[u/mrichter/AliRoot.git] / FMD / AliFMDReconstructor.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.                  *
 **************************************************************************/
/* $Id$ */
/** @file    AliFMDReconstructor.cxx
    @author  Christian Holm Christensen <cholm@nbi.dk>
    @date    Mon Mar 27 12:47:09 2006
    @brief   FMD reconstruction 
*/
//____________________________________________________________________
//
// This is a class that constructs AliFMDMult (reconstructed
// multiplicity) from of Digits
//
// This class reads either digits from a TClonesArray or raw data from
// a DDL file (or similar), and stores the read ADC counts in an
// internal cache (fAdcs). 
//
//-- Authors: Evgeny Karpechev(INR) and Alla Maevsksia
//  Latest changes by Christian Holm Christensen <cholm@nbi.dk>
//
//
//____________________________________________________________________

#include <AliLog.h>                        // ALILOG_H
#include <AliRun.h>                        // ALIRUN_H
#include <AliRunLoader.h>                  // ALIRUNLOADER_H
#include <AliLoader.h>                     // ALILOADER_H
#include <AliHeader.h>                     // ALIHEADER_H
#include <AliRawReader.h>                  // ALIRAWREADER_H
#include <AliGenEventHeader.h>             // ALIGENEVENTHEADER_H
#include "AliFMD.h"         		   // ALIFMD_H
#include "AliFMDGeometry.h"                // ALIFMDGEOMETRY_H
#include "AliFMDParameters.h"              // ALIFMDPARAMETERS_H
#include "AliFMDDetector.h"                // ALIFMDDETECTOR_H
#include "AliFMDRing.h"                    // ALIFMDRING_H
#include "AliFMDDigit.h"                   // ALIFMDDIGIT_H
#include "AliFMDReconstructor.h"           // ALIFMDRECONSTRUCTOR_H
#include "AliFMDRawStream.h"               // ALIFMDRAWSTREAM_H
#include "AliFMDRawReader.h"               // ALIFMDRAWREADER_H
#include "AliFMDRecPoint.h"	   	   // ALIFMDMULTNAIIVE_H
#include "AliESD.h"			   // ALIESD_H
#include <AliESDFMD.h>			   // ALIESDFMD_H
#include <TFile.h>

//____________________________________________________________________
ClassImp(AliFMDReconstructor)
#if 0
  ; // This is here to keep Emacs for indenting the next line
#endif

//____________________________________________________________________
AliFMDReconstructor::AliFMDReconstructor() 
  : AliReconstructor(),
    fMult(0x0), 
    fNMult(0),
    fTreeR(0x0),
    fCurrentVertex(0),
    fESDObj(0x0),
    fESD(0x0)
{
  // Make a new FMD reconstructor object - default CTOR.  
}
  

//____________________________________________________________________
AliFMDReconstructor::AliFMDReconstructor(const AliFMDReconstructor& other) 
  : AliReconstructor(), 
    fMult(other.fMult),
    fNMult(other.fNMult),
    fTreeR(other.fTreeR),
    fCurrentVertex(other.fCurrentVertex),
    fESDObj(other.fESDObj),
    fESD(other.fESD)
{
  // Copy constructor 
}
  

//____________________________________________________________________
AliFMDReconstructor&
AliFMDReconstructor::operator=(const AliFMDReconstructor& other) 
{
  // Assignment operator
  fMult   = other.fMult;
  fNMult = other.fNMult;
  fTreeR = other.fTreeR;
  fCurrentVertex = other.fCurrentVertex;
  fESDObj = other.fESDObj;
  fESD = other.fESD;
  return *this;
}

//____________________________________________________________________
AliFMDReconstructor::~AliFMDReconstructor() 
{
  // Destructor 
  if (fMult)   fMult->Delete();
  if (fMult)   delete fMult;
  if (fESDObj) delete fESDObj;
}

//____________________________________________________________________
void 
AliFMDReconstructor::Init(AliRunLoader* runLoader) 
{
  // Initialize the reconstructor 
  AliDebug(1, Form("Init called with runloader 0x%x", runLoader));
  // Initialize the geometry 
  AliFMDGeometry* geom = AliFMDGeometry::Instance();
  geom->Init();
  geom->InitTransformations();

  // Initialize the parameters
  AliFMDParameters* param = AliFMDParameters::Instance();
  param->Init();
  
