]> git.uio.no Git - u/mrichter/AliRoot.git/blobdiff - ITS/AliITS.cxx
Update of documentation to reflect changes in AliITSdigitS?D classes.
[u/mrichter/AliRoot.git] / ITS / AliITS.cxx
index 2fddab339bfaf9753f61a96cdfd1e3d2d7b21f3f..13bcd8cbb1ef48328e90b25997a29d990bc341e6 100644 (file)
 
 /*
 $Log$
+Revision 1.72  2002/06/10 17:28:55  nilsen
+Added new FillModules routine and cleaned up the old one.
+
+Revision 1.71  2002/05/13 14:27:56  hristov
+TreeC created once per event (M.Masera)
+
+Revision 1.70  2002/05/10 22:28:30  nilsen
+Changes by Massimo Masera to allow the TTree of clusters to be written to a
+file otherthan the one with digits in it.
+
+Revision 1.69  2002/05/05 21:06:55  nilsen
+Added GetSimulationMoel, and fixed up SetDefaultSimulation to do the
+proper initilization when a simulation has already been defined.
+
+Revision 1.68  2002/05/02 18:51:53  nilsen
+AliITS.h
+   Method MakeBranchR has now a second argument, with a default value:
+       Option_t *opt=" ". Opt="Fast" is to create a separate branch
+       for fast points in TreeR
+   New method MakeBranchRF: it a separate branch in TreeR for Fast Points
+
+AliITS.cxx
+1) TTree->Write() replaced with TTree->AutoSave for TreeS, TreeD and
+   TreeR
+2) Changes in MakeBranchR to allow the creation of a special branch
+   for fast points
+
+Revision 1.67  2002/03/15 17:22:51  nilsen
+Intoduced SDigits2Digits and SDigitsToDigits functions.
+
+Revision 1.66  2001/11/28 01:35:45  nilsen
+Using standard constructors instead of default constructors for Clusterfinder,
+Response, and FastSimulator.
+
+Revision 1.65  2001/11/27 16:27:28  nilsen
+Adding AliITSDigitizer class to do merging and digitization . Based on the
+TTask method. AliITSDigitizer class added to the Makefile and ITSLinkDef.h
+file. The following files required minor changes. AliITS, added functions
+SetHitsAddressBranch, MakeBranchInTreeD and modified MakeBranchD.
+AliITSsimulationSDD.cxx needed a Tree indepenent way of returning back to
+the original Root Directory in function Compress1D. Now it uses gDirectory.
+
+Revision 1.64  2001/11/19 16:17:02  nilsen
+Applyed fixes to bugs found by Rene Brun. With many thanks. Some additonal
+bugs found by Rene require more work to fix. Will be fixed soon.
+
+Revision 1.63  2001/10/24 21:16:34  nilsen
+Removed some dead code and improved comments/documntation.
+
+Revision 1.62  2001/10/21 19:23:21  nilsen
+Added function to allow to limit which detectors to digitize and reconstruct.
+The default is All. This change makes no changes to any root file.
+
+Revision 1.61  2001/10/11 15:26:07  mariana
+Correct HitsToFastRecPoints
+
+Revision 1.60  2001/10/04 22:38:10  nilsen
+Changes made to support PreDigits (SDigits) plus other helpful changes.
+
+Revision 1.59  2001/08/30 09:56:18  hristov
+The operator[] is replaced by At() or AddAt() in case of TObjArray.
+
+Revision 1.58  2001/07/26 15:05:29  hristov
+Use global gRandom generator (M.Ivanov)
+
+Revision 1.57  2001/07/24 14:26:11  mariana
+Introduce the function Digits2Reco() and write the defaults for simulation and reconstruction
+
+Revision 1.56  2001/07/05 12:49:49  mariana
+Temporary patches required by root.v3.01.05
+
+Revision 1.55  2001/06/14 14:59:00  barbera
+Tracking V1 decoupled from AliITS
+
+Revision 1.54  2001/05/31 20:37:56  barbera
+Bari/Salerno model set as defaault SPD simulation
+
+Revision 1.53  2001/05/31 18:52:24 barbera 
+Bari model becomes the default
+
+Revision 1.53  2001/05/30 07:52:24  hristov
+TPC and CONTAINERS included in the search path
+
+Revision 1.52  2001/05/30 06:04:58  hristov
+Changes made to be consitant with changes in TPC tracking classes (B.Nilsen)
+
+Revision 1.51  2001/05/16 14:57:15  alibrary
+New files for folders and Stack
+
 Revision 1.50  2001/05/11 09:15:21  barbera
 Corrected to make fast point creation working with PPR geometry
 
@@ -210,719 +299,603 @@ the AliITS class.
 #include <TFile.h>
 #include <TTree.h>
 #include <TString.h>
-#include <TParticle.h>
 
+#include "AliMC.h"
+#include "AliHeader.h"
 
-#include "AliRun.h"
 #include "AliITS.h"
-#include "AliITSMap.h"
 #include "AliITSDetType.h"
-#include "AliITSClusterFinder.h"
-//#include "AliITSsimulation.h"
-#include "AliITSsimulationSPD.h"
-#include "AliITSsimulationSDD.h"
-#include "AliITSsimulationSSD.h"
-#include "AliITSresponse.h"
-#include "AliITSsegmentationSPD.h"
 #include "AliITSresponseSPD.h"
-#include "AliITSresponseSPDbari.h"
-#include "AliITSsegmentationSDD.h"
 #include "AliITSresponseSDD.h"
-#include "AliITSsegmentationSSD.h"
 #include "AliITSresponseSSD.h"
+#include "AliITSsegmentationSPD.h"
+#include "AliITSsegmentationSDD.h"
+#include "AliITSsegmentationSSD.h"
+#include "AliITSsimulationSPD.h"
+#include "AliITSsimulationSDD.h"
+#include "AliITSsimulationSSD.h"
+#include "AliITSClusterFinderSPD.h"
+#include "AliITSClusterFinderSDD.h"
+#include "AliITSClusterFinderSSD.h"
 #include "AliITShit.h"
 #include "AliITSgeom.h"
+#include "AliITSpList.h"
 #include "AliITSdigit.h"
 #include "AliITSmodule.h"
 #include "AliITSRecPoint.h"
 #include "AliITSRawCluster.h"
-#include "AliMC.h"
-#include "stdlib.h"
-#include "AliKalmanTrack.h" 
-#include "AliMagF.h"
-
-#include "AliITStrack.h"
-#include "AliITSiotrack.h"
-#include "AliITStracking.h"
-#include "AliITSRad.h"   
-#include "../TPC/AliTPC.h"
-#include "../TPC/AliTPCParam.h"
-
 
 ClassImp(AliITS)
-//_____________________________________________________________________________
-AliITS::AliITS() : AliDetector() {
-  //
-  // Default initialiser for ITS
-  //     The default constructor of the AliITS class. In addition to
-  // creating the AliITS class it zeros the variables fIshunt (a member
-  // of AliDetector class), fEuclidOut, and fIdN, and zeros the pointers
-  // fITSpoints, fIdSens, and fIdName. The AliDetector default constructor
-  // is also called.
-  //
-
-
-  fIshunt     = 0;
-  fEuclidOut  = 0;
-
-  fNDetTypes = kNTYPES;
-  fIdN        = 0;
-  fIdName     = 0;
-  fIdSens     = 0;
-  fITSmodules = 0;
-  //
-  fDetTypes   = 0;
-  //
-  fDtype  = 0;
-  fNdtype = 0;
-  fCtype  = 0;
-  fNctype = 0;
-  fRecPoints = 0;
-  fNRecPoints = 0;
-  fTreeC = 0;
-  //
-  fITSgeom=0;
-}
-
-//_____________________________________________________________________________
-AliITS::AliITS(const char *name, const char *title):AliDetector(name,title){
-  //
-  // Default initialiser for ITS
-  //     The constructor of the AliITS class. In addition to creating the
-  // AliITS class, it allocates memory for the TClonesArrays fHits and
-  // fDigits, and for the TObjArray fITSpoints. It also zeros the variables
-  // fIshunt (a member of AliDetector class), fEuclidOut, and fIdN, and zeros
-  // the pointers fIdSens and fIdName. To help in displaying hits via the ROOT
-  // macro display.C AliITS also sets the marker color to red. The variables
-  // passes with this constructor, const char *name and *title, are used by
-  // the constructor of AliDetector class. See AliDetector class for a
-  // description of these parameters and its constructor functions.
-  //
-
-
-  fHits       = new TClonesArray("AliITShit", 1560);
-  gAlice->AddHitList(fHits);
 
-  fNDetTypes = kNTYPES;
-
-  fNdtype = new Int_t[kNTYPES];
-  fDtype = new TObjArray(kNTYPES);
-
-  fNctype = new Int_t[kNTYPES];
-  fCtype = new TObjArray(kNTYPES);
-
-
-  fRecPoints = 0;
-  fNRecPoints = 0;
-
-  fTreeC = 0;
-
-  fITSmodules = 0; 
-
-  fIshunt     = 0;
-  fEuclidOut  = 0;
-  fIdN        = 0;
-  fIdName     = 0;
-  fIdSens     = 0;
-  fDetTypes = new TObjArray(kNTYPES);  
-
-  Int_t i;
-  for(i=0;i<kNTYPES;i++) {
-    fDetTypes->AddAt(new AliITSDetType(),i); 
-    fNdtype[i]=0;
-    fNctype[i]=0;
-   }
-  //
-
-  SetMarkerColor(kRed);
+//______________________________________________________________________
+AliITS::AliITS() : AliDetector() {
+    // Default initializer for ITS
+    //      The default constructor of the AliITS class. In addition to
+    // creating the AliITS class it zeros the variables fIshunt (a member
+    // of AliDetector class), fEuclidOut, and fIdN, and zeros the pointers
+    // fITSpoints, fIdSens, and fIdName. The AliDetector default constructor
+    // is also called.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      Blank ITS class.
+
+    fIshunt     = 0;   // not zeroed in AliDetector.
+
+    // AliITS variables.
+    fEuclidOut  = 0;
+    fITSgeom    = 0;
+    fITSmodules = 0;
+    fOpt        = "All";
+//    SetDetectors(); // default to fOpt="All". This variable not written out.
+
+    fIdN        = 0;
+    fIdName     = 0;
+    fIdSens     = 0;
+
+    fNDetTypes  = kNTYPES;
+    fDetTypes   = 0;
+
+    fSDigits    = 0;
+    fNSDigits   = 0;
+
+    fNdtype     = 0;
+    fDtype      = 0;
+
+    fCtype      = 0;
+    fNctype     = 0;
+    fTreeC      = 0;
+
+    fRecPoints  = 0;
+    fNRecPoints = 0;
 
-  fITSgeom=0;
+    SetMarkerColor(kRed);
 }
-//___________________________________________________________________________
-AliITS::AliITS(AliITS &source){
-  // copy constructor
-  if(this==&source) return;
-  Error("AliITS::Copy constructor",
-       "You are not allowed to make a copy of the AliITS");
-  exit(1);
-}
-//____________________________________________________________________________
-AliITS& AliITS::operator=(AliITS &source){
-  // assignment operator
-  if(this==&source) return *this;
-  Error("AliITS::operator=",
-       "You are not allowed to make a copy of the AliITS");
-  exit(1);
-  return *this; //fake return
-}
-//____________________________________________________________________________
-void AliITS::ClearModules(){
-  //clear the modules TObjArray
+//______________________________________________________________________
+AliITS::AliITS(const char *name, const char *title):AliDetector(name,title){
+    //     The standard Constructor for the ITS class. In addition to 
+    // creating the AliITS class, it allocates memory for the TClonesArrays 
+    // fHits, fSDigits, fDigits, fITSpoints, and the TObjArray of fCtype 
+    // (clusters). It also zeros the variables
+    // fIshunt (a member of AliDetector class), fEuclidOut, and fIdN, and zeros
+    // the pointers fIdSens and fIdName. To help in displaying hits via the
+    // ROOT macro display.C AliITS also sets the marker color to red. The
+    // variables passes with this constructor, const char *name and *title,
+    // are used by the constructor of AliDetector class. See AliDetector
+    // class for a description of these parameters and its constructor
+    // functions.
+    // Inputs:
+    //      const char *name      Detector name. Should always be "ITS"
+    //      const char *title     Detector title.
+    // Outputs:
+    //      none.
+    // Return:
+    //      An ITS class.
+
+    fIshunt     = 0;  // not zeroed in AliDetector
+    fHits       = new TClonesArray("AliITShit", 1560);//not done in AliDetector
+    gAlice->AddHitList(fHits);  // Not done in AliDetector.
+
+    fEuclidOut  = 0;
+    fITSgeom    = 0;
+    fITSmodules = 0;
+    SetDetectors(); // default to fOpt="All". This variable not written out.
+
+    fIdN        = 0;
+    fIdName     = 0;
+    fIdSens     = 0;
+
+    fNDetTypes  = kNTYPES;
+    fDetTypes   = new TObjArray(fNDetTypes);
+
+    fSDigits    = new TClonesArray("AliITSpListItem",1000);
+    fNSDigits   = 0;
+
+    fNdtype     = new Int_t[fNDetTypes];
+    fDtype      = new TObjArray(fNDetTypes);
+
+    fCtype      = new TObjArray(fNDetTypes);
+    fNctype     = new Int_t[fNDetTypes];
+    fTreeC      = 0;
+
+    fRecPoints  = new TClonesArray("AliITSRecPoint",1000);
+    fNRecPoints = 0;
 
-  if(fITSmodules) fITSmodules->Delete();
+    Int_t i;
+    for(i=0;i<fNDetTypes;i++) {
+       fDetTypes->AddAt(new AliITSDetType(),i); 
+       fNdtype[i] = 0;
+       fNctype[i] = 0;
+    } // end for i
 
