Fixes to calls for MeanMaterialBudget (now in AliTracker) (From Jouri Belikov)
[u/mrichter/AliRoot.git] / HMPID / AliHMPIDRecon.cxx
index 9db34ee..2d73103 100644 (file)
@@ -24,6 +24,7 @@
 #include "AliHMPIDRecon.h"   //class header
 #include "AliHMPIDParam.h"   //CkovAngle()
 #include "AliHMPIDCluster.h" //CkovAngle()
+#include <TMinuit.h>         //FitEllipse()
 #include <TRotation.h>       //TracePhot()
 #include <TH1D.h>            //HoughResponse()
 #include <TClonesArray.h>    //CkovAngle()
@@ -52,6 +53,14 @@ AliHMPIDRecon::AliHMPIDRecon():TTask("RichRec","RichPat"),
     fPhotPhi [i] = -1;
     fPhotWei [i] =  0;
   }
+//hidden algorithm
+  fMipX=fMipY=fThTrkFit=fPhTrkFit=fCkovFit=fMipQ=fRadX=fRadY=-999;
+  fIdxMip=fNClu=0;
+  fCkovSig2=0;
+  for (Int_t i=0; i<100; i++) {
+    fXClu[i] = fYClu[i] = 0;
+    fClCk[i] = kTRUE;
+  }
 }
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 void AliHMPIDRecon::CkovAngle(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t nmean)
@@ -66,12 +75,10 @@ void AliHMPIDRecon::CkovAngle(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t n
   if(pCluLst->GetEntries()>pParam->MultCut()) fIsWEIGHT = kTRUE; // offset to take into account bkg in reconstruction
   else                                        fIsWEIGHT = kFALSE;
 
-  Float_t xRa,yRa,th,ph;       
+  Float_t xRa,yRa,th,ph;
   pTrk->GetHMPIDtrk(xRa,yRa,th,ph);        //initialize this track: th and ph angles at middle of RAD 
-  
-  th=TMath::Pi()- th;                      // right XYZ local orientation
   SetTrack(xRa,yRa,th,ph);
-  
+
   fRadNmean=nmean;
 
   Float_t dMin=999,mipX=-1,mipY=-1;Int_t chId=-1,mipId=-1,mipQ=-1;                                                                           
@@ -99,10 +106,10 @@ void AliHMPIDRecon::CkovAngle(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t n
   pTrk->SetHMPIDcluIdx(chId,mipId);                                                           //set index of cluster
   if(iNacc<1)    pTrk->SetHMPIDsignal(kNoPhotAccept);                                         //no photon candidates is accepted
   else           pTrk->SetHMPIDsignal(FindRingCkov(pCluLst->GetEntries()));                   //find best Theta ckov for ring i.e. track
-  
+
   pTrk->SetHMPIDchi2(fCkovSigma2);                                                            //errors squared 
 
-}//ThetaCerenkov()
+}//CkovAngle()
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 Bool_t AliHMPIDRecon::FindPhotCkov(Double_t cluX,Double_t cluY,Double_t &thetaCer,Double_t &phiCer)
 {
@@ -112,24 +119,21 @@ Bool_t AliHMPIDRecon::FindPhotCkov(Double_t cluX,Double_t cluY,Double_t &thetaCe
 
   TVector3 dirCkov;
   
-  Double_t zRad= 0.5*AliHMPIDRecon::fgkRadThick
-                    +AliHMPIDRecon::fgkWinThick
-                    +AliHMPIDRecon::fgkGapThick;                    //z position of middle of RAD
-
-  TVector3 rad(fTrkPos.X(),fTrkPos.Y(),zRad);                       //impact point at middle of RAD
-  TVector3  pc(cluX,cluY,0);                                        //mip at PC: z=0 @ PC
+  Double_t zRad= -0.5*fgkRadThick-0.5*fgkWinThick;                   //z position of middle of RAD
+  TVector3 rad(fTrkPos.X(),fTrkPos.Y(),zRad);                        //impact point at middle of RAD
+  TVector3  pc(cluX,cluY,0.5*fgkWinThick+fgkGapIdx);                 //mip at PC
   Double_t cluR = TMath::Sqrt((cluX-fTrkPos.X())*(cluX-fTrkPos.X())+
                               (cluY-fTrkPos.Y())*(cluY-fTrkPos.Y()));//ref. distance impact RAD-CLUSTER   
-  Double_t phi=(pc-rad).Phi();                                      //phi of photon
+  Double_t phi=(pc-rad).Phi();                                       //phi of photon
     