  // Current vertex position
  fCurrentVertex = 0;
  // Create array of reconstructed strip multiplicities 
  fMult = new TClonesArray("AliFMDRecPoint", 51200);
  // Create ESD output object 
  fESDObj = new AliESDFMD;
  
  // Check that we have a run loader
  if (!runLoader) { 
    Warning("Init", "No run loader");
    return;
  }

  // Check if we can get the header tree 
  AliHeader* header = runLoader->GetHeader();
  if (!header) {
    Warning("Init", "No header");
    return;
  }

  // Check if we can get a simulation header 
  AliGenEventHeader* eventHeader = header->GenEventHeader();
  if (eventHeader) {
    TArrayF vtx;
    eventHeader->PrimaryVertex(vtx);
    fCurrentVertex = vtx[2];
    AliDebug(1, Form("Primary vertex Z coordinate for event # %d/%d is %f", 
		     header->GetRun(), header->GetEvent(), fCurrentVertex));
    Warning("Init", "no generator event header");
  }
  else {
    Warning("Init", "No generator event header - "
	    "perhaps we get the vertex from ESD?");
  }
}

//____________________________________________________________________
void 
AliFMDReconstructor::ConvertDigits(AliRawReader* reader, 
				   TTree* digitsTree) const
{
  // Convert Raw digits to AliFMDDigit's in a tree 
  AliDebug(1, "Reading raw data into digits tree");
  AliFMDRawReader rawRead(reader, digitsTree);
  // rawRead.SetSampleRate(fFMD->GetSampleRate());
  rawRead.Exec();
}

//____________________________________________________________________
void 
AliFMDReconstructor::Reconstruct(TTree* digitsTree, 
				 TTree* clusterTree) const 
{
  // Reconstruct event from digits in tree 
  // Get the FMD branch holding the digits. 
  // FIXME: The vertex may not be known yet, so we may have to move
  // some of this to FillESD. 
  AliDebug(1, "Reconstructing from digits in a tree");
#if 1
  if (fESD) {
    const AliESDVertex* vertex = fESD->GetVertex();
    if (vertex) {
      AliDebug(1, Form("Got vertex from ESD: %f", vertex->GetZv()));
      fCurrentVertex = vertex->GetZv();
    }
  }
#endif  
  TBranch *digitBranch = digitsTree->GetBranch("FMD");
  if (!digitBranch) {
    Error("Exec", "No digit branch for the FMD found");
    return;
  }
  TClonesArray* digits = new TClonesArray("AliFMDDigit");
  digitBranch->SetAddress(&digits);

  if (fMult)   fMult->Clear();
  if (fESDObj) fESDObj->Clear();
  
  fNMult = 0;
  fTreeR = clusterTree;
  fTreeR->Branch("FMD", &fMult);
  
  AliDebug(5, "Getting entry 0 from digit branch");
  digitBranch->GetEntry(0);
  
  AliDebug(5, "Processing digits");
  ProcessDigits(digits);

  Int_t written = clusterTree->Fill();
  AliDebug(10, Form("Filled %d bytes into cluster tree", written));
  digits->Delete();
  delete digits;
}
 

//____________________________________________________________________
void
AliFMDReconstructor::ProcessDigits(TClonesArray* digits) const
{
  // For each digit, find the pseudo rapdity, azimuthal angle, and
  // number of corrected ADC counts, and pass it on to the algorithms
  // used. 
  Int_t nDigits = digits->GetEntries();
  AliDebug(1, Form("Got %d digits", nDigits));
  for (Int_t i = 0; i < nDigits; i++) {
    AliFMDDigit* digit = static_cast<AliFMDDigit*>(digits->At(i));
    AliFMDParameters* param  = AliFMDParameters::Instance();
    // Check that the strip is not marked as dead 
    if (param->IsDead(digit->Detector(), digit->Ring(), 
		      digit->Sector(), digit->Strip())) continue;

    // digit->Print();
    // Get eta and phi 
    Float_t eta, phi;
    PhysicalCoordinates(digit, eta, phi);
    
    // Substract pedestal. 
    UShort_t counts   = SubtractPedestal(digit);
    
    // Gain match digits. 
    Double_t edep     = Adc2Energy(digit, eta, counts);
    
    // Make rough multiplicity 
    Double_t mult     = Energy2Multiplicity(digit, edep);
    
