Implement module-theta readout (with per-layer merging) (#48)

* Make CellPositionsECalBarrelTool work with various segmentation classes (also theta-phi and theta-phi-merged in addition to eta-phi)

* implement module-theta (with per-layer merging) readout

* cleanup

* performance improvements

* move cell position code for module-theta merged segmentation to new tool in RecFCCeeCalorimeter

RecFCCeeCalorimeter/src/components/CellPositionsECalBarrelModuleThetaSegTool.cpp

@@ -0,0 +1,146 @@
+#include "CellPositionsECalBarrelModuleThetaSegTool.h"
+
+// EDM
+#include "edm4hep/CalorimeterHitCollection.h"
+
+#include <cmath>
+
+DECLARE_COMPONENT(CellPositionsECalBarrelModuleThetaSegTool)
+
+CellPositionsECalBarrelModuleThetaSegTool::CellPositionsECalBarrelModuleThetaSegTool(const std::string& type, const std::string& name,
+										     const IInterface* parent)
+    : GaudiTool(type, name, parent) {
+  declareInterface<ICellPositionsTool>(this);
+}
+
+StatusCode CellPositionsECalBarrelModuleThetaSegTool::initialize() {
+  StatusCode sc = GaudiTool::initialize();
+  if (sc.isFailure()) return sc;
+  m_geoSvc = service("GeoSvc");
+  if (!m_geoSvc) {
+    error() << "Unable to locate Geometry service." << endmsg;
+    return StatusCode::FAILURE;
+  }
+
+  // get segmentation
+  m_segmentation = dynamic_cast<dd4hep::DDSegmentation::FCCSWGridModuleThetaMerged*>(m_geoSvc->lcdd()->readout(m_readoutName).segmentation().segmentation());
+  if (m_segmentation == nullptr) {
+    error() << "There is no module-theta segmentation!!!!" << endmsg;
+    return StatusCode::FAILURE;
+  }
+  debug() << "Found merged module-theta segmentation" << endmsg;
+  for (int iLayer=0; iLayer<m_segmentation->nLayers(); iLayer++) {
+    info() << "Layer : " << iLayer
+	   << " theta merge : " << m_segmentation->mergedThetaCells(iLayer)
+	   << " module merge : " << m_segmentation->mergedModules(iLayer) << endmsg;
+    if (m_segmentation->mergedThetaCells(iLayer)<1) {
+      error() << "Number of cells merged along theta should be >= 1!!!!" << endmsg;
+    }
+    if (m_segmentation->mergedModules(iLayer)<1) {
+      error() << "Number of modules merged should be >= 1!!!!" << endmsg;
+    }
+  }
+
+
+  // Take readout bitfield decoder from GeoSvc
+  m_decoder = m_geoSvc->lcdd()->readout(m_readoutName).idSpec().decoder();
+  m_volman = m_geoSvc->lcdd()->volumeManager();
+
+  // check if decoder contains "layer"
+  std::vector<std::string> fields;
+  for (uint itField = 0; itField < m_decoder->size(); itField++) {
+    fields.push_back((*m_decoder)[itField].name());
+  }
+  auto iter = std::find(fields.begin(), fields.end(), "layer");
+  if (iter == fields.end()) {
+    error() << "Readout does not contain field: 'layer'" << endmsg;
+  }
+
+  return sc;
+}
+
+void CellPositionsECalBarrelModuleThetaSegTool::getPositions(const edm4hep::CalorimeterHitCollection& aCells,
+                                               edm4hep::CalorimeterHitCollection& outputColl) {
+
+  debug() << "Input collection size : " << aCells.size() << endmsg;
+
+  // Loop through input cell collection, call xyzPosition method for each cell
+  // and assign position to cloned hit to be saved in outputColl
+  for (const auto& cell : aCells) {
+    auto outSeg = CellPositionsECalBarrelModuleThetaSegTool::xyzPosition(cell.getCellID());
+    auto edmPos = edm4hep::Vector3f();
+    edmPos.x = outSeg.x() / dd4hep::mm;
+    edmPos.y = outSeg.y() / dd4hep::mm;
+    edmPos.z = outSeg.z() / dd4hep::mm;
+
+    auto positionedHit = cell.clone();
+    positionedHit.setPosition(edmPos);
+    outputColl.push_back(positionedHit);
+
+    // Debug information about cell position
+    debug() << "Cell energy (GeV) : " << positionedHit.getEnergy() << "\tcellID " << positionedHit.getCellID() << endmsg;
+    debug() << "Position of cell (mm) : \t" << outSeg.x() / dd4hep::mm << "\t" << outSeg.y() / dd4hep::mm << "\t"
+            << outSeg.z() / dd4hep::mm << "\n"
+            << endmsg;
+  }
+  debug() << "Output positions collection size: " << outputColl.size() << endmsg;
+}
+
+dd4hep::Position CellPositionsECalBarrelModuleThetaSegTool::xyzPosition(const uint64_t& aCellId) const {
+
+  dd4hep::Position outSeg;
+  double radius;
+
+  // for module-theta merged segmentation, the local position returned
+  // by the segmentation class is theta of group of merged cells 
+  // and relative phi wrt first module in group of merged modules
+  // in a vector3 scaled such that R_xy=1
+
+  // find position of volume corresponding to first of group of merged cells
+  debug() << "cellID: " << aCellId << endmsg;
+  dd4hep::DDSegmentation::CellID volumeId = aCellId;
+  m_decoder->set(volumeId, "theta", 0);
+  debug() << "volumeID: " << volumeId << endmsg;
+  auto detelement = m_volman.lookupDetElement(volumeId);
+  const auto& transformMatrix = detelement.nominal().worldTransformation();
+  double outGlobal[3];
+  double inLocal[] = {0, 0, 0};
+  transformMatrix.LocalToMaster(inLocal, outGlobal);
+  debug() << "Position of volume (mm) : \t" 
+	  << outGlobal[0] / dd4hep::mm << "\t" 
+	  << outGlobal[1] / dd4hep::mm << "\t"
+	  << outGlobal[2] / dd4hep::mm << endmsg;
+
+  // get R, phi of volume
+  radius = std::sqrt(std::pow(outGlobal[0], 2) + std::pow(outGlobal[1], 2));
+  double phi = std::atan2(outGlobal[1], outGlobal[0]);
+  debug() << "R (mm), phi of volume : \t" << radius / dd4hep::mm << " , " << phi << endmsg;
+
+  // now get offset in theta and in phi from cell ID (due to theta grid + merging in theta/modules)
+  // the local position is normalised to r_xy=1 so theta is atan(1/z)
+  dd4hep::DDSegmentation::Vector3D inSeg = m_segmentation->position(aCellId);
+  debug() << "Local position of cell (mm) : \t" 
+	  << inSeg.x() / dd4hep::mm << "\t" 
+	  << inSeg.y() / dd4hep::mm << "\t"
+	  << inSeg.z() / dd4hep::mm << endmsg;
+  double dphi = std::atan2(inSeg.y(), inSeg.x());
+  debug() << "Local phi of cell : \t"  << dphi << endmsg;
+  phi += dphi;
+  outSeg = dd4hep::Position(radius * std::cos(phi),
+			    radius * std::sin(phi),
+			    radius * inSeg.z());
+  debug() << "Position of cell (mm) : \t" << outSeg.x() / dd4hep::mm << "\t" << outSeg.y() / dd4hep::mm << "\t"
+	  << outSeg.z() / dd4hep::mm << "\n"
+	  << endmsg;
+
+  return outSeg;
+}
+
+int CellPositionsECalBarrelModuleThetaSegTool::layerId(const uint64_t& aCellId) {
+  int layer;
+  dd4hep::DDSegmentation::CellID cID = aCellId;
+  layer = m_decoder->get(cID, "layer");
+  return layer;
+}
+
+StatusCode CellPositionsECalBarrelModuleThetaSegTool::finalize() { return GaudiTool::finalize(); }

