/data/doxygen/doxygen-1.7.3/gen/CMSSW_4_2_8/src/FastSimulation/ShowerDevelopment/src/HFShower.cc

Go to the documentation of this file.

//FastSimulation Headers
#include "FastSimulation/ShowerDevelopment/interface/HFShower.h"
//#include "FastSimulation/Utilities/interface/Histos.h"
#include "FastSimulation/Utilities/interface/RandomEngine.h"


// What's this?
//#include "FastSimulation/FamosCalorimeters/interface/FASTCalorimeter.h"

#include "FastSimulation/CaloHitMakers/interface/EcalHitMaker.h"
#include "FastSimulation/CaloHitMakers/interface/HcalHitMaker.h"

// CMSSW headers
#include "FWCore/MessageLogger/interface/MessageLogger.h"

// And This???? Doesn't seem to be needed
// #include "Calorimetry/CaloDetector/interface/CellGeometry.h"

#include <cmath>

// number attempts for transverse distribution if exit on a spec. condition
#define infinity 5000
// debugging flag ( 0, 1, 2, 3)
#define debug 0

using namespace edm;

HFShower::HFShower(const RandomEngine* engine,
                   HDShowerParametrization* myParam, 
                   EcalHitMaker* myGrid,
                   HcalHitMaker* myHcalHitMaker,
                   int onECAL,
                   double epart)
  : theParam(myParam), 
    theGrid(myGrid),
    theHcalHitMaker(myHcalHitMaker),
    onEcal(onECAL),
    e(epart),
    random(engine)
{ 
  // To get an access to constants read in FASTCalorimeter
  //  FASTCalorimeter * myCalorimeter= FASTCalorimeter::instance();

  // Values taken from FamosGeneric/FamosCalorimeter/src/FASTCalorimeter.cc
  lossesOpt       = myParam->hsParameters()->getHDlossesOpt();
  nDepthSteps     = myParam->hsParameters()->getHDnDepthSteps();
  nTRsteps        = myParam->hsParameters()->getHDnTRsteps();
  transParam      = myParam->hsParameters()->getHDtransParam();
  eSpotSize       = myParam->hsParameters()->getHDeSpotSize();
  depthStep       = myParam->hsParameters()->getHDdepthStep();
  criticalEnergy  = myParam->hsParameters()->getHDcriticalEnergy();
  maxTRfactor     = myParam->hsParameters()->getHDmaxTRfactor();
  balanceEH       = myParam->hsParameters()->getHDbalanceEH();
  hcalDepthFactor = myParam->hsParameters()->getHDhcalDepthFactor();
  

  // Special tr.size fluctuations 
  transParam *= (1. + random->flatShoot()); 

  // Special ad hoc long. extension + some fluctuations
  double   depthExt;
  if (e < 50.)   depthExt =  0.8 * (50.  - e) / 50.  + 0.3; 
  else { 
    if (e < 500.)  depthExt =  (500. - e) / 500. * 0.4 - 0.1; 
    else   depthExt =  -0.1; 
  }
  hcalDepthFactor += depthExt + 0.05 * (2.* random->flatShoot() - 1.);

  // normally 1, in HF - might be smaller to take into account
  // a narrowness of the HF shower (Cherenkov light) 
  if( e < 50. )  transFactor = 0.5 - (50.   - e ) / 50.  * 0.2; 
  else           transFactor = 0.7 - (1000. - e ) /1000. * 0.2;  

  // simple protection ...
  if(e < 0) e = 0.;

  // Get the Famos Histos pointer
  //  myHistos = FamosHistos::instance();
  //  std::cout << " Hello FamosShower " << std::endl;
  
  theECALproperties = theParam->ecalProperties();
  theHCALproperties = theParam->hcalProperties();

  double emax = theParam->emax(); 
  double emid = theParam->emid(); 
  double emin = theParam->emin(); 
  double effective = e;
    

  if( e < emid ) {
    theParam->setCase(1);
    // avoid "underflow" below Emin (for parameters calculation only)
    if(e < emin) effective = emin; 
  } 
  else 
    theParam->setCase(2);
 
