[u/mrichter/AliRoot.git] / TRD / AliTRDclusterizerV1.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/*
$Log$
Revision 1.1.4.1  2000/05/08 15:09:01  cblume
Introduce AliTRDdigitsManager

Revision 1.1  2000/02/28 18:58:54  cblume
Add new TRD classes

*/

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
// TRD cluster finder for the slow simulator. 
//                                                                           //
///////////////////////////////////////////////////////////////////////////////

#include <TF1.h>

#include "AliTRDclusterizerV1.h"
#include "AliTRDmatrix.h"
#include "AliTRDgeometry.h"
#include "AliTRDdigitizer.h"
#include "AliTRDrecPoint.h"
#include "AliTRDdataArrayF.h"

ClassImp(AliTRDclusterizerV1)

//_____________________________________________________________________________
AliTRDclusterizerV1::AliTRDclusterizerV1():AliTRDclusterizer()
{
  //
  // AliTRDclusterizerV1 default constructor
  //

  fDigitsManager = NULL;

}

//_____________________________________________________________________________
AliTRDclusterizerV1::AliTRDclusterizerV1(const Text_t* name, const Text_t* title)
                    :AliTRDclusterizer(name,title)
{
  //
  // AliTRDclusterizerV1 default constructor
  //

  fDigitsManager = new AliTRDdigitsManager();

  Init();

}

//_____________________________________________________________________________
AliTRDclusterizerV1::~AliTRDclusterizerV1()
{

  if (fDigitsManager) {
    delete fDigitsManager;
  }

}

//_____________________________________________________________________________
void AliTRDclusterizerV1::Init()
{
  //
  // Initializes the cluster finder
  //

  // The default parameter for the clustering
  fClusMaxThresh = 5.0;
  fClusSigThresh = 2.0;
  fClusMethod    = 1;

}

//_____________________________________________________________________________
Bool_t AliTRDclusterizerV1::ReadDigits()
{
  //
  // Reads the digits arrays from the input aliroot file
  //

  if (!fInputFile) {
    printf("AliTRDclusterizerV1::ReadDigits -- ");
    printf("No input file open\n");
    return kFALSE;
  }

  // Read in the digit arrays
  return (fDigitsManager->ReadDigits());  

}

//_____________________________________________________________________________
Bool_t AliTRDclusterizerV1::MakeCluster()
{
  //
  // Generates the cluster.
  //

  Int_t row, col, time;

  // Get the pointer to the detector class and check for version 1
  AliTRD *TRD = (AliTRD*) gAlice->GetDetector("TRD");
  if (TRD->IsVersion() != 1) {
    printf("AliTRDclusterizerV1::MakeCluster -- ");
    printf("TRD must be version 1 (slow simulator).\n");
    return kFALSE; 
  }

  // Get the geometry
  AliTRDgeometry *Geo = TRD->GetGeometry();

  printf("AliTRDclusterizerV1::MakeCluster -- ");
  printf("Start creating clusters.\n");

  AliTRDdataArrayI *Digits;

  // Parameters
  Float_t maxThresh        = fClusMaxThresh;   // threshold value for maximum
  Float_t signalThresh     = fClusSigThresh;   // threshold value for digit signal
  Int_t   clusteringMethod = fClusMethod;      // clustering method option (for testing)

  // Iteration limit for unfolding procedure
  const Float_t epsilon = 0.01;             

  const Int_t   nClus   = 3;  
  const Int_t   nSig    = 5;

  Int_t chamBeg = 0;
  Int_t chamEnd = kNcham;
  if (TRD->GetSensChamber() >= 0) {
    chamBeg = TRD->GetSensChamber();
    chamEnd = chamBeg + 1;
  }
  Int_t planBeg = 0;
  Int_t planEnd = kNplan;
  if (TRD->GetSensPlane()   >= 0) {
    planBeg = TRD->GetSensPlane();
    planEnd = planBeg + 1;
  }
  Int_t sectBeg = 0;
  Int_t sectEnd = kNsect;
  if (TRD->GetSensSector()  >= 0) {
    sectBeg = TRD->GetSensSector();
    sectEnd = sectBeg + 1;
  }

