Merge pull request #38233 from missirol/semiRandomInitL1PSCounter_124X

Semi-random initial value in the L1 trigger prescale counter [`12_4_X`]

L1Trigger/L1TGlobal/interface/GlobalBoard.h

@@ -14,6 +14,7 @@
 
 // system include files
 #include <bitset>
+#include <cassert>
 #include <vector>
 
 // user include files
@@ -37,7 +38,7 @@
 
 #include "FWCore/Framework/interface/Event.h"
 #include "FWCore/Utilities/interface/InputTag.h"
-
+#include "FWCore/MessageLogger/interface/MessageLogger.h"
 #include "FWCore/Framework/interface/EventSetup.h"
 
 // forward declarations
@@ -164,6 +165,10 @@ namespace l1t {
     /// pointer to Tau data list
     inline const BXVector<const GlobalExtBlk*>* getCandL1External() const { return m_candL1External; }
 
+    //initializer prescale counter using a semi-random value between [1, prescale value]
+    static const std::vector<double> semirandomNumber(const edm::Event& iEvent,
+                                                      const std::vector<double>& prescaleFactorsAlgoTrig);
+
     /*  Drop individual EtSums for Now
     /// pointer to ETM data list
     inline const l1t::EtSum* getCandL1ETM() const
@@ -194,6 +199,7 @@ namespace l1t {
     void setBxLast(int bx);
 
     void setResetPSCountersEachLumiSec(bool val) { m_resetPSCountersEachLumiSec = val; }
+    void setSemiRandomInitialPSCounters(bool val) { m_semiRandomInitialPSCounters = val; }
 
   public:
     inline void setVerbosity(const int verbosity) { m_verbosity = verbosity; }
@@ -268,6 +274,9 @@ namespace l1t {
 
     //whether we reset the prescales each lumi or not
     bool m_resetPSCountersEachLumiSec = true;
+
+    // start the PS counter from a random value between [1,PS] instead of PS
+    bool m_semiRandomInitialPSCounters = false;
   };
 
 }  // namespace l1t

L1Trigger/L1TGlobal/plugins/L1TGlobalProducer.cc

@@ -69,6 +69,7 @@ void L1TGlobalProducer::fillDescriptions(edm::ConfigurationDescriptions& descrip
   // switch for muon showers in Run-3
   desc.add<bool>("useMuonShowers", false);
   desc.add<bool>("resetPSCountersEachLumiSec", true);
+  desc.add<bool>("semiRandomInitialPSCounters", false);
   // These parameters have well defined  default values and are not currently
   // part of the L1T/HLT interface.  They can be cleaned up or updated at will:
   desc.add<bool>("ProduceL1GtDaqRecord", true);
@@ -116,6 +117,7 @@ L1TGlobalProducer::L1TGlobalProducer(const edm::ParameterSet& parSet)
       m_requireMenuToMatchAlgoBlkInput(parSet.getParameter<bool>("RequireMenuToMatchAlgoBlkInput")),
       m_algoblkInputTag(parSet.getParameter<edm::InputTag>("AlgoBlkInputTag")),
       m_resetPSCountersEachLumiSec(parSet.getParameter<bool>("resetPSCountersEachLumiSec")),
+      m_semiRandomInitialPSCounters(parSet.getParameter<bool>("semiRandomInitialPSCounters")),
       m_useMuonShowers(parSet.getParameter<bool>("useMuonShowers")) {
   m_egInputToken = consumes<BXVector<EGamma>>(m_egInputTag);
   m_tauInputToken = consumes<BXVector<Tau>>(m_tauInputTag);
@@ -197,6 +199,7 @@ L1TGlobalProducer::L1TGlobalProducer(const edm::ParameterSet& parSet)
   m_uGtBrd = std::make_unique<GlobalBoard>();
   m_uGtBrd->setVerbosity(m_verbosity);
   m_uGtBrd->setResetPSCountersEachLumiSec(m_resetPSCountersEachLumiSec);
+  m_uGtBrd->setSemiRandomInitialPSCounters(m_semiRandomInitialPSCounters);
 