   Double_t ckov1=0;
-  Double_t ckov2=TMath::Pi()-fTrkDir.Theta()+0.75; //start to find theta cerenkov in DRS
+  Double_t ckov2=0.75+fTrkDir.Theta();                        //start to find theta cerenkov in DRS
   const Double_t kTol=0.01;
   Int_t iIterCnt = 0;
   while(1){
     if(iIterCnt>=50) return kFALSE;
     Double_t ckov=0.5*(ckov1+ckov2);
-    dirCkov.SetMagThetaPhi(1,TMath::Pi()-ckov,phi);
+    dirCkov.SetMagThetaPhi(1,ckov,phi);
     TVector2 posC=TraceForward(dirCkov);                      //trace photon with actual angles
     Double_t dist=cluR-(posC-fTrkPos).Mod();                  //get distance between trial point and cluster position
     if(posC.X()==-999) dist = - 999;                          //total reflection problem
@@ -139,7 +143,6 @@ Bool_t AliHMPIDRecon::FindPhotCkov(Double_t cluX,Double_t cluY,Double_t &thetaCe
     else{                                                     //precision achived: ckov in DRS found
       dirCkov.SetMagThetaPhi(1,ckov,phi);                     //
       RecPhot(dirCkov,thetaCer,phiCer);                       //find ckov (in TRS:the effective Cherenkov angle!)
-      thetaCer = TMath::Pi() - thetaCer;
       return kTRUE;
     }
   }
@@ -151,17 +154,15 @@ TVector2 AliHMPIDRecon::TraceForward(TVector3 dirCkov)const
   // Arguments: dirCkov photon vector in LORS
   //   Returns: pos of traced photon at PC
   TVector2 pos(-999,-999);
-  Double_t thetaCer = TMath::Pi()-dirCkov.Theta();
-  if(thetaCer > TMath::ASin(1./fRadNmean))  return pos;            //total refraction on WIN-GAP boundary
-  Double_t zRad= 0.5*AliHMPIDRecon::fgkRadThick
-                    +AliHMPIDRecon::fgkWinThick
-                    +AliHMPIDRecon::fgkGapThick;                   //z position of middle of RAD
-  TVector3  posCkov(fTrkPos.X(),fTrkPos.Y(),zRad);                 //RAD: photon position is track position @ middle of RAD 
-  Propagate(dirCkov,posCkov,fgkWinThick+fgkGapThick);              //go to RAD-WIN boundary  
-  Refract  (dirCkov,         fRadNmean,fgkWinIdx   );              //RAD-WIN refraction
-  Propagate(dirCkov,posCkov,            fgkGapThick);              //go to WIN-GAP boundary
-  Refract  (dirCkov,         fgkWinIdx,fgkGapIdx   );              //WIN-GAP refraction
-  Propagate(dirCkov,posCkov,                      0);              //go to PC
+  Double_t thetaCer = dirCkov.Theta();
+  if(thetaCer > TMath::ASin(1./fRadNmean))  return pos;         //total refraction on WIN-GAP boundary
+  Double_t zRad= -0.5*fgkRadThick-0.5*fgkWinThick;              //z position of middle of RAD
+  TVector3  posCkov(fTrkPos.X(),fTrkPos.Y(),zRad);              //RAD: photon position is track position @ middle of RAD 
+  Propagate(dirCkov,posCkov,           -0.5*fgkWinThick);       //go to RAD-WIN boundary  
+  Refract  (dirCkov,         fRadNmean,fgkWinIdx);              //RAD-WIN refraction
+  Propagate(dirCkov,posCkov,            0.5*fgkWinThick);       //go to WIN-GAP boundary
+  Refract  (dirCkov,         fgkWinIdx,fgkGapIdx);              //WIN-GAP refraction
+  Propagate(dirCkov,posCkov,0.5*fgkWinThick+fgkGapThick);       //go to PC
   pos.Set(posCkov.X(),posCkov.Y());
   return pos;
 }//TraceForward()
@@ -268,8 +269,6 @@ TVector2 AliHMPIDRecon::TracePhot(Double_t ckovThe,Double_t ckovPhi)const
   TRotation mrot=mphi*mtheta;
   TVector3  dirCkov,dirCkovTors;   
 
-  ckovThe = TMath::Pi()-ckovThe;
-  
   dirCkovTors.SetMagThetaPhi(1,ckovThe,ckovPhi);                    //initially photon is directed according to requested ckov angle
   dirCkov=mrot*dirCkovTors;                                         //now we know photon direction in LORS
   return TraceForward(dirCkov);
@@ -298,15 +297,16 @@ void AliHMPIDRecon::Refract(TVector3 &dir,Double_t n1,Double_t n2)const
 //            n2 - ref idx of second substance
 //   Returns: none
 //   On exit: dir is new direction
-  Double_t sinref=(n1/n2)*TMath::Sin(TMath::Pi()-dir.Theta());
+  Double_t sinref=(n1/n2)*TMath::Sin(dir.Theta());
   if(sinref>1.)    dir.SetXYZ(-999,-999,-999);
-  else             dir.SetTheta(TMath::Pi()-TMath::ASin(sinref));
+  else             dir.SetTheta(TMath::ASin(sinref));
 }//Refract()
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 Double_t AliHMPIDRecon::HoughResponse()
 {
 //
-//
+//    fIdxMip = mipId;
+
 //       
   Double_t kThetaMax=0.75;
   Int_t nChannels = (Int_t)(kThetaMax/fDTheta+0.5);
@@ -343,7 +343,7 @@ Double_t AliHMPIDRecon::HoughResponse()
 // evaluate the "BEST" theta ckov as the maximum value of histogramm
   Double_t *pVec = resultw->GetArray();
   Int_t locMax = TMath::LocMax(nBin,pVec);
-  phots->Delete();photsw->Delete();resultw->Delete(); // Reset and delete objects
+  delete phots;delete photsw;delete resultw; // Reset and delete objects
   
   return (Double_t)(locMax*fDTheta+0.5*fDTheta); //final most probable track theta ckov   
 }//HoughResponse()
@@ -359,6 +359,9 @@ Double_t AliHMPIDRecon::Sigma2(Double_t ckovTh, Double_t ckovPh)const
   
   TVector3 v(-999,-999,-999);
   Double_t trkBeta = 1./(TMath::Cos(ckovTh)*fRadNmean);
+  
+  if(trkBeta > 1) trkBeta = 1;                 //protection against bad measured thetaCer  
+  if(trkBeta < 0) trkBeta = 0.0001;            //
 
   v.SetX(SigLoc (ckovTh,ckovPh,trkBeta));
   v.SetY(SigGeom(ckovTh,ckovPh,trkBeta));
@@ -375,20 +378,29 @@ Double_t AliHMPIDRecon::SigLoc(Double_t thetaC, Double_t phiC,Double_t betaM)con
 //            dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]        
 //            MIP beta
 //   Returns: absolute error on Cerenkov angle, [radians]    
+  
   Double_t phiDelta = phiC - fTrkDir.Phi();
 
-  Double_t alpha =TMath::Cos(fTrkDir.Theta())-TMath::Tan(thetaC)*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Theta());
-  Double_t k = 1.-fRadNmean*fRadNmean+alpha*alpha/(betaM*betaM);
+  Double_t sint     = TMath::Sin(fTrkDir.Theta());
+  Double_t cost     = TMath::Cos(fTrkDir.Theta());
+  Double_t sinf     = TMath::Sin(fTrkDir.Phi());
+  Double_t cosf     = TMath::Cos(fTrkDir.Phi());
+  Double_t sinfd    = TMath::Sin(phiDelta);
+  Double_t cosfd    = TMath::Cos(phiDelta);
+  Double_t tantheta = TMath::Tan(thetaC);
+  
+  Double_t alpha =cost-tantheta*cosfd*sint;                                                 // formula (11)
+  Double_t k = 1.-fRadNmean*fRadNmean+alpha*alpha/(betaM*betaM);                            // formula (after 8 in the text)
   if (k<0) return 1e10;
+  Double_t mu =sint*sinf+tantheta*(cost*cosfd*sinf+sinfd*cosf);                             // formula (10)
+  Double_t e  =sint*cosf+tantheta*(cost*cosfd*cosf-sinfd*sinf);                             // formula (9)
 