  // *** Start clustering *** in every chamber
  for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
    for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
      for (Int_t isect = sectBeg; isect < sectEnd; isect++) {

        Int_t idet = Geo->GetDetector(iplan,icham,isect);

        Int_t nClusters = 0;
        printf("AliTRDclusterizerV1::MakeCluster -- ");
        printf("Analyzing chamber %d, plane %d, sector %d.\n"
               ,icham,iplan,isect);

        Int_t   nRowMax  = Geo->GetRowMax(iplan,icham,isect);
        Int_t   nColMax  = Geo->GetColMax(iplan);
        Int_t   nTimeMax = Geo->GetTimeMax();

        // Create a detector matrix to keep maxima
        AliTRDmatrix *digitMatrix  = new AliTRDmatrix(nRowMax,nColMax,nTimeMax
                                                     ,isect,icham,iplan);
        // Create a matrix to contain maximum flags
        AliTRDmatrix *maximaMatrix = new AliTRDmatrix(nRowMax,nColMax,nTimeMax
                                                     ,isect,icham,iplan);

        // Read in the digits
        Digits = fDigitsManager->GetDigits(idet);

        // Loop through the detector pixel
        for (time = 0; time < nTimeMax; time++) {
          for ( col = 0;  col <  nColMax;  col++) {
            for ( row = 0;  row <  nRowMax;  row++) {

              Int_t signal = Digits->GetData(row,col,time);
              Int_t index  = Digits->GetIndex(row,col,time);

              // Fill the detector matrix
              if (signal > signalThresh) {
	        // Store the signal amplitude
                digitMatrix->SetSignal(row,col,time,signal);
	        // Store the digits number
                digitMatrix->AddTrack(row,col,time,index);
              }

	    }
	  }
	}

        // Loop chamber and find maxima in digitMatrix
        for ( row = 0;  row <  nRowMax;  row++) {
          for ( col = 1;  col <  nColMax;  col++) {
            for (time = 0; time < nTimeMax; time++) {

              if (digitMatrix->GetSignal(row,col,time) 
                  < digitMatrix->GetSignal(row,col - 1,time)) {
                // really maximum?
                if (col > 1) {
                  if (digitMatrix->GetSignal(row,col - 2,time)
                      < digitMatrix->GetSignal(row,col - 1,time)) {
                    // yes, so set maximum flag
                    maximaMatrix->SetSignal(row,col - 1,time,1);
                  }
                  else maximaMatrix->SetSignal(row,col - 1,time,0);
                }
              }

            }   // time
          }     // col
        }       // row

        // now check maxima and calculate cluster position
        for ( row = 0;  row <  nRowMax;  row++) {
          for ( col = 1;  col <  nColMax;  col++) {
            for (time = 0; time < nTimeMax; time++) {

              if ((maximaMatrix->GetSignal(row,col,time) > 0)
                  && (digitMatrix->GetSignal(row,col,time) > maxThresh)) {

                // Ratio resulting from unfolding
                Float_t ratio                =  0;    
                // Signals on max and neighbouring pads
                Float_t padSignal[nSig]      = {0};   
                // Signals from cluster
                Float_t clusterSignal[nClus] = {0};
                // Cluster pad info
                Float_t clusterPads[nClus]   = {0};   
                // Cluster digit info
                Int_t   clusterDigit[nClus]  = {0};

                for (Int_t iPad = 0; iPad < nClus; iPad++) {
                  clusterSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
                  clusterDigit[iPad]  = digitMatrix->GetTrack(row,col-1+iPad,time,0);
                }

                // neighbouring maximum on right side?
                if (col < nColMax - 2) {
                  if (maximaMatrix->GetSignal(row,col + 2,time) > 0) {

                    for (Int_t iPad = 0; iPad < 5; iPad++) {
                      padSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
                    }

                    // unfold:
                    ratio = Unfold(epsilon, padSignal);

