Understanding the structure of TRD2D.

This MR contains a slightly restructured version of CbmTrdUnpackFaspAlgo which was created as part of my ongoing efforts to understand TRD2D unpacking, as a precursor to the implementation of an online-capable unpacker for TRD2D in cbm::algo.

The code here is not meant to actually be merged into the master branch. The main purpose of this MR is to provide a platform to discuss details of the unpacker code with @a.bercuci with specific code examples.

reco/detectors/trd/unpack/CbmTrdUnpackFaspAlgo.cxx

@@ -43,10 +43,7 @@ CbmTrdUnpackFaspAlgo::CbmTrdFaspMessage::CbmTrdFaspMessage(uint8_t c, uint8_t ty
 {
 }
 
-CbmTrdUnpackFaspAlgo::CbmTrdUnpackFaspAlgo()
-  : CbmRecoUnpackAlgo("CbmTrdUnpackFaspAlgo")
-{
-}
+CbmTrdUnpackFaspAlgo::CbmTrdUnpackFaspAlgo() : CbmRecoUnpackAlgo("CbmTrdUnpackFaspAlgo") {}
 
 //_________________________________________________________________________________
 CbmTrdUnpackFaspAlgo::~CbmTrdUnpackFaspAlgo() {}
@@ -54,7 +51,6 @@ CbmTrdUnpackFaspAlgo::~CbmTrdUnpackFaspAlgo() {}
 //_________________________________________________________________________________
 Bool_t CbmTrdUnpackFaspAlgo::initParSet(FairParGenericSet* parset)
 {
-  FairParamList parList;
   Int_t nModules(0);
   if (strcmp(parset->ClassName(), "CbmTrdParSetAsic") == 0) {
     CbmTrdParSetAsic* setPar = static_cast<CbmTrdParSetAsic*>(parset);
@@ -96,7+92,7 @@
     CbmTrdParSetGain* setPar = static_cast<CbmTrdParSetGain*>(parset);
     setPar->printParams();
     nModules = setPar->GetNrOfModules();
   }
   else {
     LOG(error) << "Parameter set " << parset->ClassName() << " not known. Skip.";
     return kFALSE;
@@ -144,7+140,7 @@
 //_________________________________________________________________________________
 void CbmTrdUnpackFaspAlgo::SetCrobMapping(const std::map<uint32_t, uint16_t[NCROBMOD]>& map)
 {
-  if (fCrobMap) delete fCrobMap;
-  fCrobMap = new std::map<uint32_t, uint16_t[NCROBMOD]>(map);
+  if (fCompMap) delete fCompMap;
+  fCompMap = new std::map<uint16_t, std::pair<uint16_t, uint16_t>>;  /// map eq_id -> (mod_id, crob_id)
+
+  for (auto& entry : map) {
+    uint16_t mod_id = entry.first;
+    for (uint8_t crob_id = 0; crob_id < NCROBMOD; crob_id++) {
+      uint16_t eq_id = entry.second[crob_id];
+      if (fCompMap->find(eq_id) != fCompMap->end()) {
+        LOG(error) << GetName() << "::SetCrobMapping: multiple entries for eq_id " << (int) eq_id << " found.";
+        return;
+      }
+      (*fCompMap)[eq_id] = std::make_pair(mod_id, crob_id);
+    }
+  }
 }
 
 //_________________________________________________________________________________
@@ -220,100 +228,93 @@ void CbmTrdUnpackFaspAlgo::mess_prt(CbmTrdFaspMessage* mess)
 }
 
