113 of file FCNBase.h.

◆ HasHessian()

virtual bool ROOT::Minuit2::FCNBase::HasHessian ( ) const

inlinevirtual

Reimplemented in ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 132 of file FCNBase.h.

◆ Hessian()

virtual std::vector< double > ROOT::Minuit2::FCNBase::Hessian ( std::vector< double > const & ) const

inlinevirtual

return Hessian

Reimplemented in ROOT::Minuit2::FumiliFCNBase, and ROOT::Minuit2::FCNGradAdapter< Function >.

Definition at line 130 of file FCNBase.h.

◆ operator()()

double ROOT::Minuit2::FCNBase::operator() ( std::vector< double > const & v ) const

overridepure virtual

The meaning of the vector of parameters is of course defined by the user, who uses the values of those parameters to calculate their function Value.

The order and the position of these parameters is strictly the one specified by the user when supplying the starting values for minimization. The starting values must be specified by the user, either via an std::vector<double> or the MnUserParameters supplied as input to the MINUIT minimizers such as VariableMetricMinimizer or MnMigrad. Later values are determined by MINUIT as it searches for the Minimum or performs whatever analysis is requested by the user.

Parameters

v	function parameters as defined by the user.

Returns: the Value of the function.

See also: MnUserParameters; VariableMetricMinimizer; MnMigrad

Implements ROOT::Minuit2::GenericFunction.

Implemented in ROOT::Minuit2::FumiliChi2FCN, ROOT::Minuit2::FumiliMaximumLikelihoodFCN, ROOT::Minuit2::FCNAdapter< Function >, ROOT::Minuit2::FCNGradAdapter< Function >, ROOT::Minuit2::FumiliFCNAdapter< Function >, and ROOT::Minuit2::ParametricFunction.

◆ SetErrorDef()

virtual void ROOT::Minuit2::FCNBase::SetErrorDef ( double )

inlinevirtual

add interface to set dynamically a new error definition Re-implement this function if needed.

Reimplemented in ROOT::Minuit2::FCNAdapter< Function >, ROOT::Minuit2::FCNGradAdapter< Function >, and ROOT::Minuit2::FumiliFCNAdapter< Function >.

Definition at line 111 of file FCNBase.h.

◆ Up()

virtual double ROOT::Minuit2::FCNBase::Up ( ) const

pure virtual

Error definition of the function.

MINUIT defines Parameter errors as the change in Parameter Value required to change the function Value by up. Normally, for chisquared fits it is 1, and for negative log likelihood, its Value is 0.5. If the user wants instead the 2-sigma errors for chisquared fits, it becomes 4, as Chi2(x+n*sigma) = Chi2(x) + n*n.

Implemented in ROOT::Minuit2::FCNAdapter< Function >, ROOT::Minuit2::FCNGradAdapter< Function >, ROOT::Minuit2::FumiliChi2FCN, ROOT::Minuit2::FumiliFCNAdapter< Function >, and ROOT::Minuit2::FumiliMaximumLikelihoodFCN.

Libraries for ROOT::Minuit2::FCNBase: