macro to calculate pileup factor from OCDB

diff --git a/PWGUD/macros/UPC/mu.C b/PWGUD/macros/UPC/mu.C
new file mode 100644 (file)
index 0000000..e232112
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+++ b/PWGUD/macros/UPC/mu.C
@@ -0,0 +1,71 @@
+// Macro to calculate pileup factor
+// evgeny.kryshen@cern.ch
+//
+//Two cases:
+//1) Reference trigger based on coincidence with beam pick-up counters to trigger beam-beam colliding bunches. 
+//   Run 120072 is an example. In this case one can get total number of colliding bunches from L0b scalers for 
+//   "empty" trigger corresponding to coincidence of A and C beam pick-up counters (CBEAMB-ABCE-NOPF-ALL).
+//
+//2) Reference trigger based on BC masks to constrain beam-beam colliding bunches (-B- in the class name). 
+//   In this case total number of bunches can be computed as (run duration)*(orbit rate)*(number of B-like BCs per orbit).
+//   One can switch to this option setting emptyClassName=NULL. 
+
+UInt_t dif(UInt_t stop, UInt_t start);
+
+
+Double_t mu(Int_t run=120072, char* className = "CINT1B-ABCE-NOPF-ALL", char* emptyClassName = "CBEAMB-ABCE-NOPF-ALL"){
+//void mu(Int_t run=196310, char* className = "CINT7-B-NOPF-ALLNOTRD", char* emptyClassName = NULL){
+  if (!TGrid::Connect("alien://")) return -1.;
+
+  AliCDBManager* man = AliCDBManager::Instance();
+  man->SetDefaultStorage("raw://");
+  man->SetRun(run);
+  AliTriggerConfiguration* cfg = (AliTriggerConfiguration*) man->Get("GRP/CTP/Config")->GetObject();
+
+  // Get scalers
+  AliTriggerRunScalers* scalers = (AliTriggerRunScalers*) man->Get("GRP/CTP/Scalers")->GetObject();
+  Int_t nEntries = scalers->GetScalersRecords()->GetEntries();
+  
+  // Get SOR and EOR scaler records
+  AliTriggerScalersRecord* record1 = scalers->GetScalersRecord(0);
+  AliTriggerScalersRecord* record2 = scalers->GetScalersRecord(nEntries-1);
+  
+  // Extract SOR and EOR trigger counts
+  Int_t classid      = cfg->GetClassIndexFromName(className);
+  AliTriggerScalers* scaler1 = record1->GetTriggerScalersForClass(classid);
+  AliTriggerScalers* scaler2 = record2->GetTriggerScalersForClass(classid);
+  UInt_t l0b = dif(scaler2->GetLOCB(),scaler1->GetLOCB());
+  
+  Double_t totalBCs;
+  if (emptyClassName) {
+    Int_t emptyclassid = cfg->GetClassIndexFromName(emptyClassName);
+    scaler1 = record1->GetTriggerScalersForClass(emptyclassid);
+    scaler2 = record2->GetTriggerScalersForClass(emptyclassid);
+    UInt_t l0bempty = dif(scaler2->GetLOCB(),scaler1->GetLOCB());
+    totalBCs = l0bempty;
+  }
+  else {
+    Double_t orbitRate = 11245.; // Hz
+    // Extract SOR and EOR times
+    AliTimeStamp* stemp1 = record1->GetTimeStamp();
+    AliTimeStamp* stemp2 = record2->GetTimeStamp();
+    UInt_t duration = stemp2->GetSeconds()-stemp1->GetSeconds();
+    // Extract number of bunches per orbit
+    AliTriggerClass* cl = cfg->GetTriggerClass(classid);
+    AliTriggerBCMask* mask = cl->GetBCMask();
+    Int_t nBCsPerOrbit = mask->GetNUnmaskedBCs();
+    
+    totalBCs = duration*orbitRate*nBCsPerOrbit;
+  }
+  
+  Double_t mu = -TMath::Log(1-l0b/totalBCs);
+  printf("l0b=%i totalBCs=%.0f mu=%f\n",l0b,totalBCs,mu);
+  return mu;
+}
+
+UInt_t dif(UInt_t stop, UInt_t start){
+  UInt_t d;
+  if(stop >= start) d=stop-start;
+  else d = stop+(0xffffffff-start)+1;
+  return d;
+};