}
//____________________________________________________________________________
-Bool_t AliEMCALClusterizerv1::FindFit(AliEMCALRecPoint * emcRP, AliEMCALDigit ** maxAt, Float_t * maxAtEnergy,
- Int_t nPar, Float_t * fitparameters) const
-{
- // Calls TMinuit to fit the energy distribution of a cluster with several maxima
- // The initial values for fitting procedure are set equal to the positions of local maxima.
- // Cluster will be fitted as a superposition of nPar/3 electromagnetic showers
+Bool_t AliEMCALClusterizerv1::FindFit(AliEMCALRecPoint * RecPoint, AliEMCALDigit ** maxAt,
+ Float_t* maxAtEnergy,
+ Int_t nPar, Float_t * fitparameters) const
+{
+ // Calls TMinuit to fit the energy distribution of a cluster with several maxima
+ // The initial values for fitting procedure are set equal to the
+ // positions of local maxima.
+ // Cluster will be fitted as a superposition of nPar/3
+ // electromagnetic showers
+
+ if (fGeom==0) AliFatal("Did not get geometry from EMCALLoader");
gMinuit->mncler(); // Reset Minuit's list of paramters
gMinuit->SetPrintLevel(-1) ; // No Printout
- gMinuit->SetFCN(AliEMCALClusterizerv1::UnfoldingChiSquare) ;
- // To set the address of the minimization function
+ gMinuit->SetFCN(AliEMCALClusterizerv1::UnfoldingChiSquare) ;
+ // To set the address of the minimization function
TList * toMinuit = new TList();
- toMinuit->AddAt(emcRP,0) ;
+ toMinuit->AddAt(RecPoint,0) ;
toMinuit->AddAt(fDigitsArr,1) ;
-
+ toMinuit->AddAt(fGeom,2) ;
+
gMinuit->SetObjectFit(toMinuit) ; // To tranfer pointer to UnfoldingChiSquare
// filling initial values for fit parameters
AliEMCALDigit * digit ;
- Int_t ierflg = 0;
+ Int_t ierflg = 0;
Int_t index = 0 ;
Int_t nDigits = (Int_t) nPar / 3 ;
Int_t iDigit ;
for(iDigit = 0; iDigit < nDigits; iDigit++){
- digit = maxAt[iDigit];
+ digit = maxAt[iDigit];
+ Double_t x = 0.;
+ Double_t y = 0.;
+ Double_t z = 0.;
- Float_t x = 0.;
- Float_t z = 0.;
- // have to be tune for TRD1; May 31,06
- // Int_t relid[2] ;
- // fGeom->AbsToRelNumbering(digit->GetId(), relid) ; // obsolete method
- // fGeom->PosInAlice(relid, x, z) ; // obsolete method
+ fGeom->RelPosCellInSModule(digit->GetId(), y, x, z);
Float_t energy = maxAtEnergy[iDigit] ;
gMinuit->mnparm(index, "x", x, 0.1, 0, 0, ierflg) ;
- index++ ;
- if(ierflg != 0){
- Error("FindFit", "EMCAL Unfolding Unable to set initial value for fit procedure : x = %f", x ) ;
+ index++ ;
+ if(ierflg != 0){
+ Error("FindFit", "EMCAL Unfolding Unable to set initial value for fit procedure : x = %f", x ) ;
return kFALSE;
}
gMinuit->mnparm(index, "z", z, 0.1, 0, 0, ierflg) ;
- index++ ;
+ index++ ;
if(ierflg != 0){
- Error("FindFit", "EMCAL Unfolding Unable to set initial value for fit procedure : z = %f", z) ;
+ Error("FindFit", "EMCAL Unfolding Unable to set initial value for fit procedure : z = %f", z) ;
return kFALSE;
}
gMinuit->mnparm(index, "Energy", energy , 0.05*energy, 0., 4.*energy, ierflg) ;
- index++ ;
+ index++ ;
if(ierflg != 0){
- Error("FindFit", "EMCAL Unfolding Unable to set initial value for fit procedure : energy = %f", energy) ;
+ Error("FindFit", "EMCAL Unfolding Unable to set initial value for fit procedure : energy = %f", energy) ;
return kFALSE;
}
}
- Double_t p0 = 0.1 ; // "Tolerance" Evaluation stops when EDM = 0.0001*p0 ; The number of function call slightly
- // depends on it.
+ Double_t p0 = 0.1 ; // "Tolerance" Evaluation stops when EDM = 0.0001*p0 ;
+ // The number of function call slightly depends on it.