-  Double_t mu =TMath::Sin(fTrkDir.Theta())*TMath::Sin(fTrkDir.Phi())+TMath::Tan(thetaC)*(TMath::Cos(fTrkDir.Theta())*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Phi())+TMath::Sin(phiDelta)*TMath::Cos(fTrkDir.Phi()));
-  Double_t e  =TMath::Sin(fTrkDir.Theta())*TMath::Cos(fTrkDir.Phi())+TMath::Tan(thetaC)*(TMath::Cos(fTrkDir.Theta())*TMath::Cos(phiDelta)*TMath::Cos(fTrkDir.Phi())-TMath::Sin(phiDelta)*TMath::Sin(fTrkDir.Phi()));
-
-  Double_t kk = betaM*TMath::Sqrt(k)/(8*alpha);
-  Double_t dtdxc = kk*(k*(TMath::Cos(phiDelta)*TMath::Cos(fTrkDir.Phi())-TMath::Cos(fTrkDir.Theta())*TMath::Sin(phiDelta)*TMath::Sin(fTrkDir.Phi()))-(alpha*mu/(betaM*betaM))*TMath::Sin(fTrkDir.Theta())*TMath::Sin(phiDelta));
-  Double_t dtdyc = kk*(k*(TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Phi())+TMath::Cos(fTrkDir.Theta())*TMath::Sin(phiDelta)*TMath::Cos(fTrkDir.Phi()))+(alpha* e/(betaM*betaM))*TMath::Sin(fTrkDir.Theta())*TMath::Sin(phiDelta));
+  Double_t kk = betaM*TMath::Sqrt(k)/(fgkGapThick*alpha);                                   // formula (6) and (7)
+  Double_t dtdxc = kk*(k*(cosfd*cosf-cost*sinfd*sinf)-(alpha*mu/(betaM*betaM))*sint*sinfd); // formula (6)           
+  Double_t dtdyc = kk*(k*(cosfd*sinf+cost*sinfd*cosf)+(alpha* e/(betaM*betaM))*sint*sinfd); // formula (7)            pag.4
 
-  return  TMath::Sqrt(0.2*0.2*dtdxc*dtdxc + 0.25*0.25*dtdyc*dtdyc);
+  Double_t errX = 0.2,errY=0.25;                                                            //end of page 7
+  return  TMath::Sqrt(errX*errX*dtdxc*dtdxc + errY*errY*dtdyc*dtdyc);
 }
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 Double_t AliHMPIDRecon::SigCrom(Double_t thetaC, Double_t phiC,Double_t betaM)const
@@ -399,12 +411,19 @@ Double_t AliHMPIDRecon::SigCrom(Double_t thetaC, Double_t phiC,Double_t betaM)co
 //            dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]        
 //            MIP beta
 //   Returns: absolute error on Cerenkov angle, [radians]    
+  
   Double_t phiDelta = phiC - fTrkDir.Phi();
-  Double_t alpha =TMath::Cos(fTrkDir.Theta())-TMath::Tan(thetaC)*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Theta());
 
-  Double_t dtdn = TMath::Cos(fTrkDir.Theta())*fRadNmean*betaM*betaM/(alpha*TMath::Tan(thetaC));
+  Double_t sint     = TMath::Sin(fTrkDir.Theta());
+  Double_t cost     = TMath::Cos(fTrkDir.Theta());
+  Double_t cosfd    = TMath::Cos(phiDelta);
+  Double_t tantheta = TMath::Tan(thetaC);
+  
+  Double_t alpha =cost-tantheta*cosfd*sint;                                                 // formula (11)
+  Double_t dtdn = cost*fRadNmean*betaM*betaM/(alpha*tantheta);                              // formula (12)
             
-  Double_t f = 0.00928*(7.75-5.635)/TMath::Sqrt(12.);
+//  Double_t f = 0.00928*(7.75-5.635)/TMath::Sqrt(12.);
+  Double_t f = 0.0172*(7.75-5.635)/TMath::Sqrt(24.);
 
   return f*dtdn;
 }//SigCrom()
@@ -419,21 +438,307 @@ Double_t AliHMPIDRecon::SigGeom(Double_t thetaC, Double_t phiC,Double_t betaM)co
 //   Returns: absolute error on Cerenkov angle, [radians]    
 
   Double_t phiDelta = phiC - fTrkDir.Phi();
-  Double_t alpha =TMath::Cos(fTrkDir.Theta())-TMath::Tan(thetaC)*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Theta());
 
-  Double_t k = 1.-fRadNmean*fRadNmean+alpha*alpha/(betaM*betaM);
+  Double_t sint     = TMath::Sin(fTrkDir.Theta());
+  Double_t cost     = TMath::Cos(fTrkDir.Theta());
+  Double_t sinf     = TMath::Sin(fTrkDir.Phi());
+  Double_t cosfd    = TMath::Cos(phiDelta);
+  Double_t costheta = TMath::Cos(thetaC);
+  Double_t tantheta = TMath::Tan(thetaC);
+  
+  Double_t alpha =cost-tantheta*cosfd*sint;                                                  // formula (11)
+  
+  Double_t k = 1.-fRadNmean*fRadNmean+alpha*alpha/(betaM*betaM);                             // formula (after 8 in the text)
   if (k<0) return 1e10;
 