  // A bit coarse espot size for HF...
  eSpotSize *= 2.5; 
  if(effective > 0.5 * emax) {
    eSpotSize *= 2.;
    if(effective > emax) {
      effective = emax; 
      eSpotSize *= 3.; 
      depthStep *= 2.;
     }
  }

  if(debug == 2 )
    LogDebug("FastCalorimetry") <<  " HFShower : " << std::endl 
         << "       Energy   "  <<               e << std::endl     
         << "      lossesOpt "  <<       lossesOpt << std::endl  
         << "    nDepthSteps "  <<     nDepthSteps << std::endl
         << "       nTRsteps "  <<        nTRsteps << std::endl
         << "     transParam "  <<      transParam << std::endl
         << "      eSpotSize "  <<       eSpotSize << std::endl
         << " criticalEnergy "  <<  criticalEnergy << std::endl
         << "    maxTRfactor "  <<     maxTRfactor << std::endl
         << "      balanceEH "  <<       balanceEH << std::endl
         << "hcalDepthFactor "  << hcalDepthFactor << std::endl;

  double alpEM1 = theParam->alpe1();
  double alpEM2 = theParam->alpe2();

  double betEM1 = theParam->bete1();
  double betEM2 = theParam->bete2();

  double alpHD1 = theParam->alph1();
  double alpHD2 = theParam->alph2();

  double betHD1 = theParam->beth1();
  double betHD2 = theParam->beth2();

  double part1 = theParam->part1();
  double part2 = theParam->part2();

  aloge = std::log(effective);
 
  double edpar = (theParam->e1() + aloge * theParam->e2()) * effective;
  double aedep = std::log(edpar);

  if(debug == 2)
    LogDebug("FastCalorimetry") << " HFShower : " << std::endl
         << "     edpar " <<   edpar << "   aedep " << aedep << std::endl 
         << "    alpEM1 " <<  alpEM1 << std::endl  
         << "    alpEM2 " <<  alpEM2 << std::endl  
         << "    betEM1 " <<  betEM1 << std::endl  
         << "    betEM2 " <<  betEM2 << std::endl  
         << "    alpHD1 " <<  alpHD1 << std::endl  
         << "    alpHD2 " <<  alpHD2 << std::endl  
         << "    betHD1 " <<  betHD1 << std::endl  
         << "    betHD2 " <<  betHD2 << std::endl  
         << "     part1 " <<   part1 << std::endl  
         << "     part2 " <<   part2 << std::endl; 

  // private members to set
  theR1  = theParam->r1();
  theR2  = theParam->r2();
  theR3  = theParam->r3();

  alpEM  = alpEM1 + alpEM2 * aedep;
  tgamEM = tgamma(alpEM);
  betEM  = betEM1 - betEM2 * aedep;
  alpHD  = alpHD1 + alpHD2 * aedep;
  tgamHD = tgamma(alpHD);
  betHD  = betHD1 - betHD2 * aedep;
  part   = part1  -  part2 * aedep;
  if(part > 1.) part = 1.;          // protection - just in case of 

  if(debug  == 2 )
    LogDebug("FastCalorimetry") << " HFShower : " << std::endl 
         << "    alpEM " <<  alpEM << std::endl  
         << "   tgamEM " << tgamEM << std::endl
         << "    betEM " <<  betEM << std::endl
         << "    alpHD " <<  alpHD << std::endl
         << "   tgamHD " << tgamHD << std::endl
         << "    betHD " <<  betHD << std::endl
         << "     part " <<   part << std::endl;
       

  if(onECAL){
    lambdaEM = theParam->ecalProperties()->interactionLength();
    x0EM     = theParam->ecalProperties()->radLenIncm();
  } 
  else {
    lambdaEM = 0.;
    x0EM     = 0.;
  }
  lambdaHD = theParam->hcalProperties()->interactionLength();
  x0HD     = theParam->hcalProperties()->radLenIncm();

  if(debug == 2)
    LogDebug("FastCalorimetry") << " HFShower e " << e        << std::endl
         << "          x0EM = " << x0EM     << std::endl 
         << "          x0HD = " << x0HD     << std::endl 
         << "         lamEM = " << lambdaEM << std::endl
         << "         lamHD = " << lambdaHD << std::endl;


  // Starting point of the shower
  // try first with ECAL lambda  

  double sum1   = 0.;  // lambda path from the ECAL/HF entrance;  
  double sum2   = 0.;  // lambda path from the interaction point;
  double sum3   = 0.;  // x0     path from the interaction point;
  int  nsteps   = 0;   // full number of longitudinal steps (counter);

  int nmoresteps;      // how many longitudinal steps in addition to 
                       // one (if interaction happens there) in ECAL
 

  if(e < criticalEnergy ) nmoresteps = 1;  
  else                    nmoresteps = nDepthSteps;
  
  double depthECAL  = 0.;
  double depthGAP   = 0.;
  double depthGAPx0 = 0.; 
  if(onECAL ) {
    depthECAL  = theGrid->ecalTotalL0();         // ECAL depth segment
    depthGAP   = theGrid->ecalHcalGapTotalL0();  // GAP  depth segment
    depthGAPx0 = theGrid->ecalHcalGapTotalX0();  // GAP  depth x0
  }
  
  double depthHCAL   = theGrid->hcalTotalL0();    // HCAL depth segment
  double depthToHCAL = depthECAL + depthGAP;    

  //---------------------------------------------------------------------------
  // Depth simulation & various protections, among them
  // if too deep - get flat random in the allowed region
  // if no HCAL material behind - force to deposit in ECAL
  double maxDepth    = depthToHCAL + depthHCAL - 1.1 * depthStep;

  double depthStart  = std::log(1./random->flatShoot()); // starting point lambda unts

  if(e < emin) {
    if(debug)
      LogDebug("FastCalorimetry") << " FamosHFShower : e <emin ->  depthStart = 0" << std::endl; 
    depthStart = 0.;
  }
 
  if(depthStart > maxDepth) {
    if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : depthStart too big ...   = " 
                   << depthStart << std::endl; 
    
    depthStart = maxDepth *  random->flatShoot();
    if( depthStart < 0.) depthStart = 0.;
    if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : depthStart re-calculated = " 
                   << depthStart << std::endl; 
  }
  
  if( onECAL && e < emid ) {
    if((depthECAL - depthStart)/depthECAL > 0.2 && depthECAL > depthStep ) {
      
      depthStart = 0.5 * depthECAL * random->flatShoot();
      if(debug) 
        LogDebug("FastCalorimetry") << " FamosHFShower : small energy, "
             << " depthStart reduced to = " << depthStart << std::endl; 
      
    }
  }

  if( depthHCAL < depthStep) {
    if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : depthHCAL  too small ... = " 
                   << depthHCAL << " depthStart -> forced to 0 !!!" 
                   << std::endl;
    depthStart = 0.;    
    nmoresteps = 0;
    
    if(depthECAL < depthStep) {
      nsteps = -1;
      LogInfo("FastCalorimetry") << " FamosHFShower : too small ECAL and HCAL depths - " 
           << " particle is lost !!! " << std::endl; 
    }
  }




  if(debug)
    LogDebug("FastCalorimetry") << " FamosHFShower  depths(lam) - "  << std::endl 
         << "          ECAL = " << depthECAL  << std::endl
         << "           GAP = " << depthGAP   << std::endl
         << "          HCAL = " << depthHCAL  << std::endl
         << "  starting point = " << depthStart << std::endl; 

  if( onEcal ) {
    if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : onECAL" << std::endl;
    if(depthStart < depthECAL) {
      if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : depthStart < depthECAL" << std::endl;
      if((depthECAL - depthStart)/depthECAL > 0.25 && depthECAL > depthStep) {
        if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : enough space to make ECAL step"
                       << std::endl;
        //  ECAL - one step
        nsteps++; 
        sum1   += depthECAL;             // at the end of step
        sum2   += depthECAL-depthStart; 
        sum3   += sum2 * lambdaEM / x0EM;
        lamtotal.push_back(sum1);
        lamdepth.push_back(sum2);
        lamcurr.push_back(lambdaEM);
        lamstep.push_back(depthECAL-depthStart);
        x0depth.push_back(sum3);
        x0curr.push_back(x0EM);
        detector.push_back(1);
        
        if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : " << " in ECAL sum1, sum2 "
                       << sum1 << " " << sum2 << std::endl;
        