+    SetMarkerColor(kRed);
 }
-//_____________________________________________________________________________
+//______________________________________________________________________
 AliITS::~AliITS(){
-  //
-  // Default distructor for ITS
-  //     The default destructor of the AliITS class. In addition to deleting
-  // the AliITS class it deletes the memory pointed to by the fHits, fDigits,
-  // fIdSens, fIdName, and fITSpoints.
-  //
-
-
-  delete fHits;
-  delete fDigits;
-  delete fRecPoints;
-//  delete fIdName;        // TObjArray of TObjStrings
-  if(fIdName!=0) delete[] fIdName;  // Array of TStrings
-  if(fIdSens!=0) delete[] fIdSens;
-  if(fITSmodules!=0) {
-      this->ClearModules();
-      delete fITSmodules;
-  }// end if fITSmodules!=0
-
-  //
-  if(fDtype) {
-    fDtype->Delete();
-    delete fDtype;
-  }
-  delete [] fNdtype;
-  if (fCtype) {
-    fCtype->Delete();
-    delete fCtype;
-  }
-  delete [] fNctype;
-  //
-
-  if (fDetTypes) {
-    fDetTypes->Delete();
-    delete fDetTypes;
-  }
-
-  if (fTreeC) delete fTreeC;
-
-  if (fITSgeom) delete fITSgeom;
-
-}
-
-//___________________________________________
-AliITSDetType* AliITS::DetType(Int_t id)
-{
-  //return pointer to id detector type
-    return ((AliITSDetType*) (*fDetTypes)[id]);
-
+    // Default destructor for ITS.
+    //     The default destructor of the AliITS class. In addition to deleting
+    // the AliITS class it deletes the memory pointed to by the fHits, fDigits,
+    // fSDigits, fCtype, fITSmodules, fITSgeom, fRecPoints, fIdSens, fIdName, 
+    // fITSpoints, fDetType and it's contents.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    delete fHits; fHits=0;
+    delete fSDigits; fSDigits=0;
+//    delete fDigits; fDigits=0;
+    delete fRecPoints; fRecPoints=0;
+    if(fIdName!=0) delete[] fIdName;  // Array of TStrings
+    if(fIdSens!=0) delete[] fIdSens;
+    if(fITSmodules!=0) {
+       this->ClearModules();
+       delete fITSmodules;
+    }// end if fITSmodules!=0
+
+    if(fDtype) {
+       fDtype->Delete();
+       delete fDtype;
+    } // end if fDtype
+    delete [] fNdtype;
+    if (fCtype) {
+       fCtype->Delete();
+       delete fCtype;
+    } // end if fCtype
+    delete [] fNctype;
+
+    if (fDetTypes) {
+       fDetTypes->Delete();
+       delete fDetTypes;
+    } // end if fDetTypes
+
+    if (fTreeC) delete fTreeC;
+
+    if (fITSgeom) delete fITSgeom;
 }
-//___________________________________________
-void AliITS::SetClasses(Int_t id, const char *digit, const char *cluster)
-{
-  //set the digit and cluster classes to be used for the id detector type
-    ((AliITSDetType*) (*fDetTypes)[id])->ClassNames(digit,cluster);
-
-}
-//___________________________________________
-void AliITS::SetResponseModel(Int_t id, AliITSresponse *response)
-{
-  //set the response model for the id detector type
-
-    ((AliITSDetType*) (*fDetTypes)[id])->ResponseModel(response);
-
-}
-
-//___________________________________________
-void AliITS::SetSegmentationModel(Int_t id, AliITSsegmentation *seg)
-{
-  //set the segmentation model for the id detector type
-
-    ((AliITSDetType*) (*fDetTypes)[id])->SegmentationModel(seg);
-
-}
-
-//___________________________________________
-void AliITS::SetSimulationModel(Int_t id, AliITSsimulation *sim)
-{
-  //set the simulation model for the id detector type
-
-   ((AliITSDetType*) (*fDetTypes)[id])->SimulationModel(sim);
-
-}
-//___________________________________________
-void AliITS::SetReconstructionModel(Int_t id, AliITSClusterFinder *reconst)
-{
-  //set the cluster finder model for the id detector type
-
-   ((AliITSDetType*) (*fDetTypes)[id])->ReconstructionModel(reconst);
-
-}
-
-//_____________________________________________________________________________
-void AliITS::AddHit(Int_t track, Int_t *vol, Float_t *hits){
-  //
-  // Add an ITS hit
-  //     The function to add information to the AliITShit class. See the
-  // AliITShit class for a full description. This function allocates the
-  // necessary new space for the hit information and passes the variable
-  // track, and the pointers *vol and *hits to the AliITShit constructor
-  // function.
-  //
-  TClonesArray &lhits = *fHits;
-  new(lhits[fNhits++]) AliITShit(fIshunt,track,vol,hits);
-}
-//_____________________________________________________________________________
-void AliITS::AddRealDigit(Int_t id, Int_t *digits) 
-{
-  // add a real digit - as coming from data
-
-  TClonesArray &ldigits = *((TClonesArray*)(*fDtype)[id]);
-  new(ldigits[fNdtype[id]++]) AliITSdigit(digits);
-
-}
-//_____________________________________________________________________________
-void AliITS::AddSimDigit(Int_t id, AliITSdigit *d) 
-{
-
-  // add a simulated digit
-
-  TClonesArray &ldigits = *((TClonesArray*)(*fDtype)[id]);
-
-  switch(id)
-  {
-  case 0:
-     new(ldigits[fNdtype[id]++]) AliITSdigitSPD(*((AliITSdigitSPD*)d));
-     break;
-  case 1:
-     new(ldigits[fNdtype[id]++]) AliITSdigitSDD(*((AliITSdigitSDD*)d));
-     break;
-  case 2:
-     new(ldigits[fNdtype[id]++]) AliITSdigitSSD(*((AliITSdigitSSD*)d));
-     break;
-  }
-
-}
-
-//_____________________________________________________________________________
-void AliITS::AddSimDigit(Int_t id,Float_t phys,Int_t *digits,Int_t *tracks,Int_t *hits,Float_t *charges){
-
-  // add a simulated digit to the list
-
-  TClonesArray &ldigits = *((TClonesArray*)(*fDtype)[id]);
-  switch(id)
-  {
-  case 0:
-     new(ldigits[fNdtype[id]++]) AliITSdigitSPD(digits,tracks,hits);
-     break;
-  case 1:
-     new(ldigits[fNdtype[id]++]) AliITSdigitSDD(phys,digits,tracks,hits,charges);
-     break;
-  case 2:
-     new(ldigits[fNdtype[id]++]) AliITSdigitSSD(digits,tracks,hits);
-     break;
-  }
+//______________________________________________________________________
+AliITS::AliITS(AliITS &source){
+    // Copy constructor. This is a function which is not allowed to be
+    // done to the ITS. It exits with an error.
+    // Inputs:
+    //      AliITS &source  An AliITS class.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(this==&source) return;
+    Error("Copy constructor",
+         "You are not allowed to make a copy of the AliITS");
+    exit(1);
 }
-
-//_____________________________________________________________________________
-void AliITS::AddCluster(Int_t id, AliITSRawCluster *c) 
-{
-
-  // add a cluster to the list
-
-  TClonesArray &lcl = *((TClonesArray*)(*fCtype)[id]);
-
-  switch(id)
-  {
-  case 0:
-     new(lcl[fNctype[id]++]) AliITSRawClusterSPD(*((AliITSRawClusterSPD*)c));
-     break;
-  case 1:
-     new(lcl[fNctype[id]++]) AliITSRawClusterSDD(*((AliITSRawClusterSDD*)c));
-     break;
-  case 2:
-     new(lcl[fNctype[id]++]) AliITSRawClusterSSD(*((AliITSRawClusterSSD*)c));
-     break;
-  }
-
+//______________________________________________________________________
+AliITS& AliITS::operator=(AliITS &source){
+    // Assignment operator. This is a function which is not allowed to be
+    // done to the ITS. It exits with an error.
+    // Inputs:
+    //      AliITS &source  An AliITS class.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(this==&source) return *this;
+    Error("operator=","You are not allowed to make a copy of the AliITS");
+    exit(1);
+    return *this; //fake return
 }
-
-
-//_____________________________________________________________________________
-void AliITS::AddRecPoint(const AliITSRecPoint &r)
-{
-  //
-  // Add a reconstructed space point to the list
-  //
-  TClonesArray &lrecp = *fRecPoints;
-  new(lrecp[fNRecPoints++]) AliITSRecPoint(r);
+//______________________________________________________________________
+Int_t AliITS::DistancetoPrimitive(Int_t,Int_t){
+    // Distance from mouse to ITS on the screen. Dummy routine
+    //     A dummy routine used by the ROOT macro display.C to allow for the
+    // use of the mouse (pointing device) in the macro. In general this should
+    // never be called. If it is it returns the number 9999 for any value of
+    // x and y.
+    // Inputs:
+    //      Int_t     Dummy screen coordinate.
+    //      Int_t     Dummy screen coordinate.
+    // Outputs:
+    //      none.
+    // Return:
+    //      Int_t     Dummy = 9999 distance to ITS.
+
+    return 9999;
 }
-
-//____________________________________________
-void AliITS::ResetDigits()
-{
-    //
-    // Reset number of digits and the digits array for the ITS detector
-    //
-
-    if (!fDtype) return;
-
+//______________________________________________________________________
+void AliITS::Init(){
+    // Initializer ITS after it has been built
+    //     This routine initializes the AliITS class. It is intended to be
+    // called from the Init function in AliITSv?. Besides displaying a banner
+    // indicating that it has been called it initializes the array fIdSens
+    // and sets the default segmentation, response, digit and raw cluster
+    // classes therefore it should be called after a call to CreateGeometry.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
     Int_t i;
-    for (i=0;i<kNTYPES;i++ ) {
-       if ((*fDtype)[i])    ((TClonesArray*)(*fDtype)[i])->Clear();
-       if (fNdtype)  fNdtype[i]=0;
-    }
-}
 
