GeoRegion.cxx

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
#include "ISF_FastCaloGpu/GeoRegion.h"
#include <iostream>
 
#define M_PI 3.14159265358979323846
#define M_2PI 6.28318530717958647692
 
__HOSTDEV__ double Phi_mpi_pi( double x ) {
  while ( x >= M_PI ) x -= M_2PI;
  while ( x < -M_PI ) x += M_2PI;
  return x;
}
 
__HOSTDEV__ bool GeoRegion::index_range_adjust( int& ieta, int& iphi ) const {
  while ( iphi < 0 ) { iphi += m_cell_grid_phi; };
  while ( iphi >= m_cell_grid_phi ) { iphi -= m_cell_grid_phi; };
  if ( ieta < 0 ) {
    ieta = 0;
    return false;
  }
  if ( ieta >= m_cell_grid_eta ) {
    ieta = m_cell_grid_eta - 1;
    return false;
  }
  return true;
}
 
__HOSTDEV__ float GeoRegion::calculate_distance_eta_phi( const long long DDE, float eta, float phi, float& dist_eta0,
                                                         float& dist_phi0 ) const {
 
  dist_eta0           = ( eta - m_all_cells[DDE].eta() ) / m_deta_double;
  dist_phi0           = ( Phi_mpi_pi( phi - m_all_cells[DDE].phi() ) ) / m_dphi_double;
  float abs_dist_eta0 = abs( dist_eta0 );
  float abs_dist_phi0 = abs( dist_phi0 );
  return max( abs_dist_eta0, abs_dist_phi0 ) - 0.5;
}
 
__HOSTDEV__ long long GeoRegion::getDDE( float eta, float phi, float* distance, int* steps ) {
 
  float     dist;
  long long bestDDE = -1;
  if ( !distance ) distance = &dist;
  *distance    = +10000000;
  int intsteps = 0;
  if ( !steps ) steps = &intsteps;
 
  float best_eta_corr = m_eta_correction;
  float best_phi_corr = m_phi_correction;
 
  float raw_eta = eta + best_eta_corr;
  float raw_phi = phi + best_phi_corr;
 
  int ieta = raw_eta_position_to_index( raw_eta );
  int iphi = raw_phi_position_to_index( raw_phi );
  index_range_adjust( ieta, iphi );
 
  long long newDDE   = m_cells_g[ieta * m_cell_grid_phi + iphi];
  float     bestdist = +10000000;
  ++( *steps );
  int nsearch = 0;
  while ( ( newDDE >= 0 ) && nsearch < 3 ) {
    float dist_eta0, dist_phi0;
 
    *distance = calculate_distance_eta_phi( newDDE, eta, phi, dist_eta0, dist_phi0 );
 
    bestDDE  = newDDE;
    bestdist = *distance;
 
    if ( *distance < 0 ) return newDDE;
 
    // correct ieta and iphi by the observed difference to the hit cell
    ieta += round( dist_eta0 );
    iphi += round( dist_phi0 );
    index_range_adjust( ieta, iphi );
    long long oldDDE = newDDE;
    newDDE           = m_cells_g[ieta * m_cell_grid_phi + iphi];
    ++( *steps );
    ++nsearch;
    if ( oldDDE == newDDE ) break;
  }
  float minieta = ieta + floor( m_mineta_correction / cell_grid_eta() );
  float maxieta = ieta + ceil( m_maxeta_correction / cell_grid_eta() );
  float miniphi = iphi + floor( m_minphi_correction / cell_grid_phi() );
  float maxiphi = iphi + ceil( m_maxphi_correction / cell_grid_phi() );
  if ( minieta < 0 ) minieta = 0;
  if ( maxieta >= m_cell_grid_eta ) maxieta = m_cell_grid_eta - 1;
  for ( int iieta = minieta; iieta <= maxieta; ++iieta ) {
    for ( int iiphi = miniphi; iiphi <= maxiphi; ++iiphi ) {
      ieta = iieta;
      iphi = iiphi;
      index_range_adjust( ieta, iphi );
      newDDE = m_cells_g[ieta * m_cell_grid_phi + iphi];
      ++( *steps );
      if ( newDDE >= 0 ) {
        float dist_eta0, dist_phi0;
        *distance = calculate_distance_eta_phi( newDDE, eta, phi, dist_eta0, dist_phi0 );
 
        if ( *distance < 0 ) return newDDE;
        if ( *distance < bestdist ) {
          bestDDE  = newDDE;
          bestdist = *distance;
        }
      } else {
        printf( "GeoRegin::getDDE, windows search ieta=%d iphi=%d is empty\n", ieta, iphi );
      }
    }
  }
  *distance = bestdist;
  return bestDDE;
}