        //                           // Gap - no additional step after ECAL
        //                           // just move further to HCAL over the gap
        sum1   += depthGAP;          
        sum2   += depthGAP; 
        sum3   += depthGAPx0;
      }
      // Just shift starting point to HCAL
      else { 
        //      cout << " FamosHFShower : not enough space to make ECAL step" << std::endl;
        if(debug)  LogDebug("FastCalorimetry") << " FamosHFShower : goto HCAL" << std::endl;

        depthStart = depthToHCAL;
        sum1 += depthStart;     
      }
    }
    else { // GAP or HCAL   
      
      if(depthStart >= depthECAL &&  depthStart < depthToHCAL ) {
      depthStart = depthToHCAL; // just a shift to HCAL for simplicity
      }
      sum1 += depthStart;

      if(debug) LogDebug("FastCalorimetry") << " FamosHFShower : goto HCAL" << std::endl;
    }
  }
  else {   // Forward 
    if(debug)  LogDebug("FastCalorimetry") << " FamosHFShower : forward" << std::endl;
    sum1 += depthStart;
  }
 
  for (int i = 0; i < nmoresteps ; i++) {
    sum1 += depthStep;
    if (sum1 > (depthECAL + depthGAP + depthHCAL)) break; 
    sum2 += depthStep;
    sum3 += sum2 * lambdaHD / x0HD;
    lamtotal.push_back(sum1);
    lamdepth.push_back(sum2);
    lamcurr.push_back(lambdaHD);
    lamstep.push_back(depthStep);
    x0depth.push_back(sum3);
    x0curr.push_back(x0HD);
    detector.push_back(3);
    nsteps++;
  }
  

  // Make fractions of energy and transverse radii at each step 

  // PV
  //  std::cout << "HFShower::HFShower() : Nsteps = " << nsteps << std::endl;

  if(nsteps > 0) { makeSteps(nsteps); }

}

void HFShower::makeSteps(int nsteps) {

  double sumes = 0.;
  double sum   = 0.;
  std::vector<double> temp;


  if(debug)
    LogDebug("FastCalorimetry") << " FamosHFShower::makeSteps - " 
       << " nsteps required : " << nsteps << std::endl;

  int count = 0;
  for (int i = 0; i < nsteps; i++) {    
    
    double deplam = lamdepth[i] - 0.5 * lamstep[i];
    double depx0  = x0depth[i]  - 0.5 * lamstep[i] / x0curr[i]; 
    double     x = betEM * depx0;
    double     y = betHD * deplam;
    
    if(debug == 2)
      LogDebug("FastCalorimetry") << " FamosHFShower::makeSteps " 
                                  << " - step " << i
                                  << "   depx0, x = " << depx0 << ", " << x 
                                  << "   deplam, y = " << deplam << ", "
                                  << y << std::endl;

    double est = (part * betEM * gam(x,alpEM) * lamcurr[i] /
                  (x0curr[i] * tgamEM) + 
                  (1.-part) * betHD * gam(y,alpHD) / tgamHD) * lamstep[i];
    
    // protection ...
    if(est < 0.) {
      LogDebug("FastCalorimetry") << "*** FamosHFShower::makeSteps " << " - negative step energy !!!" 
           << std::endl;
      est = 0.;
      break ; 
    }

    // for estimates only
    sum += est;
    int nPest = (int) (est * e / sum / eSpotSize) ;

    if(debug == 2)
      LogDebug("FastCalorimetry") << " FamosHFShower::makeSteps - nPoints estimate = " 
           <<  nPest << std::endl;

    if(nPest <= 1 && count !=0 ) break;

    // good step - to proceed

    temp.push_back(est);
    sumes += est;
    
    rlamStep.push_back(transParam * (theR1 + (theR2 - theR3 * aloge))
                       * deplam * transFactor); 
    count ++;
  }

  // fluctuations in ECAL and re-distribution of remaining energy in HCAL
  if(detector[0] == 1 && count > 1) {
    double oldECALenergy = temp[0];
    double oldHCALenergy = sumes - oldECALenergy ;
    double newECALenergy = 2. * sumes;
    for (int i = 0; newECALenergy > sumes && i < infinity; i++)
      newECALenergy = 2.* balanceEH * random->flatShoot() * oldECALenergy; 
     
    if(debug == 2)
      LogDebug("FastCalorimetry") << "*** FamosHFShower::makeSteps " << " ECAL fraction : old/new - "
           << oldECALenergy/sumes << "/" << newECALenergy/sumes << std::endl;

    temp[0] = newECALenergy;
    double newHCALenergy = sumes - newECALenergy;
    double newHCALreweight =  newHCALenergy / oldHCALenergy;

