MethodCategory.cxx

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// @(#)root/tmva $Id$
// Author: Andreas Hoecker, Joerg Stelzer, Helge Voss, Eckhard von Toerne

/**********************************************************************************
 * Project: TMVA - a Root-integrated toolkit for multivariate data analysis       *
 * Package: TMVA                                                                  *
 * Class  : MethodCompositeBase                                                   *
 * Web    : http://tmva.sourceforge.net                                           *
 *                                                                                *
 * Description:                                                                   *
 *      Virtual base class for all MVA method                                     *
 *                                                                                *
 * Authors (alphabetical):                                                        *
 *      Andreas Hoecker   <Andreas.Hocker@cern.ch>   - CERN, Switzerland          *
 *      Nadim Sah         <Nadim.Sah@cern.ch>        - Berlin, Germany            *
 *      Peter Speckmayer  <Peter.Speckmazer@cern.ch> - CERN, Switzerland          *
 *      Joerg Stelzer     <Joerg.Stelzer@cern.ch>    - MSU East Lansing, USA      *
 *      Helge Voss        <Helge.Voss@cern.ch>       - MPI-K Heidelberg, Germany  *
 *      Jan Therhaag      <Jan.Therhaag@cern.ch>     - U of Bonn, Germany         *
 *      Eckhard v. Toerne <evt@uni-bonn.de>          - U of Bonn, Germany         *
 *                                                                                *
 * Copyright (c) 2005-2011:                                                       *
 *      CERN, Switzerland                                                         *
 *      MSU East Lansing, USA                                                     *
 *      MPI-K Heidelberg, Germany                                                 *
 *      U. of Bonn, Germany                                                       *
 *                                                                                *
 * Redistribution and use in source and binary forms, with or without             *
 * modification, are permitted according to the terms listed in LICENSE           *
 * (http://tmva.sourceforge.net/LICENSE)                                          *
 **********************************************************************************/

//__________________________________________________________________________
//
// This class is meant to allow categorisation of the data. For different //
// categories, different classifiers may be booked and different variab-  //
// les may be considered. The aim is to account for the difference that   //
// is due to different locations/angles.                                  //
////////////////////////////////////////////////////////////////////////////////

#include "TMVA/MethodCategory.h"

#include <algorithm>
#include <iomanip>
#include <vector>
#include <iostream>

#include "Riostream.h"
#include "TRandom3.h"
#include "TMath.h"
#include "TObjString.h"
#include "TH1F.h"
#include "TGraph.h"
#include "TSpline.h"
#include "TDirectory.h"
#include "TTreeFormula.h"

#include "TMVA/ClassifierFactory.h"
#include "TMVA/Config.h"
#include "TMVA/DataSet.h"
#include "TMVA/DataSetInfo.h"
#include "TMVA/DataSetManager.h"
#include "TMVA/IMethod.h"
#include "TMVA/MethodBase.h"
#include "TMVA/MethodCompositeBase.h"
#include "TMVA/MsgLogger.h"
#include "TMVA/PDF.h"
#include "TMVA/Ranking.h"
#include "TMVA/Timer.h"
#include "TMVA/Tools.h"
#include "TMVA/Types.h"
#include "TMVA/VariableInfo.h"
#include "TMVA/VariableRearrangeTransform.h"

REGISTER_METHOD(Category)

ClassImp(TMVA::MethodCategory)

////////////////////////////////////////////////////////////////////////////////
/// standard constructor

   TMVA::MethodCategory::MethodCategory( const TString& jobName,
                                         const TString& methodTitle,
                                         DataSetInfo& theData,
                                         const TString& theOption,
                                         TDirectory* theTargetDir )
   : TMVA::MethodCompositeBase( jobName, Types::kCategory, methodTitle, theData, theOption, theTargetDir ),
   fCatTree(0),
   fDataSetManager(NULL)
{
}

////////////////////////////////////////////////////////////////////////////////
/// constructor from weight file

TMVA::MethodCategory::MethodCategory( DataSetInfo& dsi,
                                      const TString& theWeightFile,
                                      TDirectory* theTargetDir )
   : TMVA::MethodCompositeBase( Types::kCategory, dsi, theWeightFile, theTargetDir ),
     fCatTree(0),
     fDataSetManager(NULL)
{
}

////////////////////////////////////////////////////////////////////////////////
/// destructor

