Interface (abstract class) for multi-dimensional functions providing a gradient calculation.

It implements both the ROOT::Math::IBaseFunctionMultiDim and ROOT::Math::IGradientMultiDim interfaces. The method ROOT::Math::IFunction::Gradient calculates the full gradient vector, ROOT::Math::IFunction::Derivative calculates the partial derivative for each coordinate and ROOT::Math::Fdf calculates the gradient and the function value at the same time. The pure private virtual method DoDerivative() must be implemented by the derived classes, while Gradient and FdF are by default implemented using DoDerivative, butthey can be overloaded by the derived classes to improve the efficiency in the derivative calculation.

Definition at line 322 of file IFunction.h.

Public Types
typedef IBaseFunctionMultiDim	BaseFunc

typedef IGradientMultiDim	BaseGrad

Public Types inherited from ROOT::Math::IBaseFunctionMultiDim
typedef IBaseFunctionMultiDim	BaseFunc

Public Member Functions
virtual	~IGradientFunctionMultiDim ()
	Virtual Destructor (no operations) More...

virtual void	FdF (const double x, double &f, double df) const
	Optimized method to evaluate at the same time the function value and derivative at a point x. More...

virtual void	Gradient (const double x, double grad) const
	Evaluate all the vector of function derivatives (gradient) at a point x. More...

Public Member Functions inherited from ROOT::Math::IBaseFunctionMultiDim
	IBaseFunctionMultiDim ()

virtual	~IBaseFunctionMultiDim ()
	virtual destructor More...

virtual IBaseFunctionMultiDim *	Clone () const =0
	Clone a function. More...

virtual unsigned int	NDim () const =0
	Retrieve the dimension of the function. More...

double	operator() (const double *x) const
	Evaluate the function at a point x[]. More...

Public Member Functions inherited from ROOT::Math::IGradientMultiDim
virtual	~IGradientMultiDim ()
	virual destructor More...

double	Derivative (const double *x, unsigned int icoord=0) const
	Return the partial derivative with respect to the passed coordinate. More...

#include <Math/IFunction.h>

Inheritance diagram for ROOT::Math::IGradientFunctionMultiDim:

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Member Typedef Documentation

◆ BaseFunc

typedef IBaseFunctionMultiDim ROOT::Math::IGradientFunctionMultiDim::BaseFunc

Definition at line 329 of file IFunction.h.

◆ BaseGrad

typedef IGradientMultiDim ROOT::Math::IGradientFunctionMultiDim::BaseGrad

Definition at line 330 of file IFunction.h.

Constructor & Destructor Documentation

◆ ~IGradientFunctionMultiDim()

virtual ROOT::Math::IGradientFunctionMultiDim::~IGradientFunctionMultiDim ( )

inlinevirtual

Virtual Destructor (no operations)

Definition at line 336 of file IFunction.h.

Member Function Documentation

◆ FdF()

virtual void ROOT::Math::IGradientFunctionMultiDim::FdF	(	const double *	x,
		double &	f,
		double *	df
	)		const

inlinevirtual

Optimized method to evaluate at the same time the function value and derivative at a point x.

Often both value and derivatives are needed and it is often more efficient to compute them at the same time. Derived class should implement this method if performances play an important role and if it is faster to evaluate value and derivative at the same time

Implements ROOT::Math::IGradientMultiDim.

Reimplemented in ROOT::Math::LSResidualFunc, and TPyMultiGradFunction.

Definition at line 358 of file IFunction.h.