    for (int i = 1; i < count; i++) {
      temp[i] *= newHCALreweight;
    }
    
  }

  
  // final re-normalization of the energy fractions  
  double etot = 0.;
  for (int i = 0; i < count ; i++) {
    eStep.push_back(temp[i] * e / sumes );
    nspots.push_back((int)(eStep[i]/eSpotSize)+1);
    etot += eStep[i];

   if(debug)
     LogDebug("FastCalorimetry") << i << "  xO and lamdepth at the end of step = " 
          << x0depth[i] << " " 
          << lamdepth[i] << "   Estep func = " <<  eStep[i] 
          << "   Rstep = " << rlamStep[i] << "  Nspots = " <<  nspots[i]
          << std::endl; 

  }

  // The only step is in ECAL - let's make the size bigger ...  
  if(count == 1 and detector[0] == 1) rlamStep[0] *= 2.;


  if(debug) {
    if(eStep[0] > 0.95 * e && detector[0] == 1) 
      LogDebug("FastCalorimetry") << " FamosHFShower::makeSteps - " << "ECAL energy = " << eStep[0]
           << " out of total = " << e << std::endl;  
  }

}

bool HFShower::compute() {
  
  //  TimeMe theT("FamosHFShower::compute");

  bool status = false;
  int numLongit = eStep.size();
  if(debug)
    LogDebug("FastCalorimetry") << " FamosHFShower::compute - " 
            << " N_long.steps required : " << numLongit << std::endl;

  if(numLongit > 0) {

    status = true;    
    // Prepare the trsanverse probability function
    std::vector<double> Fhist;
    std::vector<double> rhist; 
    for (int j = 0; j < nTRsteps + 1; j++) {
      rhist.push_back(maxTRfactor * j / nTRsteps );  
      Fhist.push_back(transProb(maxTRfactor,1.,rhist[j]));
      if(debug == 3) 
        LogDebug("FastCalorimetry") << "indexFinder - i, Fhist[i] = " << j << " " << Fhist[j] << std::endl;
    }
    
    //================================================================
    // Longitudinal steps
    //================================================================
    for (int i = 0; i < numLongit ; i++) {
      
      double currentDepthL0 = lamtotal[i] - 0.5 * lamstep[i];
      // vary the longitudinal profile if needed
      if(detector[i] != 1) currentDepthL0 *= hcalDepthFactor;                     
      if(debug)
        LogDebug("FastCalorimetry") << " FamosHFShower::compute - detector = "
                                    << detector[i]
                                    << "  currentDepthL0 = " 
                                    << currentDepthL0 << std::endl;

      double maxTRsize   = maxTRfactor * rlamStep[i];     // in lambda units
      double rbinsize    = maxTRsize / nTRsteps; 
      double espot       = eStep[i] / (double)nspots[i];  // re-adjust espot

      if( espot > 4. || espot < 0. ) 
        LogDebug("FastCalorimetry") << " FamosHFShower::compute - unphysical espot = " 
             << espot << std::endl;

      int ecal = 0;
      if(detector[i] != 1) { 
        bool setHDdepth = theHcalHitMaker->setDepth(currentDepthL0);
        
        if(debug)
          LogDebug("FastCalorimetry") << " FamosHFShower::compute - status of " 
               << " theHcalHitMaker->setDepth(currentDepthL0) is " 
               << setHDdepth << std::endl;
        
        if(!setHDdepth) 
          {
            currentDepthL0 -= lamstep[i];
            setHDdepth =  theHcalHitMaker->setDepth(currentDepthL0);
          }
        if(!setHDdepth) continue;
        
        theHcalHitMaker->setSpotEnergy(espot);        
      }
      else {

        ecal = 1;
        bool status = theGrid->getPads(currentDepthL0);   
        
        if(debug)
          LogDebug("FastCalorimetry") << " FamosHFShower::compute - status of Grid = " 
               << status << std::endl;
        
        if(!status) continue; 

        theGrid->setSpotEnergy(espot);
      }  


      //------------------------------------------------------------
      // Transverse distribution
      //------------------------------------------------------------
      int nok   = 0;                          // counter of OK  
      int count = 0;
      int inf   = infinity;
      if(lossesOpt) inf = nspots[i];          // losses are enabled, otherwise
      // only OK points are counted ...

