+/**************************************************************************
+ * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+ * *
+ * Author: The ALICE Off-line Project. *
+ * Contributors are mentioned in the code where appropriate. *
+ * *
+ * Permission to use, copy, modify and distribute this software and its *
+ * documentation strictly for non-commercial purposes is hereby granted *
+ * without fee, provided that the above copyright notice appears in all *
+ * copies and that both the copyright notice and this permission notice *
+ * appear in the supporting documentation. The authors make no claims *
+ * about the suitability of this software for any purpose. It is *
+ * provided "as is" without express or implied warranty. *
+ **************************************************************************/
+
+/* $Id$ */
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// Class to the track points on the Riemann sphere. Inputs are
+// the set of id's (volids) of the volumes in which residuals are
+// calculated to construct a chi2 function to be minimized during
+// the alignment procedures. For the moment the track extrapolation is
+// taken at the space-point reference plane. The reference plane is
+// found using the covariance matrix of the point
+// (assuming sigma(x)=0 at the reference coordinate system.
+//
+// Internal usage of AliRieman class for minimization
+//
+//////////////////////////////////////////////////////////////////////////////
+
#include "TMatrixDSym.h"
#include "TMatrixD.h"
+#include "TArrayI.h"
#include "AliTrackFitterRieman.h"
+#include "AliLog.h"
+#include "TTreeStream.h"
+#include "AliRieman.h"
+#include "AliLog.h"
ClassImp(AliTrackFitterRieman)
+
AliTrackFitterRieman::AliTrackFitterRieman():
AliTrackFitter()
{
// default constructor
//
fAlpha = 0.;
- for (Int_t i=0;i<9;i++) fSumXY[i] = 0;
- for (Int_t i=0;i<9;i++) fSumXZ[i] = 0;
+ fNUsed = 0;
fConv = kFALSE;
+ fDebugStream = new TTreeSRedirector("RiemanAlignDebug.root");
+ fRieman = new AliRieman(10000); // allocate rieman
}
// Constructor
//
fAlpha = 0.;
- for (Int_t i=0;i<9;i++) fSumXY[i] = 0;
- for (Int_t i=0;i<9;i++) fSumXZ[i] = 0;
+ fNUsed = 0;
fConv = kFALSE;
+ if (AliLog::GetDebugLevel("","AliTrackFitterRieman")) fDebugStream = new TTreeSRedirector("RiemanAlignDebug.root");
+ fRieman = new AliRieman(10000); //allocate rieman
}
AliTrackFitterRieman::AliTrackFitterRieman(const AliTrackFitterRieman &rieman):
// copy constructor
//
fAlpha = rieman.fAlpha;
- for (Int_t i=0;i<9;i++) fSumXY[i] = rieman.fSumXY[i];
- for (Int_t i=0;i<9;i++) fSumXZ[i] = rieman.fSumXZ[i];
+ fNUsed = rieman.fNUsed;
fConv = rieman.fConv;
+ fRieman = new AliRieman(*(rieman.fRieman));
}
//_____________________________________________________________________________
