ROOT   Reference Guide
template<class Function>

template wrapped class for adapting to FCNBase signature a IGradFunction

Definition at line 34 of file FCNGradAdapter.h.

## Public Member Functions

bool CheckGradient () const override

std::vector< doubleGradient (const std::vector< double > &v) const override

std::vector< doubleGradientWithPrevResult (const std::vector< double > &v, double *previous_grad, double *previous_g2, double *previous_gstep) const override

double operator() (const double *v) const

double operator() (const std::vector< double > &v) const override
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. More...

double Up () const override
Error definition of the function. More...

Public Member Functions inherited from ROOT::Minuit2::FCNGradientBase

virtual bool CheckGradient () const

virtual std::vector< doubleGradient (const std::vector< double > &) const =0

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

Public Member Functions inherited from ROOT::Minuit2::FCNBase
~FCNBase () override

virtual double ErrorDef () const
Error definition of the function. More...

double operator() (const std::vector< double > &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. More...

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

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

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

virtual double operator() (const std::vector< double > &x) const =0
Evaluates the function using the vector containing the input values. More...

## Private Attributes

const FunctionfFunc

double fUp

#include <Minuit2/FCNGradAdapter.h>

[legend]

## Constructor & Destructor Documentation

template<class Function >
 ROOT::Minuit2::FCNGradAdapter< Function >::FCNGradAdapter ( const Function & f, double up = 1. )
inline

Definition at line 37 of file FCNGradAdapter.h.

template<class Function >
inlineoverride

Definition at line 39 of file FCNGradAdapter.h.

## Member Function Documentation

template<class Function >
inlineoverridevirtual

Definition at line 71 of file FCNGradAdapter.h.

template<class Function >
 std::vector< double > ROOT::Minuit2::FCNGradAdapter< Function >::Gradient ( const std::vector< double > & v ) const
inlineoverridevirtual

Definition at line 46 of file FCNGradAdapter.h.

template<class Function >
 std::vector< double > ROOT::Minuit2::FCNGradAdapter< Function >::GradientWithPrevResult ( const std::vector< double > & v, double * previous_grad, double * previous_g2, double * previous_gstep ) const
inlineoverridevirtual

Definition at line 57 of file FCNGradAdapter.h.

template<class Function >
inlineoverridevirtual

Definition at line 73 of file FCNGradAdapter.h.

## ◆ operator()() [1/2]

template<class Function >
 double ROOT::Minuit2::FCNGradAdapter< Function >::operator() ( const double * v ) const
inline

Definition at line 42 of file FCNGradAdapter.h.

## ◆ operator()() [2/2]

template<class Function >
 double ROOT::Minuit2::FCNGradAdapter< Function >::operator() ( const std::vector< double > & v ) const
inlineoverridevirtual

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.
MnUserParameters
VariableMetricMinimizer

Implements ROOT::Minuit2::FCNBase.

Definition at line 41 of file FCNGradAdapter.h.

## ◆ Up()

template<class Function >
 double ROOT::Minuit2::FCNGradAdapter< Function >::Up ( ) const
inlineoverridevirtual

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.

Implements ROOT::Minuit2::FCNBase.

Definition at line 44 of file FCNGradAdapter.h.

## ◆ fFunc

template<class Function >
private

Definition at line 82 of file FCNGradAdapter.h.

template<class Function >