   // initialize cached IDs
 

L1Trigger/L1TGlobal/plugins/L1TGlobalProducer.h

@@ -188,6 +188,8 @@ class L1TGlobalProducer : public edm::stream::EDProducer<> {
 
   //disables reseting the prescale counters each lumisection (needed for offline)
   bool m_resetPSCountersEachLumiSec;
+  // start the PS counter from a random value between [1,PS] instead of PS
+  bool m_semiRandomInitialPSCounters;
   // switch to load muon showers in the global board
   bool m_useMuonShowers;
 };

L1Trigger/L1TGlobal/src/GlobalBoard.cc

@@ -971,10 +971,13 @@ void l1t::GlobalBoard::runFDL(edm::Event& iEvent,
   // prescale counters are reset at the beginning of the luminosity segment
   if (m_firstEv) {
     // prescale counters: numberPhysTriggers counters per bunch cross
-    m_prescaleCounterAlgoTrig.reserve(numberPhysTriggers * totalBxInEvent);
+    m_prescaleCounterAlgoTrig.reserve(totalBxInEvent);
+
+    auto const& prescaleCountersAlgoTrig =
+        m_semiRandomInitialPSCounters ? semirandomNumber(iEvent, prescaleFactorsAlgoTrig) : prescaleFactorsAlgoTrig;
 
     for (int iBxInEvent = 0; iBxInEvent <= totalBxInEvent; ++iBxInEvent) {
-      m_prescaleCounterAlgoTrig.push_back(prescaleFactorsAlgoTrig);
+      m_prescaleCounterAlgoTrig.push_back(prescaleCountersAlgoTrig);
     }
     m_firstEv = false;
     m_currentLumi = iEvent.luminosityBlock();
@@ -984,7 +987,11 @@ void l1t::GlobalBoard::runFDL(edm::Event& iEvent,
   if (m_firstEvLumiSegment || (m_currentLumi != iEvent.luminosityBlock() && m_resetPSCountersEachLumiSec)) {
     m_prescaleCounterAlgoTrig.clear();
     for (int iBxInEvent = 0; iBxInEvent <= totalBxInEvent; ++iBxInEvent) {
-      m_prescaleCounterAlgoTrig.push_back(prescaleFactorsAlgoTrig);
+      if (m_semiRandomInitialPSCounters) {
+        m_prescaleCounterAlgoTrig.push_back(semirandomNumber(iEvent, prescaleFactorsAlgoTrig));
+      } else {
+        m_prescaleCounterAlgoTrig.push_back(prescaleFactorsAlgoTrig);
+      }
     }
     m_firstEvLumiSegment = false;
     m_currentLumi = iEvent.luminosityBlock();
@@ -1160,3 +1167,36 @@ void l1t::GlobalBoard::printGmtData(const int iBxInEvent) const {
 
   LogTrace("L1TGlobal") << std::endl;
 }
+
+//initializer prescale counter using a semi-random value between [1, prescale value]
+const std::vector<double> l1t::GlobalBoard::semirandomNumber(const edm::Event& iEvent,
+                                                             const std::vector<double>& prescaleFactorsAlgoTrig) {
+  auto out = prescaleFactorsAlgoTrig;
+  // pick a random number from a combination of run, lumi, event numbers
+  std::srand(iEvent.id().run());
+  std::srand(std::rand() + iEvent.id().luminosityBlock());
+  // this causes different (semi)random number number for different streams
+  // reminder: different streams have different initial event number
+  std::srand(std::rand() + iEvent.id().event());
+  // very large (semi)random number
+  double const semirandom = std::rand();
+  for (auto& ps : out) {
+    // if the ps is smaller than 1 (e.g. ps=0, ps=1), it is not changed
+    // else, replace ps with a semirandom integer in the [1,ps] range
+    if (ps > 1) {
+      auto nps = semirandom - floor(semirandom / ps) * ps;
+      // if nps=0 or a wrong value (<0,>ps) use PS value (standard method)
+      if (nps > 0 and nps <= ps)
+        ps = nps;
+      else {
+        if (nps != 0)  // complain only if nps <0 or nps >PS
+          edm::LogWarning("L1TGlobal::semirandomNumber")
+              << "\n The inital prescale counter obtained by L1TGlobal::semirandomNumber is wrong."
+              << "\n This is probably do to the floating-point precision. Using the PS value."
+              << "\n semirandom = " << semirandom << "\n PS = " << ps << "\n nps = " << nps
+              << " <-- it should be in the range [0 , " << ps << "]" << std::endl;
+      }
+    }
+  }
+  return out;
+}