TMVA::MethodCategory::~MethodCategory( void )
{
   std::vector<TTreeFormula*>::iterator formIt = fCatFormulas.begin();
   std::vector<TTreeFormula*>::iterator lastF = fCatFormulas.end();
   for(;formIt!=lastF; ++formIt) delete *formIt;
   delete fCatTree;
}

////////////////////////////////////////////////////////////////////////////////
/// check whether method category has analysis type
/// the method type has to be the same for all sub-methods

Bool_t TMVA::MethodCategory::HasAnalysisType( Types::EAnalysisType type, UInt_t numberClasses, UInt_t numberTargets )
{
   std::vector<IMethod*>::iterator itrMethod = fMethods.begin();

   // iterate over methods and check whether they have the analysis type
   for(; itrMethod != fMethods.end(); ++itrMethod ) {
      if ( !(*itrMethod)->HasAnalysisType(type, numberClasses, numberTargets) )
         return kFALSE;
   }
   return kTRUE;
}

////////////////////////////////////////////////////////////////////////////////
/// options for this method

void TMVA::MethodCategory::DeclareOptions()
{
}

////////////////////////////////////////////////////////////////////////////////
/// adds sub-classifier for a category

TMVA::IMethod* TMVA::MethodCategory::AddMethod( const TCut& theCut,
                                                const TString& theVariables,
                                                Types::EMVA theMethod ,
                                                const TString& theTitle,
                                                const TString& theOptions )
{
   std::string addedMethodName = std::string(Types::Instance().GetMethodName(theMethod));

   Log() << kINFO << "Adding sub-classifier: " << addedMethodName << "::" << theTitle << Endl;

   DataSetInfo& dsi = CreateCategoryDSI(theCut, theVariables, theTitle);

   IMethod* addedMethod = ClassifierFactory::Instance().Create(addedMethodName,GetJobName(),theTitle,dsi,theOptions);

   MethodBase *method = (dynamic_cast<MethodBase*>(addedMethod));
   if(method==0) return 0;

   method->SetAnalysisType( fAnalysisType );
   method->SetupMethod();
   method->ParseOptions();
   method->ProcessSetup();

   // set or create correct method base dir for added method
   const TString dirName(Form("Method_%s",method->GetMethodTypeName().Data()));
   TDirectory * dir = BaseDir()->GetDirectory(dirName);
   if (dir != 0) method->SetMethodBaseDir( dir );
   else method->SetMethodBaseDir( BaseDir()->mkdir(dirName,Form("Directory for all %s methods", method->GetMethodTypeName().Data())) );

   // method->SetBaseDir(eigenes base dir, gucken ob Fisher dir existiert, sonst erzeugen )

   // check-for-unused-options is performed; may be overridden by derived
   // classes
   method->CheckSetup();

   // disable writing of XML files and standalone classes for sub methods
   method->DisableWriting( kTRUE );

   // store method, cut and variable names and create cut formula
   fMethods.push_back(method);
   fCategoryCuts.push_back(theCut);
   fVars.push_back(theVariables);

   DataSetInfo& primaryDSI = DataInfo();

   UInt_t newSpectatorIndex = primaryDSI.GetSpectatorInfos().size();
   fCategorySpecIdx.push_back(newSpectatorIndex);

   primaryDSI.AddSpectator( Form("%s_cat%i:=%s", GetName(),(int)fMethods.size(),theCut.GetTitle()),
                            Form("%s:%s",GetName(),method->GetName()),
                            "pass", 0, 0, 'C' );

   return method;
}

////////////////////////////////////////////////////////////////////////////////
/// create a DataSetInfo object for a sub-classifier

TMVA::DataSetInfo& TMVA::MethodCategory::CreateCategoryDSI(const TCut& theCut,
                                                           const TString& theVariables,
                                                           const TString& theTitle)
{
   // create a new dsi with name: theTitle+"_dsi"
   TString dsiName=theTitle+"_dsi";
   DataSetInfo& oldDSI = DataInfo();
   DataSetInfo* dsi = new DataSetInfo(dsiName);

   // register the new dsi
   //   DataSetManager::Instance().AddDataSetInfo(*dsi); // DSMTEST replaced by following line
   fDataSetManager->AddDataSetInfo(*dsi);

   // copy the targets and spectators from the old dsi to the new dsi
   std::vector<VariableInfo>::iterator itrVarInfo;

   for (itrVarInfo = oldDSI.GetTargetInfos().begin(); itrVarInfo != oldDSI.GetTargetInfos().end(); itrVarInfo++)
      dsi->AddTarget(*itrVarInfo);

   for (itrVarInfo = oldDSI.GetSpectatorInfos().begin(); itrVarInfo != oldDSI.GetSpectatorInfos().end(); itrVarInfo++)
      dsi->AddSpectator(*itrVarInfo);