-//____________________________________________
-void AliITS::ResetDigits(Int_t i)
-{
-    //
-    // Reset number of digits and the digits array for this branch
-    //
-  if ((*fDtype)[i])    ((TClonesArray*)(*fDtype)[i])->Clear();
-  if (fNdtype)  fNdtype[i]=0;
+    SetDefaults();
+    // Array of TStrings
+    for(i=0;i<fIdN;i++) fIdSens[i] = gMC->VolId(fIdName[i]);
 }
-
-
-//____________________________________________
-void AliITS::ResetClusters()
-{
-    //
-    // Reset number of clusters and the clusters array for ITS
-    //
-
-    Int_t i;
-    for (i=0;i<kNTYPES;i++ ) {
-       if ((*fCtype)[i])    ((TClonesArray*)(*fCtype)[i])->Clear();
-       if (fNctype)  fNctype[i]=0;
-    }
-
+//______________________________________________________________________
+void AliITS::SetDefaults(){
+    // sets the default segmentation, response, digit and raw cluster classes.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(fDebug) printf("%s: SetDefaults\n",ClassName());
+
+    AliITSDetType *iDetType;
+
+    //SPD
+    iDetType=DetType(0); 
+    if (!iDetType->GetSegmentationModel()) {
+       AliITSsegmentationSPD *seg0=new AliITSsegmentationSPD(fITSgeom);
+       SetSegmentationModel(0,seg0); 
+    } // end if
+    if (!iDetType->GetResponseModel()) {
+       SetResponseModel(0,new AliITSresponseSPD()); 
+    } // end if
+    // set digit and raw cluster classes to be used
+
+    const char *kData0=(iDetType->GetResponseModel())->DataType();
+    if (strstr(kData0,"real")) {
+       iDetType->ClassNames("AliITSdigit","AliITSRawClusterSPD");
+    } else iDetType->ClassNames("AliITSdigitSPD","AliITSRawClusterSPD");
+
+    // SDD
+    iDetType=DetType(1); 
+    if (!iDetType->GetResponseModel()) {
+       SetResponseModel(1,new AliITSresponseSDD("simulated")); 
+    } // end if
+    AliITSresponse *resp1=iDetType->GetResponseModel();
+    if (!iDetType->GetSegmentationModel()) {
+       AliITSsegmentationSDD *seg1=new AliITSsegmentationSDD(fITSgeom,resp1);
+       SetSegmentationModel(1,seg1); 
+    } // end if
+    const char *kData1=(iDetType->GetResponseModel())->DataType();
+    const char *kopt=iDetType->GetResponseModel()->ZeroSuppOption();
+    if((!strstr(kopt,"2D"))&&(!strstr(kopt,"1D")) || strstr(kData1,"real") ){
+       iDetType->ClassNames("AliITSdigit","AliITSRawClusterSDD");
+    } else iDetType->ClassNames("AliITSdigitSDD","AliITSRawClusterSDD");
+
+    // SSD
+    iDetType=DetType(2); 
+    if (!iDetType->GetSegmentationModel()) {
+       AliITSsegmentationSSD *seg2=new AliITSsegmentationSSD(fITSgeom);
+       SetSegmentationModel(2,seg2); 
+    } // end if
+    if (!iDetType->GetResponseModel()) {
+       SetResponseModel(2,new AliITSresponseSSD("simulated"));
+    } // end if
+    const char *kData2=(iDetType->GetResponseModel())->DataType();
+    if (strstr(kData2,"real")) {
+       iDetType->ClassNames("AliITSdigit","AliITSRawClusterSSD");
+    } else iDetType->ClassNames("AliITSdigitSSD","AliITSRawClusterSSD");
+
+    if (kNTYPES>3) {
+       Warning("SetDefaults",
+               "Only the three basic detector types are initialized!");
+    }  // end if
 }
-
-//____________________________________________
-void AliITS::ResetClusters(Int_t i)
-{
-    //
-    // Reset number of clusters and the clusters array for this branch
-    //
-       if ((*fCtype)[i])    ((TClonesArray*)(*fCtype)[i])->Clear();
-       if (fNctype)  fNctype[i]=0;
-
+//______________________________________________________________________
+void AliITS::SetDefaultSimulation(){
+    // sets the default simulation.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    AliITSDetType *iDetType;
+    AliITSsimulation *sim;
+    iDetType=DetType(0);
+    sim = iDetType->GetSimulationModel();
+    if (!sim) {
+       AliITSsegmentation *seg0=
+           (AliITSsegmentation*)iDetType->GetSegmentationModel();
+       AliITSresponse *res0 = (AliITSresponse*)iDetType->GetResponseModel();
+       AliITSsimulationSPD *sim0=new AliITSsimulationSPD(seg0,res0);
+       SetSimulationModel(0,sim0);
+    }else{ // simulation exists, make sure it is set up properly.
+       ((AliITSsimulationSPD*)sim)->Init(
+           (AliITSsegmentationSPD*) iDetType->GetSegmentationModel(),
+           (AliITSresponseSPD*) iDetType->GetResponseModel());
+//     if(sim->GetResponseModel()==0) sim->SetResponseModel(
+//         (AliITSresponse*)iDetType->GetResponseModel());
+//     if(sim->GetSegmentationModel()==0) sim->SetSegmentationModel(
+//         (AliITSsegmentation*)iDetType->GetSegmentationModel());
+    } // end if
+    iDetType=DetType(1);
+    sim = iDetType->GetSimulationModel();
+    if (!sim) {
+       AliITSsegmentation *seg1=
+           (AliITSsegmentation*)iDetType->GetSegmentationModel();
+       AliITSresponse *res1 = (AliITSresponse*)iDetType->GetResponseModel();
+       AliITSsimulationSDD *sim1=new AliITSsimulationSDD(seg1,res1);
+       SetSimulationModel(1,sim1);
+    }else{ // simulation exists, make sure it is set up properly.
+       ((AliITSsimulationSDD*)sim)->Init(
+           (AliITSsegmentationSDD*) iDetType->GetSegmentationModel(),
+           (AliITSresponseSDD*) iDetType->GetResponseModel());
+//     if(sim->GetResponseModel()==0) sim->SetResponseModel(
+//         (AliITSresponse*)iDetType->GetResponseModel());
+//     if(sim->GetSegmentationModel()==0) sim->SetSegmentationModel(
+//         (AliITSsegmentation*)iDetType->GetSegmentationModel());
+    } //end if
+    iDetType=DetType(2);
+    sim = iDetType->GetSimulationModel();
+    if (!sim) {
+       AliITSsegmentation *seg2=
+           (AliITSsegmentation*)iDetType->GetSegmentationModel();
+       AliITSresponse *res2 = (AliITSresponse*)iDetType->GetResponseModel();
+       AliITSsimulationSSD *sim2=new AliITSsimulationSSD(seg2,res2);
+       SetSimulationModel(2,sim2);
+    }else{ // simulation exists, make sure it is set up properly.
+       ((AliITSsimulationSSD*)sim)->Init(
+           (AliITSsegmentationSSD*) iDetType->GetSegmentationModel(),
+           (AliITSresponseSSD*) iDetType->GetResponseModel());
+//     if(sim->GetResponseModel()==0) sim->SetResponseModel(
+//         (AliITSresponse*)iDetType->GetResponseModel());
+//     if(sim->GetSegmentationModel()==0) sim->SetSegmentationModel(
+//         (AliITSsegmentation*)iDetType->GetSegmentationModel());
+    } // end if
 }
-
-
-//____________________________________________
-void AliITS::ResetRecPoints()
-{
-    //
-    // Reset number of rec points and the rec points array 
-    //
-    if (fRecPoints) fRecPoints->Clear();
-    fNRecPoints = 0;
-
+//______________________________________________________________________
+void AliITS::SetDefaultClusterFinders(){
+    // Sets the default cluster finders. Used in finding RecPoints.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    MakeTreeC();
+    AliITSDetType *iDetType;
+
+    // SPD
+    iDetType=DetType(0);
+    if (!iDetType->GetReconstructionModel()) {
+       AliITSsegmentation *seg0 =
+           (AliITSsegmentation*)iDetType->GetSegmentationModel();
+       TClonesArray *dig0=DigitsAddress(0);
+       TClonesArray *recp0=ClustersAddress(0);
+       AliITSClusterFinderSPD *rec0 = new AliITSClusterFinderSPD(seg0,dig0,
+                                                                 recp0);
+       SetReconstructionModel(0,rec0);
+    } // end if
+
+    // SDD
+    iDetType=DetType(1);
+    if (!iDetType->GetReconstructionModel()) {
+       AliITSsegmentation *seg1 =
+           (AliITSsegmentation*)iDetType->GetSegmentationModel();
+       AliITSresponse *res1 = (AliITSresponse*)iDetType->GetResponseModel();
+       TClonesArray *dig1=DigitsAddress(1);
+       TClonesArray *recp1=ClustersAddress(1);
+       AliITSClusterFinderSDD *rec1 =
+           new AliITSClusterFinderSDD(seg1,res1,dig1,recp1);
+      SetReconstructionModel(1,rec1);
+    } // end if
+
+    // SSD
+    iDetType=DetType(2);
+    if (!iDetType->GetReconstructionModel()) {
+       AliITSsegmentation *seg2=
+           (AliITSsegmentation*)iDetType->GetSegmentationModel();
+       TClonesArray *dig2=DigitsAddress(2);
+       AliITSClusterFinderSSD *rec2= new AliITSClusterFinderSSD(seg2,dig2);
+       SetReconstructionModel(2,rec2);
+    } // end if
 }
-
-//_____________________________________________________________________________
-Int_t AliITS::DistancetoPrimitive(Int_t , Int_t ){
-  //
-  // Distance from mouse to ITS on the screen. Dummy routine
-  //     A dummy routine used by the ROOT macro display.C to allow for the
-  // use of the mouse (pointing device) in the macro. In general this should
-  // never be called. If it is it returns the number 9999 for any value of
-  // x and y.
-  //
-  return 9999;
+//______________________________________________________________________
+void AliITS::MakeBranch(Option_t* option, const char *file){
+    // Creates Tree branches for the ITS.
+    // Inputs:
+    //      Option_t *option    String of Tree types S,D, and/or R.
+    //      const char *file    String of the file name where these branches
+    //                          are to be stored. If blank then these branches
+    //                          are written to the same tree as the Hits were
+    //                          read from.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    Bool_t cS = (strstr(option,"S")!=0);
+    Bool_t cD = (strstr(option,"D")!=0);
+    Bool_t cR = (strstr(option,"R")!=0);
+    Bool_t cRF = (strstr(option,"RF")!=0);
+    if(cRF)cR = kFALSE;
+
+    AliDetector::MakeBranch(option,file);
+
+    if(cS) MakeBranchS(file);
+    if(cD) MakeBranchD(file);
+    if(cR) MakeBranchR(file);
+    if(cRF) MakeBranchRF(file);
 }
-
-//_____________________________________________________________________________
-void AliITS::Init(){
-  //
-  // Initialise ITS after it has been built
-  //     This routine initializes the AliITS class. It is intended to be called
-  // from the Init function in AliITSv?. Besides displaying a banner
-  // indicating that it has been called it initializes the array fIdSens
-  // and sets the default segmentation, response, digit and raw cluster classes
-  // Therefore it should be called after a call to CreateGeometry.
-  //
-  Int_t i;
-
-//
-  SetDefaults();
-// Array of TStrings
-  for(i=0;i<fIdN;i++) fIdSens[i] = gMC->VolId(fIdName[i]);
-//
+//______________________________________________________________________
+void AliITS::SetTreeAddress(){
+    // Set branch address for the Trees.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    TTree *treeS = gAlice->TreeS();
+    TTree *treeD = gAlice->TreeD();
+    TTree *treeR = gAlice->TreeR();
+
+    AliDetector::SetTreeAddress();
+
+    SetTreeAddressS(treeS);
+    SetTreeAddressD(treeD);
+    SetTreeAddressR(treeR);
 }
-
-//_____________________________________________________________________________
-void AliITS::SetDefaults()
-{
-  // sets the default segmentation, response, digit and raw cluster classes
-
-  if(fDebug) printf("%s: SetDefaults\n",ClassName());
-
-  AliITSDetType *iDetType;
-
-
-  //SPD 
-
-  iDetType=DetType(0); 
-  if (!iDetType->GetSegmentationModel()) {
-    AliITSsegmentationSPD *seg0=new AliITSsegmentationSPD(fITSgeom);
-    SetSegmentationModel(0,seg0); 
-  }
-  if (!iDetType->GetResponseModel()) {
-     SetResponseModel(0,new AliITSresponseSPD()); 
-  }
-  // set digit and raw cluster classes to be used
-  
-  const char *kData0=(iDetType->GetResponseModel())->DataType();
-  if (strstr(kData0,"real")) {
-      iDetType->ClassNames("AliITSdigit","AliITSRawClusterSPD");
-  } else iDetType->ClassNames("AliITSdigitSPD","AliITSRawClusterSPD");
-
-  // SDD                                         //
-  iDetType=DetType(1); 
-  if (!iDetType->GetResponseModel()) {
-    SetResponseModel(1,new AliITSresponseSDD()); 
-  }
-  AliITSresponse *resp1=iDetType->GetResponseModel();
-  if (!iDetType->GetSegmentationModel()) {
-    AliITSsegmentationSDD *seg1=new AliITSsegmentationSDD(fITSgeom,resp1);
-    SetSegmentationModel(1,seg1); 
-  }
-  const char *kData1=(iDetType->GetResponseModel())->DataType();
-  const char *kopt=iDetType->GetResponseModel()->ZeroSuppOption();
-  if ((!strstr(kopt,"2D")) && (!strstr(kopt,"1D")) || strstr(kData1,"real") ) {
-      iDetType->ClassNames("AliITSdigit","AliITSRawClusterSDD");
-  } else iDetType->ClassNames("AliITSdigitSDD","AliITSRawClusterSDD");
-
-  // SSD
-  iDetType=DetType(2); 
-  if (!iDetType->GetSegmentationModel()) {
-    AliITSsegmentationSSD *seg2=new AliITSsegmentationSSD(fITSgeom);
-    SetSegmentationModel(2,seg2); 
-  }
-  if (!iDetType->GetResponseModel()) {
-    SetResponseModel(2,new AliITSresponseSSD()); 
-  }
-  const char *kData2=(iDetType->GetResponseModel())->DataType();
-  if (strstr(kData2,"real")) {
-      iDetType->ClassNames("AliITSdigit","AliITSRawClusterSSD");
-  } else iDetType->ClassNames("AliITSdigitSSD","AliITSRawClusterSSD");
-
-  if (kNTYPES>3) {
-    Warning("SetDefaults","Only the three basic detector types are initialised!");
-  } 
-
+//______________________________________________________________________
+AliITSDetType* AliITS::DetType(Int_t id){
+    // Return pointer to id detector type.
+    // Inputs:
+    //      Int_t id   detector id number.
+    // Outputs:
+    //      none.
+    // Return:
+    //      returned, a pointer to a AliITSDetType.
+
+    return ((AliITSDetType*) fDetTypes->At(id));
 }
-
-
-
-//_____________________________________________________________________________
-void AliITS::SetDefaultSimulation()
-{
-  // to be written
-
+//______________________________________________________________________
+void AliITS::SetResponseModel(Int_t id, AliITSresponse *response){
+    // Set the response model for the id detector type.
+    // Inputs:
+    //      Int_t id        detector id number.
+    //      AliITSresponse* a pointer containing an instance of AliITSresponse
+    //                      to be stored/owned b y AliITSDetType.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    ((AliITSDetType*) fDetTypes->At(id))->ResponseModel(response);
 }
-//_____________________________________________________________________________
-void AliITS::SetDefaultClusterFinders()
-{
-  // to be written
-
+//______________________________________________________________________
+void AliITS::SetSegmentationModel(Int_t id, AliITSsegmentation *seg){
+    // Set the segmentation model for the id detector type.
+    // Inputs:
+    //      Int_t id            detector id number.
+    //      AliITSsegmentation* a pointer containing an instance of 
+    //                          AliITSsegmentation to be stored/owned b y 
+    //                          AliITSDetType.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    ((AliITSDetType*) fDetTypes->At(id))->SegmentationModel(seg);
 }
-//_____________________________________________________________________________
-
-void AliITS::MakeTreeC(Option_t *option)
-{
-  // create a separate tree to store the clusters
-
-//  cout << "AliITS::MakeTreeC" << endl;
-
-     const char *optC = strstr(option,"C");
-     if (optC && !fTreeC) fTreeC = new TTree("TC","Clusters in ITS");
-     else return;
-
-     Int_t buffersize = 4000;
-     char branchname[30];
-
-     const char *det[3] = {"SPD","SDD","SSD"};
-
-     char digclass[40];
-     char clclass[40];
-
-     // one branch for Clusters per type of detector
-     Int_t i;
-     for (i=0; i<kNTYPES ;i++) {
-       AliITSDetType *iDetType=DetType(i); 
-       iDetType->GetClassNames(digclass,clclass);
-       // clusters
-       (*fCtype)[i] = new TClonesArray(clclass,10000); 
-        if (kNTYPES==3) sprintf(branchname,"%sClusters%s",GetName(),det[i]);
-       else  sprintf(branchname,"%sClusters%d",GetName(),i+1);
-       if (fCtype   && fTreeC) {
-          TreeC()->Branch(branchname,&((*fCtype)[i]), buffersize);
-//        cout << "Making Branch " << branchname;
-//        cout << " for Clusters of detector type " << i+1 << endl;
-       }       
-     }
+//______________________________________________________________________
+void AliITS::SetSimulationModel(Int_t id, AliITSsimulation *sim){
+    // Set the simulation model for the id detector type.
+    // Inputs:
+    //      Int_t id        detector id number.
+    //      AliITSresponse* a pointer containing an instance of AliITSresponse
+    //                      to be stored/owned b y AliITSDetType.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+   ((AliITSDetType*) fDetTypes->At(id))->SimulationModel(sim);
 