                    // set signal on overlapping pad to ratio
                    clusterSignal[2] *= ratio;

                  }
                }
                
		// Calculate the position of the cluster
                switch (clusteringMethod) {
                case 1:
                  // method 1: simply center of mass
                  clusterPads[0] = row + 0.5;
                  clusterPads[1] = col - 0.5 + (clusterSignal[2] - clusterSignal[0]) /
                                   (clusterSignal[0] + clusterSignal[1] + clusterSignal[2]);
                  clusterPads[2] = time + 0.5;

                  nClusters++;
                  break;
                case 2:
                  // method 2: integral gauss fit on 3 pads
                  TH1F *hPadCharges = new TH1F("hPadCharges", "Charges on center 3 pads"
	                                                    , 5, -1.5, 3.5);
                  for (Int_t iCol = -1; iCol <= 3; iCol++) {
                    if (clusterSignal[iCol] < 1) clusterSignal[iCol] = 1;
                    hPadCharges->Fill(iCol, clusterSignal[iCol]);
                  }
                  hPadCharges->Fit("gaus", "IQ", "SAME", -0.5, 2.5);
                  TF1     *fPadChargeFit = hPadCharges->GetFunction("gaus");
                  Double_t  colMean = fPadChargeFit->GetParameter(1);

                  clusterPads[0] = row + 0.5;
                  clusterPads[1] = col - 1.5 + colMean;
                  clusterPads[2] = time + 0.5;

                  delete hPadCharges;

                  nClusters++;
                  break;
                }

                Float_t clusterCharge =   clusterSignal[0]
                                        + clusterSignal[1]
                                        + clusterSignal[2];

                // Add the cluster to the output array 
                TRD->AddRecPoint(clusterPads,clusterDigit,idet,clusterCharge);

              }
            }  // time
          }    // col
        }      // row

        printf("AliTRDclusterizerV1::MakeCluster -- ");
        printf("Number of clusters found: %d\n",nClusters);

        delete digitMatrix;
        delete maximaMatrix;

      }          // isect
    }            // iplan
  }              // icham

  printf("AliTRDclusterizerV1::MakeCluster -- ");
  printf("Total number of points found: %d\n"
        ,TRD->RecPoints()->GetEntries());

  // Get the pointer to the cluster branch
  TTree *ClusterTree = gAlice->TreeR(); 

  // Fill the cluster-branch
  printf("AliTRDclusterizerV1::MakeCluster -- ");
  printf("Fill the cluster tree.\n");
  ClusterTree->Fill();
  printf("AliTRDclusterizerV1::MakeCluster -- ");
  printf("Done.\n");

  return kTRUE;

}

//_____________________________________________________________________________
Float_t AliTRDclusterizerV1::Unfold(Float_t eps, Float_t* padSignal)
{
  //
  // Method to unfold neighbouring maxima.
  // The charge ratio on the overlapping pad is calculated
  // until there is no more change within the range given by eps.
  // The resulting ratio is then returned to the calling method.
  //

  Int_t   itStep            = 0;      // count iteration steps

  Float_t ratio             = 0.5;    // start value for ratio
  Float_t prevRatio         = 0;      // store previous ratio

  Float_t newLeftSignal[3]  = {0};    // array to store left cluster signal
  Float_t newRightSignal[3] = {0};    // array to store right cluster signal

  // start iteration:
  while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {

    itStep++;
    prevRatio = ratio;

    // cluster position according to charge ratio
    Float_t maxLeft  = (ratio*padSignal[2] - padSignal[0]) /
                       (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
    Float_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2]) /
                       ((1-ratio)*padSignal[2] + padSignal[3] + padSignal[4]);

    // set cluster charge ratio
    Float_t ampLeft  = padSignal[1];
    Float_t ampRight = padSignal[3];