   // split string that contains the variables into tiny little pieces
   std::vector<TString> variables = gTools().SplitString(theVariables,':' );

   // prepare to create varMap
   std::vector<UInt_t> varMap;
   Int_t counter=0;

   // add the variables that were specified in theVariables
   std::vector<TString>::iterator itrVariables;
   Bool_t found = kFALSE;

   // iterate over all variables in 'variables' and add them
   for (itrVariables = variables.begin(); itrVariables != variables.end(); itrVariables++) {
      counter=0;

      // check the variables of the old dsi for the variable that we want to add
      for (itrVarInfo = oldDSI.GetVariableInfos().begin(); itrVarInfo != oldDSI.GetVariableInfos().end(); itrVarInfo++) {
         if((*itrVariables==itrVarInfo->GetLabel()) ) { // || (*itrVariables==itrVarInfo->GetExpression())) { 
            // don't compare the expression, since the user might take two times the same expression, but with different labels
            // and apply different transformations to the variables.
            dsi->AddVariable(*itrVarInfo);
            varMap.push_back(counter);
            found = kTRUE;
         }
         counter++;
      }
      
      // check the spectators of the old dsi for the variable that we want to add
      for (itrVarInfo = oldDSI.GetSpectatorInfos().begin(); itrVarInfo != oldDSI.GetSpectatorInfos().end(); itrVarInfo++) {
         if((*itrVariables==itrVarInfo->GetLabel()) ) { // || (*itrVariables==itrVarInfo->GetExpression())) {
            // don't compare the expression, since the user might take two times the same expression, but with different labels
            // and apply different transformations to the variables.
            dsi->AddVariable(*itrVarInfo);
            varMap.push_back(counter);
            found = kTRUE;
         }
         counter++;
      }

      // if the variable is neither in the variables nor in the spectators, we abort
      if (!found) {
         Log() << kFATAL <<"The variable " << itrVariables->Data() << " was not found and could not be added " << Endl;
      }
      found = kFALSE;
   }

   // in the case that no variables are specified, add the default-variables from the original dsi
   if (theVariables=="") {
      for (UInt_t i=0; i<oldDSI.GetVariableInfos().size(); i++) {
         dsi->AddVariable(oldDSI.GetVariableInfos()[i]);
         varMap.push_back(i);
      }
   }

   // add the variable map 'varMap' to the vector of varMaps
   fVarMaps.push_back(varMap);

   // set classes and cuts
   UInt_t nClasses=oldDSI.GetNClasses();
   TString className;
  
   for (UInt_t i=0; i<nClasses; i++) {
      className = oldDSI.GetClassInfo(i)->GetName();
      dsi->AddClass(className);
      dsi->SetCut(oldDSI.GetCut(i),className);
      dsi->AddCut(theCut,className);
      dsi->SetWeightExpression(oldDSI.GetWeightExpression(i),className);
   }

   // set split options, root dir and normalization for the new dsi
   dsi->SetSplitOptions(oldDSI.GetSplitOptions());
   dsi->SetRootDir(oldDSI.GetRootDir());
   TString norm(oldDSI.GetNormalization().Data());
   dsi->SetNormalization(norm);

   DataSetInfo& dsiReference= (*dsi);

   return dsiReference;  
}

////////////////////////////////////////////////////////////////////////////////
/// initialize the method

void TMVA::MethodCategory::Init()
{
}

////////////////////////////////////////////////////////////////////////////////
/// initialize the circular tree

void TMVA::MethodCategory::InitCircularTree(const DataSetInfo& dsi)
{
   delete fCatTree;

   std::vector<VariableInfo>::const_iterator viIt;
   const std::vector<VariableInfo>& vars  = dsi.GetVariableInfos();
   const std::vector<VariableInfo>& specs = dsi.GetSpectatorInfos();

   Bool_t hasAllExternalLinks = kTRUE;
   for (viIt = vars.begin(); viIt != vars.end(); ++viIt)
      if( viIt->GetExternalLink() == 0 ) {
         hasAllExternalLinks = kFALSE;
         break;
      }
   for (viIt = specs.begin(); viIt != specs.end(); ++viIt)
      if( viIt->GetExternalLink() == 0 ) {
         hasAllExternalLinks = kFALSE;
         break;
      }

   if(!hasAllExternalLinks) return;