 }
-
-//_____________________________________________________________________________
-void AliITS::GetTreeC(Int_t event)
-{
-
-//  cout << "AliITS::GetTreeC" << endl;
-
-  // get the clusters tree for this event and set the branch address
-    char treeName[20];
-    char branchname[30];
-
-    const char *det[3] = {"SPD","SDD","SSD"};
-
-    ResetClusters();
-    if (fTreeC) {
-         delete fTreeC;
-    }
-
-    sprintf(treeName,"TreeC%d",event);
-    fTreeC = (TTree*)gDirectory->Get(treeName);
-
-    TBranch *branch;
-    if (fTreeC) {
-        Int_t i;
-       for (i=0; i<kNTYPES; i++) {
-          if (kNTYPES==3) sprintf(branchname,"%sClusters%s",GetName(),det[i]);
-          else  sprintf(branchname,"%sClusters%d",GetName(),i+1);
-          if (fCtype) {
-               branch = fTreeC->GetBranch(branchname);
-                if (branch) branch->SetAddress(&((*fCtype)[i]));
-           }
-       }
-    } else {
-       Error("AliITS::GetTreeC",
-               "cannot find Clusters Tree for event:%d\n",event);
-    }
-
+//______________________________________________________________________
+void AliITS::SetReconstructionModel(Int_t id, AliITSClusterFinder *reconst){
+    // Set the cluster finder model for the id detector type.
+    // Inputs:
+    //      Int_t id             detector id number.
+    //      AliITSClusterFinder* a pointer containing an instance of 
+    //                           AliITSClusterFinder to be stored/owned b y 
+    //                           AliITSDetType.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    ((AliITSDetType*) fDetTypes->At(id))->ReconstructionModel(reconst);
 }
-//_____________________________________________________________________________
-void AliITS::MakeBranch(Option_t* option, const char *file)
-{
-  //
-  // Creates Tree branches for the ITS.
-  //
-  //
-  Int_t buffersize = 4000;
-  char branchname[30];
-  sprintf(branchname,"%s",GetName());
-
-  AliDetector::MakeBranch(option,file);
-
-  const char *cD = strstr(option,"D");
-  const char *cR = strstr(option,"R");
-
-  if (cD) {
-  //
-  // one branch for digits per type of detector
-  //
-   const char *det[3] = {"SPD","SDD","SSD"};
-
-   char digclass[40];
-   char clclass[40];
-
-   Int_t i;
-   for (i=0; i<kNTYPES ;i++) {
-       AliITSDetType *iDetType=DetType(i); 
-       iDetType->GetClassNames(digclass,clclass);
-       // digits
-       if(!((*fDtype)[i])) (*fDtype)[i] = new TClonesArray(digclass,10000);
-       else ResetDigits(i);
-   }
-
-   for (i=0; i<kNTYPES ;i++) {
-      if (kNTYPES==3) sprintf(branchname,"%sDigits%s",GetName(),det[i]);
-      else  sprintf(branchname,"%sDigits%d",GetName(),i+1);      
-      if (fDtype && gAlice->TreeD()) {
-        MakeBranchInTree(gAlice->TreeD(), 
-                         branchname, &((*fDtype)[i]), buffersize, file);
-//         cout << "Making Branch " << branchname;
-//         cout << " for digits of type "<< i+1 << endl;
-      }        
-    }
-  }
-
-  if (cR) {
-  //
-  // only one branch for rec points for all detector types
-  //
-    sprintf(branchname,"%sRecPoints",GetName());
-    if(!fRecPoints) fRecPoints=new TClonesArray("AliITSRecPoint",10000);
-
-    if (fRecPoints && gAlice->TreeR()) {
-      MakeBranchInTree(gAlice->TreeR(), 
-                               branchname, &fRecPoints, buffersize, file) ;
-//      cout << "Making Branch " << branchname;
-//      cout << " for reconstructed space points" << endl;
-    }
-  }    
+//______________________________________________________________________
+void AliITS::SetClasses(Int_t id, const char *digit, const char *cluster){
+    // Set the digit and cluster classes name to be used for the id detector
+    // type.
+    // Inputs:
+    //      Int_t id            detector id number.
+    //      const char *digit   Digit class name for detector id.
+    //      const char *cluster Cluster class name for detector id.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    ((AliITSDetType*) fDetTypes->At(id))->ClassNames(digit,cluster);
 }
-
-//___________________________________________
-void AliITS::SetTreeAddress()
-{
-
-  // Set branch address for the Trees.
-
-  char branchname[30];
-  AliDetector::SetTreeAddress();
-
-  const char *det[3] = {"SPD","SDD","SSD"};
-
-  TBranch *branch;
-  TTree *treeD = gAlice->TreeD();
-  TTree *treeR = gAlice->TreeR();
-
-  Int_t i;
-  if (treeD) {
-      for (i=0; i<kNTYPES; i++) {
-         if (kNTYPES==3) sprintf(branchname,"%sDigits%s",GetName(),det[i]);
-         else  sprintf(branchname,"%sDigits%d",GetName(),i+1);
-         if (fDtype) {
-             branch = treeD->GetBranch(branchname);
-             if (branch) branch->SetAddress(&((*fDtype)[i]));
-         }
-      }
-  }
-
-  if (treeR) {
-    sprintf(branchname,"%sRecPoints",GetName());
-      branch = treeR->GetBranch(branchname);
-      if (branch) branch->SetAddress(&fRecPoints);
-  }
-  
-
+//______________________________________________________________________
+void AliITS::AddHit(Int_t track, Int_t *vol, Float_t *hits){
+    // Add an ITS hit
+    //     The function to add information to the AliITShit class. See the
+    // AliITShit class for a full description. This function allocates the
+    // necessary new space for the hit information and passes the variable
+    // track, and the pointers *vol and *hits to the AliITShit constructor
+    // function.
+    // Inputs:
+    //      Int_t   track   Track number which produced this hit.
+    //      Int_t   *vol    Array of Integer Hit information. See AliITShit.h
+    //      Float_t *hits   Array of Floating Hit information.  see AliITShit.h
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &lhits = *fHits;
+    new(lhits[fNhits++]) AliITShit(fIshunt,track,vol,hits);
 }
-
-//____________________________________________________________________________
+//______________________________________________________________________
 void AliITS::InitModules(Int_t size,Int_t &nmodules){
-
-  //initialize the modules array
-
-  if(fITSmodules){ 
-      fITSmodules->Delete();
-      delete fITSmodules;
-  }
+    // Initialize the modules array.
+    // Inputs:
+    //      Int_t size  Size of array of the number of modules to be
+    //                  created. If size <=0 then the number of modules
+    //                  is gotten from AliITSgeom class kept in fITSgeom.
+    // Outputs:
+    //      Int_t &nmodules The number of modules existing.
+    // Return:
+    //      none.
+
+    if(fITSmodules){ 
+       fITSmodules->Delete();
+       delete fITSmodules;
+    } // end fir fITSmoudles
 
     Int_t nl,indexMAX,index;
 
     if(size<=0){ // default to using data stored in AliITSgeom
        if(fITSgeom==0) {
-           Error("AliITS::InitModules",
-               "in AliITS::InitModule fITSgeom not defined\n");
+           Error("InitModules","fITSgeom not defined");
            return;
        } // end if fITSgeom==0
        nl = fITSgeom->GetNlayers();
@@ -931,87 +904,84 @@ void AliITS::InitModules(Int_t size,Int_t &nmodules){
        nmodules = indexMAX;
        fITSmodules = new TObjArray(indexMAX);
        for(index=0;index<indexMAX;index++){
-               fITSmodules->AddAt( new AliITSmodule(index),index);
+           fITSmodules->AddAt( new AliITSmodule(index),index);
        } // end for index
     }else{
        fITSmodules = new TObjArray(size);
        for(index=0;index<size;index++) {
            fITSmodules->AddAt( new AliITSmodule(index),index);
-       }
+       } // end for index
 
         nmodules = size;
     } // end i size<=0
 }
-
-//____________________________________________________________________________
-void AliITS::FillModules(Int_t evnt,Int_t bgrev,Int_t nmodules,Option_t *option,Text_t *filename){
-
-  // fill the modules with the sorted by module hits; add hits from background
-  // if option=Add
-
-
+//______________________________________________________________________
+void AliITS::FillModules(Int_t evnt,Int_t bgrev,Int_t nmodules,
+                        Option_t *option,Text_t *filename){
+    // fill the modules with the sorted by module hits; add hits from
+    // background if option=Add.
+    // Inputs:
+    //      Int_t evnt       Event to be processed.
+    //      Int_t bgrev      Background Hit tree number.
+    //      Int_t nmodules   Not used.
+    //      Option_t *option String indicating if merging hits or not. To
+    //                       merge hits set equal to "Add". Otherwise no
+    //                       background hits are considered.
+    //      Test_t *filename File name containing the background hits..
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
     static TTree *trH1;                 //Tree with background hits
-    static TClonesArray *fHits2;        //List of hits for one track only
-
+//    static TClonesArray *fHits2;        //List of hits for one track only
     static Bool_t first=kTRUE;
     static TFile *file;
     const char *addBgr = strstr(option,"Add");
 
-
     if (addBgr ) {
        if(first) {
-//         cout<<"filename "<<filename<<endl;
            file=new TFile(filename);
-//         cout<<"I have opened "<<filename<<" file "<<endl;
-           fHits2     = new TClonesArray("AliITShit",1000  );
-       }           
+//         fHits2     = new TClonesArray("AliITShit",1000  );
+       } // end if first
        first=kFALSE;
        file->cd();
        file->ls();
        // Get Hits Tree header from file
-       if(fHits2) fHits2->Clear();
+//     if(fHits2) fHits2->Clear();
        if(trH1) delete trH1;
        trH1=0;
-       
+
        char treeName[20];
        sprintf(treeName,"TreeH%d",bgrev);
        trH1 = (TTree*)gDirectory->Get(treeName);
-        //printf("TrH1 %p of treename %s for event %d \n",trH1,treeName,bgrev);
-       
        if (!trH1) {
-           Error("AliITS::FillModules",
-           "cannot find Hits Tree for event:%d\n",bgrev);
-       }
+           Error("FillModules","cannot find Hits Tree for event:%d",bgrev);
+       } // end if !trH1
        // Set branch addresses
+/*
        TBranch *branch;
        char branchname[20];
        sprintf(branchname,"%s",GetName());
        if (trH1 && fHits2) {
            branch = trH1->GetBranch(branchname);
            if (branch) branch->SetAddress(&fHits2);
-       }
-
-        // test
-       //Int_t ntracks1 =(Int_t)TrH1->GetEntries();
-       //printf("background - ntracks1 - %d\n",ntracks1);
-   }
+       } // end if trH1 && fHits
+*/
+    } // end if addBgr
 
-    //Int_t npart = gAlice->GetEvent(evnt);
-    //if(npart<=0) return;
+    FillModules(gAlice->TreeH(),0); // fill from this file's tree.
+/*
     TClonesArray *itsHits = this->Hits();
     Int_t lay,lad,det,index;
     AliITShit *itsHit=0;
     AliITSmodule *mod=0;
-
     TTree *iTH = gAlice->TreeH();
     Int_t ntracks =(Int_t) iTH->GetEntries();
-
     Int_t t,h;
     for(t=0; t<ntracks; t++){
        gAlice->ResetHits();
        iTH->GetEvent(t);
        Int_t nhits = itsHits->GetEntriesFast();
-       //printf("nhits %d\n",nhits);
         if (!nhits) continue;
        for(h=0; h<nhits; h++){
            itsHit = (AliITShit *)itsHits->UncheckedAt(h);
@@ -1024,816 +994,944 @@ void AliITS::FillModules(Int_t evnt,Int_t bgrev,Int_t nmodules,Option_t *option,
            mod->AddHit(itsHit,t,h);
        } // end loop over hits 
     } // end loop over tracks
-
+*/
     // open the file with background
     
     if (addBgr ) {
-          Int_t track,i;
-          ntracks =(Int_t)trH1->GetEntries();
-           //printf("background - ntracks1 %d\n",ntracks);
-           //printf("background - Start loop over tracks \n");     
-            //   Loop over tracks
-
-           for (track=0; track<ntracks; track++) {
-
-               if (fHits2)       fHits2->Clear();
-               trH1->GetEvent(track);
-                //   Loop over hits
-               for(i=0;i<fHits2->GetEntriesFast();++i) {
-
-                   itsHit=(AliITShit*) (*fHits2)[i];
-                   itsHit->GetDetectorID(lay,lad,det);
-                   // temporarily index=det-1 !!!
-                   if(fITSgeom) index = fITSgeom->GetModuleIndex(lay,lad,det);
-                   else index=det-1;
-                   //
-                   mod = this->GetModule(index);
-                   mod->AddHit(itsHit,track,i);
-              }  // end loop over hits
-           } // end loop over tracks
-
-           TTree *fAli=gAlice->TreeK();
-            TFile *fileAli=0;
-           
-           if (fAli) fileAli =fAli->GetCurrentFile();
-           fileAli->cd();
-
+       FillModules(trH1,10000000); // Default mask 10M.
+/*
+       Int_t track,i;
+       ntracks =(Int_t)trH1->GetEntries();     
+       // Loop over tracks
+       for (track=0; track<ntracks; track++) {
+           if (fHits2)       fHits2->Clear();
+           trH1->GetEvent(track);
+           //   Loop over hits
+           for(i=0;i<fHits2->GetEntriesFast();++i) {
+               itsHit=(AliITShit*) (*fHits2)[i];
+               itsHit->GetDetectorID(lay,lad,det);
+               // temporarily index=det-1 !!!
+               if(fITSgeom) index = fITSgeom->GetModuleIndex(lay,lad,det);
+               else index=det-1;
+               //
+               mod = this->GetModule(index);
+               mod->AddHit(itsHit,track,i);
+           }  // end loop over hits
+       } // end loop over tracks
+*/
+       TTree *fAli=gAlice->TreeK();
+       TFile *fileAli=0;
+       if (fAli) fileAli =fAli->GetCurrentFile();
+       fileAli->cd();
     } // end if add
-
-    //gObjectTable->Print();
-
 }
+//______________________________________________________________________
+void AliITS::FillModules(TTree *treeH, Int_t mask) {
+    // fill the modules with the sorted by module hits; 
+    // can be called many times to do a merging
+    // Inputs:
+    //      TTree *treeH  The tree containing the hits to be copied into
+    //                    the modules.
+    //      Int_t mask    The track number mask to indecate which file
+    //                    this hits came from.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
 
-//____________________________________________________________________________
-
-void AliITS::SDigits2Digits()
-{
-  
-  AliITSgeom *geom = GetITSgeom();
-  
-  // SPD
-  AliITSDetType *iDetType;
-  iDetType=DetType(0);
-  AliITSsegmentationSPD *seg0=(AliITSsegmentationSPD*)iDetType->GetSegmentationModel();
-  AliITSresponseSPD *res0 = (AliITSresponseSPD*)iDetType->GetResponseModel();
-  AliITSsimulationSPD *sim0=new AliITSsimulationSPD(seg0,res0);
-  SetSimulationModel(0,sim0);
-  // test
-  // printf("SPD dimensions %f %f \n",seg0->Dx(),seg0->Dz());
-  // printf("SPD npixels %d %d \n",seg0->Npz(),seg0->Npx());
-  // printf("SPD pitches %d %d \n",seg0->Dpz(0),seg0->Dpx(0));
-  // end test
-  // 
-  // SDD
-  //Set response functions
-  // SDD compression param: 2 fDecrease, 2fTmin, 2fTmax or disable, 2 fTolerance
-
-  iDetType=DetType(1);
-  AliITSresponseSDD *res1 = (AliITSresponseSDD*)iDetType->GetResponseModel();
-  if (!res1) {
-    res1=new AliITSresponseSDD();
-    SetResponseModel(1,res1);
-  }
-  Float_t noise, baseline;
-  res1->GetNoiseParam(noise,baseline);
-  Float_t noise_after_el =  res1->GetNoiseAfterElectronics();
-  Float_t fCutAmp = baseline + 2.*noise_after_el;
-  Int_t cp[8]={0,0,(int)fCutAmp,(int)fCutAmp,0,0,0,0}; //1D
-  res1->SetCompressParam(cp);
-  AliITSsegmentationSDD *seg1=(AliITSsegmentationSDD*)iDetType->GetSegmentationModel();
-  if (!seg1) {
-    seg1 = new AliITSsegmentationSDD(geom,res1);
-    SetSegmentationModel(1,seg1);
-  }
-  AliITSsimulationSDD *sim1=new AliITSsimulationSDD(seg1,res1);
-  SetSimulationModel(1,sim1);
-
-  // SSD
-  iDetType=DetType(2);
-  AliITSsegmentationSSD *seg2=(AliITSsegmentationSSD*)iDetType->GetSegmentationModel();
-  AliITSresponseSSD *res2 = (AliITSresponseSSD*)iDetType->GetResponseModel();
-  res2->SetSigmaSpread(3.,2.);
-  AliITSsimulationSSD *sim2=new AliITSsimulationSSD(seg2,res2);
-  SetSimulationModel(2,sim2);
-  cerr<<"Digitizing ITS...\n";
-  TStopwatch timer;
-  timer.Start();
-  HitsToDigits(gAlice->GetEvNumber(),0,-1," ","All"," ");
-  timer.Stop(); timer.Print();
-
-  delete sim0;
-  delete sim1;
-  delete sim2;
+    Int_t lay,lad,det,index;
+    AliITShit *itsHit=0;
+    AliITSmodule *mod=0;
+    char branchname[20];
+    sprintf(branchname,"%s",GetName());
+    TBranch *branch = treeH->GetBranch(branchname);
+    if (!branch) {
+       Error("FillModules","%s branch in TreeH not found",branchname);
+       return;
+    } // end if !branch
+    branch->SetAddress(&fHits);
+    Int_t nTracks =(Int_t) treeH->GetEntries();
+    Int_t iPrimTrack,h;
+    for(iPrimTrack=0; iPrimTrack<nTracks; iPrimTrack++){
+       ResetHits();
+       Int_t nBytes = treeH->GetEvent(iPrimTrack);
+       if (nBytes <= 0) continue;
+       Int_t nHits = fHits->GetEntriesFast();
+       for(h=0; h<nHits; h++){
+           itsHit = (AliITShit *)fHits->UncheckedAt(h);
+           itsHit->GetDetectorID(lay,lad,det);
+           if (fITSgeom) {
+               index = fITSgeom->GetModuleIndex(lay,lad,det);
+           } else {
+               index=det-1; // This should not be used.
+           } // end if [You must have fITSgeom for this to work!]
+           mod = GetModule(index);
+           itsHit->SetTrack(itsHit->GetTrack()+mask); // Set track mask.
+           mod->AddHit(itsHit,iPrimTrack,h);
+       } // end loop over hits 
+    } // end loop over tracks
 }
+//______________________________________________________________________
+void AliITS::ClearModules(){
+    // Clear the modules TObjArray.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
 