    AliDebug(10, Form("FMD%d%c[%2d,%3d]: "
		      "ADC: %d, Counts: %d, Energy: %f, Mult: %f", 
		      digit->Detector(), digit->Ring(), digit->Sector(),
		      digit->Strip(), digit->Counts(), counts, edep, mult));
    
    // Create a `RecPoint' on the output branch. 
    AliFMDRecPoint* m = 
      new ((*fMult)[fNMult]) AliFMDRecPoint(digit->Detector(), 
					    digit->Ring(), 
					    digit->Sector(),
					    digit->Strip(),
					    eta, phi, 
					    edep, mult);
    (void)m; // Suppress warnings about unused variables. 
    fNMult++;

    fESDObj->SetMultiplicity(digit->Detector(), digit->Ring(), 
			     digit->Sector(),  digit->Strip(), mult);
    fESDObj->SetEta(digit->Detector(), digit->Ring(), 
		    digit->Sector(),  digit->Strip(), eta);
  }
}

//____________________________________________________________________
UShort_t
AliFMDReconstructor::SubtractPedestal(AliFMDDigit* digit) const
{
  // Member function to subtract the pedestal from a digit
  // This implementation does nothing, but a derived class could over
  // load this to subtract a pedestal that was given in a database or
  // something like that. 

  Int_t             counts = 0;
  AliFMDParameters* param  = AliFMDParameters::Instance();
  Float_t           pedM   = param->GetPedestal(digit->Detector(), 
						digit->Ring(), 
						digit->Sector(), 
						digit->Strip());
  AliDebug(10, Form("Subtracting pedestal %f from signal %d", 
		   pedM, digit->Counts()));
  if (digit->Count3() > 0)      counts = digit->Count3();
  else if (digit->Count2() > 0) counts = digit->Count2();
  else                          counts = digit->Count1();
  counts = TMath::Max(Int_t(counts - pedM), 0);
  if (counts > 0) AliDebug(10, "Got a hit strip");
  
  return  UShort_t(counts);
}

//____________________________________________________________________
Float_t
AliFMDReconstructor::Adc2Energy(AliFMDDigit* digit, 
				Float_t      /* eta */, 
				UShort_t     count) const
{
  // Converts number of ADC counts to energy deposited. 
  // Note, that this member function can be overloaded by derived
  // classes to do strip-specific look-ups in databases or the like,
  // to find the proper gain for a strip. 
  // 
  // In this simple version, we calculate the energy deposited as 
  // 
  //    EnergyDeposited = cos(theta) * gain * count
  // 
  // where 
  // 
  //           Pre_amp_MIP_Range
  //    gain = ----------------- * Energy_deposited_per_MIP
  //           ADC_channel_size    
  // 
  // is constant and the same for all strips.

  // Double_t theta = 2 * TMath::ATan(TMath::Exp(-eta));
  // Double_t edep  = TMath::Abs(TMath::Cos(theta)) * fGain * count;
  AliFMDParameters* param = AliFMDParameters::Instance();
  Float_t           gain  = param->GetPulseGain(digit->Detector(), 
						digit->Ring(), 
						digit->Sector(), 
						digit->Strip());
  Double_t          edep  = count * gain;
  AliDebug(10, Form("Converting counts %d to energy via factor %f", 
		    count, gain));
  return edep;
}

//____________________________________________________________________
Float_t
AliFMDReconstructor::Energy2Multiplicity(AliFMDDigit* /* digit */, 
					 Float_t      edep) const
{
  // Converts an energy signal to number of particles. 
  // Note, that this member function can be overloaded by derived
  // classes to do strip-specific look-ups in databases or the like,
  // to find the proper gain for a strip. 
  // 
  // In this simple version, we calculate the multiplicity as 
  // 
  //   multiplicity = Energy_deposited / Energy_deposited_per_MIP
  // 
  // where 
  //
  //   Energy_deposited_per_MIP = 1.664 * SI_density * SI_thickness 
  // 
  // is constant and the same for all strips 
  AliFMDParameters* param   = AliFMDParameters::Instance();
  Double_t          edepMIP = param->GetEdepMip();
  Float_t           mult    = edep / edepMIP;
  if (edep > 0) 
    AliDebug(10, Form("Translating energy %f to multiplicity via "
		     "divider %f->%f", edep, edepMIP, mult));
  return mult;
}

