[TMVA] DataSet - Add method DeleteAllResults

When doing CV, we reuse the same DataSet (and the corresponding list of
results). Thus we need to empty the DataSet results between folds.
A convenient way of doing this was missing.

tmva/tmva/inc/TMVA/DataSet.h

@@ -117,6 +117,8 @@ namespace TMVA {
       void      DeleteResults   ( const TString &,
                                   Types::ETreeType type,
                                   Types::EAnalysisType analysistype );
+      void      DeleteAllResults(Types::ETreeType type,
+                                 Types::EAnalysisType analysistype);
 
       void      SetVerbose( Bool_t ) {}
 

tmva/tmva/src/DataSet.cxx

@@ -336,6 +336,35 @@ void TMVA::DataSet::DeleteResults( const TString & resultsName,
             << " of type " << type << " which I should have deleted" << Endl;
    }
 }
+
+////////////////////////////////////////////////////////////////////////////////
+/// Deletes all results currently in the dataset.
+///
+void TMVA::DataSet::DeleteAllResults(Types::ETreeType type,
+                                     Types::EAnalysisType /* analysistype */ )
+{
+   if (fResults.empty()) return;
+
+   if (UInt_t(type) > fResults.size()){
+      Log()<<kFATAL<< Form("Dataset[%s] : ",fdsi->GetName()) << "you asked for an Treetype (training/testing/...)"
+           << " whose index " << type << " does not exist " << Endl;
+   }
+
+   std::map<TString, Results *> & resultsForType = fResults[UInt_t(type)];
+
+   for (auto && it : resultsForType) {
+      auto & resultsName = it.first;
+
+      Log() << kDEBUG << Form("Dataset[%s] : ", fdsi->GetName())
+                      << " DeleteAllResults previous existing result: "
+                      << resultsName << " of type " << type << Endl;
+
+      delete it.second;
+   }
+
+   resultsForType.clear();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// divide training set