JetTagging: Add Ntrk to DNN tagger

The code responsible to get the number of tracks for the DNN tagger in the BoostedJetTagger is missing. It was added for the ANN tagger, not for DNN. This merge request is to include the same block that is present in JSSWTopTaggerANN.cxx and add it to JSSWTopTaggerDNN.cxx

Reconstruction/Jet/BoostedJetTaggers/Root/JSSWTopTaggerDNN.cxx

@@ -364,6 +364,25 @@ std::map<std::string,double> JSSWTopTaggerDNN::getJetProperties( const xAOD::Jet
     DNN_inputValues["ZCut12"] = jet.getAttribute<float>("ZCut12");
     DNN_inputValues["KtDR"] = jet.getAttribute<float>("KtDR");
 
+    int pv_location = findPV();
+
+    if(pv_location != -1){
+      if( GetUnGroomTracks(jet, pv_location).isSuccess()){
+        SG::ReadDecorHandle<xAOD::JetContainer, int> readNtrk500(m_readNtrk500Key);
+
+        DNN_inputValues["Ntrk500"] = readNtrk500(jet);
+      }
+      else{
+        ATH_MSG_ERROR("Either the ungroomed parent jet doesn't have 'NumTrkPt500' as an attribute or the parent link is broken");
+        DNN_inputValues["Ntrk500"] = -999;
+      }
+    }
+    else {
+      ATH_MSG_ERROR("Could not find a primary vertex");
+      DNN_inputValues["Ntrk500"] = -999;
+    }
+
+
   }
 
   else if ( m_tagClass == TAGCLASS::TopQuark ) {