AliTrackFitterRieman &AliTrackFitterRieman::operator =(const AliTrackFitterRieman& rieman)
{
- // assignment operator
+ //
+ // Assignment operator
//
if(this==&rieman) return *this;
((AliTrackFitter *)this)->operator=(rieman);
- fAlpha = rieman.fAlpha;
- for (Int_t i=0;i<9;i++) fSumXY[i] = rieman.fSumXY[i];
- for (Int_t i=0;i<9;i++) fSumXZ[i] = rieman.fSumXZ[i];
- fConv = rieman.fConv;
-
+ fAlpha = rieman.fAlpha;
+ fNUsed = rieman.fNUsed;
+ fConv = rieman.fConv;
+ fRieman = new AliRieman(*(rieman.fRieman));
return *this;
}
-AliTrackFitterRieman::~AliTrackFitterRieman()
-{
- // destructor
+
+AliTrackFitterRieman::~AliTrackFitterRieman(){
+ //
+ //
//
+ delete fRieman;
+ delete fDebugStream;
}
void AliTrackFitterRieman::Reset()
{
// Reset the track parameters and
// rieman sums
+ //
AliTrackFitter::Reset();
+ fRieman->Reset();
fAlpha = 0.;
- for (Int_t i=0;i<9;i++) fSumXY[i] = 0;
- for (Int_t i=0;i<9;i++) fSumXZ[i] = 0;
+ fNUsed = 0;
fConv =kFALSE;
}
-Bool_t AliTrackFitterRieman::Fit(UShort_t volId,
- AliTrackPointArray *pVolId, AliTrackPointArray *pTrack,
+Bool_t AliTrackFitterRieman::Fit(const TArrayI *volIds,const TArrayI *volIdsFit,
AliAlignObj::ELayerID layerRangeMin,
- AliAlignObj::ELayerID layerRangeMax)
+ AliAlignObj::ELayerID layerRangeMax)
{
// Fit the track points. The method takes as an input
- // the id (volid) of the volume to be skipped from fitting.
- // The following two parameters are used to define the
+ // the set of id's (volids) of the volumes in which
+ // one wants to calculate the residuals.
+ // The following parameters are used to define the
// range of volumes to be used in the fitting
// As a result two AliTrackPointArray's obects are filled.
// The first one contains the space points with
- // volume id = volid. The second array of points represents
- // the track extrapolation corresponding to the space points
+ // volume id's from volids list. The second array of points represents
+ // the track extrapolations corresponding to the space points
// in the first array. The two arrays can be used to find
- // the residuals in the volid and consequently construct a
+ // the residuals in the volids and consequently construct a
// chi2 function to be minimized during the alignment
// procedures. For the moment the track extrapolation is taken
- // as follows: in XY plane - at the CDA between track circle
- // and the space point; in Z - the track extrapolation on the Z
- // plane defined by the space point.
-
- pVolId = pTrack = 0x0;
- fConv = kFALSE;
+ // at the space-point reference plane. The reference plane is
+ // found using the covariance matrix of the point
+ // (assuming sigma(x)=0 at the reference coordinate system.
+ Reset();
Int_t npoints = fPoints->GetNPoints();
