PixelDiodeMap.cxx

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/

// PixelDiodeMap.cxx
//   Implementation file for class PixelDiodeMap
// (c) ATLAS Pixel Detector software
// Version 4.2 14/08/2001 David Calvet
// Modified: Grant Gorfine
 
#include "ReadoutGeometryBase/PixelDiodeMap.h"
#include "ReadoutGeometryBase/PixelDiodeMatrix.h"
#include "ReadoutGeometryBase/SiCellId.h"
 
#include <algorithm>
#include <cmath>
#include <utility>
 
namespace InDetDD {
 
 
 
// Implicit constructor:
PixelDiodeMap::PixelDiodeMap(std::shared_ptr<const PixelDiodeMatrix> matrix) :
  m_matrix(std::move(matrix)),
  m_generalLayout(false) 
{
}
 
PixelDiodeMap::~PixelDiodeMap()
= default;
 
 
  SiCellId PixelDiodeMap::cellIdOfPosition(const Amg::Vector2D & localPos) const
{
  using std::abs;
  using Trk::distPhi;
  using Trk::distEta;
 
  // Check that we are in the bounds of the top level matrix
  // NB. edge is included in bounds.
 
  double halfWidth = 0.5*width();
  double halfLength = 0.5*length();
  if ( (abs(localPos[distPhi]) > halfWidth) || 
       (abs(localPos[distEta]) > halfLength) ) {
    return {}; // Invalid Id.
  }
 
  // position relative to bottom left corner.
  Amg::Vector2D relativePos = localPos + Amg::Vector2D(halfWidth, halfLength);
 
  // The cellId returned will be added to this so we must start with 0,0.
  SiCellId cellId(0,0);
 
  const PixelDiodeMatrix *cell = m_matrix->cellIdOfPosition(relativePos, cellId);
  // return invalid Id if there was a problem (don't expect this to be the case).
  if (cell==nullptr) {
    return {}; // Invalid id.
  } 
 
  return cellId;
  
}
 
  
// Get diodes parameters (position and size):
SiDiodesParameters
PixelDiodeMap::parameters(const SiCellId & cellId) const
{
 
  // Check we are in range
  
  if (!cellId.isValid() || 
      (cellId.phiIndex() < 0) || 
      (cellId.phiIndex() >= m_matrix->phiCells()) ||
      (cellId.etaIndex() < 0) ||
      (cellId.etaIndex() >= m_matrix->etaCells())) {
    return {};
  }
 
  //
  // Position is relative to left bottom corner.
  //
  Amg::Vector2D position;
  const PixelDiodeMatrix *cell = m_matrix->positionOfCell(cellId, position);
  if (cell != nullptr) {
    
    // get size
    Amg::Vector2D size(cell->phiWidth(), cell->etaWidth());
 
    // return parameters
    return SiDiodesParameters(position,size);
  }
 
  // return something in case of failure.
  return {};
}
 
void PixelDiodeMap::neighboursOfCell(const SiCellId & cellId,
                     std::vector<SiCellId> &neighbours) const
{
  neighbours.clear();
 
  if (!cellId.isValid()) return;
 
  // If non regular layout revert to slower method
  if (m_generalLayout) return neighboursOfCellGeneral(cellId, neighbours);
 
  neighbours.reserve(8);
  // neighbours easily determined from cell number
  // normally 8 neighbours 4 edge and 4 corners
  
  int phiIndex = cellId.phiIndex();
  int etaIndex = cellId.etaIndex();
 
  // M = minus
  // P = plus
  int phiM = phiIndex-1;
  int phiP = phiIndex+1;
  int etaM = etaIndex-1;
  int etaP = etaIndex+1;
 
  // -,0
  if (phiM >= 0)                                 neighbours.emplace_back(phiM,etaIndex);
  // -,-
  if (phiM >= 0 && etaM >= 0)                    neighbours.emplace_back(phiM,etaM);
  // 0,-
  if (etaM >= 0)                                 neighbours.emplace_back(phiIndex,etaM);
  // +,-
  if (phiP < phiDiodes() && etaM >= 0)           neighbours.emplace_back(phiP,etaM);
  // +,0
  if (phiP < phiDiodes())                        neighbours.emplace_back(phiP,etaIndex);
  // -,+
  if (phiM >= 0 && etaP < etaDiodes())           neighbours.emplace_back(phiM,etaP);
  // 0,+
  if (etaP < etaDiodes())                        neighbours.emplace_back(phiIndex,etaP);
  // +,+
  if (phiP < phiDiodes() && etaP < etaDiodes())  neighbours.emplace_back(phiP,etaP);
}
 
// Get the neighbouring PixelDiodes of a given PixelDiode:
// This will work for more complex layouts such as bricking. Probably never really needed but
// since the code was here I keep it available.
void PixelDiodeMap::neighboursOfCellGeneral(const SiCellId & cellId,
                        std::vector<SiCellId> &neighbours) const
{
  // extract the diode spatial parameters
  const SiDiodesParameters params=parameters(cellId);
  const SiLocalPosition diodeCenter=params.centre();
  const SiLocalPosition diodeSize=params.width();
  const double &centerColumn=diodeCenter.xColumn();
  const double &centerRow=diodeCenter.xRow();
  const double halfSizeColumn=diodeSize.xColumn()/2;
  const double halfSizeRow=diodeSize.xRow()/2;
 