-  Double_t eTr = 0.5*1.5*betaM*TMath::Sqrt(k)/(8*alpha);
-  Double_t lambda = 1.-TMath::Sin(fTrkDir.Theta())*TMath::Sin(fTrkDir.Theta())*TMath::Sin(phiC)*TMath::Sin(phiC);
-
-  Double_t c = 1./(1.+ eTr*k/(alpha*alpha*TMath::Cos(thetaC)*TMath::Cos(thetaC)));
-  Double_t i = betaM*TMath::Tan(thetaC)*lambda*TMath::Power(k,1.5);
-  Double_t ii = 1.+eTr*betaM*i;
+  Double_t eTr = 0.5*fgkRadThick*betaM*TMath::Sqrt(k)/(fgkGapThick*alpha);                   // formula (14)
+  Double_t lambda = 1.-sint*sint*sinf*sinf;                                                  // formula (15)
 
-  Double_t err = c * (i/(alpha*alpha*8) +  ii*(1.-lambda) / ( alpha*alpha*8*betaM*(1.+eTr)) );
-  Double_t trErr = 1.5/(TMath::Sqrt(12.)*TMath::Cos(fTrkDir.Theta()));
+  Double_t c1 = 1./(1.+ eTr*k/(alpha*alpha*costheta*costheta));                              // formula (13.a)
+  Double_t c2 = betaM*TMath::Power(k,1.5)*tantheta*lambda/(fgkGapThick*alpha*alpha);         // formula (13.b)
+  Double_t c3 = (1.+eTr*k*betaM*betaM)/((1+eTr)*alpha*alpha);                                // formula (13.c)
+  Double_t c4 = TMath::Sqrt(k)*tantheta*(1-lambda)/(fgkGapThick*betaM);                      // formula (13.d)
+  Double_t dtdT = c1 * (c2+c3*c4);
+  Double_t trErr = fgkRadThick/(TMath::Sqrt(12.)*cost);
 
