Add macro for synthetic flow study in OO

Author: abmodak

MC/config/PWGLF/pythia8/generator_pythia8_syntheFlowOO.C

@@ -0,0 +1,107 @@
+
+#include "Pythia8/Pythia.h"
+#include "Pythia8/HeavyIons.h"
+#include "FairGenerator.h"
+#include "FairPrimaryGenerator.h"
+#include "Generators/GeneratorPythia8.h"
+#include "TRandom3.h"
+#include "TParticlePDG.h"
+#include "TDatabasePDG.h"
+#include "CCDB/BasicCCDBManager.h"
+#include "TH1F.h"
+#include "TH1D.h"
+
+#include <map>
+#include <unordered_set>
+
+class GeneratorPythia8SyntheFlow : public o2::eventgen::GeneratorPythia8
+{
+public:
+  /// Constructor
+  GeneratorPythia8SyntheFlow() {
+    lutGen = new o2::eventgen::FlowMapper();
+    
+    // -------- CONFIGURE SYNTHETIC FLOW ------------
+    // establish connection to ccdb
+    o2::ccdb::CcdbApi ccdb_api;
+    ccdb_api.init("https://alice-ccdb.cern.ch");
+
+    // config was placed at midpoint of run 564356, retrieve that
+    std::map<string, string> metadataRCT, headers;
+    headers = ccdb_api.retrieveHeaders("RCT/Info/RunInformation/564356", metadataRCT, -1);
+    int64_t tsSOR = atol(headers["SOR"].c_str());
+    int64_t tsEOR = atol(headers["EOR"].c_str());    
+    int64_t midRun = 0.5*tsSOR+0.5*tsEOR;
+
+    map<string, string> metadata; // can be empty
+    auto list = ccdb_api.retrieveFromTFileAny<TList>("Users/d/ddobrigk/syntheflow", metadata, midRun);
+  
+    TH1D *hv2vspT = (TH1D*) list->FindObject("hFlowVsPt_ins1116150_v1_Table_1");
+    TH1D *heccvsb = (TH1D*) list->FindObject("hEccentricityVsB");
+    
+    cout<<"Generating LUT for flow test"<<endl;
+    lutGen->CreateLUT(hv2vspT, heccvsb);
+    cout<<"Finished creating LUT!"<<endl;
+    // -------- END CONFIGURE SYNTHETIC FLOW ------------
+  }
+
+  ///  Destructor
+  ~GeneratorPythia8SyntheFlow() = default;
+  
+  //__________________________________________________________________
+  Bool_t generateEvent() override {
+    
+    // Generate PYTHIA event
+    Bool_t lPythiaOK = kFALSE;
+    while (!lPythiaOK){
+      lPythiaOK = mPythia.next();
+    }
+    
+    //+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    // loop over the entire event record and rotate all particles
+    // synthetic flow exercise
+    // first: get event plane
+    float eventPlaneAngle = mPythia.info.hiInfo->phi();
+    float impactParameter = mPythia.info.hiInfo->b();
+
+    for ( Long_t j=0; j < mPythia.event.size(); j++ ) {
+      float pyphi = mPythia.event[j].phi();
+      float pypT = mPythia.event[j].pT();
+
+      // calculate delta with EP
+      float deltaPhiEP = pyphi - eventPlaneAngle;
+      float shift = 0.0;
+      while(deltaPhiEP<0.0){
+        deltaPhiEP += 2*TMath::Pi();
+        shift += 2*TMath::Pi();
+      }
+      while(deltaPhiEP>2*TMath::Pi()){
+        deltaPhiEP -= 2*TMath::Pi();
+        shift -= 2*TMath::Pi();
+      }
+      float newDeltaPhiEP = lutGen->MapPhi(deltaPhiEP, impactParameter, pypT);
+      float pyphiNew = newDeltaPhiEP - shift + eventPlaneAngle;
+
+      if(pyphiNew>TMath::Pi())
+        pyphiNew -= 2.0*TMath::Pi();
+      if(pyphiNew<-TMath::Pi())
+        pyphiNew += 2.0*TMath::Pi();
+      mPythia.event[j].rot(0.0, pyphiNew-pyphi);
+    }
+    //+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    
+    return true;
+  }
+  
+private:
+  o2::eventgen::FlowMapper *lutGen; // for mapping phi angles
+};
+
+ FairGenerator *generator_syntheFlow()
+ {
+  auto generator = new GeneratorPythia8SyntheFlow();
+  gRandom->SetSeed(0);
+  generator->readString("Random:setSeed = on");
+  generator->readString("Random:seed =" + std::to_string(gRandom->Integer(900000000 - 2) + 1));
+  return generator;
+ }