  // parameter
  const double epsilon=0.01;
 
  // compute the points to check
  const double left1=centerColumn-halfSizeColumn*(1+epsilon);
  const double right1=centerColumn+halfSizeColumn*(1+epsilon);
  const double left2=centerColumn-halfSizeColumn*(1-epsilon);
  const double right2=centerColumn+halfSizeColumn*(1-epsilon);
  const double top1=centerRow+halfSizeRow*(1+epsilon);
  const double bot1=centerRow-halfSizeRow*(1+epsilon);
  const double top2=centerRow+halfSizeRow*(1-epsilon);
  const double bot2=centerRow-halfSizeRow*(1-epsilon);
 
  // build the list of positions to check
  std::vector<SiLocalPosition> positions;
  positions.reserve(12);
  SiLocalPosition position;
  position.xRow(bot1); position.xColumn(left2); positions.push_back(position);
  position.xRow(bot1); position.xColumn(left1); positions.push_back(position);
  position.xRow(bot2); position.xColumn(left1); positions.push_back(position);
  position.xRow(top2); position.xColumn(left1); positions.push_back(position);
  position.xRow(top1); position.xColumn(left1); positions.push_back(position);
  position.xRow(top1); position.xColumn(left2); positions.push_back(position);
  position.xRow(bot1); position.xColumn(right2); positions.push_back(position);
  position.xRow(bot1); position.xColumn(right1); positions.push_back(position);
  position.xRow(bot2); position.xColumn(right1); positions.push_back(position);
  position.xRow(top2); position.xColumn(right1); positions.push_back(position);
  position.xRow(top1); position.xColumn(right1); positions.push_back(position);
  position.xRow(top1); position.xColumn(right2); positions.push_back(position);
 
  // build the list of neighbours
  neighbours.reserve(8);
 
  // loop on all positions to check
  for(const auto & position : positions) {
 
    // get the PixelDiode for this position
    SiCellId cellId_neighb = cellIdOfPosition(position);
 
    if (cellId.isValid()) {
      // check if the diode is already in the list
      //bool found=false;
      std::vector<SiCellId>::const_iterator foundIter
    = std::find(neighbours.begin(), neighbours.end(), cellId_neighb );
 
      // If not found add this diode to the list
      if (foundIter ==  neighbours.end()) neighbours.push_back(cellId_neighb);
            
    } 
  }
}
 
 
// Compute the intersection length of two diodes:
double PixelDiodeMap::intersectionLength(const SiCellId &diode1,
                     const SiCellId &diode2) const
{ 
  if(!diode1.isValid() || !diode2.isValid()) return 0;
  // If non regular layout revert to slower method
  if (m_generalLayout) return intersectionLengthGeneral(diode1, diode2);
 
  const SiLocalPosition size = parameters(diode1).width();
 
  int phiIndexDelta = std::abs(diode1.phiIndex() - diode2.phiIndex());
  int etaIndexDelta = std::abs(diode1.etaIndex() - diode2.etaIndex());
 
  // Intersection length is just the length or width of the diode depending on which neighbour.
  if (phiIndexDelta == 1 && etaIndexDelta == 0) return size.xEta();
  if (phiIndexDelta == 0 && etaIndexDelta == 1) return size.xPhi();
  // Will return 0 if it is a corner neighbour or if its not a neighbour or if they are oth the same diode.
  return 0;
}
 
// Compute the intersection length of two diodes:
// This will work for more complex layouts such as bricking. Probably never really needed but
// since the code was here I keep it available.
double PixelDiodeMap::intersectionLengthGeneral(const SiCellId &diode1,
                        const SiCellId &diode2) const
 
{
  const SiDiodesParameters params1=parameters(diode1);
  const SiDiodesParameters params2=parameters(diode2);
  const SiLocalPosition center1=params1.centre();
  const SiLocalPosition center2=params2.centre();
  const SiLocalPosition size1=params1.width();
  const SiLocalPosition size2=params2.width();
  
  // compute intersection length on column direction
  const double intersectionColumn=intersectionLength1D(center1.xColumn(),
                      size1.xColumn(),
                      center2.xColumn(),
                      size2.xColumn());
  // compute intersection length on row direction
  const double intersectionRow=intersectionLength1D(center1.xRow(),
                       size1.xRow(),
                       center2.xRow(),
                       size2.xRow());
 
  // return the real intersection 
  // (if both directions intersect, there is a problem)
  if (intersectionColumn>0) {
    if (intersectionRow>0) return 0;
    return intersectionColumn;
  } else {
    return intersectionRow;
  }
}
 
// Compute the intersection length along one direction:
double PixelDiodeMap::intersectionLength1D(const double x1,const double dx1,
                       const double x2,const double dx2) 
{
  // compute distance between the two centers
  double distance=std::abs(x1-x2);
 
  // compute theoretical intersection
  double intersection=(dx1+dx2)/2-distance;
 
  // if intersection if negative, no intersection
  if (intersection<-1e-10) return intersection;
  else if (intersection<1e-10) return 0;
  else {
    // intersection cannot exceed size
    if (intersection>dx1) intersection=dx1;
    if (intersection>dx2) intersection=dx2;
    return intersection;
  }
}
 
} // namespace InDetDD