ROOT   Reference Guide
ROOT::Math::IGradientFunctionMultiDimTempl< T > Class Template Reference
template<class T>
class ROOT::Math::IGradientFunctionMultiDimTempl< T >

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

It implements both the ROOT::Math::IBaseFunctionMultiDimTempl and ROOT::Math::IGradientMultiDimTempl 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 326 of file IFunction.h.

## Public Types

typedef IBaseFunctionMultiDimTempl< T > BaseFunc

typedef IGradientMultiDimTempl< T > BaseGrad

Public Types inherited from ROOT::Math::IBaseFunctionMultiDimTempl< T >
typedef T BackendType

typedef IBaseFunctionMultiDimTempl< T > BaseFunc

## Public Member Functions

virtual ~IGradientFunctionMultiDimTempl ()
Virtual Destructor (no operations) More...

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

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

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

Public Member Functions inherited from ROOT::Math::IBaseFunctionMultiDimTempl< T >
IBaseFunctionMultiDimTempl ()

virtual ~IBaseFunctionMultiDimTempl ()
virtual destructor More...

virtual IBaseFunctionMultiDimTempl< T > * Clone () const =0
Clone a function. More...

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

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

Public Member Functions inherited from ROOT::Math::IGradientMultiDimTempl< T >
virtual ~IGradientMultiDimTempl ()
virual destructor More...

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

virtual void FdF (const T *x, T &f, T *df) const =0
Optimized method to evaluate at the same time the function value and derivative at a point x. More...

virtual void Gradient (const T *x, T *grad) const =0
Evaluate all the vector of function derivatives (gradient) at a point x. More...

#include <Math/IFunction.h>

Inheritance diagram for ROOT::Math::IGradientFunctionMultiDimTempl< T >:
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## ◆ BaseFunc

template<class T >
 typedef IBaseFunctionMultiDimTempl ROOT::Math::IGradientFunctionMultiDimTempl< T >::BaseFunc

Definition at line 330 of file IFunction.h.

## ◆ BaseGrad

template<class T >
 typedef IGradientMultiDimTempl ROOT::Math::IGradientFunctionMultiDimTempl< T >::BaseGrad

Definition at line 331 of file IFunction.h.

## ◆ ~IGradientFunctionMultiDimTempl()

template<class T >
 virtual ROOT::Math::IGradientFunctionMultiDimTempl< T >::~IGradientFunctionMultiDimTempl ( )
inlinevirtual

Virtual Destructor (no operations)

Definition at line 336 of file IFunction.h.

## ◆ FdF()

template<class T >
 virtual void ROOT::Math::IGradientFunctionMultiDimTempl< T >::FdF ( const T * x, T & f, T * 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::IGradientMultiDimTempl< T >.

Definition at line 357 of file IFunction.h.

## ◆ Gradient()

template<class T >
 virtual void ROOT::Math::IGradientFunctionMultiDimTempl< T >::Gradient ( const T * x, T * grad ) const
inlinevirtual

Evaluate all the vector of function derivatives (gradient) at a point x.

Derived classes must re-implement it if more efficient than evaluting one at a time

Implements ROOT::Math::IGradientMultiDimTempl< T >.

Definition at line 342 of file IFunction.h.

## ◆ NDim()

template<class T >
 virtual unsigned int ROOT::Math::IBaseFunctionMultiDimTempl< T >::NDim ( ) const
virtual

Retrieve the dimension of the function.

Implements ROOT::Math::IBaseFunctionMultiDimTempl< T >.

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