From 5f136a33d757d486b08d98941776125d76bd6cc1 Mon Sep 17 00:00:00 2001
From: bistapf <79460851+bistapf@users.noreply.github.com>
Date: Wed, 19 Apr 2023 13:08:33 +0200
Subject: [PATCH] Add event header to conversion  (#106)

---
 .../k4SimDelphes/DelphesEDM4HepConverter.h    |  8 +++++++
 converter/src/DelphesEDM4HepConverter.cc      | 21 +++++++++++++++++--
 standalone/src/DelphesPythia8Common.h         |  2 +-
 standalone/src/DelphesPythia8Reader.h         |  2 ++
 tests/CMakeLists.txt                          |  1 -
 5 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h b/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h
index 878b10a..0358090 100644
--- a/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h
+++ b/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h
@@ -14,6 +14,7 @@
 #include "TTree.h"
 
 //Delphes
+#include "classes/DelphesClasses.h"
 #include "modules/Delphes.h"
 
 #include <array>
@@ -51,6 +52,11 @@ namespace k4SimDelphes {
    */
   constexpr auto CALORIMETERHIT_OUTPUT_NAME = "CalorimeterHits";
 
+  /**
+   * * Eventheader class will be stored only
+   */
+  constexpr auto EVENTHEADER_NAME = "EventHeader";
+
   struct BranchSettings {
     std::string input;
     std::string name;
@@ -95,6 +101,8 @@ namespace k4SimDelphes {
         const std::unordered_map<UInt_t, edm4hep::MCParticle>& mc_map);
 
   private:
+    void createEventHeader(const HepMCEvent* delphesEvent);
+
     void processParticles(const TClonesArray* delphesCollection, std::string const& branch);
     void processTracks(const TClonesArray* delphesCollection, std::string const& branch);
     void processClusters(const TClonesArray* delphesCollection, std::string const& branch);
diff --git a/converter/src/DelphesEDM4HepConverter.cc b/converter/src/DelphesEDM4HepConverter.cc
index 7a518fb..280840f 100644
--- a/converter/src/DelphesEDM4HepConverter.cc
+++ b/converter/src/DelphesEDM4HepConverter.cc
@@ -5,6 +5,7 @@
 
 #include "edm4hep/CalorimeterHitCollection.h"
 #include "edm4hep/ClusterCollection.h"
+#include "edm4hep/EventHeaderCollection.h"
 #include "edm4hep/MCParticleCollection.h"
 #include "edm4hep/MCRecoParticleAssociationCollection.h"
 #include "edm4hep/ParticleIDCollection.h"
@@ -15,8 +16,6 @@
 
 #include "podio/UserDataCollection.h"
 
-#include "classes/DelphesClasses.h"
-
 #include <TMatrixDSym.h>
 
 #include <iostream>
@@ -130,6 +129,15 @@ namespace k4SimDelphes {
     // Make sure the shared collections are present
     registerGlobalCollections();
 
+    //filling the event header
+    auto* eventBranch = delphesTree->GetBranch("Event");
+
+    if (eventBranch) {
+      auto* delphesEvents = *(TClonesArray**)eventBranch->GetAddress();
+      auto* delphesEvent  = static_cast<HepMCEvent*>(delphesEvents->At(0));
+      createEventHeader(delphesEvent);
+    }
+
     for (const auto& branch : m_branches) {
       // at this point it is not guaranteed that all entries in branch (which follow
       // the input from the delphes card) are also present in the processing
@@ -153,6 +161,15 @@ namespace k4SimDelphes {
     m_recoParticleIds.clear();
   }
 
+  //convert the eventHeader with metaData
+  void DelphesEDM4HepConverter::createEventHeader(const HepMCEvent* delphesEvent) {
+    auto* collection = createCollection<edm4hep::EventHeaderCollection>(EVENTHEADER_NAME);
+    auto  cand       = collection->create();
+
+    cand.setWeight(delphesEvent->Weight);
+    cand.setEventNumber(delphesEvent->Number);
+  }
+
   void DelphesEDM4HepConverter::processParticles(const TClonesArray* delphesCollection, std::string const& branch) {
     auto* collection = createCollection<edm4hep::MCParticleCollection>(branch);
 
diff --git a/standalone/src/DelphesPythia8Common.h b/standalone/src/DelphesPythia8Common.h
index bf64111..8b03b55 100644
--- a/standalone/src/DelphesPythia8Common.h
+++ b/standalone/src/DelphesPythia8Common.h
@@ -41,7 +41,7 @@ void ConvertInput(Long64_t eventCounter, Pythia8::Pythia* pythia, ExRootTreeBran
   Double_t x, y, z, t;
 
   // event information
-  element = new HepMCEvent();  //(branch->NewEntry());
+  element = static_cast<HepMCEvent*>(branch->NewEntry());
 
   element->Number = eventCounter;
 
diff --git a/standalone/src/DelphesPythia8Reader.h b/standalone/src/DelphesPythia8Reader.h
index 9522542..a0d4151 100644
--- a/standalone/src/DelphesPythia8Reader.h
+++ b/standalone/src/DelphesPythia8Reader.h
@@ -51,6 +51,8 @@ class DelphesPythia8Reader : public DelphesInputReader {
     m_treeWriter->SetTree(m_converterTree.get());
     modularDelphes->SetTreeWriter(m_treeWriter);
 
+    m_branchEvent = std::unique_ptr<ExRootTreeBranch>(m_treeWriter->NewBranch("Event", HepMCEvent::Class()));
+
     // Initialize Pythia
     m_pythia = std::make_unique<Pythia8::Pythia>();
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index b86f4c2..f22fda8 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -56,4 +56,3 @@ if(DELPHES_CARD)
 else()
   message(WARNING "Cannot find IDEA delphes card from the delphes installation. Cannot use it for testing")
 endif()
-