Gradient interface (abstract class) defining the signature for calculating the gradient of a multidimensional function.
Three methods are provided:
Concrete classes should derive from ROOT::Math::IGradientFunctionMultiDim and not from this class.
Definition at line 201 of file IFunction.h.
Public Member Functions  
virtual  ~IGradientMultiDimTempl () 
virual destructor  
T  Derivative (const T *x, unsigned int icoord, T *previous_grad, T *previous_g2, T *previous_gstep) const 
In some cases, the derivative algorithm will use information from the previous step, these can be passed in with this overload.  
T  Derivative (const T *x, unsigned int icoord=0) const 
Return the partial derivative with respect to the passed coordinate.  
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.  
virtual void  Gradient (const T *x, T *grad) const =0 
Evaluate all the vector of function derivatives (gradient) at a point x.  
Private Member Functions  
virtual T  DoDerivative (const T *x, unsigned int icoord) const =0 
function to evaluate the derivative with respect each coordinate.  
virtual T  DoDerivativeWithPrevResult (const T *x, unsigned int icoord, T *, T *, T *) const 
In some cases, the derivative algorithm will use information from the previous step, these can be passed in with this overload.  
#include <Math/IFunction.h>

inlinevirtual 
virual destructor
Definition at line 206 of file IFunction.h.

inline 
In some cases, the derivative algorithm will use information from the previous step, these can be passed in with this overload.
The previous_*
arrays can also be used to return second derivative and step size so that these can be passed forward again as well at the call site, if necessary.
Definition at line 221 of file IFunction.h.

inline 
Return the partial derivative with respect to the passed coordinate.
Definition at line 217 of file IFunction.h.

privatepure virtual 
function to evaluate the derivative with respect each coordinate.
To be implemented by the derived class

inlineprivatevirtual 
In some cases, the derivative algorithm will use information from the previous step, these can be passed in with this overload.
The previous_*
arrays can also be used to return second derivative and step size so that these can be passed forward again as well at the call site, if necessary.
Definition at line 246 of file IFunction.h.

pure virtual 
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
Implemented in ROOT::Math::IGradientFunctionMultiDimTempl< T >.

pure virtual 
Evaluate all the vector of function derivatives (gradient) at a point x.
Derived classes must reimplement if it is more efficient than evaluting one at a time
Implemented in ROOT::Math::IGradientFunctionMultiDimTempl< T >.