 //_________________________________________________________________________________
-bool CbmTrdUnpackFaspAlgo::pushDigis(std::vector<CbmTrdUnpackFaspAlgo::CbmTrdFaspMessage> messes)
+bool CbmTrdUnpackFaspAlgo::pushDigis(std::vector<CbmTrdUnpackFaspAlgo::CbmTrdFaspMessage> messes, const uint16_t mod_id)
 {
-  UChar_t lFasp(0xff);
-  UShort_t lchR, lchT;
-  Double_t r, t;
-  Int_t dt, dtime, ch, pad;
-  ULong64_t lTime, tdaqOffset(0);
-  CbmTrdParFasp* faspPar(nullptr);
-  const CbmTrdParFaspChannel* chCalib(nullptr);
-  CbmTrdParModDigi* digiPar(nullptr);
+  const UChar_t lFasp             = messes[0].fasp;
+  const CbmTrdParFasp* faspPar    = (CbmTrdParFasp*) fAsicPar.GetAsicPar(mod_id * 1000 + lFasp);
+  const CbmTrdParModDigi* digiPar = (CbmTrdParModDigi*) fDigiSet->GetModulePar(mod_id);
+
+  // link data to the position on the padplane
+  if (!faspPar) {
+    LOG(error) << GetName() << "::pushDigis - Par for FASP " << (int) lFasp << " in module " << mod_id
+               << " missing. Skip.";
+    return false;
+  }
+  if (!digiPar) {
+    LOG(error) << GetName() << "::pushDigis - DIGI par for module " << mod_id << " missing. Skip.";
+    return false;
+  }
 
-  for (auto imess : messes) {
-    if (lFasp == 0xff) {
-      lFasp = messes[0].fasp;
-      // link data to the position on the padplane
-      if (!(faspPar = (CbmTrdParFasp*) fAsicPar.GetAsicPar(fMod * 1000 + lFasp))) {
-        LOG(error) << GetName() << "::pushDigis - Par for FASP " << (int) lFasp << " in module " << fMod
-                   << " missing. Skip.";
-        return false;
-      }
-      if (!(digiPar = (CbmTrdParModDigi*) fDigiSet->GetModulePar(fMod))) {
-        LOG(error) << GetName() << "::pushDigis - DIGI par for module " << fMod << " missing. Skip.";
-        return false;
-      }
-      // TODO temporary add DAQ time calibration for FASPRO.
-      // Should be absorbed in the ASIC parameter definition
-      if (digiPar->GetPadRow(faspPar->GetPadAddress(imess.ch)) % 2 == 0) tdaqOffset = 3;
+  // TODO temporary add DAQ time calibration for FASPRO.
+  // Should be absorbed in the ASIC parameter definition
+  ULong64_t tdaqOffset(0);
+  if (digiPar->GetPadRow(faspPar->GetPadAddress(messes[0].ch)) % 2 == 0) tdaqOffset = 3;
 
-      if (VERBOSE) faspPar->Print();
-    }
-    if (VERBOSE) mess_prt(&imess);
-
-    pad     = faspPar->GetPadAddress(imess.ch);
-    chCalib = faspPar->GetChannel(imess.ch);
-    ch      = 2 * pad + chCalib->HasPairingR();
-    lTime   = fTime + tdaqOffset + imess.tlab;
-    lchR    = 0;
-    lchT    = 0;
-    if (chCalib->HasPairingR()) lchR = imess.data;
-    else
-      lchT = imess.data;
-    if (VERBOSE)
+  if (VERBOSE) faspPar->Print();
+
+  for (auto imess : messes) {
+    const Int_t pad                     = faspPar->GetPadAddress(imess.ch);
+    const CbmTrdParFaspChannel* chCalib = faspPar->GetChannel(imess.ch);
+    const ULong64_t lTime               = fTime + tdaqOffset + imess.tlab;
+    const UShort_t lchR                 = chCalib->HasPairingR() ? imess.data : 0;
+    const UShort_t lchT                 = chCalib->HasPairingR() ? 0 : imess.data;
+    std::vector<CbmTrdDigi>& digiBuffer = fDigiBuffer[pad];
+
+    if (VERBOSE) {
+      const Int_t ch = 2 * pad + chCalib->HasPairingR();
+      mess_prt(&imess);
       printf("fasp[%2d] ch[%4d / %2d] pad[%4d] row[%2d] col[%2d] %c[%4d]\n", lFasp, ch, imess.ch, pad,
              digiPar->GetPadRow(pad), digiPar->GetPadColumn(pad), (chCalib->HasPairingT() ? 'T' : 'R'),
              lchT > 0 ? lchT : lchR);
+    }
 