+ if (fPoints && AliLog::GetDebugLevel("","AliTrackFitterRieman")>1){
+ Int_t nVol = volIds->GetSize();
+ Int_t nVolFit = volIdsFit->GetSize();
+ Int_t volId = volIds->At(0);
+ (*fDebugStream)<<"PInput"<<
+ "NPoints="<<npoints<< // number of points
+ "VolId="<<volId<< // first vol ID
+ "NVol="<<nVol<< // number of volumes
+ "NvolFit="<<nVolFit<< // number of volumes to fit
+ "fPoints.="<<fPoints<< // input points
+ "\n";
+ }
if (npoints < 3) return kFALSE;
- AliTrackPoint p;
- fPoints->GetPoint(p,0);
- fAlpha = TMath::ATan2(p.GetY(),p.GetX());
- Double_t sin = TMath::Sin(fAlpha);
- Double_t cos = TMath::Cos(fAlpha);
+ Bool_t isAlphaCalc = kFALSE;
+ AliTrackPoint p,plocal;
+// fPoints->GetPoint(p,0);
+// fAlpha = TMath::ATan2(p.GetY(),p.GetX());
Int_t npVolId = 0;
- Int_t npused = 0;
+ fNUsed = 0;
Int_t *pindex = new Int_t[npoints];
for (Int_t ipoint = 0; ipoint < npoints; ipoint++)
{
fPoints->GetPoint(p,ipoint);
UShort_t iVolId = p.GetVolumeID();
- if (iVolId == volId) {
+ if (FindVolId(volIds,iVolId)) {
pindex[npVolId] = ipoint;
npVolId++;
}
- if (iVolId < AliAlignObj::LayerToVolUID(layerRangeMin,0) ||
- iVolId >= AliAlignObj::LayerToVolUID(layerRangeMax,0)) continue;
- Float_t x = p.GetX()*cos + p.GetY()*sin;
- Float_t y = p.GetY()*cos - p.GetX()*sin;
- AddPoint(x,y,p.GetZ(),1,1);
- npused++;
+ if (volIdsFit != 0x0) {
+ if (!FindVolId(volIdsFit,iVolId)) continue;
+ }
+ else {
+ if (iVolId < AliAlignObj::LayerToVolUID(layerRangeMin,0) ||
+ iVolId > AliAlignObj::LayerToVolUID(layerRangeMax,
+ AliAlignObj::LayerSize(layerRangeMax))) continue;
+ }
+ if (!isAlphaCalc) {
+ fAlpha = p.GetAngle();
+ isAlphaCalc = kTRUE;
+ }
+ plocal = p.Rotate(fAlpha);
+ if (TMath::Abs(plocal.GetX())>500 || TMath::Abs(plocal.GetX())<2){
+ printf("<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<</n");
+ p.Dump();
+ plocal.Dump();
+ printf("Problematic point\n");
+ printf("<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<</n");
+ }
+ AddPoint(plocal.GetX(),plocal.GetY(),plocal.GetZ(),
+ TMath::Sqrt(plocal.GetCov()[3]),TMath::Sqrt(plocal.GetCov()[5]));
+ // fNUsed++; AddPoint should be responsible
}
- if (npused < 3) {
+ if (npVolId == 0 || fNUsed < fMinNPoints) {
delete [] pindex;
return kFALSE;
}
Update();
-
+
if (!fConv) {
delete [] pindex;
return kFALSE;
return kFALSE;
}
- pVolId = new AliTrackPointArray(npVolId);
- pTrack = new AliTrackPointArray(npVolId);
+
+ if (fNUsed < fMinNPoints) {
+ delete [] pindex;
+ return kFALSE;
+ }
+
+ fPVolId = new AliTrackPointArray(npVolId);
+ fPTrack = new AliTrackPointArray(npVolId);
AliTrackPoint p2;
for (Int_t ipoint = 0; ipoint < npVolId; ipoint++)
{
Int_t index = pindex[ipoint];
fPoints->GetPoint(p,index);
if (GetPCA(p,p2)) {
- pVolId->AddPoint(ipoint,&p);
- pTrack->AddPoint(ipoint,&p2);
