CbmStsAlgoFindClusters.cxx

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/* Copyright (C) 2020 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Volker Friese [committer] */
 
#include "CbmStsAlgoFindClusters.h"
 
#include "CbmStsCluster.h"
#include "CbmStsDigi.h"
#include "CbmStsParAsic.h"
#include "CbmStsParModule.h"
 
#include <cassert>
#include <iostream>
 
using std::pair;
using std::vector;
 
using InputData = CbmStsAlgoFindClusters::InputData;
 
 
// ----- Search for a matching cluster for a given channel   ---------------
Bool_t CbmStsAlgoFindClusters::CheckChannel(Short_t channel, Double_t time)
{
 
  // Neighbours of first or last channel without cross-connection
  if (channel == -1 || channel == fNofChannels) return kFALSE;
 
  // Check channel number
  assert(channel < fNofChannels);
 
  // No match if no active digi in the channel
  if (!IsActive(channel)) return kFALSE;
 
  // Check time ordering of input digis
  assert(time >= fStatus[channel].second);
 
  // Time difference
  Double_t tResol = fModPar->GetParAsic(channel).GetTimeResol();
  Double_t deltaT = (fTimeCutAbs > 0. ? fTimeCutAbs : fTimeCutSig * 1.4142 * tResol);
 
  // Channel is active, but time is not matching: close cluster
  if (time - fStatus[channel].second > deltaT) {
    CreateCluster(channel);
    return kFALSE;
  }
 
  // Matching digi found
  return kTRUE;
}
// -------------------------------------------------------------------------
 
 
// -----   Algorithm execution   -------------------------------------------
Long64_t CbmStsAlgoFindClusters::Exec(const vector<InputData>& input, vector<CbmStsCluster>& output, UInt_t address,
                                      UShort_t nChannels, UShort_t channelOffset, Double_t timeCutSigma,
                                      Double_t timeCutAbs, Bool_t connectEdge, const CbmStsParModule* modPar)
{
 
  // --- Set parameters and output
  fAddress       = address;
  fNofChannels   = nChannels;
  fChannelOffset = channelOffset;
  fTimeCutSig    = timeCutSigma;
  fTimeCutAbs    = timeCutAbs;
  fConnectEdge   = connectEdge;
  fOutput        = &output;
  fModPar        = modPar;
 
  // --- Reset buffer and output
  fStatus.assign(fNofChannels, {-1, 0.});
  fOutput->clear();
 
  // --- Process digis one by one
  Long64_t nDigis = 0;
  Bool_t result   = kTRUE;
  for (auto data : input) {
    UShort_t channel = data.first->GetChannel();
    assert(channel >= channelOffset);
    channel -= channelOffset;  // Transform into [0, nofChannels-1]
    result = ProcessDigi(channel, data.first->GetTime(), data.second);
    if (result) nDigis++;
  }
 
  // --- Create clusters from the remaining digis in the buffer
  for (UShort_t channel = 0; channel < nChannels; channel++) {
    CreateCluster(channel);
  }
 
  return nDigis;
}
// -------------------------------------------------------------------------
 
 
// -----   Close a cluster   -----------------------------------------------
void CbmStsAlgoFindClusters::CreateCluster(UShort_t channel)
{
 
  assert(channel < fNofChannels);
  if (!IsActive(channel)) return;
 
  // --- Find start and stop channel of cluster
  Short_t start = channel;
  Short_t stop  = channel;
  while (IsActive(ChanLeft(start)))
    start = ChanLeft(start);
  while (IsActive(ChanRight(stop)))
    stop = ChanRight(stop);
 
  // --- Just a check
  assert(start >= 0 && start < fNofChannels);
  assert(stop >= 0 && stop < fNofChannels);
  if (!fConnectEdge) assert(stop >= start);
 
  // --- Create a cluster object
  CbmStsCluster cluster{};
  cluster.SetAddress(fAddress);
 
  // --- Add digis to cluster and reset the respective buffer channels
  Short_t iChannel = start;
  while (kTRUE) {
    assert(IsActive(iChannel));
    cluster.AddDigi(fStatus[iChannel].first);
    fStatus[iChannel].first  = -1;
    fStatus[iChannel].second = 0.;
    if (iChannel == stop) break;
    iChannel = ChanRight(iChannel);
  }
 
  // --- Add cluster to output array
  fOutput->push_back(std::move(cluster));
}
// -------------------------------------------------------------------------
 
 
// -----   Process one digi   ----------------------------------------------
Bool_t CbmStsAlgoFindClusters::ProcessDigi(UShort_t channel, Double_t time, Int_t index)
{
 
  // Assert channel number
  assert(channel < fNofChannels);
 
  // Check for matching digi in the same channel (can only happen if
  // time resolution is not much smaller than the dead time.)
  // In this case, the digi is ignored.
  if (CheckChannel(channel, time)) return kFALSE;
 
  assert(ChanLeft(channel) >= -1);
  assert(ChanLeft(channel) < fNofChannels + 1);
  assert(ChanRight(channel) < fNofChannels + 1);
 
  // Check for not-matching digis in the neighbour channels
  CheckChannel(ChanLeft(channel), time);
  CheckChannel(ChanRight(channel), time);
 
  // Set channel status with this digi
  fStatus[channel].first  = index;
  fStatus[channel].second = time;
 
  return kTRUE;
}
// -------------------------------------------------------------------------