root/Math/IRootFinderMethod.h

0001 // @(#)root/mathcore:$Id$
0002 // Authors: David Gonzalez Maline    01/2008
0003
0004 /**********************************************************************
0005  *                                                                    *
0006  * Copyright (c) 2006 , LCG ROOT MathLib Team                         *
0007  *                                                                    *
0008  *                                                                    *
0009  **********************************************************************/
0010
0011 // Header for the IRootFinderMethod interface
0012 //
0013 // Created by: David Gonzalez Maline  : Fri Jan 25 2008
0014 //
0015
0016 #ifndef ROOT_Math_IRootFinderMethod
0017 #define ROOT_Math_IRootFinderMethod
0018
0019 #include "Math/Error.h"
0020
0021 #include "Math/IFunctionfwd.h"
0022
0023 namespace ROOT {
0024 namespace Math {
0025
0026 //___________________________________________________________________________________________
0027 /**
0028    Interface for finding function roots of one-dimensional functions
0029
0030    @ingroup RootFinders
0031
0032  */
0033
0034 class IRootFinderMethod {
0035 public:
0036    /** Default Destructor. */
0037    virtual ~IRootFinderMethod() {}
0038
0039    /** Default Constructor. */
0040    IRootFinderMethod() {}
0041
0042    // Common functionality
0043
0044    /** Sets the function for algorithms using derivatives.  */
0045    virtual bool SetFunction(const ROOT::Math::IGradFunction&, double)
0046    {
0047       MATH_ERROR_MSG("SetFunction", "This method must be used with a Root Finder algorithm using derivatives");
0048       return false;
0049    }
0050
0051    /** Sets the function for the rest of the algorithms.
0052        The parameters set the interval where the root has to be calculated. */
0053    virtual bool SetFunction(const ROOT::Math::IGenFunction& , double , double )
0054    {
0055       MATH_ERROR_MSG("SetFunction", "Algorithm requires derivatives");
0056       return false;
0057    }
0058
0059    /** Returns the previously calculated root. */
0060    virtual double Root() const = 0;
0061
0062    /** Returns the status of the previous estimate */
0063    virtual int Status() const = 0;
0064
0065    // Methods to be Implemented in the derived classes
0066
0067    /** Stimates the root for the function.
0068        \@param maxIter maximum number of iterations.
0069        \@param absTol desired absolute error in the minimum position.
0070        \@param absTol desired relative error in the minimum position.
0071    */
0072    virtual bool Solve(int maxIter = 100, double absTol = 1E-8, double relTol = 1E-10) = 0;
0073
0074    /** Return name of root finder algorithm */
0075    virtual const char* Name() const = 0;
0076
0077    /** This method is  implemented only by the GSLRootFinder
0078        and GSLRootFinderDeriv classes and will return an error if it's not one of them. */
0079    virtual int Iterate() {
0080       MATH_ERROR_MSG("Iterate", "This method must be used with a Root Finder algorithm wrapping the GSL Library");
0081       return -1;
0082    }
0083
0084    /** Return number of iterations used to find the root
0085        Must be implemented by derived classes
0086    */
0087    virtual int Iterations() const { return -1; }
0088
0089 };
0090
0091 } // namespace Math
0092 } // namespace ROOT
0093
0094
0095 #endif /* ROOT_Math_IRootFinderMethod */