Double_t p1 = 1.0 ;
Double_t p2 = 0.0 ;
- gMinuit->mnexcm("SET STR", &p2, 0, ierflg) ; // force TMinuit to reduce function calls
- gMinuit->mnexcm("SET GRA", &p1, 1, ierflg) ; // force TMinuit to use my gradient
+ gMinuit->mnexcm("SET STR", &p2, 0, ierflg) ; // force TMinuit to reduce function calls
+ gMinuit->mnexcm("SET GRA", &p1, 1, ierflg) ; // force TMinuit to use my gradient
gMinuit->SetMaxIterations(5);
gMinuit->mnexcm("SET NOW", &p2 , 0, ierflg) ; // No Warnings
+ gMinuit->mnexcm("MIGRAD", &p0, 0, ierflg) ; // minimize
- gMinuit->mnexcm("MIGRAD", &p0, 0, ierflg) ; // minimize
-
- if(ierflg == 4){ // Minimum not found
- Error("FindFit", "EMCAL Unfolding Fit not converged, cluster abandoned " ) ;
+ if(ierflg == 4){ // Minimum not found
+ Error("FindFit", "EMCAL Unfolding Fit not converged, cluster abandoned " ) ;
return kFALSE ;
- }
+ }
for(index = 0; index < nPar; index++){
Double_t err ;
Double_t val ;
gMinuit->GetParameter(index, val, err) ; // Returns value and error of parameter index
fitparameters[index] = val ;
- }
+ }
delete toMinuit ;
return kTRUE;
{
// Initializes the parameters for the Clusterizer
fNumberOfECAClusters = 0;
-
- fECALocMaxCut = 0.03; // ??
-
fTimeCut = 300e-9 ; // 300 ns time cut (to be tuned)
- fToUnfold = kFALSE ;
fCalibData = 0 ;
else {
fECAClusteringThreshold = recParam->GetClusteringThreshold();
fECAW0 = recParam->GetW0();
- fMinECut = recParam->GetMinECut();
- AliDebug(1,Form("Reconstruction parameters: fECAClusteringThreshold=%.3f, fECAW=%.3f, fMinECut=%.3f",
- fECAClusteringThreshold,fECAW0,fMinECut));
+ fMinECut = recParam->GetMinECut();
+ fToUnfold = recParam->GetUnfold();
+ fECALocMaxCut = recParam->GetLocMaxCut();
+
+ AliDebug(1,Form("Reconstruction parameters: fECAClusteringThreshold=%.3f, fECAW=%.3f, fMinECut=%.3f, fToUnfold=%d, fECALocMaxCut=%.3f",
+ fECAClusteringThreshold,fECAW0,fMinECut,fToUnfold,fECALocMaxCut));
}
}
}
//____________________________________________________________________________
-void AliEMCALClusterizerv1::MakeUnfolding() const
+void AliEMCALClusterizerv1::MakeUnfolding()
{
- Fatal("AliEMCALClusterizerv1::MakeUnfolding", "--> Unfolding not implemented") ;
+ // Unfolds clusters using the shape of an ElectroMagnetic shower
+ // Performs unfolding of all clusters
+
+ if(fNumberOfECAClusters > 0){
+ if (fGeom==0)
+ AliFatal("Did not get geometry from EMCALLoader") ;
+ Int_t nModulesToUnfold = fGeom->GetNCells();
+
+ Int_t numberofNotUnfolded = fNumberOfECAClusters ;
+ Int_t index ;
+ for(index = 0 ; index < numberofNotUnfolded ; index++){
+
+ AliEMCALRecPoint * RecPoint = dynamic_cast<AliEMCALRecPoint *>( fRecPoints->At(index) ) ;
+
+ TVector3 gpos;
+ Int_t absId;
+ RecPoint->GetGlobalPosition(gpos);
+ fGeom->GetAbsCellIdFromEtaPhi(gpos.Eta(),gpos.Phi(),absId);
+ if(absId > nModulesToUnfold)
+ break ;
+
+ Int_t nMultipl = RecPoint->GetMultiplicity() ;
+ AliEMCALDigit ** maxAt = new AliEMCALDigit*[nMultipl] ;
+ Float_t * maxAtEnergy = new Float_t[nMultipl] ;
+ Int_t nMax = RecPoint->GetNumberOfLocalMax(maxAt, maxAtEnergy,fECALocMaxCut,fDigitsArr) ;