-
-//____________________________________________________________________________
-void AliITS::HitsToDigits(Int_t evNumber,Int_t bgrev,Int_t size, Option_t *option, Option_t *opt,Text_t *filename)
-{
-    // keep galice.root for signal and name differently the file for 
-    // background when add! otherwise the track info for signal will be lost !
-  
-   // the condition below will disappear when the geom class will be
-   // initialised for all versions - for the moment it is only for v5 !
-   // 7 is the SDD beam test version  
-   Int_t ver = this->IsVersion(); 
-   if(ver!=5 && ver!=7 && ver!=8 && ver!=9) return; 
-
-   const char *all = strstr(opt,"All");
-   const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),strstr(opt,"SSD")};
-//   cout<<" 1 AliITS "<<endl;
-   Int_t nmodules;
-   InitModules(size,nmodules); 
-//   cout<<" 2 AliITS "<<endl;
-   FillModules(evNumber,bgrev,nmodules,option,filename);
-//   cout<<" 3 AliITS "<<endl;
-
-   //TBranch *branch;
-   AliITSsimulation* sim;
-   //TObjArray *branches=gAlice->TreeD()->GetListOfBranches();
-   AliITSgeom *geom = GetITSgeom();
-
-   Int_t id,module;
-//   Int_t lay, lad, detect;
-   Int_t first,last;
-   for (id=0;id<kNTYPES;id++) {
-        if (!all && !det[id]) continue;
-       //branch = (TBranch*)branches->UncheckedAt(id);
-       AliITSDetType *iDetType=DetType(id); 
-       sim = (AliITSsimulation*)iDetType->GetSimulationModel();
-
-       if (!sim) {
-           Error("HitsToDigits","The simulation class was not instantiated!");
-           exit(1);
-          // or SetDefaultSimulation();
-       }
-
-       if(geom) {
-         first = geom->GetStartDet(id);
-         last = geom->GetLastDet(id);
-       } else first=last=0;
-//     cout << "det type " << id << " first, last "<< first << last << endl;
-       for(module=first;module<=last;module++) {
-           AliITSmodule *mod = (AliITSmodule *)fITSmodules->At(module);
-/*
-           geom->GetModuleId(module,lay, lad, detect);
-            if ( lay == 6 )
-             ((AliITSsegmentationSSD*)(((AliITSsimulationSSD*)sim)->GetSegmentation()))->SetLayer(6);
-           if ( lay == 5 )
-             ((AliITSsegmentationSSD*)(((AliITSsimulationSSD*)sim)->GetSegmentation()))->SetLayer(5);
-*/
-           sim->DigitiseModule(mod,module,evNumber);
-           // fills all branches - wasted disk space
-           gAlice->TreeD()->Fill(); 
-           ResetDigits();
-           // try and fill only the branch 
-           //branch->Fill();
-           //ResetDigits(id);
-       } // loop over modules
-   } // loop over detector types
-
-   ClearModules();
-
-//   Int_t nentries=(Int_t)
-   gAlice->TreeD()->GetEntries();
-//   cout << "nentries in TreeD" << nentries << endl;
-
-   char hname[30];
-   sprintf(hname,"TreeD%d",evNumber);
-   gAlice->TreeD()->Write(hname,TObject::kOverwrite);
-   // reset tree
-   gAlice->TreeD()->Reset();
-
+    if(fITSmodules) fITSmodules->Delete();
 }
+//______________________________________________________________________
+void AliITS::MakeBranchS(const char *fl){
+    // Creates Tree Branch for the ITS summable digits.
+    // Inputs:
+    //      cont char *fl  File name where SDigits branch is to be written
+    //                     to. If blank it write the SDigits to the same
+    //                     file in which the Hits were found.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    Int_t buffersize = 4000;
+    char branchname[30];
 
+    // only one branch for SDigits.
+    sprintf(branchname,"%s",GetName());
+    if(fSDigits && gAlice->TreeS()){
+       MakeBranchInTree(gAlice->TreeS(),branchname,&fSDigits,buffersize,fl);
+    } // end if
+}
+//______________________________________________________________________
+void AliITS::SetTreeAddressS(TTree *treeS){
+    // Set branch address for the ITS summable digits Trees.
+    // Inputs:
+    //      TTree *treeS   Tree containing the SDigits.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    char branchname[30];
 
-//____________________________________________________________________________
-void AliITS::DigitsToRecPoints(Int_t evNumber,Int_t lastentry,Option_t *opt)
-{
-  // cluster finding and reconstruction of space points
-  
-   // the condition below will disappear when the geom class will be
-   // initialised for all versions - for the moment it is only for v5 !
-   // 7 is the SDD beam test version  
-   Int_t ver = this->IsVersion(); 
-   if(ver!=5 && ver!=8 && ver!=9) return;
-
-   const char *all = strstr(opt,"All");
-   const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),strstr(opt,"SSD")};
-
-   static Bool_t first=kTRUE;
-   if (!TreeC() && first) {
-       MakeTreeC("C");
-       first=kFALSE;
-   }
-
-   TTree *treeC=TreeC();
-
-   //TBranch *branch;
-   AliITSClusterFinder* rec;
+    if(!treeS) return;
+    TBranch *branch;
+    sprintf(branchname,"%s",GetName());
+    branch = treeS->GetBranch(branchname);
+    if (branch) branch->SetAddress(&fSDigits);
+}
+//______________________________________________________________________
+void AliITS::MakeBranchInTreeD(TTree *treeD,const char *file){
+    // Creates Tree branches for the ITS.
+    // Inputs:
+    //      TTree     *treeD Pointer to the Digits Tree.
+    //      cont char *file  File name where Digits branch is to be written
+    //                       to. If blank it write the SDigits to the same
+    //                       file in which the Hits were found.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    Int_t buffersize = 4000;
+    char branchname[30];
 
-   //TObjArray *branches=gAlice->TreeR()->GetListOfBranches();
-   AliITSgeom *geom = GetITSgeom();
+    sprintf(branchname,"%s",GetName());
+    // one branch for digits per type of detector
+    const char *det[3] = {"SPD","SDD","SSD"};
+    char digclass[40];
+    char clclass[40];
+    Int_t i;
+    for (i=0; i<kNTYPES ;i++) {
+       DetType(i)->GetClassNames(digclass,clclass);
+       // digits
+       if(!(fDtype->At(i))) fDtype->AddAt(new TClonesArray(digclass,1000),i);
+       else ResetDigits(i);
+    } // end for i
+    for (i=0; i<kNTYPES ;i++) {
+       if (kNTYPES==3) sprintf(branchname,"%sDigits%s",GetName(),det[i]);
+       else  sprintf(branchname,"%sDigits%d",GetName(),i+1);      
+       if (fDtype && treeD) {
+           MakeBranchInTree(treeD, 
+                            branchname, &((*fDtype)[i]),buffersize,file);
+       } // end if
+    } // end for i
+}
+//______________________________________________________________________
+void AliITS::SetTreeAddressD(TTree *treeD){
+    // Set branch address for the Trees.
+    // Inputs:
+    //      TTree *treeD   Tree containing the Digits.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    char branchname[30];
+    const char *det[3] = {"SPD","SDD","SSD"};
+    TBranch *branch;
+    char digclass[40];
+    char clclass[40];
+    Int_t i;
 
-   Int_t id,module;
-   for (id=0;id<kNTYPES;id++) {
+    if(!treeD) return;
+    for (i=0; i<kNTYPES; i++) {
+       DetType(i)->GetClassNames(digclass,clclass);
+       // digits
+       if(!(fDtype->At(i))) fDtype->AddAt(new TClonesArray(digclass,1000),i);
+       else ResetDigits(i);
+       if (kNTYPES==3) sprintf(branchname,"%sDigits%s",GetName(),det[i]);
+       else  sprintf(branchname,"%sDigits%d",GetName(),i+1);
+       if (fDtype) {
+           branch = treeD->GetBranch(branchname);
+           if (branch) branch->SetAddress(&((*fDtype)[i]));
+       } // end if fDtype
+    } // end for i
+}
+//______________________________________________________________________
+void AliITS::Hits2SDigits(){
+    // Standard Hits to summable Digits function.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+
+//    return; // Using Hits in place of the larger sDigits.
+    AliHeader *header=gAlice->GetHeader(); // Get event number from this file.
+    // Do the Hits to Digits operation. Use Standard input values.
+    // Event number from file, no background hit merging , use size from
+    // AliITSgeom class, option="All", input from this file only.
+    HitsToSDigits(header->GetEvent(),0,-1," ",fOpt," ");
+}
+//______________________________________________________________________
+void AliITS::Hits2PreDigits(){
+    // Standard Hits to summable Digits function.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+
+    AliHeader *header=gAlice->GetHeader(); // Get event number from this file.
+    // Do the Hits to Digits operation. Use Standard input values.
+    // Event number from file, no background hit merging , use size from
+    // AliITSgeom class, option="All", input from this file only.
+    HitsToPreDigits(header->GetEvent(),0,-1," ",fOpt," ");
+}
+//______________________________________________________________________
+void AliITS::SDigitsToDigits(Option_t *opt){
+    // Standard Summable digits to Digits function.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+    char name[20] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+
+    if(!GetITSgeom()) return; // need transformations to do digitization.
+    AliITSgeom *geom = GetITSgeom();
+
+    const char *all = strstr(opt,"All");
+    const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),
+                         strstr(opt,"SSD")};
+    if( !det[0] && !det[1] && !det[2] ) all = "All";
+    else all = 0;
+    static Bool_t setDef=kTRUE;
+    if (setDef) SetDefaultSimulation();
+    setDef=kFALSE;
+
+    AliITSsimulation *sim      = 0;
+    AliITSDetType    *iDetType = 0;
+    TTree            *trees    = gAlice->TreeS();
+    if( !(trees && this->GetSDigits()) ){
+       Error("SDigits2Digits","Error: No trees or SDigits. Returning.");
+       return;
+    } // end if
+    sprintf( name, "%s", this->GetName() );
+    TBranch *brchSDigits = trees->GetBranch( name );
+    
+    Int_t id,module;
+    for(module=0;module<geom->GetIndexMax();module++){
+       id       = geom->GetModuleType(module);
         if (!all && !det[id]) continue;
-       //branch = (TBranch*)branches->UncheckedAt(id);
-       AliITSDetType *iDetType=DetType(id); 
-       rec = (AliITSClusterFinder*)iDetType->GetReconstructionModel();
-       if (!rec) {
-           Error("DigitsToRecPoints","The cluster finder class was not instantiated!");
-           exit(1);
-          // or SetDefaultClusterFinders();
-       }
-        TClonesArray *itsDigits  = this->DigitsAddress(id);
+       iDetType = DetType(id);
+       sim      = (AliITSsimulation*)iDetType->GetSimulationModel();
+       if (!sim) {
+           Error("SDigit2Digits",
+                 "The simulation class was not instanciated!");
+           exit(1);
+       } // end if !sim
+       sim->InitSimulationModule(module,gAlice->GetEvNumber());
+//
+       // add summable digits to module
+       this->GetSDigits()->Clear();
+       brchSDigits->GetEvent(module);
+       sim->AddSDigitsToModule(GetSDigits(),0);
+//
+        // Digitise current module sum(SDigits)->Digits
+        sim->FinishSDigitiseModule();
 
-        Int_t first,last;
-       if(geom) {
-         first = geom->GetStartDet(id);
-         last = geom->GetLastDet(id);
-       } else first=last=0;
-       printf("first module - last module %d %d\n",first,last);
-       for(module=first;module<=last;module++) {
-              this->ResetDigits();
-              if (all) gAlice->TreeD()->GetEvent(lastentry+module);
-             else gAlice->TreeD()->GetEvent(lastentry+(module-first));
-             Int_t ndigits = itsDigits->GetEntriesFast();
-             if (ndigits) rec->FindRawClusters(module);
-             gAlice->TreeR()->Fill(); 
-             ResetRecPoints();
-             treeC->Fill();
-              ResetClusters();
-             // try and fill only the branch 
-             //branch->Fill();
-             //ResetRecPoints(id);
-       } // loop over modules
-   } // loop over detector types
-
-
-//   Int_t nentries=(Int_t)
-   gAlice->TreeR()->GetEntries();
-//   Int_t ncentries=(Int_t)
-   treeC->GetEntries();
-//   cout << " nentries ncentries " << nentries << ncentries <<  endl;
-
-   char hname[30];
-   sprintf(hname,"TreeR%d",evNumber);
-   gAlice->TreeR()->Write(hname,TObject::kOverwrite);
-   // reset tree
-   gAlice->TreeR()->Reset();
-
-   sprintf(hname,"TreeC%d",evNumber);
-   treeC->Write(hname,TObject::kOverwrite);
-   treeC->Reset();
-}
+        // fills all branches - wasted disk space
+        gAlice->TreeD()->Fill();
+        this->ResetDigits();
+    } // end for module
 
+    gAlice->TreeD()->GetEntries();
 
