root/Math/GSLRootFinder.h

0001 // @(#)root/mathmore:$Id$
0002 // Author: L. Moneta, A. Zsenei   08/2005
0003
0004  /**********************************************************************
0005   *                                                                    *
0006   * Copyright (c) 2004 ROOT Foundation,  CERN/PH-SFT                   *
0007   *                                                                    *
0008   * This library is free software; you can redistribute it and/or      *
0009   * modify it under the terms of the GNU General Public License        *
0010   * as published by the Free Software Foundation; either version 2     *
0011   * of the License, or (at your option) any later version.             *
0012   *                                                                    *
0013   * This library is distributed in the hope that it will be useful,    *
0014   * but WITHOUT ANY WARRANTY; without even the implied warranty of     *
0015   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU   *
0016   * General Public License for more details.                           *
0017   *                                                                    *
0018   * You should have received a copy of the GNU General Public License  *
0019   * along with this library (see file COPYING); if not, write          *
0020   * to the Free Software Foundation, Inc., 59 Temple Place, Suite      *
0021   * 330, Boston, MA 02111-1307 USA, or contact the author.             *
0022   *                                                                    *
0023   **********************************************************************/
0024
0025 // Header file for class GSLRootFinder
0026 //
0027 // Created by: moneta  at Sun Nov 14 11:27:11 2004
0028 //
0029 // Last update: Sun Nov 14 11:27:11 2004
0030 //
0031 #ifndef ROOT_Math_GSLRootFinder
0032 #define ROOT_Math_GSLRootFinder
0033
0034
0035 #include "Math/GSLFunctionAdapter.h"
0036
0037 #include "Math/IFunctionfwd.h"
0038
0039 #include "Math/IRootFinderMethod.h"
0040
0041 #include <iostream>
0042
0043 namespace ROOT {
0044 namespace Math {
0045
0046
0047    class GSLRootFSolver;
0048    class GSLFunctionWrapper;
0049
0050
0051 //________________________________________________________________________________________________________
0052   /**
0053      Base class for GSL Root-Finding algorithms for one dimensional functions which do not use function derivatives.
0054      For finding the roots users should not use this class directly but instantiate the derived classes,
0055      for example  ROOT::Math::Roots::Brent for using the Brent algorithm.
0056      All the classes defining the alhorithms are defined in the header Math/RootFinderAlgorithm.h
0057      They possible types implementing root bracketing algorithms which they do not require function
0058      derivatives are:
0059      <ul>
0060          <li>ROOT::Math::Roots::Bisection
0061          <li>ROOT::Math::Roots::FalsePos
0062          <li>ROOT::Math::Roots::Brent
0063      </ul>
0064
0065      See also the specific  classes for the documentation.
0066      See the GSL <A HREF="http://www.gnu.org/software/gsl/manual/html_node/Root-Bracketing-Algorithms.html"> online manual</A> for
0067      information on the GSL Root-Finding algorithms
0068
0069      @ingroup RootFinders
0070   */
0071
0072
0073  class GSLRootFinder: public IRootFinderMethod {
0074
0075  public:
0076     GSLRootFinder();
0077     ~GSLRootFinder() override;
0078
0079  private:
0080     // usually copying is non trivial, so we make this unaccessible
0081     GSLRootFinder(const GSLRootFinder &);
0082     GSLRootFinder & operator = (const GSLRootFinder &);
0083
0084  public:
0085
0086
0087 #if defined(__MAKECINT__) || defined(G__DICTIONARY)
0088     bool SetFunction( const IGradFunction & , double ) override {
0089        std::cerr <<"GSLRootFinder - Error : this method must be used with a Root Finder algorithm using derivatives" << std::endl;
0090        return false;
0091     }
0092 #endif
0093
0094     bool SetFunction( const IGenFunction & f, double xlow, double xup) override;
0095
0096     typedef double ( * GSLFuncPointer ) ( double, void *);
0097     bool SetFunction( GSLFuncPointer  f, void * params, double xlow, double xup);
0098
0099     using IRootFinderMethod::SetFunction;
0100
0101     // iterate to find ROOTS return GSL_CONTINUE if iteration was successful or another error
0102     int Iterate() override;
0103
0104     double Root() const override;
0105
0106     //double XLower() const;
0107
0108     //double XUpper() const;
0109
0110     /// Find the root
0111     bool Solve( int maxIter = 100, double absTol = 1E-8, double relTol = 1E-10) override;
0112
0113     /// Return number of iterations
0114     int Iterations() const override {
0115        return fIter;
0116     }
0117
0118     /// Return the status of last root finding
0119     int Status() const override { return fStatus; }
0120
0121     const char * Name() const override;
0122
0123
0124  protected:
0125
0126
0127     void SetSolver (  GSLRootFSolver * s );
0128
0129     void FreeSolver();
0130
0131  private:
0132
0133     GSLFunctionWrapper * fFunction;
0134     GSLRootFSolver * fS;
0135
0136     double fRoot;
0137     double fXlow;
0138     double fXup;
0139     int fIter;
0140     int fStatus;
0141     bool fValidInterval;
0142
0143  };
0144
0145 } // namespace Math
0146 } // namespace ROOT
0147
0148
0149 #endif /* ROOT_Math_GSLRootFinder */