+
+ if( nMax > 1 ) { // if cluster is very flat (no pronounced maximum) then nMax = 0
+ UnfoldCluster(RecPoint, nMax, maxAt, maxAtEnergy) ;
+ fRecPoints->Remove(RecPoint);
+ fRecPoints->Compress() ;
+ index-- ;
+ fNumberOfECAClusters-- ;
+ numberofNotUnfolded-- ;
+ }
+ else{
+ RecPoint->SetNExMax(1) ; //Only one local maximum
+ }
+
+ delete[] maxAt ;
+ delete[] maxAtEnergy ;
+ }
+ }
+ // End of Unfolding of clusters
}
//____________________________________________________________________________
-Double_t AliEMCALClusterizerv1::ShowerShape(Double_t r)
+Double_t AliEMCALClusterizerv1::ShowerShape(Double_t x, Double_t y)
{
- // Shape of the shower (see EMCAL TDR)
+ // Shape of the shower
// If you change this function, change also the gradient evaluation in ChiSquare()
- Double_t r4 = r*r*r*r ;
- Double_t r295 = TMath::Power(r, 2.95) ;
- Double_t shape = TMath::Exp( -r4 * (1. / (2.32 + 0.26 * r4) + 0.0316 / (1 + 0.0652 * r295) ) ) ;
+ Double_t r = sqrt(x*x+y*y);
+ Double_t r133 = TMath::Power(r, 1.33) ;
+ Double_t r669 = TMath::Power(r, 6.69) ;
+ Double_t shape = TMath::Exp( -r133 * (1. / (1.57 + 0.0860 * r133) - 0.55 / (1 + 0.000563 * r669) ) ) ;
return shape ;
}
//____________________________________________________________________________
-void AliEMCALClusterizerv1::UnfoldCluster(AliEMCALRecPoint * /*iniTower*/,
- Int_t /*nMax*/,
- AliEMCALDigit ** /*maxAt*/,
- Float_t * /*maxAtEnergy*/) const
+void AliEMCALClusterizerv1::UnfoldCluster(AliEMCALRecPoint * iniTower,
+ Int_t nMax,
+ AliEMCALDigit ** maxAt,
+ Float_t * maxAtEnergy)
{
// Performs the unfolding of a cluster with nMax overlapping showers
-
- Fatal("UnfoldCluster", "--> Unfolding not implemented") ;
+ Int_t nPar = 3 * nMax ;
+ Float_t * fitparameters = new Float_t[nPar] ;
+
+ if (fGeom==0)
+ AliFatal("Did not get geometry from EMCALLoader") ;
+
+ Bool_t rv = FindFit(iniTower, maxAt, maxAtEnergy, nPar, fitparameters) ;
+ if( !rv ) {
+ // Fit failed, return and remove cluster
+ iniTower->SetNExMax(-1) ;
+ delete[] fitparameters ;
+ return ;
+ }
+
+ // create unfolded rec points and fill them with new energy lists
+ // First calculate energy deposited in each sell in accordance with
+ // fit (without fluctuations): efit[]
+ // and later correct this number in acordance with actual energy
+ // deposition
+
+ Int_t nDigits = iniTower->GetMultiplicity() ;
+ Float_t * efit = new Float_t[nDigits] ;
+ Double_t xDigit=0.,yDigit=0.,zDigit=0. ;
+ Float_t xpar=0.,zpar=0.,epar=0. ;
+
+ AliEMCALDigit * digit = 0 ;
+ Int_t * Digits = iniTower->GetDigitsList() ;
+
+ Int_t iparam ;
+ Int_t iDigit ;
+ for(iDigit = 0 ; iDigit < nDigits ; iDigit ++){
+ digit = dynamic_cast<AliEMCALDigit*>( fDigitsArr->At(Digits[iDigit] ) ) ;
+ fGeom->RelPosCellInSModule(digit->GetId(), yDigit, xDigit, zDigit);
+ efit[iDigit] = 0;
+
+ iparam = 0 ;
+ while(iparam < nPar ){
+ xpar = fitparameters[iparam] ;
+ zpar = fitparameters[iparam+1] ;
+ epar = fitparameters[iparam+2] ;
+ iparam += 3 ;
+ efit[iDigit] += epar * ShowerShape(xDigit - xpar,zDigit - zpar) ;
