CaloSubdetectorTopology.cc

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#include "Geometry/CaloTopology/interface/CaloSubdetectorTopology.h"
#include <cassert>

std::vector<DetId> CaloSubdetectorTopology::getWindow(const DetId& id, const int& northSouthSize, const int& eastWestSize) const
{
  
  std::vector<DetId> cellsInWindow;
  // check pivot
  if (id.null())
    return cellsInWindow;

  //
  DetId myTmpId(id);
  std::vector<std::pair<Coordinate,DetId> > fringe;
  fringe.emplace_back(std::pair<Coordinate,DetId>(Coordinate(0,0),myTmpId));
  
  int halfWestEast = eastWestSize/2 ;
  int halfNorthSouth = northSouthSize/2 ;

  std::vector<CellInfo> visited_cells;
  visited_cells.resize(northSouthSize * eastWestSize);
  
  while (!fringe.empty())
    {
      std::pair<Coordinate,DetId> cur = fringe.back();
      fringe.pop_back();
      
      // check all four neighbours
      const CaloDirection directions[4] = { NORTH, SOUTH, EAST, WEST };
      
      for (auto direction : directions)
        {
          Coordinate neighbour = getNeighbourIndex(cur.first,direction);
      //If outside the window range
      if ( neighbour.first < -halfWestEast ||
           neighbour.first > halfWestEast ||
           neighbour.second < -halfNorthSouth ||
           neighbour.second > halfNorthSouth )
        continue;
      
      
      //Found integer index in the matrix
      unsigned int_index =  neighbour.first + halfWestEast +  
        eastWestSize * (neighbour.second + halfNorthSouth );
      assert(int_index < visited_cells.size());
      
          // check whether we have seen this neighbour already
          if (visited_cells[int_index].visited)
            // we have seen this one already
            continue;
              
          // a new cell, get the DetId of the neighbour, mark it
          // as visited and add it to the fringe
          visited_cells[int_index].visited = true;
      std::vector<DetId> neighbourCells = getNeighbours(cur.second,direction);

      if ( neighbourCells.size() == 1 )
        visited_cells[int_index].cell = neighbourCells[0];
      else if ( neighbourCells.empty() )
        visited_cells[int_index].cell = DetId(0);
      else
        throw cms::Exception("getWindowError") << "Not supported subdetector for getWindow method";
      
          if (!visited_cells[int_index].cell.null())
            fringe.emplace_back(std::pair<Coordinate,DetId>(neighbour,visited_cells[int_index].cell));
          
    } // loop over all possible directions
    } // while some cells are left on the fringe
  
  
  for (auto & visited_cell : visited_cells)
    if (!visited_cell.cell.null())
      cellsInWindow.emplace_back(visited_cell.cell);
  
  return cellsInWindow;
}