    // apply pad response to parameters
    newLeftSignal[0] = ampLeft*PadResponse(-1 - maxLeft);
    newLeftSignal[1] = ampLeft*PadResponse( 0 - maxLeft);
    newLeftSignal[2] = ampLeft*PadResponse( 1 - maxLeft);

    newRightSignal[0] = ampRight*PadResponse(-1 - maxRight);
    newRightSignal[1] = ampRight*PadResponse( 0 - maxRight);
    newRightSignal[2] = ampRight*PadResponse( 1 - maxRight);

    // calculate new overlapping ratio
    ratio = newLeftSignal[2]/(newLeftSignal[2] + newRightSignal[0]);

  }

  return ratio;

}

//_____________________________________________________________________________
Float_t AliTRDclusterizerV1::PadResponse(Float_t x)
{
  //
  // The pad response for the chevron pads. 
  // We use a simple Gaussian approximation which should be good
  // enough for our purpose.
  //

  // The parameters for the response function
  const Float_t aa  =  0.8872;
  const Float_t bb  = -0.00573;
  const Float_t cc  =  0.454;
  const Float_t cc2 =  cc*cc;

  Float_t pr = aa * (bb + TMath::Exp(-x*x / (2. * cc2)));

  return (pr);

}
Commit	Line	Data
f7336fa3	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
	16	/*
	17	$Log$
6f1e466d	18	Revision 1.1.4.1 2000/05/08 15:09:01 cblume
	19	Introduce AliTRDdigitsManager
	20
c0dd96c3	21	Revision 1.1 2000/02/28 18:58:54 cblume
	22	Add new TRD classes
	23
f7336fa3	24	*/
	25
	26	///////////////////////////////////////////////////////////////////////////////
	27	// //
	28	// TRD cluster finder for the slow simulator.
	29	// //
	30	///////////////////////////////////////////////////////////////////////////////
	31
	32	#include <TF1.h>
	33
	34	#include "AliTRDclusterizerV1.h"
	35	#include "AliTRDmatrix.h"
	36	#include "AliTRDgeometry.h"
	37	#include "AliTRDdigitizer.h"
	38	#include "AliTRDrecPoint.h"
6f1e466d	39	#include "AliTRDdataArrayF.h"
f7336fa3	40
	41	ClassImp(AliTRDclusterizerV1)
	42
	43	//_____________________________________________________________________________
	44	AliTRDclusterizerV1::AliTRDclusterizerV1():AliTRDclusterizer()
	45	{
	46	//
	47	// AliTRDclusterizerV1 default constructor
	48	//
	49
6f1e466d	50	fDigitsManager = NULL;
f7336fa3	51
	52	}
	53
	54	//_____________________________________________________________________________
	55	AliTRDclusterizerV1::AliTRDclusterizerV1(const Text_t* name, const Text_t* title)
	56	:AliTRDclusterizer(name,title)
	57	{
	58	//
	59	// AliTRDclusterizerV1 default constructor
	60	//
	61
6f1e466d	62	fDigitsManager = new AliTRDdigitsManager();
f7336fa3	63
	64	Init();
	65
	66	}
	67
	68	//_____________________________________________________________________________
	69	AliTRDclusterizerV1::~AliTRDclusterizerV1()
	70	{
	71
6f1e466d	72	if (fDigitsManager) {
6f1e466d	73	delete fDigitsManager;
f7336fa3	74	}
	75
	76	}
	77
	78	//_____________________________________________________________________________
	79	void AliTRDclusterizerV1::Init()
	80	{
	81	//
	82	// Initializes the cluster finder
	83	//
	84
	85	// The default parameter for the clustering
	86	fClusMaxThresh = 5.0;
	87	fClusSigThresh = 2.0;
	88	fClusMethod = 1;
	89
	90	}
	91
	92	//_____________________________________________________________________________
	93	Bool_t AliTRDclusterizerV1::ReadDigits()
	94	{
	95	//
	96	// Reads the digits arrays from the input aliroot file
	97	//
	98