+ Float_t xyz[3],xyz2[3];
+ p.GetXYZ(xyz); p2.GetXYZ(xyz2);
+ // printf("residuals %f %d %d %f %f %f %f %f %f\n",fChi2,fNUsed,fConv,xyz[0],xyz[1],xyz[2],xyz2[0]-xyz[0],xyz2[1]-xyz[1],xyz2[2]-xyz[2]);
+ fPVolId->AddPoint(ipoint,&p);
+ fPTrack->AddPoint(ipoint,&p2);
+ }else{
+ // what should be default bahavior -
+ delete [] pindex;
+ delete fPVolId;
+ delete fPTrack;
+ fPVolId =0;
+ fPTrack =0;
+ return kFALSE;
}
}
+
+ if (AliLog::GetDebugLevel("","AliTrackFitterRieman")>0){
+ //
+ // Debug Info
+ //
+ AliTrackPointArray *lPVolId = new AliTrackPointArray(npVolId);
+ AliTrackPointArray *lPTrack = new AliTrackPointArray(npVolId);
+ AliRieman * residual = fRieman->MakeResiduals();
+ AliTrackPoint p2local;
+ for (Int_t ipoint = 0; ipoint < npVolId; ipoint++){
+ Int_t index = pindex[ipoint];
+ fPoints->GetPoint(p,index);
+ if (GetPCA(p,p2)) {
+ plocal = p.Rotate(fAlpha);
+ // plocal.Rotate(fAlpha);
+ Float_t xyz[3],xyz2[3];
+ p2local = plocal;
+ plocal.GetXYZ(xyz);
+ xyz2[0] = xyz[0];
+ xyz2[1] = GetYat(xyz[0]);
+ xyz2[2] = GetZat(xyz[0]);
+ p2local.SetXYZ(xyz2);
+ lPVolId->AddPoint(ipoint,&plocal);
+ lPTrack->AddPoint(ipoint,&p2local);
+ }
+ }
+ //
+ // debug info
+ //
+ Int_t nVol = volIds->GetSize();
+ Int_t nVolFit = volIdsFit->GetSize();
+ Int_t volId = volIds->At(0);
+ Int_t modId =0;
+ Int_t layer = AliAlignObj::VolUIDToLayer(volId,modId);
+
+ (*fDebugStream)<<"Fit"<<
+ "VolId="<<volId<< // volume ID
+ "Layer="<<layer<< // layer ID
+ "Module="<<modId<< // module ID
+ "NVol="<<nVol<< // number of volumes
+ "NvolFit="<<nVolFit<< // number of volumes to fit
+ "Points0.="<<fPVolId<< // original points
+ "Points1.="<<fPTrack<< // fitted points
+ "LPoints0.="<<lPVolId<< // original points - local frame
+ "LPoints1.="<<lPTrack<< // fitted points - local frame
+ "Rieman.="<<this<< // original rieman fit
+ "Res.="<<residual<< // residuals of rieman fit
+ "\n";
+ delete lPVolId;
+ delete lPTrack;
+ delete residual;
+ }
delete [] pindex;
-
return kTRUE;
}
+
void AliTrackFitterRieman::AddPoint(Float_t x, Float_t y, Float_t z, Float_t sy, Float_t sz)
{
//
- // Rieman update
- //
- //------------------------------------------------------
- // XY direction
- //
- // (x-x0)^2+(y-y0)^2-R^2=0 ===>
- //
- // (x^2+y^2 -2*x*x0 - 2*y*y0+ x0^2 -y0^2 -R^2 =0; ==>
- //
- // substitution t = 1/(x^2+y^2), u = 2*x*t, y = 2*y*t, D0 = R^2 - x0^2- y0^2
- //
- // 1 - u*x0 - v*y0 - t *D0 =0 ; - linear equation
- //
- // next substition a = 1/y0 b = -x0/y0 c = -D0/y0
+ // add point to rieman fitter
//
- // final linear equation : a + u*b +t*c - v =0;
- //
- // Minimization :
- //
- // sum( (a + ui*b +ti*c - vi)^2)/(sigmai)^2 = min;
- //
- // where sigmai is the error of maesurement (a + ui*b +ti*c - vi)
- //
- // neglecting error of xi, and supposing xi>>yi sigmai ~ sigmaVi ~ 2*sigmay*t
