ROOT  6.06/09
Reference Guide
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ROOT::Math::IGradientFunctionMultiDim Class Reference

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 Gradient (const double *x, double *grad) const
 Evaluate all the vector of function derivatives (gradient) at a point x. 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...
 
- Public Member Functions inherited from ROOT::Math::IBaseFunctionMultiDim
 IBaseFunctionMultiDim ()
 
virtual ~IBaseFunctionMultiDim ()
 virtual destructor More...
 
virtual IBaseFunctionMultiDimClone () 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:
+ Collaboration diagram for ROOT::Math::IGradientFunctionMultiDim:

Member Typedef Documentation

Definition at line 329 of file IFunction.h.

Definition at line 330 of file IFunction.h.

Constructor & Destructor Documentation

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

Virtual Destructor (no operations)

Definition at line 336 of file IFunction.h.

Member Function Documentation

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.

Referenced by TPyMultiGradFunction::FdF().

virtual void ROOT::Math::IGradientFunctionMultiDim::Gradient ( const double x,
double 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::IGradientMultiDim.

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

Definition at line 342 of file IFunction.h.

Referenced by TMinuitMinimizer::FcnGrad(), FdF(), TPyMultiGradFunction::Gradient(), and ROOT::Math::mingradfunction().


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