	99	if (!fInputFile) {
	100	printf("AliTRDclusterizerV1::ReadDigits -- ");
	101	printf("No input file open\n");
	102	return kFALSE;
	103	}
	104
f7336fa3	105	// Read in the digit arrays
6f1e466d	106	return (fDigitsManager->ReadDigits());
f7336fa3	107
	108	}
	109
	110	//_____________________________________________________________________________
	111	Bool_t AliTRDclusterizerV1::MakeCluster()
	112	{
	113	//
	114	// Generates the cluster.
	115	//
	116
	117	Int_t row, col, time;
	118
	119	// Get the pointer to the detector class and check for version 1
	120	AliTRD TRD = (AliTRD) gAlice->GetDetector("TRD");
	121	if (TRD->IsVersion() != 1) {
	122	printf("AliTRDclusterizerV1::MakeCluster -- ");
	123	printf("TRD must be version 1 (slow simulator).\n");
	124	return kFALSE;
	125	}
	126
	127	// Get the geometry
	128	AliTRDgeometry *Geo = TRD->GetGeometry();
	129
	130	printf("AliTRDclusterizerV1::MakeCluster -- ");
	131	printf("Start creating clusters.\n");
	132
6f1e466d	133	AliTRDdataArrayI *Digits;
f7336fa3	134
	135	// Parameters
	136	Float_t maxThresh = fClusMaxThresh; // threshold value for maximum
	137	Float_t signalThresh = fClusSigThresh; // threshold value for digit signal
	138	Int_t clusteringMethod = fClusMethod; // clustering method option (for testing)
	139
	140	// Iteration limit for unfolding procedure
	141	const Float_t epsilon = 0.01;
	142
	143	const Int_t nClus = 3;
	144	const Int_t nSig = 5;
	145
	146	Int_t chamBeg = 0;
	147	Int_t chamEnd = kNcham;
	148	if (TRD->GetSensChamber() >= 0) {
	149	chamBeg = TRD->GetSensChamber();
6f1e466d	150	chamEnd = chamBeg + 1;
f7336fa3	151	}
	152	Int_t planBeg = 0;
	153	Int_t planEnd = kNplan;
	154	if (TRD->GetSensPlane() >= 0) {
	155	planBeg = TRD->GetSensPlane();
	156	planEnd = planBeg + 1;
	157	}
	158	Int_t sectBeg = 0;
	159	Int_t sectEnd = kNsect;
	160	if (TRD->GetSensSector() >= 0) {
	161	sectBeg = TRD->GetSensSector();
	162	sectEnd = sectBeg + 1;
	163	}
	164
	165	// * Start clustering * in every chamber
	166	for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
	167	for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
	168	for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
	169
	170	Int_t idet = Geo->GetDetector(iplan,icham,isect);
	171
	172	Int_t nClusters = 0;
	173	printf("AliTRDclusterizerV1::MakeCluster -- ");
	174	printf("Analyzing chamber %d, plane %d, sector %d.\n"
	175	,icham,iplan,isect);
	176
	177	Int_t nRowMax = Geo->GetRowMax(iplan,icham,isect);
	178	Int_t nColMax = Geo->GetColMax(iplan);
	179	Int_t nTimeMax = Geo->GetTimeMax();
	180
	181	// Create a detector matrix to keep maxima
	182	AliTRDmatrix *digitMatrix = new AliTRDmatrix(nRowMax,nColMax,nTimeMax
	183	,isect,icham,iplan);
	184	// Create a matrix to contain maximum flags
	185	AliTRDmatrix *maximaMatrix = new AliTRDmatrix(nRowMax,nColMax,nTimeMax
	186	,isect,icham,iplan);
	187
	188	// Read in the digits
6f1e466d	189	Digits = fDigitsManager->GetDigits(idet);
f7336fa3	190
	191	// Loop through the detector pixel
	192	for (time = 0; time < nTimeMax; time++) {
	193	for ( col = 0; col < nColMax; col++) {
	194	for ( row = 0; row < nRowMax; row++) {
	195
	196	Int_t signal = Digits->GetData(row,col,time);
	197	Int_t index = Digits->GetIndex(row,col,time);
	198
	199	// Fill the detector matrix
	200	if (signal > signalThresh) {
