Add example for plotting VD steps with RooUtil

Author: AndrewEdmonds11

rooutil/examples/PlotVDSteps.C

@@ -0,0 +1,52 @@
+//
+// An example of how to plot reco vs true
+// This uses cut functions defined in common_cuts.hh
+//
+
+#include "EventNtuple/rooutil/inc/RooUtil.hh"
+#include "EventNtuple/rooutil/inc/common_cuts.hh"
+
+#include "TCanvas.h"
+#include "TH1F.h"
+#include "TH2F.h"
+
+using namespace rooutil;
+void PlotVDSteps(std::string filename) {
+
+  // Create the histogram you want to fill
+  TH2F* hVD13_XY = new TH2F("hVD13_XY", "XY position at VD13 (tracker entrance)", 100,-500,500, 100,-500,500);
+  hVD13_XY->SetXTitle("X (det. coords) [mm]");
+  hVD13_XY->SetYTitle("Y (det. coords) [mm]");
+
+  TH1F* hVD13_Mom = new TH1F("hVD13_Mom", "Momentum at VD13 (tracker entrance)", 120,0,120);
+  hVD13_Mom->SetXTitle("Momentum [MeV/c]");
+
+  // Set up RooUtil
+  RooUtil util(filename);
+
+  // Loop through the events
+  for (int i_event = 0; i_event < util.GetNEvents(); ++i_event) {
+    // Get the next event
+    auto& event = util.GetEvent(i_event);
+
+    // Get the e_minus tracks from the event
+    if (event.mcsteps_virtualdetector != nullptr) {
+      for (const auto& vdstep : *(event.mcsteps_virtualdetector)) {
+        if (vdstep.vid == mu2e::VirtualDetectorId::TT_FrontHollow) {
+          // Fill the histogram
+          hVD13_XY->Fill(vdstep.pos.x(), vdstep.pos.y());
+
+          hVD13_Mom->Fill(vdstep.mom.R());
+        }
+      }
+    }
+  }
+
+  // Draw the histogram
+  TCanvas* c = new TCanvas();
+  c->Divide(2);
+  c->cd(1);
+  hVD13_XY->Draw("COLZ");
+  c->cd(2);
+  hVD13_Mom->Draw("HIST E");
+}

rooutil/inc/common_cuts.hh

@@ -10,6 +10,7 @@
 #include "Offline/MCDataProducts/inc/ProcessCode.hh"
 #include "Offline/MCDataProducts/inc/GenId.hh"
 #include "Offline/MCDataProducts/inc/MCRelationship.hh"
+#include "Offline/DataProducts/inc/VirtualDetectorId.hh"
 
 #include "EventNtuple/rooutil/inc/Track.hh"
 #include "EventNtuple/rooutil/inc/TrackSegment.hh"