-  return trErr*err;
+  return trErr*dtdT;
 }//SigGeom()
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+//
+// From here HTA....
+//
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Bool_t AliHMPIDRecon::CkovHiddenTrk(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t nmean)
+{
+// Pattern recognition method without any infos from tracking:HTA (Hidden Track Algorithm)...
+// The method finds in the chmber the cluster with the highest charge
+// compatibile with a MIP, then the strategy is applied
+// Arguments:  pTrk     - pointer to ESD track
+//             pCluLs   - list of clusters for a given chamber 
+//             nmean    - mean freon ref. index
+//   Returns:           - 0=ok,1=not fitted 
+  
+  AliHMPIDParam *pParam=AliHMPIDParam::Instance();
+    
+  fRadNmean=nmean;
+
+  if(pCluLst->GetEntriesFast()>100) return kFALSE;                                            //boundary check for CluX,CluY...
+  Float_t mipX=-1,mipY=-1;Int_t mipId=-1,mipQ=-1;                                                                           
+  Double_t qRef = 0;
+  Int_t nCh=0;
+  for (Int_t iClu=0;iClu<pCluLst->GetEntriesFast();iClu++){                                   //clusters loop
+    AliHMPIDCluster *pClu=(AliHMPIDCluster*)pCluLst->UncheckedAt(iClu);                       //get pointer to current cluster    
+    nCh = pClu->Ch();
+    fXClu[iClu] = pClu->X();fYClu[iClu] = pClu->Y();                                          //store x,y for fitting procedure
+    fClCk[iClu] = kTRUE;                                                                      //all cluster are accepted at this stage to be reconstructed
+    if(pClu->Q()>qRef){                                                                       //searching the highest charge to select a MIP      
+      qRef = pClu->Q();
+      mipId=iClu; mipX=pClu->X();mipY=pClu->Y();mipQ=(Int_t)pClu->Q();
+    }                                                                                    
+  }//clusters loop
+
+  fNClu = pCluLst->GetEntriesFast();
+  if(qRef>pParam->QCut()){                                                                     //charge compartible with MIP clusters
+    fIdxMip = mipId;
+    fClCk[mipId] = kFALSE;
+    fMipX = mipX; fMipY=mipY; fMipQ = qRef;
+    if(!DoRecHiddenTrk(pCluLst)) {
+      pTrk->SetHMPIDsignal(kNoPhotAccept);
+      return kFALSE;
+    }                                                                           //Do track and ring reconstruction,if problems returns 1
+    pTrk->SetHMPIDtrk(fRadX,fRadY,fThTrkFit,fPhTrkFit);                                        //store track intersection info
+    pTrk->SetHMPIDmip(fMipX,fMipY,(Int_t)fMipQ,fNClu);                                         //store mip info 
+    pTrk->SetHMPIDcluIdx(nCh,fIdxMip);                                                         //set cham number and index of cluster
+    pTrk->SetHMPIDsignal(fCkovFit);                                                            //find best Theta ckov for ring i.e. track
+    pTrk->SetHMPIDchi2(fCkovSig2);                                                             //errors squared
+//    Printf(" n clusters tot %i accepted %i",pCluLst->GetEntriesFast(),fNClu);
+    return kTRUE;
+  }
+  
+  return kFALSE;
+}//CkovHiddenTrk()
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Bool_t AliHMPIDRecon::DoRecHiddenTrk(TClonesArray *pCluLst)
+{
+// Pattern recognition method without any infos from tracking...
+// First a preclustering filter to avoid part of the noise
+// Then only ellipsed-rings are fitted (no possibility, 
+// for the moment, to reconstruct very inclined tracks)
+// Finally a fitting with (th,ph) free, starting by very close values
+// previously evaluated.
+// Arguments:   none
+//   Returns:   none
+  Double_t phiRec;
+  if(!CluPreFilter(pCluLst)) {return kFALSE;}
+  if(!FitEllipse(phiRec)) {return kFALSE;}
+  Int_t nClTmp1 = pCluLst->GetEntriesFast()-1;  //minus MIP...
+  Int_t nClTmp2 = 0;
+  while(nClTmp1 != nClTmp2){
+    SetNClu(pCluLst->GetEntriesFast());
+    if(!FitFree(phiRec)) {return kFALSE;}
+    nClTmp2 = NClu();