	201	// Store the signal amplitude
	202	digitMatrix->SetSignal(row,col,time,signal);
	203	// Store the digits number
	204	digitMatrix->AddTrack(row,col,time,index);
	205	}
	206
	207	}
	208	}
	209	}
	210
	211	// Loop chamber and find maxima in digitMatrix
	212	for ( row = 0; row < nRowMax; row++) {
	213	for ( col = 1; col < nColMax; col++) {
	214	for (time = 0; time < nTimeMax; time++) {
	215
	216	if (digitMatrix->GetSignal(row,col,time)
	217	< digitMatrix->GetSignal(row,col - 1,time)) {
	218	// really maximum?
	219	if (col > 1) {
	220	if (digitMatrix->GetSignal(row,col - 2,time)
	221	< digitMatrix->GetSignal(row,col - 1,time)) {
	222	// yes, so set maximum flag
	223	maximaMatrix->SetSignal(row,col - 1,time,1);
	224	}
	225	else maximaMatrix->SetSignal(row,col - 1,time,0);
	226	}
	227	}
	228
	229	} // time
	230	} // col
	231	} // row
	232
	233	// now check maxima and calculate cluster position
	234	for ( row = 0; row < nRowMax; row++) {
	235	for ( col = 1; col < nColMax; col++) {
	236	for (time = 0; time < nTimeMax; time++) {
	237
	238	if ((maximaMatrix->GetSignal(row,col,time) > 0)
	239	&& (digitMatrix->GetSignal(row,col,time) > maxThresh)) {
	240
	241	// Ratio resulting from unfolding
	242	Float_t ratio = 0;
	243	// Signals on max and neighbouring pads
	244	Float_t padSignal[nSig] = {0};
	245	// Signals from cluster
	246	Float_t clusterSignal[nClus] = {0};
	247	// Cluster pad info
	248	Float_t clusterPads[nClus] = {0};
	249	// Cluster digit info
	250	Int_t clusterDigit[nClus] = {0};
	251
	252	for (Int_t iPad = 0; iPad < nClus; iPad++) {
	253	clusterSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
254	clusterDigit[iPad] = digitMatrix->GetTrack(row,col-1+iPad,time,0);
255	}
256
257	// neighbouring maximum on right side?
258	if (col < nColMax - 2) {
259	if (maximaMatrix->GetSignal(row,col + 2,time) > 0) {
260
261	for (Int_t iPad = 0; iPad < 5; iPad++) {
262	padSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
263	}
264
265	// unfold:
266	ratio = Unfold(epsilon, padSignal);
267
268	// set signal on overlapping pad to ratio
269	clusterSignal[2] *= ratio;
270
271	}
272	}
273
274	// Calculate the position of the cluster
275	switch (clusteringMethod) {
276	case 1:
277	// method 1: simply center of mass
278	clusterPads[0] = row + 0.5;
279	clusterPads[1] = col - 0.5 + (clusterSignal[2] - clusterSignal[0]) /
c0dd96c3	280	(clusterSignal[0] + clusterSignal[1] + clusterSignal[2]);
f7336fa3	281	clusterPads[2] = time + 0.5;
	282
	283	nClusters++;
	284	break;
	285	case 2:
	286	// method 2: integral gauss fit on 3 pads
	287	TH1F *hPadCharges = new TH1F("hPadCharges", "Charges on center 3 pads"
	288	, 5, -1.5, 3.5);
	289	for (Int_t iCol = -1; iCol <= 3; iCol++) {
	290	if (clusterSignal[iCol] < 1) clusterSignal[iCol] = 1;
	291	hPadCharges->Fill(iCol, clusterSignal[iCol]);
	292	}
	293	hPadCharges->Fit("gaus", "IQ", "SAME", -0.5, 2.5);
	294	TF1 *fPadChargeFit = hPadCharges->GetFunction("gaus");
	295	Double_t colMean = fPadChargeFit->GetParameter(1);
	296
	297	clusterPads[0] = row + 0.5;
	298	clusterPads[1] = col - 1.5 + colMean;
	299	clusterPads[2] = time + 0.5;
	300
	301	delete hPadCharges;
	302
	303	nClusters++;
	304	break;
	305	}
	306
	307	Float_t clusterCharge = clusterSignal[0]
	308	+ clusterSignal[1]
	309	+ clusterSignal[2];
	310