-    if (fDigiBuffer[fCrob][pad].size()) {
-      // check if last digi has both R/T message components. Update if not and is within time window
-      auto id = fDigiBuffer[fCrob][pad].rbegin();  // Should always be valid here.
-                                                   // No need to extra check
-      dtime = (*id).GetTimeDAQ() - lTime;
-      bool use(false);
-      if (TMath::Abs(dtime) < 5) {  // test message part of (last) digi
-        r = (*id).GetCharge(t, dt);
-        if (lchR && r < 0.1) {  // set R charge on an empty slot
-          (*id).SetCharge(t, lchR, -dtime);
-          use = true;
-        }
-        else if (lchT && t < 0.1) {  // set T charge on an empty slot
-          (*id).SetCharge(lchT, r, +dtime);
-          (*id).SetTimeDAQ(ULong64_t((*id).GetTimeDAQ() - dtime));
-          use = true;
-        }
-      }
+    if (digiBuffer.size() == 0) {  // init pad position in map and build digi for message
+      digiBuffer.emplace_back(pad, lchT, lchR, lTime);
+      digiBuffer.back().SetAddressModule(mod_id);
+      continue;
+    }
 
-      // build digi for message when update failed
-      if (!use) {
-        fDigiBuffer[fCrob][pad].emplace_back(pad, lchT, lchR, lTime);
-        fDigiBuffer[fCrob][pad].back().SetAddressModule(fMod);
-        id = fDigiBuffer[fCrob][pad].rbegin();
-      }
+    // check if last digi has both R/T message components. Update if not and is within time window
+    auto id = digiBuffer.rbegin();  // Should always be valid here.
+                                    // No need to extra check
+    Double_t r, t;
+    Int_t dt;
+    const Int_t dtime = (*id).GetTimeDAQ() - lTime;
+    bool use(false);
 
-      if (id != fDigiBuffer[fCrob][pad].rend()) id++;
-
-      // update charge for previously allocated digis to account for FASPRO ADC buffering and read-out feature
-      use = false;
-      for (; id != fDigiBuffer[fCrob][pad].rend(); ++id) {
-        r = (*id).GetCharge(t, dt);
-        if (lchR && int(r)) {  // update R charge and mark on digi
-          (*id).SetCharge(t, lchR, dt);
-          (*id).SetFlag(1);
-          use = true;
-        }
-        else if (lchT && int(t)) {  // update T charge and mark on digi
-          (*id).SetCharge(lchT, r, dt);
-          (*id).SetFlag(0);
-          use = true;
-        }
-        if (use) break;
+    if (TMath::Abs(dtime) < 5) {  // test message part of (last) digi
+      r = (*id).GetCharge(t, dt);
+      if (lchR && r < 0.1) {  // set R charge on an empty slot
+        (*id).SetCharge(t, lchR, -dtime);
+        use = true;
+      }
+      else if (lchT && t < 0.1) {  // set T charge on an empty slot
+        (*id).SetCharge(lchT, r, +dtime);
+        (*id).SetTimeDAQ(ULong64_t((*id).GetTimeDAQ() - dtime));
+        use = true;
       }
     }
-    else {  // init pad position in map and build digi for message
-      fDigiBuffer[fCrob][pad].emplace_back(pad, lchT, lchR, lTime);
-      fDigiBuffer[fCrob][pad].back().SetAddressModule(fMod);
+
+    // build digi for message when update failed
+    if (!use) {
+      digiBuffer.emplace_back(pad, lchT, lchR, lTime);
+      digiBuffer.back().SetAddressModule(mod_id);
+      id = digiBuffer.rbegin();
+    }
+
+    // update charge for previously allocated digis to account for FASPRO ADC buffering and read-out feature
+    for (++id; id != digiBuffer.rend(); ++id) {
+      r = (*id).GetCharge(t, dt);
+      if (lchR && int(r)) {  // update R charge and mark on digi
+        (*id).SetCharge(t, lchR, dt);
+        (*id).SetFlag(1);
+        break;
+      }
+      else if (lchT && int(t)) {  // update T charge and mark on digi
+        (*id).SetCharge(lchT, r, dt);
+        (*id).SetFlag(0);
+        break;
+      }
     }
   }
   messes.clear();
@@ -325,17 +326,16 @@ uint32_t CbmTrdUnpackFaspAlgo::ResetTimeslice()
 {
   uint32_t uNbLostDigis = 0;
   /// PAL 03/08/2022: clear internal buffer at latest between two timeslices (TS are self contained!)
+  /// D.Smith: As of 27.4.2023 only loops over pads of a single component.
 