-//____________________________________________________________________________
-void AliITS::HitsToFastRecPoints(Int_t evNumber,Int_t bgrev,Int_t size,
-Option_t *option,Option_t *opt,Text_t *filename)
-{
+    gAlice->TreeD()->AutoSave();
+    // reset tree
+    gAlice->TreeD()->Reset();
+    
+}
+//______________________________________________________________________
+void AliITS::Hits2Digits(){
+    // Standard Hits to Digits function.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+
+    AliHeader *header=gAlice->GetHeader(); // Get event number from this file.
+    // Do the Hits to Digits operation. Use Standard input values.
+    // Event number from file, no background hit merging , use size from
+    // AliITSgeom class, option="All", input from this file only.
+    HitsToDigits(header->GetEvent(),0,-1," ",fOpt," ");
+}
+//______________________________________________________________________
+void AliITS::HitsToSDigits(Int_t evNumber,Int_t bgrev,Int_t size,
+                         Option_t *option, Option_t *opt,Text_t *filename){
     // keep galice.root for signal and name differently the file for 
     // background when add! otherwise the track info for signal will be lost !
-  
-
-   // the condition below will disappear when the geom class will be
-   // initialised for all versions - for the moment it is only for v5 !  
-   Int_t ver = this->IsVersion(); 
-   if(ver!=5 && ver!=8 && ver!=9) return;
-   //if(ver!=5) return; 
-
-   const char *all = strstr(opt,"All");
-   const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),strstr(opt,"SSD")};
-
-   Int_t nmodules;
-   InitModules(size,nmodules);
-   FillModules(evNumber,bgrev,nmodules,option,filename);
-
-
-   AliITSsimulation* sim;
-   AliITSgeom *geom = GetITSgeom();
-
-   TRandom *random=new TRandom[9];
-   random[0].SetSeed(111);
-   random[1].SetSeed(222);
-   random[2].SetSeed(333);             
-   random[3].SetSeed(444);
-   random[4].SetSeed(555);
-   random[5].SetSeed(666);             
-   random[6].SetSeed(777);
-   random[7].SetSeed(888);
-   random[8].SetSeed(999);             
-
-
-   Int_t id,module;
-   for (id=0;id<kNTYPES;id++) {
+    // the condition below will disappear when the geom class will be
+    // initialized for all versions - for the moment it is only for v5 !
+    // 7 is the SDD beam test version. Dummy routine. Hits are ITS's Summable
+    // Digits.
+    // Inputs:
+    //      Int_t evnt       Event to be processed.
+    //      Int_t bgrev      Background Hit tree number.
+    //      Int_t nmodules   Not used.
+    //      Option_t *option String indicating if merging hits or not. To
+    //                       merge hits set equal to "Add". Otherwise no
+    //                       background hits are considered.
+    //      Test_t *filename File name containing the background hits..
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+//    return; // using Hits instead of the larger sdigits.
+
+    HitsToPreDigits(evNumber,bgrev,size,option,opt,filename);
+}
+//______________________________________________________________________
+void AliITS::HitsToPreDigits(Int_t evNumber,Int_t bgrev,Int_t size,
+                         Option_t *option, Option_t *opt,Text_t *filename){
+    //   Keep galice.root for signal and name differently the file for 
+    // background when add! otherwise the track info for signal will be lost !
+    // the condition below will disappear when the geom class will be
+    // initialized for all versions - for the moment it is only for v5 !
+    // 7 is the SDD beam test version.
+    // Inputs:
+    //      Int_t evnt       Event to be processed.
+    //      Int_t bgrev      Background Hit tree number.
+    //      Int_t nmodules   Not used.
+    //      Option_t *option String indicating if merging hits or not. To
+    //                       merge hits set equal to "Add". Otherwise no
+    //                       background hits are considered.
+    //      Test_t *filename File name containing the background hits..
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(!GetITSgeom()) return; // need transformations to do digitization.
+    AliITSgeom *geom = GetITSgeom();
+
+    const char *all = strstr(opt,"All");
+    const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),
+                         strstr(opt,"SSD")};
+    static Bool_t setDef=kTRUE;
+    if (setDef) SetDefaultSimulation();
+    setDef=kFALSE;
+
+    Int_t nmodules;
+    InitModules(size,nmodules);
+    FillModules(evNumber,bgrev,nmodules,option,filename);
+
+    AliITSsimulation *sim      = 0;
+    AliITSDetType    *iDetType = 0;
+    AliITSmodule     *mod      = 0;
+    Int_t id,module;
+    for(module=0;module<geom->GetIndexMax();module++){
+       id       = geom->GetModuleType(module);
         if (!all && !det[id]) continue;
-       AliITSDetType *iDetType=DetType(id); 
-       sim = (AliITSsimulation*)iDetType->GetSimulationModel();
+       iDetType = DetType(id);
+       sim      = (AliITSsimulation*)iDetType->GetSimulationModel();
        if (!sim) {
-           Error("HitsToFastPoints","The simulation class was not instantiated!");
-           exit(1);
-          // or SetDefaultSimulation();
-       }
-
-        Int_t first,last;
-        if(geom) {
-         first = geom->GetStartDet(id);
-         last = geom->GetLastDet(id);
-        } else first=last=0;
-        printf("first module - last module %d %d\n",first,last);
-       for(module=first;module<=last;module++) {
-           AliITSmodule *mod = (AliITSmodule *)fITSmodules->At(module);
-           sim->CreateFastRecPoints(mod,module,random);
-           gAlice->TreeR()->Fill(); 
-           ResetRecPoints();
-       } // loop over modules
-   } // loop over detector types
-
-
-   ClearModules();
-
-   //Int_t nentries=(Int_t)gAlice->TreeR()->GetEntries();
-
-   char hname[30];
-   sprintf(hname,"TreeR%d",evNumber);
-   gAlice->TreeR()->Write(hname,TObject::kOverwrite);
-   // reset tree
-   gAlice->TreeR()->Reset();
-
-   delete [] random;
-
+           Error("HitsToSDigits",
+                 "The simulation class was not instanciated!");
+           exit(1);
+       } // end if !sim
+       mod      = (AliITSmodule *)fITSmodules->At(module);
+       sim->SDigitiseModule(mod,module,evNumber);
+       // fills all branches - wasted disk space
+       gAlice->TreeS()->Fill(); 
+       ResetSDigits();
+    } // end for module
+
+    ClearModules();
+
+    gAlice->TreeS()->GetEntries();
+    gAlice->TreeS()->AutoSave();
+    // reset tree
+    gAlice->TreeS()->Reset();
 }
-
-//________________________________________________________________
-AliITStrack  AliITS::Tracking(AliITStrack &track, AliITStrack *reference,TObjArray *fastpoints, Int_t
-**vettid, Bool_t flagvert,  AliITSRad *rl  ) { 
-                                                                               
-//Origin  A. Badala' and G.S. Pappalardo:  e-mail Angela.Badala@ct.infn.it, Giuseppe.S.Pappalardo@ct.infn.it 
-
-                                                                                   
-  TList *list= new TList();   
-
-  AliITStrack tr(track);
-  
-  list->AddLast(&tr);
-  
-  Double_t Pt=(tr).GetPt();
-//  cout << "\n Pt = " << Pt <<"\n";  //stampa
-
-  AliITStracking obj(list, reference, this, fastpoints,TMath::Abs(Pt),vettid, flagvert, rl);
-  list->Delete();
-  delete list;
-
-  Int_t itot=-1;
-  TVector VecTotLabref(18);
-  Int_t lay, k;
-  for(lay=5; lay>=0; lay--) {
-    TVector VecLabref(3); 
-    VecLabref=(*reference).GetLabTrack(lay);
-    Float_t ClustZ=(*reference).GetZclusterTrack( lay);   //aggiunta il 5-3-2001
-    for(k=0; k<3; k++){ //{itot++; VecTotLabref(itot)=VecLabref(k);} //cambiata il 5-3-2001 
-               Int_t lpp=(Int_t)VecLabref(k);
-               if(lpp>=0) {
-                 TParticle *p=(TParticle*) gAlice->Particle(lpp);
-                 Int_t pcode=p->GetPdgCode();
-                 if(pcode==11) VecLabref(k)=p->GetFirstMother();
-               }    
-    itot++; VecTotLabref(itot)=VecLabref(k);
-    if(VecLabref(k)==0. && ClustZ == 0.) VecTotLabref(itot) =-3.; }  
-  }
-  Long_t labref;
-  Int_t freq;  
-  (*reference).Search(VecTotLabref, labref, freq);
-    
-  //if(freq < 4) labref=-labref;
-  //if(freq < 6) labref=-labref;        // cinque - sei
-  if(freq < 5) labref=-labref;        // cinque - sei  
-  (*reference).SetLabel(labref);
-
-  return *reference; 
-
+//______________________________________________________________________
+void AliITS::HitsToDigits(Int_t evNumber,Int_t bgrev,Int_t size,
+                         Option_t *option, Option_t *opt,Text_t *filename){
+    //   Keep galice.root for signal and name differently the file for 
+    // background when add! otherwise the track info for signal will be lost !
+    // the condition below will disappear when the geom class will be
+    // initialized for all versions - for the moment it is only for v5 !
+    // 7 is the SDD beam test version.
+    // Inputs:
+    //      Int_t evnt       Event to be processed.
+    //      Int_t bgrev      Background Hit tree number.
+    //      Int_t nmodules   Not used.
+    //      Option_t *option String indicating if merging hits or not. To
+    //                       merge hits set equal to "Add". Otherwise no
+    //                       background hits are considered.
+    //      Test_t *filename File name containing the background hits..
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(!GetITSgeom()) return; // need transformations to do digitization.
+    AliITSgeom *geom = GetITSgeom();
+
+    const char *all = strstr(opt,"All");
+    const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),
+                         strstr(opt,"SSD")};
+    static Bool_t setDef=kTRUE;
+    if (setDef) SetDefaultSimulation();
+    setDef=kFALSE;
+
+    Int_t nmodules;
+    InitModules(size,nmodules);
+    FillModules(evNumber,bgrev,nmodules,option,filename);
+
+    AliITSsimulation *sim      = 0;
+    AliITSDetType    *iDetType = 0;
+    AliITSmodule     *mod      = 0;
+    Int_t id,module;
+    for(module=0;module<geom->GetIndexMax();module++){
+       id       = geom->GetModuleType(module);
+        if (!all && !det[id]) continue;
+       iDetType = DetType(id);
+       sim      = (AliITSsimulation*)iDetType->GetSimulationModel();
+       if (!sim) {
+           Error("HitsToDigits",
+                 "The simulation class was not instanciated!");
+           exit(1);
+       } // end if !sim
+       mod      = (AliITSmodule *)fITSmodules->At(module);
+       sim->DigitiseModule(mod,module,evNumber);
+       // fills all branches - wasted disk space
+       gAlice->TreeD()->Fill(); 
+       ResetDigits();
+    } // end for module
+
+    ClearModules();
+
+    gAlice->TreeD()->GetEntries();
+    gAlice->TreeD()->AutoSave();
+    // reset tree
+    gAlice->TreeD()->Reset();
 }
+//______________________________________________________________________
+void AliITS::ResetSDigits(){
+    // Reset the Summable Digits array.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+
+    if (fSDigits) fSDigits->Clear();
+    fNSDigits = 0;
+}
+//______________________________________________________________________
+void AliITS::ResetDigits(){
+    // Reset number of digits and the digits array for the ITS detector.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
 
+    if (!fDtype) return;
 
+    Int_t i;
+    for (i=0;i<kNTYPES;i++ ) {
+       if (fDtype->At(i))    ((TClonesArray*)fDtype->At(i))->Clear();
+       if (fNdtype)  fNdtype[i]=0;
+    } // end for i
+}
+//______________________________________________________________________
+void AliITS::ResetDigits(Int_t i){
+    // Reset number of digits and the digits array for this branch.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+
+    if (fDtype->At(i))    ((TClonesArray*)fDtype->At(i))->Clear();
+    if (fNdtype)  fNdtype[i]=0;
+}
+//______________________________________________________________________
+void AliITS::AddSumDigit(AliITSpListItem &sdig){
+    // Adds the a module full of summable digits to the summable digits tree.
+    // Inputs:
+    //      AliITSpListItem &sdig   SDigit to be added to SDigits tree.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &lsdig = *fSDigits;
+    new(lsdig[fNSDigits++]) AliITSpListItem(sdig);
+}
+//______________________________________________________________________
+void AliITS::AddRealDigit(Int_t id, Int_t *digits){
+    //   Add a real digit - as coming from data.
+    // Inputs:
+    //      Int_t id        Detector type number.
+    //      Int_t *digits   Integer array containing the digits info. See 
+    //                      AliITSdigit.h
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &ldigits = *((TClonesArray*)fDtype->At(id));
+    new(ldigits[fNdtype[id]++]) AliITSdigit(digits);
+}
+//______________________________________________________________________
+void AliITS::AddSimDigit(Int_t id, AliITSdigit *d){
+    //    Add a simulated digit.
+    // Inputs:
+    //      Int_t id        Detector type number.
+    //      AliITSdigit *d  Digit to be added to the Digits Tree. See 
+    //                      AliITSdigit.h
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &ldigits = *((TClonesArray*)fDtype->At(id));
+
+    switch(id){
+    case 0:
+       new(ldigits[fNdtype[id]++]) AliITSdigitSPD(*((AliITSdigitSPD*)d));
+       break;
+    case 1:
+       new(ldigits[fNdtype[id]++]) AliITSdigitSDD(*((AliITSdigitSDD*)d));
+       break;
+    case 2:
+       new(ldigits[fNdtype[id]++]) AliITSdigitSSD(*((AliITSdigitSSD*)d));
+       break;
+    } // end switch id
+}
+//______________________________________________________________________
+void AliITS::AddSimDigit(Int_t id,Float_t phys,Int_t *digits,Int_t *tracks,
+                        Int_t *hits,Float_t *charges){
+    //   Add a simulated digit to the list.
+    // Inputs:
+    //      Int_t id        Detector type number.
+    //      Float_t phys    Physics indicator. See AliITSdigits.h
+    //      Int_t *digits   Integer array containing the digits info. See 
+    //                      AliITSdigit.h
+    //      Int_t *tracks   Integer array [AliITSdigitS?D::GetNTracks()] 
+    //                      containing the track numbers that contributed to
+    //                      this digit.
+    //      Int_t *hits     Integer array [AliITSdigitS?D::GetNTracks()]
+    //                      containing the hit numbers, from AliITSmodule, that
+    //                      contributed to this digit.
+    //      Float_t *charge Floating point array of the signals contributed
+    //                      to this digit by each track.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &ldigits = *((TClonesArray*)fDtype->At(id));
+    switch(id){
+    case 0:
+       new(ldigits[fNdtype[id]++]) AliITSdigitSPD(digits,tracks,hits);
+       break;
+    case 1:
+       new(ldigits[fNdtype[id]++]) AliITSdigitSDD(phys,digits,tracks,
+                                                  hits,charges);
+       break;
+    case 2:
+       new(ldigits[fNdtype[id]++]) AliITSdigitSSD(digits,tracks,hits);
+       break;
+    } // end switch id
+}
+//______________________________________________________________________
+void AliITS::MakeTreeC(Option_t *option){
+    //   Create a separate tree to store the clusters.
+    // Inputs:
+    //      Option_t *option  string which must contain "C" otherwise
+    //                        no Cluster Tree is created.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+  TDirectory *cwd = gDirectory;
+  TFile *fileRecPoints = gAlice->GetTreeRFile();
+  if(fileRecPoints)fileRecPoints->cd();
+    const char *optC = strstr(option,"C");
+    char hname[30];
+    Int_t cureve = gAlice->GetEvNumber();
+    sprintf(hname,"TreeC%d",cureve);
+    if(fTreeC){
+      const char *curname = fTreeC->GetName();
+      char *exists = strstr(hname,curname);
+      if(!exists){
+        delete fTreeC; 
+        fTreeC=0;
+      }
+    }
+    if (optC && !fTreeC) fTreeC = new TTree(hname,"Clusters in ITS");
+    else return;
 