	311	// Add the cluster to the output array
	312	TRD->AddRecPoint(clusterPads,clusterDigit,idet,clusterCharge);
	313
	314	}
	315	} // time
	316	} // col
	317	} // row
	318
	319	printf("AliTRDclusterizerV1::MakeCluster -- ");
	320	printf("Number of clusters found: %d\n",nClusters);
	321
	322	delete digitMatrix;
	323	delete maximaMatrix;
	324
	325	} // isect
	326	} // iplan
	327	} // icham
	328
	329	printf("AliTRDclusterizerV1::MakeCluster -- ");
	330	printf("Total number of points found: %d\n"
	331	,TRD->RecPoints()->GetEntries());
	332
	333	// Get the pointer to the cluster branch
	334	TTree *ClusterTree = gAlice->TreeR();
	335
	336	// Fill the cluster-branch
	337	printf("AliTRDclusterizerV1::MakeCluster -- ");
	338	printf("Fill the cluster tree.\n");
	339	ClusterTree->Fill();
	340	printf("AliTRDclusterizerV1::MakeCluster -- ");
	341	printf("Done.\n");
	342
	343	return kTRUE;
	344
345	}
346
347	//_____________________________________________________________________________
348	Float_t AliTRDclusterizerV1::Unfold(Float_t eps, Float_t* padSignal)
349	{
350	//
351	// Method to unfold neighbouring maxima.
352	// The charge ratio on the overlapping pad is calculated
353	// until there is no more change within the range given by eps.
354	// The resulting ratio is then returned to the calling method.
355	//
356
357	Int_t itStep = 0; // count iteration steps
358
359	Float_t ratio = 0.5; // start value for ratio
360	Float_t prevRatio = 0; // store previous ratio
361
362	Float_t newLeftSignal[3] = {0}; // array to store left cluster signal
363	Float_t newRightSignal[3] = {0}; // array to store right cluster signal
364
365	// start iteration:
366	while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
367
368	itStep++;
369	prevRatio = ratio;
370
371	// cluster position according to charge ratio
372	Float_t maxLeft = (ratio*padSignal[2] - padSignal[0]) /
373	(padSignal[0] + padSignal[1] + ratio*padSignal[2]);
374	Float_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2]) /
375	((1-ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
376
377	// set cluster charge ratio
378	Float_t ampLeft = padSignal[1];
379	Float_t ampRight = padSignal[3];
380
381	// apply pad response to parameters
382	newLeftSignal[0] = ampLeft*PadResponse(-1 - maxLeft);
383	newLeftSignal[1] = ampLeft*PadResponse( 0 - maxLeft);
384	newLeftSignal[2] = ampLeft*PadResponse( 1 - maxLeft);
385
386	newRightSignal[0] = ampRight*PadResponse(-1 - maxRight);
387	newRightSignal[1] = ampRight*PadResponse( 0 - maxRight);
388	newRightSignal[2] = ampRight*PadResponse( 1 - maxRight);
389
390	// calculate new overlapping ratio
391	ratio = newLeftSignal[2]/(newLeftSignal[2] + newRightSignal[0]);
392
393	}
394
395	return ratio;
396
397	}
398
399	//_____________________________________________________________________________
400	Float_t AliTRDclusterizerV1::PadResponse(Float_t x)
401	{
402	//
403	// The pad response for the chevron pads.
404	// We use a simple Gaussian approximation which should be good
405	// enough for our purpose.
406	//
407
408	// The parameters for the response function
409	const Float_t aa = 0.8872;
410	const Float_t bb = -0.00573;
411	const Float_t cc = 0.454;
412	const Float_t cc2 = cc*cc;
413
414	Float_t pr = aa * (bb + TMath::Exp(-xx / (2. cc2)));
415
416	return (pr);
417
418	}