-  for (auto crobBuffer : fDigiBuffer) {
-    for (auto pad_id(0); pad_id < NFASPMOD * NFASPCH; pad_id++) {
-      if (!crobBuffer.second[pad_id].size()) continue;
+  for (auto pad_id(0); pad_id < NFASPMOD * NFASPCH; pad_id++) {
+    if (!fDigiBuffer[pad_id].size()) continue;
 
-      LOG(warn) << fName << "::ResetTimeslice - buffered digi @ CROB=" << crobBuffer.first << " / pad=" << pad_id
-                << " store " << crobBuffer.second[pad_id].size() << " unprocessed digi.";
-      uNbLostDigis += crobBuffer.second[pad_id].size();
+    LOG(warn) << fName << "::ResetTimeslice - buffered digi @ CROB=" << fCrob << " / pad=" << pad_id << " store "
+              << fDigiBuffer[pad_id].size() << " unprocessed digi.";
+    uNbLostDigis += fDigiBuffer[pad_id].size();
 
-      crobBuffer.second[pad_id].clear();
-    }
+    fDigiBuffer[pad_id].clear();
   }
   return uNbLostDigis;
 }
@@ -346,9 +346,9 @@ void CbmTrdUnpackFaspAlgo::FinalizeComponent()
   Int_t dt;
   // push finalized digits to the next level
   for (uint16_t ipad(0); ipad < NFASPMOD * NFASPCH; ipad++) {
-    if (!fDigiBuffer[fCrob][ipad].size()) continue;
+    if (!fDigiBuffer[ipad].size()) continue;
     uint nIncomplete(0);
-    for (auto id = fDigiBuffer[fCrob][ipad].begin(); id != fDigiBuffer[fCrob][ipad].end(); id++) {
+    for (auto id = fDigiBuffer[ipad].begin(); id != fDigiBuffer[ipad].end(); id++) {
       r = (*id).GetCharge(t, dt);
       // check if digi has all signals CORRECTED
       if (((t > 0) != (*id).IsFlagged(0)) || ((r > 0) != (*id).IsFlagged(1))) {
@@ -362,7 +362,7 @@ void CbmTrdUnpackFaspAlgo::FinalizeComponent()
       fOutputVec.emplace_back(std::move((*id)));
     }
     // clear digi buffer wrt the digi which was forwarded to higher structures
-    fDigiBuffer[fCrob][ipad].clear();
+    fDigiBuffer[ipad].clear();
     if (nIncomplete > 2) {
       LOG(warn) << fName << "FinalizeComponent(" << fCrob << ") skip " << nIncomplete << " incomplete digi at pad "
                 << ipad << ".\n";
@@ -371,48 +371,33 @@ void CbmTrdUnpackFaspAlgo::FinalizeComponent()
   fCrob = 0xffff;  // reset current crob id
 }
 
-// ---- unpack ----
+// ----unpack----
 bool CbmTrdUnpackFaspAlgo::unpack(const fles::Timeslice* ts, std::uint16_t icomp, UInt_t imslice)
 {
   if (VERBOSE) printf("CbmTrdUnpackFaspAlgo::unpack 0x%04x %d\n", icomp, imslice);
   // LOG(info) << "Component " << icomp << " connected to config CbmTrdUnpackConfig2D. Slice "<<imslice;
 
-  uint8_t crob_id = 0;
-  uint16_t eq_id;
-  bool unpackOk   = true;
+  bool unpackOk = true;
   //Double_t fdMsSizeInNs = 1.28e6;
 
   auto msdesc = ts->descriptor(icomp, imslice);
+
   // Cast required to silence a warning on macos (there a uint64_t is a llu)
   if (VERBOSE) printf("time start %lu\n", static_cast<size_t>(msdesc.idx));
+
   // define time wrt start of time slice in TRD/FASP clks [80 MHz]
   fTime = ULong64_t((msdesc.idx - fTsStartTime - fSystemTimeOffset) / 12.5);
 