-//________________________________________________________________
+    Int_t buffersize = 4000;
+    char branchname[30];
+    const char *det[3] = {"SPD","SDD","SSD"};
+    char digclass[40];
+    char clclass[40];
+
+    // one branch for Clusters per type of detector
+    Int_t i;   
+    for (i=0; i<kNTYPES ;i++) {
+        AliITSDetType *iDetType=DetType(i); 
+        iDetType->GetClassNames(digclass,clclass);
+       // clusters
+        if(!ClustersAddress(i)){
+          fCtype->AddAt(new TClonesArray(clclass,1000),i);
+        }
+        if (kNTYPES==3) sprintf(branchname,"%sClusters%s",GetName(),det[i]);
+       else  sprintf(branchname,"%sClusters%d",GetName(),i+1);
+       if (fCtype   && fTreeC) {
+           TreeC()->Branch(branchname,&((*fCtype)[i]), buffersize);
+       } // end if fCtype && fTreeC
+    } // end for i
+    cwd->cd();
+}
+//______________________________________________________________________
+void AliITS::GetTreeC(Int_t event){
+    //    Get the clusters tree for this event and set the branch address.
+    // Inputs:
+    //      Int_t event    Event number for the cluster tree.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    char treeName[20];
+    char branchname[30];
+    const char *det[3] = {"SPD","SDD","SSD"};
 
+    ResetClusters();
+    if (fTreeC) {
+       delete fTreeC;
+    } // end if fTreeC
 
+    sprintf(treeName,"TreeC%d",event);
+    TFile *fileRecPoints = gAlice->GetTreeRFile();
+    if(!fileRecPoints){
+      fTreeC = (TTree*)gDirectory->Get(treeName);
+    }
+    else {
+      fTreeC = (TTree*)fileRecPoints->Get(treeName);
+    }
 
-void AliITS::DoTracking(Int_t evNumber, Int_t min_t, Int_t max_t, TFile *file, Bool_t flagvert) {
+    TBranch *branch;
 
-//   ex macro for tracking ITS
+    if (fTreeC) {
+        Int_t i;
+       char digclass[40];
+       char clclass[40];
+       for (i=0; i<kNTYPES; i++) {
+           AliITSDetType *iDetType=DetType(i); 
+           iDetType->GetClassNames(digclass,clclass);
+           // clusters
+           if(!fCtype->At(i)) fCtype->AddAt(new TClonesArray(clclass,1000),i);
+           if(kNTYPES==3) sprintf(branchname,"%sClusters%s",GetName(),det[i]);
+           else  sprintf(branchname,"%sClusters%d",GetName(),i+1);
+           if (fCtype) {
+               branch = fTreeC->GetBranch(branchname);
+                if (branch) branch->SetAddress(&((*fCtype)[i]));
+           } // end if fCtype
+       } // end for i
+    } else {
+       Error("GetTreeC","cannot find Clusters Tree for event:%d",event);
+    } // end if fTreeC
+}
+//______________________________________________________________________
+void AliITS::AddCluster(Int_t id, AliITSRawCluster *c){
+    //   Add a cluster to the list.
+    // Inputs:
+    //      Int_t id             Detector type number.
+    //      AliITSRawCluster *c  Cluster class to be added to the tree of
+    //                           clusters.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &lc = *((TClonesArray*)fCtype->At(id));
+
+    switch(id){
+    case 0:
+       new(lc[fNctype[id]++]) AliITSRawClusterSPD(*((AliITSRawClusterSPD*)c));
+       break;
+    case 1:
+       new(lc[fNctype[id]++]) AliITSRawClusterSDD(*((AliITSRawClusterSDD*)c));
+       break;
+    case 2:
+       new(lc[fNctype[id]++]) AliITSRawClusterSSD(*((AliITSRawClusterSSD*)c));
+       break;
+    } // end switch id
+}
+//______________________________________________________________________
+void AliITS::ResetClusters(){
+    // Reset number of clusters and the clusters array for ITS.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
 
-  printf("begin DoTracking - file %p\n",file);
+    Int_t i;
+    for (i=0;i<kNTYPES;i++ ) ResetClusters(i);
+}
+//______________________________________________________________________
+void AliITS::ResetClusters(Int_t i){
+    //    Reset number of clusters and the clusters array for this branch.
+    // Inputs:
+    //      Int_t i        Detector type number.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if (fCtype->At(i))    ((TClonesArray*)fCtype->At(i))->Clear();
+    if (fNctype)  fNctype[i]=0;
+}
+//______________________________________________________________________
+void AliITS::MakeBranchR(const char *file, Option_t *opt){
+    // Creates Tree branches for the ITS Reconstructed points.
+    // Inputs:
+    //      cont char *file  File name where RecPoints branch is to be written
+    //                       to. If blank it write the SDigits to the same
+    //                       file in which the Hits were found.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    Int_t buffsz = 4000;
+    char branchname[30];
 
-  //const char *pname="75x40_100x60";
-  
- Int_t imax=200,jmax=450;
-  AliITSRad *rl = new AliITSRad(imax,jmax);
-  //cout<<" dopo costruttore AliITSRad\n"; getchar();
-    
-  struct GoodTrack {
-    Int_t lab,code;
-    Float_t px,py,pz,x,y,z,pxg,pyg,pzg,ptg;
-    Bool_t flag;
-  };
-  
-
-  gAlice->GetEvent(0);
-  //  AliKalmanTrack *kkprov;
-  //  kkprov->SetConvConst(100/0.299792458/0.2/gAlice->Field()->Factor());  
-
-  /*  //modificato il 26-4-2001
-  AliTPC *TPC=(AliTPC*)gAlice->GetDetector("TPC");
-  AliTPCParam *digp = (AliTPCParam*)file->Get(pname);
-  if (digp!=0) TPC->SetParam(digp);
-  */
-  TFile *cf=TFile::Open("AliTPCclusters.root");  
-  AliTPCParam *digp= (AliTPCParam*)cf->Get("75x40_100x60");
-  if (!digp) { cerr<<"TPC parameters have not been found !\n"; getchar();}
-     
-  
-  GoodTrack gt[15000];
-  Int_t ngood=0;
-  ifstream in("itsgood_tracks");
-
-  cerr<<"Reading itsgood tracks...\n";
-  while (in>>gt[ngood].lab>>gt[ngood].code
-         >>gt[ngood].px >>gt[ngood].py>>gt[ngood].pz
-         >>gt[ngood].x  >>gt[ngood].y >>gt[ngood].z
-         >>gt[ngood].pxg  >>gt[ngood].pyg >>gt[ngood].pzg
-         >>gt[ngood].ptg >>gt[ngood].flag) {
-    ngood++;
-    cerr<<ngood<<'\r';
-    if (ngood==15000) {
-      cerr<<"Too many good tracks !\n";
-      break;
+    // only one branch for rec points for all detector types
+    Bool_t oFast= (strstr(opt,"Fast")!=0);
+    if(oFast){
+      sprintf(branchname,"%sRecPointsF",GetName());
+    } else {
+      sprintf(branchname,"%sRecPoints",GetName());
     }
-  }
-  if (!in.eof()) cerr<<"Read error (itsgood_tracks) !\n";
-  
-  
-// Load tracks
- // TFile *tf=TFile::Open("tpctracks.root"); //commentato 26-4-2001 
-  TFile *tf=TFile::Open("AliTPCtracks.root"); 
-  if (!tf->IsOpen()) {cerr<<"Can't open AliTPCtracks.root !\n"; return ;}
-  TObjArray tracks(200000);
-  TTree *tracktree=(TTree*)tf->Get("TreeT");
-  TBranch *tbranch=tracktree->GetBranch("tracks");
-  Int_t nentr=(Int_t)tracktree->GetEntries();
-  Int_t kk;
-  /*  commentato il 26-4-2001
-  for (kk=0; kk<nentr; kk++) {
-    AliTPCtrack *iotrack=new AliTPCtrack;
-    tbranch->SetAddress(&iotrack);
-    tracktree->GetEvent(kk);
-    tracks.AddLast(iotrack);
-  } 
-  */
-   AliTPCtrack *iotracktpc=0;    
-  for (kk=0; kk<nentr; kk++) {
-    iotracktpc=new AliTPCtrack; 
-    tbranch->SetAddress(&iotracktpc);
-    tracktree->GetEvent(kk);
-    tracks.AddLast(iotracktpc);    
-  }      
-  tf->Close();
-
-
-  Int_t nt = tracks.GetEntriesFast();
-  cerr<<"Number of found tracks "<<nt<<endl;
-  
-  TVector DataOut(9);
-  Int_t kkk=0;
-  
-  Double_t ptg=0.,pxg=0.,pyg=0.,pzg=0.;
-
-  //////////////////////////////  good tracks definition in TPC  ////////////////////////////////
-      
-  ofstream out1 ("AliITSTrag.out");
-  Int_t i;
-  for (i=0; i<ngood; i++) out1 << gt[i].ptg << "\n";
-  out1.close();
-
-
-  TVector vec(5);
-  TTree *TR=gAlice->TreeR();
-  Int_t nent=(Int_t)TR->GetEntries();
-  TClonesArray  *recPoints = RecPoints();
-  Int_t numbpoints;
-  Int_t totalpoints=0;
-  Int_t *np = new Int_t[nent];
-  Int_t **vettid = new Int_t* [nent];
-  Int_t mod;
-  for (mod=0; mod<nent; mod++) {
-    vettid[mod]=0;
-    this->ResetRecPoints();
-    //gAlice->TreeR()->GetEvent(mod+1); //first entry in TreeR is empty
-    gAlice->TreeR()->GetEvent(mod); //first entry in TreeR is empty
-    numbpoints = recPoints->GetEntries();
-    totalpoints+=numbpoints;
-    np[mod] = numbpoints;
-  //cout<<" mod = "<<mod<<"   numbpoints = "<<numbpoints<<"\n"; getchar();
-    vettid[mod] = new Int_t[numbpoints];
-    Int_t ii;
-    for (ii=0;ii<numbpoints; ii++) *(vettid[mod]+ii)=0;
-  }
-
-  AliTPCtrack *track=0;
-
-     
-  if(min_t < 0) {min_t = 0; max_t = nt-1;}   
+    if (fRecPoints && gAlice->TreeR()) {
+       MakeBranchInTree(gAlice->TreeR(),branchname,&fRecPoints,buffsz,file);
+    } // end if
+}
+//______________________________________________________________________
+void AliITS::SetTreeAddressR(TTree *treeR){
+    // Set branch address for the Reconstructed points Trees.
+    // Inputs:
+    //      TTree *treeR   Tree containing the RecPoints.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+    char branchname[30];
 
-/*
-  ///////////////////////////////// Definition of vertex end its error ////////////////////////////
-  ////////////////////////// In the future it will be given by a method ///////////////////////////
-  Double_t Vx=0.;
-  Double_t Vy=0.;
-  Double_t Vz=0.;
-  
-  Float_t sigmavx=0.0050;      // 50  microns
-  Float_t sigmavy=0.0050;      // 50  microns
-  Float_t sigmavz=0.010;       // 100 microns
-
-  //Vx+=gRandom->Gaus(0,sigmavx);  Vy+=gRandom->Gaus(0,sigmavy);  Vz+=gRandom->Gaus(0,sigmavz);
-  TVector vertex(3), ervertex(3)
-  vertex(0)=Vx; vertex(1)=Vy; vertex(2)=Vz;
-  ervertex(0)=sigmavx;  ervertex(1)=sigmavy;  ervertex(2)=sigmavz;
-  /////////////////////////////////////////////////////////////////////////////////////////////////
-*/      
-
-  TTree tracktree1("TreeT","Tree with ITS tracks");
-  AliITSiotrack *iotrack=0;
-  tracktree1.Branch("ITStracks","AliITSiotrack",&iotrack,32000,0);
-
-  ofstream out ("AliITSTra.out");
-  //ofstream outprova ("AliITSprova.out"); //commentato il 26-4-2001 
-  
-  Int_t j;       
-  for (j=min_t; j<=max_t; j++) {     
-    track=(AliTPCtrack*)tracks.UncheckedAt(j);
-    Int_t flaglab=0;
-    if (!track) continue;
-    ////// elimination of not good tracks ////////////  
-    Int_t ilab=TMath::Abs(track->GetLabel());
-    Int_t iii;
-    for (iii=0;iii<ngood;iii++) {
-        //cout<<" ilab, gt[iii].lab = "<<ilab<<" "<<gt[iii].lab<<"\n"; getchar();
-      if (ilab==gt[iii].lab) { 
-       flaglab=1;
-       ptg=gt[iii].ptg; 
-       pxg=gt[iii].pxg;
-       pyg=gt[iii].pyg;
-       pzg=gt[iii].pzg;        
-       break;
+    if(!treeR) return;
+    TBranch *branch;
+    sprintf(branchname,"%sRecPoints",GetName());
+    branch = treeR->GetBranch(branchname);
+    if (branch) {
+      branch->SetAddress(&fRecPoints);
+    }
+    else {
+      sprintf(branchname,"%sRecPointsF",GetName());
+      branch = treeR->GetBranch(branchname);
+      if (branch) {
+        branch->SetAddress(&fRecPoints);
       }
     }
-        //cout<<" j flaglab =  " <<j<<" "<<flaglab<<"\n";  getchar();
-    if (!flaglab) continue;  
-        //cout<<" j =  " <<j<<"\n";  getchar();
-  /*           
-    ////// old propagation to the end of TPC //////////////       
-    Double_t xk=76.;
-    track->PropagateTo(xk);
-    xk-=0.11;
-    track->PropagateTo(xk,42.7,2.27); //C
-    xk-=2.6;
-    track->PropagateTo(xk,36.2,1.98e-3); //C02
-    xk-=0.051;
-    track->PropagateTo(xk,42.7,2.27); //C 
-    /////////////////////////////////////////////////// 
-        */
-                
-        ////// new propagation to the end of TPC //////////////
-    Double_t xk=77.415;
-    track->PropagateTo(xk, 28.94, 1.204e-3);    //Ne
-        xk -=0.01;
-    track->PropagateTo(xk, 44.77, 1.71);        //Tedlar
-        xk -=0.04;
-    track->PropagateTo(xk, 44.86, 1.45);        //Kevlar
-        xk -=2.0;
-    track->PropagateTo(xk, 41.28, 0.029);       //Nomex         
-    xk-=16;
-    track->PropagateTo(xk,36.2,1.98e-3); //C02
-        xk -=0.01;
-    track->PropagateTo(xk, 24.01, 2.7);         //Al    
-        xk -=0.01;
-    track->PropagateTo(xk, 44.77, 1.71);        //Tedlar
-        xk -=0.04;
-    track->PropagateTo(xk, 44.86, 1.45);        //Kevlar
-        xk -=0.5;
-    track->PropagateTo(xk, 41.28, 0.029);       //Nomex                                                 
-                    
-       ///////////////////////////////////////////////////////////////                          
-  
-   ///////////////////////////////////////////////////////////////
-    AliITStrack trackITS(*track);
-    AliITStrack result(*track);
-    AliITStrack primarytrack(*track); 
+}
+//______________________________________________________________________
+void AliITS::AddRecPoint(const AliITSRecPoint &r){
+    // Add a reconstructed space point to the list
+    // Inputs:
+    //      const AliITSRecPoint &r RecPoint class to be added to the tree
+    //                              of reconstructed points TreeR.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    TClonesArray &lrecp = *fRecPoints;
+    new(lrecp[fNRecPoints++]) AliITSRecPoint(r);
+}
+//______________________________________________________________________
+void AliITS::HitsToFastRecPoints(Int_t evNumber,Int_t bgrev,Int_t size,
+                                Option_t *opt0,Option_t *opt1,Text_t *flnm){
+    // keep galice.root for signal and name differently the file for 
+    // background when add! otherwise the track info for signal will be lost !
+    // the condition below will disappear when the geom class will be
+    // initialized for all versions - for the moment it is only for v5 !
+    // Inputs:
+    //      Int_t evnt       Event to be processed.
+    //      Int_t bgrev      Background Hit tree number.
+    //      Int_t size       Size used by InitModules. See InitModules.
+    //      Option_t *opt0   Option passed to FillModules. See FillModules.
+    //      Option_t *opt1   String indicating if merging hits or not. To
+    //                       merge hits set equal to "Add". Otherwise no
+    //                       background hits are considered.
+    //      Test_t *flnm     File name containing the background hits..
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(!GetITSgeom()) return;
+    AliITSgeom *geom = GetITSgeom();
+
+    const char *all = strstr(opt1,"All");
+    const char *det[3] ={strstr(opt1,"SPD"),strstr(opt1,"SDD"),
+                        strstr(opt1,"SSD")};
+    Int_t nmodules;
+    InitModules(size,nmodules);
+    FillModules(evNumber,bgrev,nmodules,opt0,flnm);
+
+    AliITSsimulation *sim      = 0;
+    AliITSDetType    *iDetType = 0;
+    AliITSmodule     *mod      = 0;
+    Int_t id,module;
+
+    //m.b. : this change is nothing but a nice way to make sure
+    //the CPU goes up !
+    for(module=0;module<geom->GetIndexMax();module++){
+       id       = geom->GetModuleType(module);
+        if (!all && !det[id]) continue;
+       iDetType = DetType(id);
+       sim      = (AliITSsimulation*)iDetType->GetSimulationModel();
+       if (!sim) {
+           Error("HitsToFastPoints",
+                 "The simulation class was not instanciated!");
+           exit(1);
+       } // end if !sim
+       mod      = (AliITSmodule *)fITSmodules->At(module);
+       sim->CreateFastRecPoints(mod,module,gRandom);
+    // gAlice->TreeR()->Fill(); 
+    TBranch *br=gAlice->TreeR()->GetBranch("ITSRecPointsF");
+    br->Fill();
+       ResetRecPoints();
+    } // end for module
+
+    ClearModules();
+
+    gAlice->TreeR()->AutoSave();
+    // reset tree
+    gAlice->TreeR()->Reset();
+}
+//______________________________________________________________________
+void AliITS::Digits2Reco(){
+    // Find clusters and reconstruct space points.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
+
+    AliHeader *header=gAlice->GetHeader();
+    // to Digits to RecPoints for event in file, all digits in file, and
+    // all ITS detectors.
+    DigitsToRecPoints(header->GetEvent(),0,fOpt);
+}
+//______________________________________________________________________
+void AliITS::DigitsToRecPoints(Int_t evNumber,Int_t lastentry,Option_t *opt){
+    // cluster finding and reconstruction of space points
+    // the condition below will disappear when the geom class will be
+    // initialized for all versions - for the moment it is only for v5 !
+    // 7 is the SDD beam test version
+    // Inputs:
+    //      Int_t evNumber   Event number to be processed.
+    //      Int_t lastentry  Offset for module when not all of the modules
+    //                       are processed.
+    //      Option_t *opt    String indicating which ITS sub-detectors should
+    //                       be processed. If ="All" then all of the ITS
+    //                       sub detectors are processed.
+    // Outputs:
+    //      none.
+    // Return:
+    //      none.
+
+    if(!GetITSgeom()) return;
+    AliITSgeom *geom = GetITSgeom();
     