+    if(nClTmp2!=nClTmp1) {nClTmp1=nClTmp2;nClTmp2=0;}
+  }
+  fNClu = nClTmp2;
+  return kTRUE;
+}//DoRecHiddenTrk()
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Bool_t AliHMPIDRecon::CluPreFilter(TClonesArray *pCluLst)
+{
+// Filter of bkg clusters
+// based on elliptical-shapes...
+//
+  if(pCluLst->GetEntriesFast()>50||pCluLst->GetEntriesFast()<4) return kFALSE; 
+  else return kTRUE;
+}
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Bool_t AliHMPIDRecon::FitEllipse(Double_t &phiRec)
+{
+//Fit a set of clusters with an analitical conical section function:
+  //
+  // Ax^2 + B*y^2 + 2Hxy + 2Gx + 2Fy + 1 = 0   ---> conical section
+  //
+  //  H*H - A*B > 0 hyperbola
+  //            < 0 ellipse
+  //            = 0 parabola
+  //
+  // tan 2alfa = 2H/(A-B)  alfa=angle of rotation
+  //
+  // coordinate of the centre of the conical section:
+  //   x = x' + a
+  //   y = y' + b
+  //
+  //       HF - BG
+  //  a = ---------
+  //       AB - H^2
+  //
+  //       HG - AF
+  //  b = --------
+  //       AB - H^2
+  Double_t cA,cB,cF,cG,cH;
+  Double_t aArg=-1;      Int_t iErrFlg;                                                //tmp vars for TMinuit
+
+  if(!gMinuit) gMinuit = new TMinuit(5);                                               //init MINUIT with this number of parameters (5 params)
+  gMinuit->mncler();                                                                   // reset Minuit list of paramters
+  gMinuit->SetObjectFit((TObject*)this);  gMinuit->SetFCN(AliHMPIDRecon::FunMinEl);    //set fit function
+  gMinuit->mnexcm("SET PRI",&aArg,1,iErrFlg);                                          //suspend all printout from TMinuit 
+  gMinuit->mnexcm("SET NOW",&aArg,0,iErrFlg);                                          //suspend all warning printout from TMinuit
+  
+  Double_t d1,d2,d3;
+  TString sName;
+
+  gMinuit->mnparm(0," A ",1,0.01,0,0,iErrFlg);
+  gMinuit->mnparm(1," B ",1,0.01,0,0,iErrFlg);
+  gMinuit->mnparm(2," H ",1,0.01,0,0,iErrFlg);
+  gMinuit->mnparm(3," G ",1,0.01,0,0,iErrFlg);
+  gMinuit->mnparm(4," F ",1,0.01,0,0,iErrFlg);
+
+  gMinuit->mnexcm("SIMPLEX",&aArg,0,iErrFlg);
+  gMinuit->mnexcm("MIGRAD" ,&aArg,0,iErrFlg);   
+  gMinuit->mnpout(0,sName,cA,d1,d2,d3,iErrFlg);
+  gMinuit->mnpout(1,sName,cB,d1,d2,d3,iErrFlg);
+  gMinuit->mnpout(2,sName,cH,d1,d2,d3,iErrFlg);
+  gMinuit->mnpout(3,sName,cG,d1,d2,d3,iErrFlg);
+  gMinuit->mnpout(4,sName,cF,d1,d2,d3,iErrFlg);
+  delete gMinuit;
+
+  Double_t i2 = cA*cB-cH*cH;                                       //quartic invariant : i2 > 0  ellipse, i2 < 0 hyperbola
+  if(i2<=0) return kFALSE;
+  Double_t aX = (cH*cF-cB*cG)/i2;                                  //x centre of the canonical section 
+  Double_t bY = (cH*cG-cA*cF)/i2;                                  //y centre of the canonical section 
+  Double_t alfa1 = TMath::ATan(2*cH/(cA-cB));                      //alpha = angle of rotation of the conical section
+  if(alfa1<0) alfa1+=TMath::Pi(); 
+  alfa1*=0.5;
+//  Double_t alfa2 = alfa1+TMath::Pi();
+  Double_t phiref = TMath::ATan2(bY-fMipY,aX-fMipX);               //evaluate in a unique way the angle of rotation comparing it
+  if(phiref<0) phiref+=TMath::TwoPi();                             //with the vector that points to the centre from the mip 
+  if(i2<0) phiref+=TMath::Pi();
+  if(phiref>TMath::TwoPi()) phiref-=TMath::TwoPi();
+
+//  Printf(" alfa1 %f",alfa1*TMath::RadToDeg());
+//  Printf(" alfa2 %f",alfa2*TMath::RadToDeg());
+//  Printf(" firef %f",phiref*TMath::RadToDeg());
+//  if(TMath::Abs(alfa1-phiref)<TMath::Abs(alfa2-phiref)) phiRec = alfa1; else phiRec = alfa2;  
+  
+//  Printf("FitEllipse: phi reconstructed %f",phiRec*TMath::RadToDeg());
+  phiRec=phiref;
+  return kTRUE;
+//
+}
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Bool_t AliHMPIDRecon::FitFree(Double_t phiRec)
+{
+// Fit performed by minimizing RMS/sqrt(n) of the
+// photons reconstructed. First phi is fixed and theta
+// is fouond, then (th,ph) of the track
+// as free parameters
+// Arguments:    PhiRec phi of the track
+//   Returns:    none
+  Double_t aArg=-1;  Int_t iErrFlg;                                                    //tmp vars for TMinuit