//____________________________________________________________________
void
AliFMDReconstructor::PhysicalCoordinates(AliFMDDigit* digit, 
					 Float_t& eta, 
					 Float_t& phi) const
{
  // Get the eta and phi of a digit 
  // 
  // Get geometry. 
  AliFMDGeometry* geom = AliFMDGeometry::Instance();
  Double_t x, y, z, r, theta;
  geom->Detector2XYZ(digit->Detector(), digit->Ring(), digit->Sector(), 
		    digit->Strip(), x, y, z);
  // Correct for vertex offset. 
  z     += fCurrentVertex;
  phi   =  TMath::ATan2(y, x);
  r     =  TMath::Sqrt(y * y + x * x);
  theta =  TMath::ATan2(r, z);
  eta   = -TMath::Log(TMath::Tan(theta / 2));
}

      
//____________________________________________________________________
void 
AliFMDReconstructor::FillESD(TTree*  /* digitsTree */, 
			     TTree*  /* clusterTree */,
			     AliESD* esd) const
{
  // nothing to be done
  // FIXME: The vertex may not be known when Reconstruct is executed,
  // so we may have to move some of that member function here. 
  AliDebug(1, Form("Calling FillESD with two trees and one ESD"));
  // fESDObj->Print();

  if (esd) { 
    AliDebug(1, Form("Writing FMD data to ESD tree"));
    esd->SetFMDData(fESDObj);
  }
}


//____________________________________________________________________
void 
AliFMDReconstructor::Reconstruct(AliRawReader*,TTree*) const 
{
  // Cannot be used.  See member function with same name but with 2
  // TTree arguments.   Make sure you do local reconstrucion 
  AliDebug(1, Form("Calling FillESD with loader and tree"));
  AliError("MayNotUse");
}
//____________________________________________________________________
void 
AliFMDReconstructor::Reconstruct(AliRunLoader*) const 
{
  // Cannot be used.  See member function with same name but with 2
  // TTree arguments.   Make sure you do local reconstrucion 
  AliDebug(1, Form("Calling FillESD with loader"));
  AliError("MayNotUse");
}
//____________________________________________________________________
void 
AliFMDReconstructor::Reconstruct(AliRunLoader*, AliRawReader*) const 
{
  // Cannot be used.  See member function with same name but with 2
  // TTree arguments.   Make sure you do local reconstrucion 
  AliDebug(1, Form("Calling FillESD with loader and raw reader"));
  AliError("MayNotUse");
}
//____________________________________________________________________
void 
AliFMDReconstructor::FillESD(AliRawReader*,TTree*,AliESD*) const 
{
  // Cannot be used.  See member function with same name but with 2
  // TTree arguments.   Make sure you do local reconstrucion 
  AliDebug(1, Form("Calling FillESD with raw reader, tree, and ESD"));
  AliError("MayNotUse");
}
//____________________________________________________________________
void 
AliFMDReconstructor::FillESD(AliRunLoader*,AliESD*) const
{
  // Cannot be used.  See member function with same name but with 2
  // TTree arguments.   Make sure you do local reconstrucion 
  AliDebug(1, Form("Calling FillESD with loader and ESD"));
  AliError("MayNotUse");
}
//____________________________________________________________________
void 
AliFMDReconstructor::FillESD(AliRunLoader*,AliRawReader*,AliESD*) const 
{
  // Cannot be used.  See member function with same name but with 2
  // TTree arguments.   Make sure you do local reconstrucion 
  AliDebug(1, Form("Calling FillESD with loader, raw reader, and ESD"));
  AliError("MayNotUse");
}