+ }
+ }
+
+
+ // Now create new RecPoints and fill energy lists with efit corrected to fluctuations
+ // so that energy deposited in each cell is distributed between new clusters proportionally
+ // to its contribution to efit
+
+ Float_t * Energies = iniTower->GetEnergiesList() ;
+ Float_t ratio ;
+
+ iparam = 0 ;
+ while(iparam < nPar ){
+ xpar = fitparameters[iparam] ;
+ zpar = fitparameters[iparam+1] ;
+ epar = fitparameters[iparam+2] ;
+ iparam += 3 ;
+
+ AliEMCALRecPoint * RecPoint = 0 ;
+
+ if(fNumberOfECAClusters >= fRecPoints->GetSize())
+ fRecPoints->Expand(2*fNumberOfECAClusters) ;
+
+ (*fRecPoints)[fNumberOfECAClusters] = new AliEMCALRecPoint("") ;
+ RecPoint = dynamic_cast<AliEMCALRecPoint *>( fRecPoints->At(fNumberOfECAClusters) ) ;
+ fNumberOfECAClusters++ ;
+ RecPoint->SetNExMax((Int_t)nPar/3) ;
+
+ Float_t eDigit ;
+ for(iDigit = 0 ; iDigit < nDigits ; iDigit ++){
+ digit = dynamic_cast<AliEMCALDigit*>( fDigitsArr->At( Digits[iDigit] ) ) ;
+ fGeom->RelPosCellInSModule(digit->GetId(), yDigit, xDigit, zDigit);
+
+ ratio = epar * ShowerShape(xDigit - xpar,zDigit - zpar) / efit[iDigit] ;
+ eDigit = Energies[iDigit] * ratio ;
+ RecPoint->AddDigit( *digit, eDigit ) ;
+ }
+ }
+
+ delete[] fitparameters ;
+ delete[] efit ;
}
//_____________________________________________________________________________
-void AliEMCALClusterizerv1::UnfoldingChiSquare(Int_t & /*nPar*/, Double_t * /*Grad*/,
- Double_t & /*fret*/,
- Double_t * /*x*/, Int_t /*iflag*/)
+void AliEMCALClusterizerv1::UnfoldingChiSquare(Int_t & nPar, Double_t * Grad,
+ Double_t & fret,
+ Double_t * x, Int_t iflag)
{
// Calculates the Chi square for the cluster unfolding minimization
// Number of parameters, Gradient, Chi squared, parameters, what to do
-
- ::Fatal("UnfoldingChiSquare","Unfolding not implemented") ;
+
+ TList * toMinuit = dynamic_cast<TList*>( gMinuit->GetObjectFit() ) ;
+
+ AliEMCALRecPoint * RecPoint = dynamic_cast<AliEMCALRecPoint*>( toMinuit->At(0) ) ;
+ TClonesArray * digits = dynamic_cast<TClonesArray*>( toMinuit->At(1) ) ;
+ // A bit buggy way to get an access to the geometry
+ // To be revised!
+ AliEMCALGeometry *geom = dynamic_cast<AliEMCALGeometry *>(toMinuit->At(2));
+
+ Int_t * Digits = RecPoint->GetDigitsList() ;
+
+ Int_t nOdigits = RecPoint->GetDigitsMultiplicity() ;
+
+ Float_t * Energies = RecPoint->GetEnergiesList() ;
+
+ fret = 0. ;
+ Int_t iparam ;
+
+ if(iflag == 2)
+ for(iparam = 0 ; iparam < nPar ; iparam++)
+ Grad[iparam] = 0 ; // Will evaluate gradient
+
+ Double_t efit ;
+
+ AliEMCALDigit * digit ;
+ Int_t iDigit ;
+
+ for( iDigit = 0 ; iDigit < nOdigits ; iDigit++) {
+
+ digit = dynamic_cast<AliEMCALDigit*>( digits->At( Digits[iDigit] ) );
+
+ Double_t xDigit=0 ;
+ Double_t zDigit=0 ;
+ Double_t yDigit=0 ;//not used yet, assumed to be 0
+
+ geom->RelPosCellInSModule(digit->GetId(), yDigit, xDigit, zDigit);
+
+ if(iflag == 2){ // calculate gradient
+ Int_t iParam = 0 ;
+ efit = 0 ;
+ while(iParam < nPar ){
+ Double_t dx = (xDigit - x[iParam]) ;
+ iParam++ ;