   {
      // Rather than having TTree::TTree add to the current directory and then remove it, let
      // make sure to not add it in the first place.
      // The add-then-remove can lead to  a problem if gDirectory points to the same directory (for example
      // gROOT) in the current thread and another one (and both try to add to the directory at the same time).
      TDirectory::TContext ctxt(nullptr);
      fCatTree = new TTree(Form("Circ%s",GetMethodName().Data()),"Circlar Tree for categorization");
      fCatTree->SetCircular(1);
   }

   for (viIt = vars.begin(); viIt != vars.end(); ++viIt) {
      const VariableInfo& vi = *viIt;
      fCatTree->Branch(vi.GetExpression(),(Float_t*)vi.GetExternalLink(), TString(vi.GetExpression())+TString("/F"));
   }
   for (viIt = specs.begin(); viIt != specs.end(); ++viIt) {
      const VariableInfo& vi = *viIt;
      if(vi.GetVarType()=='C') continue;
      fCatTree->Branch(vi.GetExpression(),(Float_t*)vi.GetExternalLink(), TString(vi.GetExpression())+TString("/F"));
   }

   for(UInt_t cat=0; cat!=fCategoryCuts.size(); ++cat) {
      fCatFormulas.push_back(new TTreeFormula(Form("Category_%i",cat), fCategoryCuts[cat].GetTitle(), fCatTree));
   }
}

////////////////////////////////////////////////////////////////////////////////
/// train all sub-classifiers

void TMVA::MethodCategory::Train()
{
   // specify the minimum # of training events and set 'classification'
   const Int_t  MinNoTrainingEvents = 10;

   Types::EAnalysisType analysisType = GetAnalysisType();

   // start the training
   Log() << kINFO << "Train all sub-classifiers for "
         << (analysisType == Types::kRegression ? "Regression" : "Classification") << " ..." << Endl;

   // don't do anything if no sub-classifier booked
   if (fMethods.empty()) {
      Log() << kINFO << "...nothing found to train" << Endl;
      return;
   }

   std::vector<IMethod*>::iterator itrMethod;

   // iterate over all booked sub-classifiers  and train them
   for (itrMethod = fMethods.begin(); itrMethod != fMethods.end(); ++itrMethod ) {

      MethodBase* mva = dynamic_cast<MethodBase*>(*itrMethod);
      if(!mva) continue;
      mva->SetAnalysisType( analysisType );
      if (!mva->HasAnalysisType( analysisType,
                                 mva->DataInfo().GetNClasses(),
                                 mva->DataInfo().GetNTargets() ) ) {
         Log() << kWARNING << "Method " << mva->GetMethodTypeName() << " is not capable of handling " ;
         if (analysisType == Types::kRegression)
            Log() << "regression with " << mva->DataInfo().GetNTargets() << " targets." << Endl;
         else
            Log() << "classification with " << mva->DataInfo().GetNClasses() << " classes." << Endl;
         itrMethod = fMethods.erase( itrMethod );
         continue;
      }
      if (mva->Data()->GetNTrainingEvents() >= MinNoTrainingEvents) {

         Log() << kINFO << "Train method: " << mva->GetMethodName() << " for "
               << (analysisType == Types::kRegression ? "Regression" : "Classification") << Endl;
         mva->TrainMethod();
         Log() << kINFO << "Training finished" << Endl;

      } else {

         Log() << kWARNING << "Method " << mva->GetMethodName()
               << " not trained (training tree has less entries ["
               << mva->Data()->GetNTrainingEvents()
               << "] than required [" << MinNoTrainingEvents << "]" << Endl;

         Log() << kERROR << " w/o training/test events for that category, I better stop here and let you fix " << Endl;
         Log() << kFATAL << "that one first, otherwise things get too messy later ... " << Endl;

      }
   }

   if (analysisType != Types::kRegression) {

      // variable ranking
      Log() << kINFO << "Begin ranking of input variables..." << Endl;
      for (itrMethod = fMethods.begin(); itrMethod != fMethods.end(); itrMethod++) {
         MethodBase* mva = dynamic_cast<MethodBase*>(*itrMethod);
         if (mva && mva->Data()->GetNTrainingEvents() >= MinNoTrainingEvents) {
            const Ranking* ranking = (*itrMethod)->CreateRanking();
            if (ranking != 0)
               ranking->Print();
            else
               Log() << kINFO << "No variable ranking supplied by classifier: "
                     << dynamic_cast<MethodBase*>(*itrMethod)->GetMethodName() << Endl;
         }
      }
   }
}