//____________________________________________________________________
//
// EOF
//
Commit	Line	Data
	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	/* $Id$ */
	16	/** @file AliFMDReconstructor.cxx
	17	@author Christian Holm Christensen <cholm@nbi.dk>
	18	@date Mon Mar 27 12:47:09 2006
	19	@brief FMD reconstruction
	20	*/
	21	//____________________________________________________________________
	22	//
	23	// This is a class that constructs AliFMDMult (reconstructed
	24	// multiplicity) from of Digits
	25	//
	26	// This class reads either digits from a TClonesArray or raw data from
	27	// a DDL file (or similar), and stores the read ADC counts in an
	28	// internal cache (fAdcs).
	29	//
	30	//-- Authors: Evgeny Karpechev(INR) and Alla Maevsksia
	31	// Latest changes by Christian Holm Christensen <cholm@nbi.dk>
	32	//
	33	//
	34	//____________________________________________________________________
	35
	36	#include <AliLog.h> // ALILOG_H
	37	#include <AliRun.h> // ALIRUN_H
	38	#include <AliRunLoader.h> // ALIRUNLOADER_H
	39	#include <AliLoader.h> // ALILOADER_H
	40	#include <AliHeader.h> // ALIHEADER_H
	41	#include <AliRawReader.h> // ALIRAWREADER_H
	42	#include <AliGenEventHeader.h> // ALIGENEVENTHEADER_H
	43	#include "AliFMD.h" // ALIFMD_H
	44	#include "AliFMDGeometry.h" // ALIFMDGEOMETRY_H
	45	#include "AliFMDParameters.h" // ALIFMDPARAMETERS_H
	46	#include "AliFMDDetector.h" // ALIFMDDETECTOR_H
	47	#include "AliFMDRing.h" // ALIFMDRING_H
	48	#include "AliFMDDigit.h" // ALIFMDDIGIT_H
	49	#include "AliFMDReconstructor.h" // ALIFMDRECONSTRUCTOR_H
	50	#include "AliFMDRawStream.h" // ALIFMDRAWSTREAM_H
	51	#include "AliFMDRawReader.h" // ALIFMDRAWREADER_H
	52	#include "AliFMDRecPoint.h" // ALIFMDMULTNAIIVE_H
	53	#include "AliESD.h" // ALIESD_H
	54	#include <AliESDFMD.h> // ALIESDFMD_H
	55	#include <TFile.h>
	56
	57	//____________________________________________________________________
	58	ClassImp(AliFMDReconstructor)
	59	#if 0
	60	; // This is here to keep Emacs for indenting the next line
	61	#endif
	62
	63	//____________________________________________________________________
	64	AliFMDReconstructor::AliFMDReconstructor()
	65	: AliReconstructor(),
	66	fMult(0x0),
	67	fNMult(0),
	68	fTreeR(0x0),
	69	fCurrentVertex(0),
	70	fESDObj(0x0),
	71	fESD(0x0)
	72	{
	73	// Make a new FMD reconstructor object - default CTOR.
	74	}
	75
	76
	77	//____________________________________________________________________
	78	AliFMDReconstructor::AliFMDReconstructor(const AliFMDReconstructor& other)
	79	: AliReconstructor(),
	80	fMult(other.fMult),
	81	fNMult(other.fNMult),
	82	fTreeR(other.fTreeR),
	83	fCurrentVertex(other.fCurrentVertex),
	84	fESDObj(other.fESDObj),
	85	fESD(other.fESD)
	86	{
	87	// Copy constructor
	88	}
	89
	90
	91	//____________________________________________________________________
	92	AliFMDReconstructor&
	93	AliFMDReconstructor::operator=(const AliFMDReconstructor& other)
	94	{
	95	// Assignment operator
	96	fMult = other.fMult;
	97	fNMult = other.fNMult;
	98	fTreeR = other.fTreeR;
	99	fCurrentVertex = other.fCurrentVertex;
	100	fESDObj = other.fESDObj;
	101	fESD = other.fESD;
	102	return *this;
	103	}
	104
	105	//____________________________________________________________________
	106	AliFMDReconstructor::~AliFMDReconstructor()
	107	{
	108	// Destructor
	109	if (fMult) fMult->Delete();
	110	if (fMult) delete fMult;
	111	if (fESDObj) delete fESDObj;
	112	}
	113
	114	//____________________________________________________________________
	115	void
	116	AliFMDReconstructor::Init(AliRunLoader* runLoader)
	117	{
	118	// Initialize the reconstructor
	119	AliDebug(1, Form("Init called with runloader 0x%x", runLoader));
	120	// Initialize the geometry
	121	AliFMDGeometry* geom = AliFMDGeometry::Instance();
	122	geom->Init();
	123	geom->InitTransformations();
	124
	125	// Initialize the parameters
	126	AliFMDParameters* param = AliFMDParameters::Instance();
	127	param->Init();
	128