+ Double_t dz = (zDigit - x[iParam]) ;
+ iParam++ ;
+ efit += x[iParam] * ShowerShape(dx,dz) ;
+ iParam++ ;
+ }
+ Double_t sum = 2. * (efit - Energies[iDigit]) / Energies[iDigit] ; // Here we assume, that sigma = sqrt(E)
+ iParam = 0 ;
+ while(iParam < nPar ){
+ Double_t xpar = x[iParam] ;
+ Double_t zpar = x[iParam+1] ;
+ Double_t epar = x[iParam+2] ;
+ Double_t dr = TMath::Sqrt( (xDigit - xpar) * (xDigit - xpar) + (zDigit - zpar) * (zDigit - zpar) );
+ Double_t shape = sum * ShowerShape(xDigit - xpar,zDigit - zpar) ;
+ Double_t r133 = TMath::Power(dr, 1.33);
+ Double_t r669 = TMath::Power(dr,6.69);
+ Double_t deriv =-1.33 * TMath::Power(dr,0.33)*dr * ( 1.57 / ( (1.57 + 0.0860 * r133) * (1.57 + 0.0860 * r133) )
+ - 0.55 / (1 + 0.000563 * r669) / ( (1 + 0.000563 * r669) * (1 + 0.000563 * r669) ) ) ;
+
+ Grad[iParam] += epar * shape * deriv * (xpar - xDigit) ; // Derivative over x
+ iParam++ ;
+ Grad[iParam] += epar * shape * deriv * (zpar - zDigit) ; // Derivative over z
+ iParam++ ;
+ Grad[iParam] += shape ; // Derivative over energy
+ iParam++ ;
+ }
+ }
+ efit = 0;
+ iparam = 0 ;
+
+
+ while(iparam < nPar ){
+ Double_t xpar = x[iparam] ;
+ Double_t zpar = x[iparam+1] ;
+ Double_t epar = x[iparam+2] ;
+ iparam += 3 ;
+ efit += epar * ShowerShape(xDigit - xpar,zDigit - zpar) ;
+ }
+
+ fret += (efit-Energies[iDigit])*(efit-Energies[iDigit])/Energies[iDigit] ;
+ // Here we assume, that sigma = sqrt(E)
+ }
}
//____________________________________________________________________________
void AliEMCALClusterizerv1::Print(Option_t * /*option*/)const
#include <TObjString.h>
#include <TVector2.h>
#include <TVector3.h>
-
+#include <TParticle.h>
// -- ALICE Headers.
#include "AliLog.h"
return fPhiCentersOfSM[i];
}
+//____________________________________________________________________________
+Bool_t AliEMCALGeometry::Impact(const TParticle * particle) const
+{
+ // Tells if a particle enters EMCAL
+ Bool_t in=kFALSE;
+ Int_t AbsID=0;
+ TVector3 vtx(particle->Vx(),particle->Vy(),particle->Vz());
+ TVector3 vimpact(0,0,0);
+ ImpactOnEmcal(vtx,particle->Theta(),particle->Phi(),AbsID,vimpact);
+ if(AbsID!=0)
+ in=kTRUE;
+ return in;
+}
+//____________________________________________________________________________
+void AliEMCALGeometry::ImpactOnEmcal(TVector3 vtx, Double_t theta, Double_t phi,
+ Int_t & absId, TVector3 & vimpact) const
+{
+ // calculates the impact coordinates on EMCAL (centre of a tower/not on EMCAL surface)
+ // of a neutral particle
+ // emitted in the vertex vtx[3] with direction theta and phi in the ALICE global coordinate system
+
+ TVector3 p(TMath::Sin(theta)*TMath::Cos(phi),TMath::Sin(theta)*TMath::Sin(phi),TMath::Cos(theta)) ;
+
+ vimpact.SetXYZ(0,0,0);
+ absId=-1;
+ if(phi==0 || theta==0) return;
+
+ TVector3 direction;
+ Double_t factor = (GetIPDistance()-vtx[1])/p[1];
+ direction = vtx + factor*p;
+
+ if (!gGeoManager){
+ AliFatal("Geo manager not initialized\n");
+ }
+ //from particle direction -> tower hitted
+ GetAbsCellIdFromEtaPhi(direction.Eta(),direction.Phi(),absId);
+