////////////////////////////////////////////////////////////////////////////////
/// create XML description of Category classifier

void TMVA::MethodCategory::AddWeightsXMLTo( void* parent ) const
{
   void* wght = gTools().AddChild(parent, "Weights");
   gTools().AddAttr( wght, "NSubMethods", fMethods.size() );
   void* submethod(0);

   std::vector<IMethod*>::iterator itrMethod;

   // iterate over methods and write them to XML file
   for (UInt_t i=0; i<fMethods.size(); i++) {
      MethodBase* method = dynamic_cast<MethodBase*>(fMethods[i]);
      submethod = gTools().AddChild(wght, "SubMethod");
      gTools().AddAttr(submethod, "Index", i);
      gTools().AddAttr(submethod, "Method", method->GetMethodTypeName() + "::" + method->GetMethodName());
      gTools().AddAttr(submethod, "Cut", fCategoryCuts[i]);
      gTools().AddAttr(submethod, "Variables", fVars[i]);
      method->WriteStateToXML( submethod );
   }
}

////////////////////////////////////////////////////////////////////////////////
/// read weights of sub-classifiers of MethodCategory from xml weight file

void TMVA::MethodCategory::ReadWeightsFromXML( void* wghtnode )
{
   UInt_t nSubMethods;
   TString fullMethodName;
   TString methodType;
   TString methodTitle;
   TString theCutString;
   TString theVariables;
   Int_t titleLength;
   gTools().ReadAttr( wghtnode, "NSubMethods",  nSubMethods );
   void* subMethodNode = gTools().GetChild(wghtnode);

   Log() << kINFO << "Recreating sub-classifiers from XML-file " << Endl;

   // recreate all sub-methods from weight file
   for (UInt_t i=0; i<nSubMethods; i++) {
      gTools().ReadAttr( subMethodNode, "Method",    fullMethodName );
      gTools().ReadAttr( subMethodNode, "Cut",       theCutString   );
      gTools().ReadAttr( subMethodNode, "Variables", theVariables   );

      // determine sub-method type
      methodType = fullMethodName(0,fullMethodName.Index("::"));
      if (methodType.Contains(" ")) methodType = methodType(methodType.Last(' ')+1,methodType.Length());

      // determine sub-method title
      titleLength = fullMethodName.Length()-fullMethodName.Index("::")-2;
      methodTitle = fullMethodName(fullMethodName.Index("::")+2,titleLength);

      // reconstruct dsi for sub-method
      DataSetInfo& dsi = CreateCategoryDSI(TCut(theCutString), theVariables, methodTitle);

      // recreate sub-method from weights and add to fMethods
      MethodBase* method = dynamic_cast<MethodBase*>( ClassifierFactory::Instance().Create( methodType.Data(),
                                                                                            dsi, "none" ) );
      if(method==0)
         Log() << kFATAL << "Could not create sub-method " << method << " from XML." << Endl;

      method->SetupMethod();
      method->ReadStateFromXML(subMethodNode);

      fMethods.push_back(method);
      fCategoryCuts.push_back(TCut(theCutString));
      fVars.push_back(theVariables);

      DataSetInfo& primaryDSI = DataInfo();

      UInt_t spectatorIdx = 10000;
      UInt_t counter=0;

      // find the spectator index
      std::vector<VariableInfo>& spectators=primaryDSI.GetSpectatorInfos();
      std::vector<VariableInfo>::iterator itrVarInfo;
      TString specName= Form("%s_cat%i", GetName(),(int)fCategorySpecIdx.size()+1);

      for (itrVarInfo = spectators.begin(); itrVarInfo != spectators.end(); ++itrVarInfo, ++counter) {
         if((specName==itrVarInfo->GetLabel()) || (specName==itrVarInfo->GetExpression())) {
            spectatorIdx=counter;
            fCategorySpecIdx.push_back(spectatorIdx);
            break;
         }
      }

      subMethodNode = gTools().GetNextChild(subMethodNode);
   }

   InitCircularTree(DataInfo());