	129	// Current vertex position
	130	fCurrentVertex = 0;
	131	// Create array of reconstructed strip multiplicities
	132	fMult = new TClonesArray("AliFMDRecPoint", 51200);
	133	// Create ESD output object
	134	fESDObj = new AliESDFMD;
	135
	136	// Check that we have a run loader
	137	if (!runLoader) {
	138	Warning("Init", "No run loader");
	139	return;
	140	}
	141
	142	// Check if we can get the header tree
	143	AliHeader* header = runLoader->GetHeader();
	144	if (!header) {
	145	Warning("Init", "No header");
	146	return;
	147	}
	148
	149	// Check if we can get a simulation header
	150	AliGenEventHeader* eventHeader = header->GenEventHeader();
	151	if (eventHeader) {
	152	TArrayF vtx;
	153	eventHeader->PrimaryVertex(vtx);
	154	fCurrentVertex = vtx[2];
	155	AliDebug(1, Form("Primary vertex Z coordinate for event # %d/%d is %f",
	156	header->GetRun(), header->GetEvent(), fCurrentVertex));
	157	Warning("Init", "no generator event header");
	158	}
	159	else {
	160	Warning("Init", "No generator event header - "
	161	"perhaps we get the vertex from ESD?");
	162	}
	163	}
	164
	165	//____________________________________________________________________
	166	void
	167	AliFMDReconstructor::ConvertDigits(AliRawReader* reader,
	168	TTree* digitsTree) const
	169	{
	170	// Convert Raw digits to AliFMDDigit's in a tree
	171	AliDebug(1, "Reading raw data into digits tree");
	172	AliFMDRawReader rawRead(reader, digitsTree);
	173	// rawRead.SetSampleRate(fFMD->GetSampleRate());
	174	rawRead.Exec();
	175	}
	176
	177	//____________________________________________________________________
	178	void
	179	AliFMDReconstructor::Reconstruct(TTree* digitsTree,
	180	TTree* clusterTree) const
	181	{
	182	// Reconstruct event from digits in tree
	183	// Get the FMD branch holding the digits.
	184	// FIXME: The vertex may not be known yet, so we may have to move
	185	// some of this to FillESD.
	186	AliDebug(1, "Reconstructing from digits in a tree");
	187	#if 1
	188	if (fESD) {
	189	const AliESDVertex* vertex = fESD->GetVertex();
	190	if (vertex) {
	191	AliDebug(1, Form("Got vertex from ESD: %f", vertex->GetZv()));
	192	fCurrentVertex = vertex->GetZv();
	193	}
	194	}
	195	#endif
	196	TBranch *digitBranch = digitsTree->GetBranch("FMD");
	197	if (!digitBranch) {
	198	Error("Exec", "No digit branch for the FMD found");
	199	return;
	200	}
	201	TClonesArray* digits = new TClonesArray("AliFMDDigit");
	202	digitBranch->SetAddress(&digits);
	203
	204	if (fMult) fMult->Clear();
	205	if (fESDObj) fESDObj->Clear();
	206
	207	fNMult = 0;
	208	fTreeR = clusterTree;
	209	fTreeR->Branch("FMD", &fMult);
	210
	211	AliDebug(5, "Getting entry 0 from digit branch");
	212	digitBranch->GetEntry(0);
	213
	214	AliDebug(5, "Processing digits");
	215	ProcessDigits(digits);
	216
	217	Int_t written = clusterTree->Fill();
	218	AliDebug(10, Form("Filled %d bytes into cluster tree", written));
	219	digits->Delete();
	220	delete digits;
	221	}
	222
	223
	224	//____________________________________________________________________
	225	void
	226	AliFMDReconstructor::ProcessDigits(TClonesArray* digits) const
	227	{
	228	// For each digit, find the pseudo rapdity, azimuthal angle, and
	229	// number of corrected ADC counts, and pass it on to the algorithms
	230	// used.
	231	Int_t nDigits = digits->GetEntries();
	232	AliDebug(1, Form("Got %d digits", nDigits));
	233	for (Int_t i = 0; i < nDigits; i++) {
	234	AliFMDDigit* digit = static_cast<AliFMDDigit*>(digits->At(i));
	235	AliFMDParameters* param = AliFMDParameters::Instance();
	236	// Check that the strip is not marked as dead
	237	if (param->IsDead(digit->Detector(), digit->Ring(),
	238	digit->Sector(), digit->Strip())) continue;
	239
	240	// digit->Print();
	241	// Get eta and phi
	242	Float_t eta, phi;
	243	PhysicalCoordinates(digit, eta, phi);
	244
	245	// Substract pedestal.
	246	UShort_t counts = SubtractPedestal(digit);
	247
	248	// Gain match digits.
	249	Double_t edep = Adc2Energy(digit, eta, counts);
	250
