WireEfficiencyAlgorithm.cc

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#include <cdc/calibration/WireEfficiencyAlgorithm.h>
#include <calibration/CalibrationAlgorithm.h>
 
#include <cdc/topology/CDCWireTopology.h>
#include <cdc/topology/CDCWireLayer.h>
 
#include <cdc/geometry/CDCGeometryPar.h>
#include <cdc/dbobjects/CDCBadWires.h>
#include <framework/logging/Logger.h>
#include <TH2F.h>
#include <TFitResult.h>
#include <TF1.h>
#include <TGraphAsymmErrors.h>
#include <TMath.h>
 
using namespace Belle2;
using namespace CDC;
WireEfficiencyAlgorithm::WireEfficiencyAlgorithm(): CalibrationAlgorithm("CDCBadWireCollector")
{
  setDescription(
    " -------------------------- Wire Efficiency Estimation Algorithm -------------------------\n"
  );
}
 
bool WireEfficiencyAlgorithm::buildEfficiencies()
{
  B2INFO("Creating efficiencies for every layer");
 
  unsigned short wireID;
  unsigned short layerID;
  float z;
  bool isFound;
 
  auto efftree = getObjectPtr<TTree>("efftree");
  efftree->SetBranchAddress("wireID", &wireID);
  efftree->SetBranchAddress("layerID", &layerID);
  efftree->SetBranchAddress("z", &z);
  efftree->SetBranchAddress("isFound", &isFound);
 
  // Set ranges and names for the TEfficiency objects
  B2INFO("Building empty efficiency objects");
  static const CDCWireTopology& wireTopology = CDCWireTopology::getInstance();
  B2INFO("Wire Topology found");
  static const CDCGeometryPar& cdcgeo = CDCGeometryPar::Instance();
  B2INFO("CDC Geometry found");
 
  for (const CDCWireLayer& wireLayer : wireTopology.getWireLayers()) {
    unsigned short layerNo = wireLayer.getICLayer();
    //B2INFO("Got layer " << layerNo);
    //std::string m_nameOfLayer = std::string("effLayer_").append(std::to_string(layerNo));
    //std::string m_titleOfLayer = std::string("Efficiency of wires in layer ").append(std::to_string(layerNo));
    //B2INFO("Built names for " << layerNo);
 
    unsigned short nzbins = 30 - layerNo / 7;
    unsigned short nwidbins = cdcgeo.nWiresInLayer(layerNo);
    double widbins[2] = { -0.5, cdcgeo.nWiresInLayer(layerNo) - 0.5};
    double zbins[2] = {wireLayer.getBackwardZ(), wireLayer.getForwardZ()};
 
    TEfficiency* effInLayer = new TEfficiency(Form("effLayer_%d", layerNo), Form("Hit efficiency pf L%d ; z (cm) ; IWire ", layerNo),
                                              nzbins, zbins[0], zbins[1], nwidbins,  widbins[0], widbins[1]);
    m_efficiencyList->Add(effInLayer);
    B2INFO("Teff for layer " << layerNo << " was successfully listed.");
  }
  TFile* outputCollection = new TFile("LayerEfficiencies.root", "RECREATE");
 
  // loop over entries in the tree and build the TEfficiencies
  B2INFO("Filling the efficiencies");
  const Long64_t nEntries = efftree->GetEntries();
  B2INFO("Number of entries in tree: " << nEntries);
  for (Long64_t i = 0; i < nEntries; i++) {
    efftree->GetEntry(i);
    TEfficiency* efficiencyInLayer = (TEfficiency*)m_efficiencyList->At(layerID);
    efficiencyInLayer->Fill(isFound, z, wireID);
  }
  m_efficiencyList->Write();
  B2INFO("TEfficiencies successfully filled.");
  outputCollection->Close();
  B2INFO("TEfficiencies successfully saved");
  // setting 1000 entries as the minimum value to consider "enough data", but this might need to be tailored in the future.
  if (nEntries > 1000) return true;
  else return false;
}
 
void WireEfficiencyAlgorithm::detectBadWires()
{
  B2INFO("Beginning detection of bad wires");
  static const CDCWireTopology& wireTopology = CDCWireTopology::getInstance();
  B2INFO("Wire Topology found");
 
  for (const CDCWireLayer& wireLayer : wireTopology.getWireLayers()) {
    unsigned short layerNo = wireLayer.getICLayer();
    B2INFO("Checking layer " << layerNo);
 
    // need to use casting here because GetPassedHistogram assumes it returns TH1
    auto efficiencyInLayer = (TEfficiency*)m_efficiencyList->At(layerNo);
    auto passed = (TH2F*)efficiencyInLayer->GetPassedHistogram();
    auto total = (TH2F*)efficiencyInLayer->GetTotalHistogram();
 
    // Ignoring layers that have no hits at all
    if (!total->GetEntries()) continue;
 
    // prepare fitting functions
    double minFitRange = wireLayer.getBackwardZ() + 30;
    double maxFitRange = wireLayer.getForwardZ() - 30;
    TF1* constantFunction = new TF1("constantFunction", "pol0", minFitRange, maxFitRange);
 
    // Estimate average efficiency of the layer as function of z
    auto passedProjectedX = passed->ProjectionX("projectionx1");
    auto totalProjectedX = total->ProjectionX("projectionx2");
    TEfficiency* efficiencyProjectedX = new TEfficiency(*passedProjectedX, *totalProjectedX);
 
    unsigned short minFitBin = passedProjectedX->FindBin(minFitRange) + 1;
    unsigned short maxFitBin = passedProjectedX->FindBin(maxFitRange) - 1;
 
