gFEXCompression.cxx

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
//***************************************************************************
//    gFEXCompression - Energy encoder/decoder for gFEX
//                              -------------------
//     begin                : 01 04 2021
//     email                : cecilia.tosciri@cern.ch
//***************************************************************************
#include "L1CaloFEXSim/gFEXCompression.h"
#include <cmath>
 
namespace LVL1 {
 
const int gFEXCompression::s_steps[] = {12800, 50, 25, 50, 100, 25600};//MeV
const int gFEXCompression::s_minET[] = {-101200, -50000, -12800, 12800, 51200, 200000};//MeV
const int gFEXCompression::s_minCode[] = {2, 6, 750, 1774, 2542, 4030};
 
 
unsigned int gFEXCompression::compress(float floatEt) {
 
    int Et = std::round(floatEt);
 
    // Check for overflow
    if (Et >= s_maxET) return s_LArOverflow;
 
    // Find which range the ET value is in
    int range = -1;
    for (unsigned int i = 0; i < s_nRanges; i++) {
        if (Et < s_minET[i]) break;
        range = i;
    }
 
    // Calculate code
    unsigned int code = 0;
 
    if (range < 0) {
        // Below minimum value
        code = s_LArUnderflow;
    }
    else {
        // Lies inside one of the value ranges
        int steps = (Et - s_minET[range])/s_steps[range];
        code = s_minCode[range] + steps;
    }
 
    return code;
}
 
int gFEXCompression::expand(unsigned int code) {
 
  // Deal with special codes first:
  if (code == s_NoData)  return 0;
  if (code == s_LArInvalid || (code > s_LArReserved_min && code < s_LArReserved_max) || code > s_LArMaxCode) return s_error;
  if (code == s_LArOverflow ) return s_maxET;

  int range = 0;
  for (unsigned int i = 0; i < s_nRanges-1; ++i) {
    if (code < (unsigned int)s_minCode[i+1]) break;
    range++;
  }
  int Et = s_minET[range] + (code-s_minCode[range])*s_steps[range];
 
  return Et;
}
 
 
unsigned int gFEXCompression::threshold(unsigned int code, int threshold) {

  unsigned int cut = gFEXCompression::compress(threshold);

  if (code < cut) code = 0;
 
  return code;
}
 
 
unsigned int gFEXCompression::linearize(unsigned int code, int threshold) {

  if (threshold < 0) threshold = 0;
  code = gFEXCompression::threshold(code, threshold);

  int Et = gFEXCompression::expand(code);
 
  // Check for overflow
  if (Et >= s_maxET) return s_gFEXOverflow;

  unsigned int gFexET = Et/s_gFEXstep;
  return gFexET;
}
 
} // end of namespace bracket