	251	// Make rough multiplicity
	252	Double_t mult = Energy2Multiplicity(digit, edep);
	253
	254	AliDebug(10, Form("FMD%d%c[%2d,%3d]: "
	255	"ADC: %d, Counts: %d, Energy: %f, Mult: %f",
	256	digit->Detector(), digit->Ring(), digit->Sector(),
	257	digit->Strip(), digit->Counts(), counts, edep, mult));
	258
	259	// Create a `RecPoint' on the output branch.
	260	AliFMDRecPoint* m =
	261	new ((*fMult)[fNMult]) AliFMDRecPoint(digit->Detector(),
	262	digit->Ring(),
	263	digit->Sector(),
	264	digit->Strip(),
	265	eta, phi,
	266	edep, mult);
	267	(void)m; // Suppress warnings about unused variables.
	268	fNMult++;
	269
	270	fESDObj->SetMultiplicity(digit->Detector(), digit->Ring(),
	271	digit->Sector(), digit->Strip(), mult);
	272	fESDObj->SetEta(digit->Detector(), digit->Ring(),
	273	digit->Sector(), digit->Strip(), eta);
	274	}
	275	}
	276
	277	//____________________________________________________________________
	278	UShort_t
	279	AliFMDReconstructor::SubtractPedestal(AliFMDDigit* digit) const
	280	{
	281	// Member function to subtract the pedestal from a digit
	282	// This implementation does nothing, but a derived class could over
	283	// load this to subtract a pedestal that was given in a database or
	284	// something like that.
	285
	286	Int_t counts = 0;
	287	AliFMDParameters* param = AliFMDParameters::Instance();
	288	Float_t pedM = param->GetPedestal(digit->Detector(),
	289	digit->Ring(),
	290	digit->Sector(),
	291	digit->Strip());
	292	AliDebug(10, Form("Subtracting pedestal %f from signal %d",
	293	pedM, digit->Counts()));
	294	if (digit->Count3() > 0) counts = digit->Count3();
	295	else if (digit->Count2() > 0) counts = digit->Count2();
	296	else counts = digit->Count1();
	297	counts = TMath::Max(Int_t(counts - pedM), 0);
	298	if (counts > 0) AliDebug(10, "Got a hit strip");
	299
	300	return UShort_t(counts);
	301	}
	302
	303	//____________________________________________________________________
	304	Float_t
	305	AliFMDReconstructor::Adc2Energy(AliFMDDigit* digit,
	306	Float_t /* eta */,
	307	UShort_t count) const
	308	{
	309	// Converts number of ADC counts to energy deposited.
	310	// Note, that this member function can be overloaded by derived
	311	// classes to do strip-specific look-ups in databases or the like,
	312	// to find the proper gain for a strip.
	313	//
	314	// In this simple version, we calculate the energy deposited as
	315	//
	316	// EnergyDeposited = cos(theta) * gain * count
	317	//
	318	// where
	319	//
	320	// Pre_amp_MIP_Range
	321	// gain = ----------------- * Energy_deposited_per_MIP
	322	// ADC_channel_size
	323	//
	324	// is constant and the same for all strips.
	325
	326	// Double_t theta = 2 * TMath::ATan(TMath::Exp(-eta));
	327	// Double_t edep = TMath::Abs(TMath::Cos(theta)) * fGain * count;
	328	AliFMDParameters* param = AliFMDParameters::Instance();
	329	Float_t gain = param->GetPulseGain(digit->Detector(),
	330	digit->Ring(),
	331	digit->Sector(),
	332	digit->Strip());
	333	Double_t edep = count * gain;
	334	AliDebug(10, Form("Converting counts %d to energy via factor %f",
	335	count, gain));
	336	return edep;
	337	}
	338
	339	//____________________________________________________________________
	340	Float_t
	341	AliFMDReconstructor::Energy2Multiplicity(AliFMDDigit* /* digit */,
	342	Float_t edep) const
	343	{
	344	// Converts an energy signal to number of particles.
	345	// Note, that this member function can be overloaded by derived
	346	// classes to do strip-specific look-ups in databases or the like,
	347	// to find the proper gain for a strip.
	348	//
	349	// In this simple version, we calculate the multiplicity as
	350	//
	351	// multiplicity = Energy_deposited / Energy_deposited_per_MIP
	352	//
	353	// where
	354	//
	355	// Energy_deposited_per_MIP = 1.664 * SI_density * SI_thickness
	356	//
	357	// is constant and the same for all strips
	358	AliFMDParameters* param = AliFMDParameters::Instance();
	359	Double_t edepMIP = param->GetEdepMip();