+  if(!gMinuit) gMinuit = new TMinuit(2);                                               //init MINUIT with this number of parameters (5 params)
+  gMinuit->mncler();                                                                   // reset Minuit list of paramters
+  gMinuit->SetObjectFit((TObject*)this);  gMinuit->SetFCN(AliHMPIDRecon::FunMinPhot);  //set fit function
+  gMinuit->mnexcm("SET PRI",&aArg,1,iErrFlg);                                          //suspend all printout from TMinuit 
+  gMinuit->mnexcm("SET NOW",&aArg,0,iErrFlg);                                          //suspend all warning printout from TMinuit
+  
+  Double_t d1,d2,d3;
+  TString sName;
+  Double_t th,ph;
+  
+  gMinuit->mnparm(0," theta ",  0.01,0.01,0,TMath::PiOver2(),iErrFlg);
+  gMinuit->mnparm(1," phi   ",phiRec,0.01,0,TMath::TwoPi()  ,iErrFlg);
+  
+  gMinuit->FixParameter(1);
+  gMinuit->mnexcm("SIMPLEX" ,&aArg,0,iErrFlg);   
+  gMinuit->mnexcm("MIGRAD"  ,&aArg,0,iErrFlg);
+  gMinuit->Release(1);  
+  gMinuit->mnexcm("MIGRAD"  ,&aArg,0,iErrFlg);
+  
+  gMinuit->mnpout(0,sName,th,d1,d2,d3,iErrFlg);
+  gMinuit->mnpout(1,sName,ph,d1,d2,d3,iErrFlg);   
+
+  Double_t outPar[2] = {th,ph}; Double_t g; Double_t f;Int_t flag = 3;
+  gMinuit->Eval(2, &g, f, outPar,flag);  
+
+  SetTrkFit(th,ph);
+  
+  return kTRUE;
+}
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Double_t AliHMPIDRecon::FunConSect(Double_t *c,Double_t x,Double_t y)
+{
+  return c[0]*x*x+c[1]*y*y+2*c[2]*x*y+2*c[3]*x+2*c[4]*y+1;
+}
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+void AliHMPIDRecon::FunMinEl(Int_t &/* */,Double_t* /* */,Double_t &f,Double_t *par,Int_t /* */)
+{
+  AliHMPIDRecon *pRec=(AliHMPIDRecon*)gMinuit->GetObjectFit();
+  Double_t minFun = 0;
+  Int_t np = pRec->NClu();
+  for(Int_t i=0;i<np;i++) {
+    if(i==pRec->IdxMip()) continue;
+    Double_t el = pRec->FunConSect(par,pRec->XClu(i),pRec->YClu(i));
+    minFun +=el*el;
+  }
+  f = minFun;
+}
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+void AliHMPIDRecon::FunMinPhot(Int_t &/* */,Double_t* /* */,Double_t &f,Double_t *par,Int_t iflag)
+{
+  AliHMPIDRecon *pRec=(AliHMPIDRecon*)gMinuit->GetObjectFit();
+  Double_t sizeCh = 0.5*fgkRadThick+fgkWinThick+fgkGapThick;
+  Double_t thTrk = par[0]; 
+  Double_t phTrk = par[1]; 
+  Double_t xrad = pRec->MipX() - sizeCh*TMath::Tan(thTrk)*TMath::Cos(phTrk);
+  Double_t yrad = pRec->MipY() - sizeCh*TMath::Tan(thTrk)*TMath::Sin(phTrk);
+  pRec->SetRadXY(xrad,yrad);
+  pRec->SetTrack(xrad,yrad,thTrk,phTrk);
+
+  Double_t meanCkov =0;
+  Double_t meanCkov2=0;
+  Double_t thetaCer,phiCer;
+  Int_t nClAcc = 0;
+  Int_t nClTot=pRec->NClu();
+    
+  for(Int_t i=0;i<nClTot;i++) {
+    if(!(pRec->ClCk(i))) continue;
+    pRec->FindPhotCkov(pRec->XClu(i),pRec->YClu(i),thetaCer,phiCer);  
+    meanCkov  += thetaCer;
+    meanCkov2 += thetaCer*thetaCer;
+    nClAcc++;
+  }
+  if(nClAcc==0) {f=999;return;}
+  meanCkov/=nClAcc;
+  Double_t rms = (meanCkov2 - meanCkov*meanCkov*nClAcc)/nClAcc;
+  if(rms<0) Printf(" rms2 = %f, strange!!!",rms);
+  rms = TMath::Sqrt(rms);
+  f = rms/TMath::Sqrt(nClAcc);
+  
+  
+  if(iflag==3) {
+    Printf("FunMinPhot before: photons candidates %i used %i",nClTot,nClAcc);
+    nClAcc = 0;
+    Double_t meanCkov1=0;
+    Double_t meanCkov2=0;
+    for(Int_t i=0;i<nClTot;i++) {
+      if(!(pRec->ClCk(i))) continue;
+      pRec->FindPhotCkov(pRec->XClu(i),pRec->YClu(i),thetaCer,phiCer);  
+      if(TMath::Abs(thetaCer-meanCkov)<2*rms) {
+        meanCkov1 += thetaCer;
+        meanCkov2 += thetaCer*thetaCer;
+        nClAcc++;
+      } else pRec->SetClCk(i,kFALSE);
+    }
+    meanCkov1/=nClAcc;
+    Double_t rms2 = (meanCkov2 - meanCkov*meanCkov*nClAcc)/nClAcc;
+    Printf("FunMinPhot after: photons candidates %i used %i thetaCer %f",nClTot,nClAcc,meanCkov1);
+    pRec->SetCkovFit(meanCkov1);
+    pRec->SetCkovSig2(rms2);
+    pRec->SetNClu(nClAcc);
+  }
+}//FunMinPhot()
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+//
+// ended Hidden track algorithm....
+//
+//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++