-  // get MOD_id and CROB id from the equipment
-  bool mapped = false;
-  eq_id       = msdesc.eq_id;
-  for (auto mod_id : fModuleId) {
-    for (crob_id = 0; crob_id < NCROBMOD; crob_id++) {
-      if (((*fCrobMap)[mod_id])[crob_id] == eq_id) break;
-    }
-    if (crob_id == NCROBMOD) continue;
-
-    // found module-cri pair
-    // buffer module configuration
-    if (fMod == 0xffff || fMod != mod_id) {
-      fMod = mod_id;
-      if (!init()) {
-        LOG(error) << GetName() << "::unpack - init mod_id=" << mod_id << " failed.";
-        return false;
-      }
-    }
-    mapped = true;
-    break;
-  }
-  if (!mapped) {
+  // get MOD_id and CROB id from the equipment, using the comp map: eq_id -> (mod_id, crob_id)
+  const uint16_t eq_id = msdesc.eq_id;
+  const auto it        = fCompMap->find(eq_id);
+  if (it == fCompMap->end() || std::find(fModuleId.begin(), fModuleId.end(), it->second.first) == fModuleId.end()) {
     LOG(error) << GetName() << "::unpack - CROB eq_id=" << eq_id << " not registered in the unpacker.";
     return false;
   }
+  const uint16_t mod_id = (*fCompMap)[eq_id].first;
+  const uint8_t crob_id = (*fCompMap)[eq_id].second;
+
   if (fCrob == 0xffff) fCrob = icomp;
 
   // Get the µslice size in bytes to calculate the number of completed words
@@ -452,7 +437,7 @@ bool CbmTrdUnpackFaspAlgo::unpack(const fles::Timeslice* ts, std::uint16_t icomp
     if (isaux) {
       if (!ch_id) {
         // clear buffer
-        if (vMess.size()) { pushDigis(vMess); }
+        if (vMess.size()) { pushDigis(vMess, mod_id); }
         vMess.clear();
 
         if (VERBOSE)
@@ -465,30 +450,30 @@ bool CbmTrdUnpackFaspAlgo::unpack(const fles::Timeslice* ts, std::uint16_t icomp
       else if (ch_id == 1) {
         if (VERBOSE) cout << boost::format("    PAUSE: fasp_id=%02d\n") % static_cast<unsigned int>(fasp_id);
       }
+      continue;
     }
-    else {
-      if (fFaspMap) fasp_id = ((*fFaspMap)[fMod])[fasp_id];
 
-      if (lFaspOld != fasp_id) {
-        // push
-        if (vMess.size()) { pushDigis(vMess); }
-        vMess.clear();
-        lFaspOld = fasp_id;
-      }
-      if (data & 0x1) {
-        LOG(warn) << GetName() << "::unpack - Data corrupted : detect end bit set.";
-        continue;
-      }
-      if (VERBOSE)
-        cout << boost::format("    DD : fasp_id=%02d ch_id=%02d slice=%03d data=%4d\n")
-                  % static_cast<unsigned int>(fasp_id) % static_cast<unsigned int>(ch_id)
-                  % static_cast<unsigned int>(slice) % static_cast<unsigned int>(data >> 1);
-      if (data & 0x2000) {
-        LOG(debug) << GetName() << "::unpack - Self-triggered data.";
-        data &= 0x1fff;
-      }
-      vMess.emplace_back(ch_id, kData, slice, data >> 1, crob_id, lFaspOld);
+    if (fFaspMap) fasp_id = ((*fFaspMap)[mod_id])[fasp_id];
+
+    if (lFaspOld != fasp_id) {
+      // push
+      if (vMess.size()) { pushDigis(vMess, mod_id); }
+      vMess.clear();
+      lFaspOld = fasp_id;
+    }
+    if (data & 0x1) {
+      LOG(warn) << GetName() << "::unpack - Data corrupted : detect end bit set.";
+      continue;
+    }
+    if (VERBOSE)
+      cout << boost::format("    DD : fasp_id=%02d ch_id=%02d slice=%03d data=%4d\n")
+                % static_cast<unsigned int>(fasp_id) % static_cast<unsigned int>(ch_id)
+                % static_cast<unsigned int>(slice) % static_cast<unsigned int>(data >> 1);
+    if (data & 0x2000) {
+      LOG(debug) << GetName() << "::unpack - Self-triggered data.";
+      data &= 0x1fff;
     }
+    vMess.emplace_back(ch_id, kData, slice, data >> 1, crob_id, lFaspOld);
     //prt_wd(*wd);
   }
   return unpackOk;