	360	Float_t mult = edep / edepMIP;
	361	if (edep > 0)
	362	AliDebug(10, Form("Translating energy %f to multiplicity via "
	363	"divider %f->%f", edep, edepMIP, mult));
	364	return mult;
	365	}
	366
	367	//____________________________________________________________________
	368	void
	369	AliFMDReconstructor::PhysicalCoordinates(AliFMDDigit* digit,
	370	Float_t& eta,
	371	Float_t& phi) const
	372	{
	373	// Get the eta and phi of a digit
	374	//
	375	// Get geometry.
	376	AliFMDGeometry* geom = AliFMDGeometry::Instance();
	377	Double_t x, y, z, r, theta;
	378	geom->Detector2XYZ(digit->Detector(), digit->Ring(), digit->Sector(),
	379	digit->Strip(), x, y, z);
	380	// Correct for vertex offset.
	381	z += fCurrentVertex;
	382	phi = TMath::ATan2(y, x);
	383	r = TMath::Sqrt(y * y + x * x);
	384	theta = TMath::ATan2(r, z);
	385	eta = -TMath::Log(TMath::Tan(theta / 2));
	386	}
	387
	388
	389
	390	//____________________________________________________________________
	391	void
	392	AliFMDReconstructor::FillESD(TTree* /* digitsTree */,
	393	TTree* /* clusterTree */,
	394	AliESD* esd) const
	395	{
	396	// nothing to be done
	397	// FIXME: The vertex may not be known when Reconstruct is executed,
	398	// so we may have to move some of that member function here.
	399	AliDebug(1, Form("Calling FillESD with two trees and one ESD"));
	400	// fESDObj->Print();
	401
	402	if (esd) {
	403	AliDebug(1, Form("Writing FMD data to ESD tree"));
	404	esd->SetFMDData(fESDObj);
	405	}
	406	}
	407
	408
	409	//____________________________________________________________________
	410	void
	411	AliFMDReconstructor::Reconstruct(AliRawReader,TTree) const
	412	{
	413	// Cannot be used. See member function with same name but with 2
	414	// TTree arguments. Make sure you do local reconstrucion
	415	AliDebug(1, Form("Calling FillESD with loader and tree"));
	416	AliError("MayNotUse");
	417	}
	418	//____________________________________________________________________
	419	void
	420	AliFMDReconstructor::Reconstruct(AliRunLoader*) const
	421	{
	422	// Cannot be used. See member function with same name but with 2
	423	// TTree arguments. Make sure you do local reconstrucion
	424	AliDebug(1, Form("Calling FillESD with loader"));
	425	AliError("MayNotUse");
	426	}
	427	//____________________________________________________________________
	428	void
	429	AliFMDReconstructor::Reconstruct(AliRunLoader, AliRawReader) const
	430	{
	431	// Cannot be used. See member function with same name but with 2
	432	// TTree arguments. Make sure you do local reconstrucion
	433	AliDebug(1, Form("Calling FillESD with loader and raw reader"));
	434	AliError("MayNotUse");
	435	}
	436	//____________________________________________________________________
	437	void
	438	AliFMDReconstructor::FillESD(AliRawReader,TTree,AliESD*) const
	439	{
	440	// Cannot be used. See member function with same name but with 2
	441	// TTree arguments. Make sure you do local reconstrucion
	442	AliDebug(1, Form("Calling FillESD with raw reader, tree, and ESD"));
	443	AliError("MayNotUse");
	444	}
	445	//____________________________________________________________________
	446	void
	447	AliFMDReconstructor::FillESD(AliRunLoader,AliESD) const
	448	{
	449	// Cannot be used. See member function with same name but with 2
	450	// TTree arguments. Make sure you do local reconstrucion
	451	AliDebug(1, Form("Calling FillESD with loader and ESD"));
	452	AliError("MayNotUse");
	453	}
	454	//____________________________________________________________________
	455	void
	456	AliFMDReconstructor::FillESD(AliRunLoader,AliRawReader,AliESD*) const
	457	{
	458	// Cannot be used. See member function with same name but with 2
	459	// TTree arguments. Make sure you do local reconstrucion
	460	AliDebug(1, Form("Calling FillESD with loader, raw reader, and ESD"));
	461	AliError("MayNotUse");
	462	}
	463
	464	//____________________________________________________________________
	465	//
	466	// EOF
	467	//