}

////////////////////////////////////////////////////////////////////////////////
/// process user options

void TMVA::MethodCategory::ProcessOptions() 
{
}

////////////////////////////////////////////////////////////////////////////////
/// Get help message text
///
/// typical length of text line:
///         "|--------------------------------------------------------------|"

void TMVA::MethodCategory::GetHelpMessage() const
{
   Log() << Endl;
   Log() << gTools().Color("bold") << "--- Short description:" << gTools().Color("reset") << Endl;
   Log() << Endl;
   Log() << "This method allows to define different categories of events. The" <<Endl;  
   Log() << "categories are defined via cuts on the variables. For each" << Endl; 
   Log() << "category, a different classifier and set of variables can be" <<Endl;
   Log() << "specified. The categories which are defined for this method must" << Endl;
   Log() << "be disjoint." << Endl;
}

////////////////////////////////////////////////////////////////////////////////
/// no ranking 

const TMVA::Ranking* TMVA::MethodCategory::CreateRanking()
{ 
   return 0;
}

////////////////////////////////////////////////////////////////////////////////

Bool_t TMVA::MethodCategory::PassesCut( const Event* ev, UInt_t methodIdx )
{
   // if it's not a simple 'spectator' variable (0 or 1) that the categories are defined by
   // (but rather some 'formula' (i.e. eta>0), then this formulas are stored in fCatTree and that
   // one will be evaluated.. (the formulae return 'true' or 'false' 
   if (fCatTree) {
      if (methodIdx>=fCatFormulas.size()) {
         Log() << kFATAL << "Large method index " << methodIdx << ", number of category formulas = "
               << fCatFormulas.size() << Endl;
      }
      TTreeFormula* f = fCatFormulas[methodIdx];
      return f->EvalInstance(0) > 0.5;
   } 
   // otherwise, it simply looks if "variable == true"  ("greater 0.5 to be "sure" )
   else {

      // checks whether an event lies within a cut
      if (methodIdx>=fCategorySpecIdx.size()) {
         Log() << kFATAL << "Unknown method index " << methodIdx << " maximum allowed index="
               << fCategorySpecIdx.size() << Endl;
      }
      UInt_t spectatorIdx = fCategorySpecIdx[methodIdx];
      Float_t specVal = ev->GetSpectator(spectatorIdx);
      Bool_t pass = (specVal>0.5);
      return pass;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// returns the mva value of the right sub-classifier

Double_t TMVA::MethodCategory::GetMvaValue( Double_t* err, Double_t* errUpper )
{
   if (fMethods.empty()) return 0;

   UInt_t methodToUse = 0;
   const Event* ev = GetEvent();

   // determine which sub-classifier to use for this event
   Int_t suitableCutsN = 0;

   for (UInt_t i=0; i<fMethods.size(); ++i) {
      if (PassesCut(ev, i)) {
         ++suitableCutsN;
         methodToUse=i;
      }
   }

   if (suitableCutsN == 0) {
      Log() << kWARNING << "Event does not lie within the cut of any sub-classifier." << Endl;
      return 0;
   }

   if (suitableCutsN > 1) {
      Log() << kFATAL << "The defined categories are not disjoint." << Endl;
      return 0;
   }

   // get mva value from the suitable sub-classifier
   ev->SetVariableArrangement(&fVarMaps[methodToUse]);
   Double_t mvaValue = dynamic_cast<MethodBase*>(fMethods[methodToUse])->GetMvaValue(ev,err,errUpper);
   ev->SetVariableArrangement(0);

   return mvaValue;
}



////////////////////////////////////////////////////////////////////////////////
/// returns the mva value of the right sub-classifier

const std::vector<Float_t> &TMVA::MethodCategory::GetRegressionValues() 
{
   if (fMethods.empty()) return MethodBase::GetRegressionValues();

   UInt_t methodToUse = 0;
   const Event* ev = GetEvent();

   // determine which sub-classifier to use for this event
   Int_t suitableCutsN = 0;

   for (UInt_t i=0; i<fMethods.size(); ++i) {
      if (PassesCut(ev, i)) {
         ++suitableCutsN;
         methodToUse=i;
      }
   }

   if (suitableCutsN == 0) {
      Log() << kWARNING << "Event does not lie within the cut of any sub-classifier." << Endl;
      return MethodBase::GetRegressionValues();
   }

   if (suitableCutsN > 1) {
      Log() << kFATAL << "The defined categories are not disjoint." << Endl;
      return MethodBase::GetRegressionValues();
   }
   MethodBase* meth = dynamic_cast<MethodBase*>(fMethods[methodToUse]);
   if (!meth){
      Log() << kFATAL << "method not found in Category Regression method" << Endl;
      return MethodBase::GetRegressionValues();
   }
   // get mva value from the suitable sub-classifier
   return meth->GetRegressionValues(ev);
}