+ //tower absID hitted -> tower/module plane (evaluated at the center of the tower)
+ Int_t nSupMod, nModule, nIphi, nIeta;
+ Double_t loc[3],loc2[3],loc3[3];
+ Double_t glob[3]={},glob2[3]={},glob3[3]={};
+
+ if(!RelPosCellInSModule(absId,loc)) return;
+
+ //loc is cell center of tower
+ GetCellIndex(absId, nSupMod, nModule, nIphi, nIeta);
+
+ //look at 2 neighbours-s cell using nIphi={0,1} and nIeta={0,1}
+ Int_t nIphi2,nIeta2,absId2,absId3;
+ if(nIeta==0) nIeta2=1;
+ else nIeta2=0;
+ absId2=GetAbsCellId(nSupMod,nModule,nIphi,nIeta2);
+ if(nIphi==0) nIphi2=1;
+ else nIphi2=0;
+ absId3=GetAbsCellId(nSupMod,nModule,nIphi2,nIeta);
+
+ //2nd point on emcal cell plane
+ if(!RelPosCellInSModule(absId2,loc2)) return;
+
+ //3rd point on emcal cell plane
+ if(!RelPosCellInSModule(absId3,loc3)) return;
+
+ TString volpath = "ALIC_1/XEN1_1/SMOD_";
+ volpath += (nSupMod+1);
+
+ if(GetKey110DEG() && nSupMod>=10) {
+ volpath = "ALIC_1/XEN1_1/SM10_";
+ volpath += (nSupMod-10+1);
+ }
+ if(!gGeoManager->cd(volpath.Data())){
+ AliFatal(Form("GeoManager cannot find path %s!",volpath.Data()))
+ return;
+ }
+ TGeoHMatrix* m = gGeoManager->GetCurrentMatrix();
+ if(m) {
+ m->LocalToMaster(loc, glob);
+ m->LocalToMaster(loc2, glob2);
+ m->LocalToMaster(loc3, glob3);
+ } else {
+ AliFatal("Geo matrixes are not loaded \n") ;
+ }
+
+ //Equation of Plane from glob,glob2,glob3 (Ax+By+Cz+D=0)
+ Double_t A = glob[1]*(glob2[2]-glob3[2]) + glob2[1]*(glob3[2]-glob[2]) + glob3[1]*(glob[2]-glob2[2]);
+ Double_t B = glob[2]*(glob2[0]-glob3[0]) + glob2[2]*(glob3[0]-glob[0]) + glob3[2]*(glob[0]-glob2[0]);
+ Double_t C = glob[0]*(glob2[1]-glob3[1]) + glob2[0]*(glob3[1]-glob[1]) + glob3[0]*(glob[1]-glob2[1]);
+ Double_t D = glob[0]*(glob2[1]*glob3[2]-glob3[1]*glob2[2]) + glob2[0]*(glob3[1]*glob[2]-glob[1]*glob3[2]) + glob3[0]*(glob[1]*glob2[2]-glob2[1]*glob[2]);
+ D=-D;
+
+ //shift equation of plane from tower/module center to surface along vector (A,B,C) normal to tower/module plane
+ Double_t dist = GetLongModuleSize()/2.;
+ Double_t norm = TMath::Sqrt(A*A+B*B+C*C);
+ Double_t glob4[3]={};
+ TVector3 dir(A,B,C);
+ TVector3 point(glob[0],glob[1],glob[2]);
+ if(point.Dot(dir)<0) dist*=-1;
+ glob4[0]=glob[0]-dist*A/norm;
+ glob4[1]=glob[1]-dist*B/norm;
+ glob4[2]=glob[2]-dist*C/norm;
+ D = glob4[0]*A + glob4[1]*B + glob4[2]*C ;
+ D = -D;
+
+ //Line determination (2 points for equation of line : vtx and direction)
+ //impact between line (particle) and plane (module/tower plane)
+ Double_t den = A*(vtx(0)-direction(0)) + B*(vtx(1)-direction(1)) + C*(vtx(2)-direction(2));
+ if(den==0){
+ printf("ImpactOnEmcal() No solution :\n");
+ return;
+ }
+
+ Double_t length = A*vtx(0)+B*vtx(1)+C*vtx(2)+D;
+ length /=den;
+
+ vimpact.SetXYZ(vtx(0)+length*(direction(0)-vtx(0)),vtx(1)+length*(direction(1)-vtx(1)),vtx(2)+length*(direction(2)-vtx(2)));
+
+ //shift vimpact from tower/module surface to center along vector (A,B,C) normal to tower/module plane
+ vimpact.SetXYZ(vimpact(0)+dist*A/norm,vimpact(1)+dist*B/norm,vimpact(2)+dist*C/norm);
+
+ return;
+}