    // Estimate average efficiency of each wire in the layer
    auto passedProjectedY = passed->ProjectionY("projectiony1", minFitRange, maxFitRange);
    auto totalProjectedY = total->ProjectionY("projectiony2", minFitRange, maxFitRange);
    TEfficiency* efficiencyProjectedY = new TEfficiency(*passedProjectedY, *totalProjectedY);
 
    // Estimate average efficiency of the whole layer by summing up averages of individual wires
    float totalAverage = 0;
    int nonZeroWires = 0;
    for (int i = 0; i <= passedProjectedY->GetNbinsX(); ++i) {
      float efficiencyAtBin = efficiencyProjectedY->GetEfficiency(i);
      if (efficiencyAtBin > 0.2) {
        totalAverage += efficiencyAtBin;
        nonZeroWires++;
      }
    }
    // safeguard in case all wires are 0
    nonZeroWires > 0 ? totalAverage /= nonZeroWires : totalAverage == 0;
 
    TGraphAsymmErrors* graphEfficiencyProjected = efficiencyProjectedX->CreateGraph();
 
    B2INFO("Successfully determined average properties of layer " << layerNo);
    B2INFO("Looping over wires");
 
    // Due to the way histograms are binned, every bin center should correspond a wire ID.
    for (int i = 0; i <= passed->GetNbinsY(); ++i) {
 
      // project out 1 wire
      auto singleWirePassed = passed->ProjectionX("single wire projection passed", i, i);
      auto singleWireTotal = total->ProjectionX("single wire projection total", i, i);
 
      // if not a single hit within the central area of wire then mark it as bad
      if (!singleWirePassed->Integral(minFitBin, maxFitBin)) {
        double wireID = passed->GetYaxis()->GetBinCenter(i);
        unsigned short maxWires = CDCGeometryPar::Instance().nWiresInLayer(layerNo);
        if (wireID < 0 || wireID >= maxWires) {
          B2ERROR("Invalid wireID: " << wireID << " for LayerID: " << layerNo
                  << ". Max wires: " << maxWires);
          continue; // remove invalid wireID
        }
        m_badWireList->setWire(layerNo, round(wireID), 0);
        continue;
      }
      // constructs efficiency of one wire
      TEfficiency* singleWireEfficiency = new TEfficiency(*singleWirePassed, *singleWireTotal);
      TGraphAsymmErrors* graphSingleWireEfficiency = singleWireEfficiency->CreateGraph();
 
      // fits the efficiency with a constant
      TFitResultPtr singleWireFitResults = graphSingleWireEfficiency->Fit(constantFunction, "SQR");
      double singleWireEfficiencyFromFit = (singleWireFitResults.Get())->Value(0);
      double singleWireUpErrorFromFit = (singleWireFitResults.Get())->UpperError(0);
 
      // applies a chi test on the wire
      float p_value = chiTest(graphSingleWireEfficiency, graphEfficiencyProjected, minFitRange, maxFitRange);
      // check three conditions and decide if wire should be marked as bad
      bool averageCondition = (0.95 * totalAverage) > (singleWireEfficiencyFromFit + 3 * singleWireUpErrorFromFit);
      bool pvalueCondition = p_value < 0.01;
      bool generalCondition = singleWireEfficiencyFromFit < 0.4;
      if (generalCondition || (averageCondition && pvalueCondition)) {
        double wireID = passed->GetYaxis()->GetBinCenter(i);
        m_badWireList->setWire(layerNo, round(wireID), singleWireEfficiencyFromFit);
      }
    }
    B2INFO("Bad wires for " << layerNo << " recorded");
  }
  m_badWireList->outputToFile("wireFile.txt");
  saveCalibration(m_badWireList, "CDCBadWires");
  B2INFO("Bad wire list successfully saved.");
}
 
double WireEfficiencyAlgorithm::chiTest(TGraphAsymmErrors* graph1, TGraphAsymmErrors* graph2, double minValue, double maxValue)
{
 
  // Vars to perform the chi test
  double chi = 0;
  unsigned short ndof = 0;
 
 
  int numOfEntries1 = graph1->GetN();
  int numOfEntries2 = graph2->GetN();
 
  // loop over entries in both graphs, index by index.
 
  for (int index1 = 0; index1 < numOfEntries1; ++index1) {
    // TGraph values are usually not listed in increasing order. Need to check that they are within min/max range for comparison.
    if (graph1->GetX()[index1] < minValue) continue;
    if (graph1->GetX()[index1] > maxValue) continue;
    for (int index2 = 0; index2 < numOfEntries2; ++index2) {
      if (graph1->GetX()[index1] == graph2->GetX()[index2]) {
        // this is broken up just for readability
        double chiNumerator = pow(graph1->GetY()[index1] - graph2->GetY()[index2], 2);
        double chiDenominator = pow(graph1->GetErrorYhigh(index1), 2) + pow(graph1->GetErrorYlow(index1), 2);
        chi += chiNumerator / chiDenominator;
        ndof++;
        continue;
      }
    }
  }
  return TMath::Prob(chi, ndof);
}
 
CalibrationAlgorithm::EResult WireEfficiencyAlgorithm::calibrate()
{
  const auto exprun = getRunList()[0];
  B2INFO("ExpRun used for DB Geometry : " << exprun.first << " " << exprun.second);
  updateDBObjPtrs(1, exprun.second, exprun.first);
 
  B2INFO("Creating CDCGeometryPar object");
  CDC::CDCGeometryPar::Instance(&(*m_cdcGeo));
 
  bool enoughEventsInInput;
  enoughEventsInInput = buildEfficiencies();
 
  detectBadWires();
 
  if (enoughEventsInInput) return c_OK;
  else return c_NotEnoughData;
}