-///////////////////////////////////////////////////////////////////////////////////////////////
-        TVector Vgeant(3);
-        Vgeant=result.GetVertex(); 
-                         
-  // Definition of Dv and Zv for vertex constraint     
-     Double_t sigmaDv=0.0050;  Double_t sigmaZv=0.010; 
-    //Double_t sigmaDv=0.0015;  Double_t sigmaZv=0.0015;                                 
-       Double_t uniform= gRandom->Uniform();
-       Double_t signdv;
-       if(uniform<=0.5) signdv=-1.;
-          else
-                signdv=1.;
-        
-       Double_t Vr=TMath::Sqrt(Vgeant(0)*Vgeant(0)+ Vgeant(1)*Vgeant(1));
-         Double_t Dv=gRandom->Gaus(signdv*Vr,(Float_t)sigmaDv); 
-    Double_t Zv=gRandom->Gaus(Vgeant(2),(Float_t)sigmaZv);
-                               
-  //cout<<" Dv e Zv = "<<Dv<<" "<<Zv<<"\n";                            
-    trackITS.SetDv(Dv);  trackITS.SetZv(Zv);
-    trackITS.SetsigmaDv(sigmaDv); trackITS.SetsigmaZv(sigmaZv); 
-    result.SetDv(Dv);  result.SetZv(Zv);
-    result.SetsigmaDv(sigmaDv); result.SetsigmaZv(sigmaZv);
-    primarytrack.SetDv(Dv);  primarytrack.SetZv(Zv);
-    primarytrack.SetsigmaDv(sigmaDv); primarytrack.SetsigmaZv(sigmaZv);                                                                
-
-/////////////////////////////////////////////////////////////////////////////////////////////////       
-               
-    primarytrack.PrimaryTrack(rl);
-    TVector  d2=primarytrack.Getd2();
-    TVector  tgl2=primarytrack.Gettgl2();
-    TVector  dtgl=primarytrack.Getdtgl();
-    trackITS.Setd2(d2); trackITS.Settgl2(tgl2);  trackITS.Setdtgl(dtgl); 
-    result.Setd2(d2); result.Settgl2(tgl2);  result.Setdtgl(dtgl);        
-        /*                      
-    trackITS.SetVertex(vertex); trackITS.SetErrorVertex(ervertex);
-    result.SetVertex(vertex);   result.SetErrorVertex(ervertex);   
-    */
-                         
-    Tracking(trackITS,&result,recPoints,vettid, flagvert,rl);  
-            
-    // cout<<" progressive track number = "<<j<<"\r";
-   // cout<<j<<"\r";
-    Int_t NumofCluster=result.GetNumClust();  
-//    cout<<" progressive track number = "<<j<<"\n";    // stampa
-    Long_t labITS=result.GetLabel();
-//    cout << " ITS track label = " << labITS << "\n";         // stampa           
-    int lab=track->GetLabel();             
-//    cout << " TPC track label = " << lab <<"\n";      // stampa
-        
-            
-//propagation to vertex
-       
-    Double_t rbeam=3.;
-     
-    result.Propagation(rbeam);
-                
-        Double_t C00,C10,C11,C20,C21,C22,C30,C31,C32,C33,C40,C41,C42,C43,C44;
-        result.GetCElements(C00,C10,C11,C20,C21,C22,C30,C31,C32,C33,C40,C41,C42,C43,C44);
-                
-    Double_t pt=TMath::Abs(result.GetPt());
-    Double_t Dr=result.GetD();
-    Double_t Z=result.GetZ();
-    Double_t tgl=result.GetTgl();
-    Double_t C=result.GetC();
-    Double_t Cy=C/2.;
-    Double_t Dz=Z-(tgl/Cy)*TMath::ASin(result.arga(rbeam));
-        Dz-=Vgeant(2);
-         
-        // cout<<" Dr e dz alla fine = "<<Dr<<" "<<Dz<<"\n"; getchar();
-    Double_t phi=result.Getphi();
-    Double_t phivertex = phi - TMath::ASin(result.argA(rbeam));
-    Double_t duepi=2.*TMath::Pi();      
-    if(phivertex>duepi) phivertex-=duepi;
-    if(phivertex<0.) phivertex+=duepi;
-    Double_t Dtot=TMath::Sqrt(Dr*Dr+Dz*Dz);
-        
-//////////////////////////////////////////////////////////////////////////////////////////     
-  
-    Int_t idmodule,idpoint;
-        if(NumofCluster >=5)  {            // cinque - sei
-        //if(NumofCluster ==6)  {            // cinque - sei 
-
-
-      AliITSiotrack outtrack;
-
-      iotrack=&outtrack;
-
-      iotrack->SetStatePhi(phi);
-      iotrack->SetStateZ(Z);
-      iotrack->SetStateD(Dr);
-      iotrack->SetStateTgl(tgl);
-      iotrack->SetStateC(C);
-               Double_t radius=result.Getrtrack();
-               iotrack->SetRadius(radius);
-               Int_t charge;
-               if(C>0.) charge=-1;  else charge=1;
-               iotrack->SetCharge(charge);
-               
-
-
-      iotrack->SetCovMatrix(C00,C10,C11,C20,C21,C22,C30,C31,C32,C33,C40,C41,C42,C43,C44);  
-
-      Double_t px=pt*TMath::Cos(phivertex);
-      Double_t py=pt*TMath::Sin(phivertex);
-      Double_t pz=pt*tgl;
-               
-      Double_t xtrack=Dr*TMath::Sin(phivertex);
-      Double_t ytrack=Dr*TMath::Cos(phivertex);
-      Double_t ztrack=Dz+Vgeant(2);
-
-
-      iotrack->SetPx(px);
-      iotrack->SetPy(py);
-      iotrack->SetPz(pz);
-      iotrack->SetX(xtrack);
-      iotrack->SetY(ytrack);
-      iotrack->SetZ(ztrack);
-      iotrack->SetLabel(labITS);
-               
-      Int_t il;                
-               for(il=0;il<6; il++){
-                 iotrack->SetIdPoint(il,result.GetIdPoint(il));
-                 iotrack->SetIdModule(il,result.GetIdModule(il));              
-               }
-      tracktree1.Fill();
-
-   //cout<<" labITS = "<<labITS<<"\n";
-       //cout<<" phi z Dr tgl C = "<<phi<<" "<<Z<<" "<<Dr<<" "<<tgl<<" "<<C<<"\n";  getchar();    
-
-     DataOut(kkk) = ptg; kkk++; DataOut(kkk)=labITS; kkk++; DataOut(kkk)=lab; kkk++;           
-
-      for (il=0;il<6;il++) {
-        idpoint=result.GetIdPoint(il);
-        idmodule=result.GetIdModule(il);
-       *(vettid[idmodule]+idpoint)=1; 
-       iotrack->SetIdPoint(il,idpoint);
-        iotrack->SetIdModule(il,idmodule);
-      }
-      
-    //  cout<<"  +++++++++++++  pt e ptg = "<<pt<<" "<<ptg<<"  ++++++++++\n";
-      Double_t difpt= (pt-ptg)/ptg*100.;                                       
-      DataOut(kkk)=difpt; kkk++;                                             
-      Double_t lambdag=TMath::ATan(pzg/ptg);
-      Double_t   lam=TMath::ATan(tgl);      
-      Double_t diflam = (lam - lambdag)*1000.;
-      DataOut(kkk) = diflam; kkk++;                                        
-      Double_t phig=TMath::ATan2(pyg,pxg);  if(phig<0) phig=2.*TMath::Pi()+phig;       
-      Double_t phi=phivertex;
-        
-      Double_t difphi = (phi - phig)*1000.;
-      DataOut(kkk)=difphi; kkk++;
-      DataOut(kkk)=Dtot*1.e4; kkk++;
-      DataOut(kkk)=Dr*1.e4; kkk++;
-      DataOut(kkk)=Dz*1.e4; kkk++; 
-      Int_t r;
-      for (r=0; r<9; r++) { out<<DataOut(r)<<" ";}
-      out<<"\n";
-      kkk=0;  
-               
-           
-    } // end if on NumofCluster
-  //gObjectTable->Print();    // stampa memoria     
-  }  //  end for (int j=min_t; j<=max_t; j++)
-  
-  out.close();  
-  //outprova.close();   
-  static Bool_t first=kTRUE;
-  static TFile *tfile;
-
-       if(first) {
-           tfile=new TFile("itstracks.root","RECREATE");
-           //cout<<"I have opened itstracks.root file "<<endl;
-       }           
-       first=kFALSE;
-       tfile->cd();
-       tfile->ls();
-
-   char hname[30];
-   sprintf(hname,"TreeT%d",evNumber);
-
-  tracktree1.Write(hname);
-
-
-  
-           TTree *fAli=gAlice->TreeK();
-            TFile *fileAli=0;
-           
-           if (fAli) fileAli =fAli->GetCurrentFile();
-           fileAli->cd();
-     
-  ////////////////////////////////////////////////////////////////////////////////////////////////
-
-  printf("delete vectors\n");
-  if(np) delete [] np;
-  if(vettid) delete [] vettid;
-  
+    const char *all = strstr(opt,"All");
+    const char *det[3] = {strstr(opt,"SPD"),strstr(opt,"SDD"),
+                         strstr(opt,"SSD")};
+    static Bool_t setRec=kTRUE;
+    if (setRec) SetDefaultClusterFinders();
+    setRec=kFALSE;
+
+    TTree *treeC=TreeC();
+    AliITSClusterFinder *rec     = 0;
+    AliITSDetType      *iDetType = 0;
+    Int_t id,module,first=0;
+    for(module=0;module<geom->GetIndexMax();module++){
+       id       = geom->GetModuleType(module);
+        if (!all && !det[id]) continue;
+       if(det[id]) first = geom->GetStartDet(id);
+       iDetType = DetType(id);
+       rec = (AliITSClusterFinder*)iDetType->GetReconstructionModel();
+        TClonesArray *itsDigits  = this->DigitsAddress(id);
+       if (!rec) {
+           Error("DigitsToRecPoints",
+                 "The reconstruction class was not instanciated!");
+           exit(1);
+       } // end if !rec
+       this->ResetDigits();
+       if (all) gAlice->TreeD()->GetEvent(lastentry+module);
+       else gAlice->TreeD()->GetEvent(lastentry+(module-first));
+       Int_t ndigits = itsDigits->GetEntriesFast();
+       if (ndigits) rec->FindRawClusters(module);
+    gAlice->TreeR()->Fill(); 
+       ResetRecPoints();
+       treeC->Fill();
+       ResetClusters();
+    } // end for module
+
+    gAlice->TreeR()->GetEntries();
+    treeC->GetEntries();
+    gAlice->TreeR()->AutoSave();
+    // reset tree
+    gAlice->TreeR()->Reset();
+
+    treeC->AutoSave();
+    treeC->Reset();
 }
+//______________________________________________________________________
+void AliITS::ResetRecPoints(){
+    // Reset number of rec points and the rec points array.
+    // Inputs:
+    //      none.
+    // Outputs:
+    //      none.
 
+    if (fRecPoints) fRecPoints->Clear();
+    fNRecPoints = 0;
+}