      // Total energy in this layer
      double eremaining = eStep[i];
      bool converged    = false;

      while (eremaining > 0. && !converged && count<infinity ) {

        ++count;

        // energy spot  (HFL)
        double newespot =  espot;       

        // We need to know a priori if this energy spot if for
        // a long (1) or short (2) fiber

        unsigned layer = 1;
        if( currentDepthL0 < 1.3 ) // first 22 cm = 1.3 lambda - only HFL
          layer = 1;
        else  
          layer = random->flatShoot() < 0.5 ? 1 : 2;

        if ( layer == 2 ) newespot = 2. * espot;

        if ( eremaining - newespot < 0. ) newespot = eremaining;

        // process transverse distribution
        
        double prob   = random->flatShoot();
        int index     = indexFinder(prob,Fhist);
        double radius = rlamStep[i] * rhist[index] +
          random->flatShoot() * rbinsize; // in-bin  
        double phi = 2.*M_PI*random->flatShoot();
        
        if(debug == 2)
          LogDebug("FastCalorimetry") << std::endl << " FamosHFShower::compute " << " r = " << radius 
               << "    phi = " << phi << std::endl;

        // add hit
        
        theHcalHitMaker->setSpotEnergy(newespot);
        theGrid->setSpotEnergy(newespot);
        
        bool result;
        if(ecal) {                                 
          result = theGrid->addHit(radius,phi,0);  // shouldn't get here !
          
          if(debug == 2)
            LogDebug("FastCalorimetry") << " FamosHFShower::compute - " 
                 << " theGrid->addHit result = " 
                 << result << std::endl;

        }
        else {
          // PV assign espot to long/short fibers
          result = theHcalHitMaker->addHit(radius,phi,layer);

          if(debug == 2)
            LogDebug("FastCalorimetry") << " FamosHFShower::compute - " 
                 << " theHcalHitMaker->addHit result = " 
                 << result << std::endl;

        }    

        if (result) {
          ++nok;
          eremaining -= newespot;
          if ( eremaining <= 0. ) converged = true;
          //      std::cout << "Transverse : " << nok << " "
          //                << " , E= "     << newespot
          //                << " , Erem = " << eremaining 
          //                << std::endl;
        } else {
          //      std::cout << "WARNING : hit not added" << std::endl;
        }
      }

    // end of tranverse simulation
    //-----------------------------------------------------

      if(count == infinity) { 
        status = false; 
        if(debug)
          LogDebug("FastCalorimetry") << "*** FamosHFShower::compute " << " maximum number of" 
               << " transverse points " << count << " is used !!!" << std::endl; 
        break;
      }

      if(debug)
        LogDebug("FastCalorimetry") << " FamosHFShower::compute " << " long.step No." << i 
             << "   Ntry, Nok = " << count
             << " " << nok << std::endl; 
      
    } // end of longitudinal steps
  } // end of no steps
  return status;

}

int HFShower::indexFinder(double x, const std::vector<double> & Fhist) {
  // binary search in the vector of doubles
  int size = Fhist.size();

  int curr = size / 2;
  int step = size / 4;
  int iter;
  int prevdir = 0; 
  int actudir = 0; 

  for (iter = 0; iter < size ; iter++) {

    if( curr >= size || curr < 1 )
      LogWarning("FastCalorimetry") << " FamosHFShower::indexFinder - wrong current index = " 
           << curr << " !!!" << std::endl;

    if ((x <= Fhist[curr]) && (x > Fhist[curr-1])) break;
    prevdir = actudir;
    if(x > Fhist[curr]) {actudir =  1;}
    else                {actudir = -1;}
    if(prevdir * actudir < 0) { if(step > 1) step /= 2;}
    curr += actudir * step;
    if(curr > size) curr = size;
    else { if(curr < 1) {curr = 1;}}
 
    if(debug == 3)
      LogDebug("FastCalorimetry") << " indexFinder - end of iter." << iter 
           << " curr, F[curr-1], F[curr] = "
           << curr << " " << Fhist[curr-1] << " " << Fhist[curr] << std::endl;
    
  }

  if(debug == 3)
    LogDebug("FastCalorimetry") << " indexFinder x = " << x << "  found index = " << curr-1
         << std::endl;


  return curr-1;
}