RecFCCeeCalorimeter/src/components/CellPositionsECalBarrelModuleThetaSegTool.h

@@ -0,0 +1,65 @@
+#ifndef RECCALORIMETER_CELLPOSITIONSECALBARRELMODULETHETASEGTOOL_H
+#define RECCALORIMETER_CELLPOSITIONSECALBARRELMODULETHETASEGTOOL_H
+
+// GAUDI
+#include "GaudiAlg/GaudiTool.h"
+#include "GaudiKernel/ServiceHandle.h"
+
+// FCCSW
+#include "DetCommon/DetUtils.h"
+#include "k4Interface/IGeoSvc.h"
+#include "DetSegmentation/FCCSWGridModuleThetaMerged.h"
+#include "k4FWCore/DataHandle.h"
+#include "k4Interface/ICellPositionsTool.h"
+
+// DD4hep
+#include "DD4hep/Readout.h"
+#include "DD4hep/Volumes.h"
+#include "DDSegmentation/Segmentation.h"
+#include "TGeoManager.h"
+
+class IGeoSvc;
+namespace DD4hep {
+namespace DDSegmentation {
+class Segmentation;
+}
+}
+
+/** @class CellPositionsECalBarrelModuleThetaSegTool Reconstruction/RecFCCeeCalorimeter/src/components/CellPositionsECalBarrelModuleThetaSegTool.h
+ * CellPositionsECalBarrelModuleThetaSegTool.h
+ *
+ *  Tool to determine each Calorimeter cell position.
+ *
+ *   For the FCCee Barrel ECAL, determined from the placed volumes and the FCCSW theta-module segmentation.   
+ * 
+ *  @author Giovanni Marchiori
+ */
+
+class CellPositionsECalBarrelModuleThetaSegTool : public GaudiTool, virtual public ICellPositionsTool {
+public:
+  CellPositionsECalBarrelModuleThetaSegTool(const std::string& type, const std::string& name, const IInterface* parent);
+  ~CellPositionsECalBarrelModuleThetaSegTool() = default;
+
+  virtual StatusCode initialize() final;
+
+  virtual StatusCode finalize() final;
+
+  virtual void getPositions(const edm4hep::CalorimeterHitCollection& aCells, edm4hep::CalorimeterHitCollection& outputColl) final;
+
+  virtual dd4hep::Position xyzPosition(const uint64_t& aCellId) const final;
+
+  virtual int layerId(const uint64_t& aCellId) final;
+
+private:
+  /// Pointer to the geometry service
+  SmartIF<IGeoSvc> m_geoSvc;
+  /// Name of the electromagnetic calorimeter readout
+  Gaudi::Property<std::string> m_readoutName{this, "readoutName", "ECalBarrelModuleThetaMerged"};
+  /// Merged module-theta segmentation
+  dd4hep::DDSegmentation::FCCSWGridModuleThetaMerged* m_segmentation;
+  /// Cellid decoder
+  dd4hep::DDSegmentation::BitFieldCoder* m_decoder;
+  /// Volume manager
+  dd4hep::VolumeManager m_volman;
+};
+#endif /* RECCALORIMETER_CELLPOSITIONSECALBARRELMODULETHETASEGTOOL_H */