- //
- //
- // XY part
- //
- Double_t t = x*x+y*y;
- if (t<2) return;
- t = 1./t;
- Double_t u = 2.*x*t;
- Double_t v = 2.*y*t;
- Double_t error = 2.*sy*t;
- error *=error;
- Double_t weight = 1./error;
- fSumXY[0] +=weight;
- fSumXY[1] +=u*weight; fSumXY[2]+=v*weight; fSumXY[3]+=t*weight;
- fSumXY[4] +=u*u*weight; fSumXY[5]+=t*t*weight;
- fSumXY[6] +=u*v*weight; fSumXY[7]+=u*t*weight; fSumXY[8]+=v*t*weight;
- //
- // XZ part
- //
- weight = 1./sz;
- fSumXZ[0] +=weight;
- fSumXZ[1] +=weight*x; fSumXZ[2] +=weight*x*x; fSumXZ[3] +=weight*x*x*x; fSumXZ[4] += weight*x*x*x*x;
- fSumXZ[5] +=weight*z; fSumXZ[6] +=weight*x*z; fSumXZ[7] +=weight*x*x*z;
+ fRieman->AddPoint(x,y,z,sy,sz);
+ fNUsed = fRieman->GetN();
}
+
+
void AliTrackFitterRieman::Update(){
//
- // Rieman update
- //
+ //
//
- for (Int_t i=0;i<6;i++)fParams[i]=0;
- Int_t conv=0;
- //
- // XY part
- //
- TMatrixDSym smatrix(3);
- TMatrixD sums(1,3);
- //
- // smatrix(0,0) = s0; smatrix(1,1)=su2; smatrix(2,2)=st2;
- // smatrix(0,1) = su; smatrix(0,2)=st; smatrix(1,2)=sut;
- // sums(0,0) = sv; sums(0,1)=suv; sums(0,2)=svt;
-
- smatrix(0,0) = fSumXY[0]; smatrix(1,1)=fSumXY[4]; smatrix(2,2)=fSumXY[5];
- smatrix(0,1) = fSumXY[1]; smatrix(0,2)=fSumXY[3]; smatrix(1,2)=fSumXY[7];
- sums(0,0) = fSumXY[2]; sums(0,1) =fSumXY[6]; sums(0,2) =fSumXY[8];
- smatrix.Invert();
- if (smatrix.IsValid()){
- for (Int_t i=0;i<3;i++)
- for (Int_t j=0;j<=i;j++){
- (*fCov)(i,j)=smatrix(i,j);
- }
- TMatrixD res = sums*smatrix;
- fParams[0] = res(0,0);
- fParams[1] = res(0,1);
- fParams[2] = res(0,2);
- conv++;
- }
- //
- // XZ part
- //
- TMatrixDSym smatrixz(3);
- smatrixz(0,0) = fSumXZ[0]; smatrixz(0,1) = fSumXZ[1]; smatrixz(0,2) = fSumXZ[2];
- smatrixz(1,1) = fSumXZ[2]; smatrixz(1,2) = fSumXZ[3];
- smatrixz(2,2) = fSumXZ[4];
- smatrixz.Invert();
- if (smatrixz.IsValid()){
- sums(0,0) = fSumXZ[5];
- sums(0,1) = fSumXZ[6];
- sums(0,2) = fSumXZ[7];
- TMatrixD res = sums*smatrixz;
- fParams[3] = res(0,0);
- fParams[4] = res(0,1);
- fParams[5] = res(0,2);
- for (Int_t i=0;i<3;i++)
- for (Int_t j=0;j<=i;j++){
- (*fCov)(i+2,j+2)=smatrixz(i,j);
+ fRieman->Update();
+ fConv = kFALSE;
+ if (fRieman->IsValid()){
+ for (Int_t ipar=0; ipar<6; ipar++){
+ fParams[ipar] = fRieman->GetParam()[ipar];
}
- conv++;
+ fChi2 = fRieman->GetChi2();
+ fNdf = fRieman->GetN()- 2;
+ fNUsed = fRieman->GetN();
+ fConv = kTRUE;
}
-
- // (x-x0)^2+(y-y0)^2-R^2=0 ===>
- //
- // (x^2+y^2 -2*x*x0 - 2*y*y0+ x0^2 -y0^2 -R^2 =0; ==>
- // substitution t = 1/(x^2+y^2), u = 2*x*t, y = 2*y*t, D0 = R^2 - x0^2- y0^2
- //
- // 1 - u*x0 - v*y0 - t *D0 =0 ; - linear equation
- //
- // next substition a = 1/y0 b = -x0/y0 c = -D0/y0
- // final linear equation : a + u*b +t*c - v =0;
- //
- // fParam[0] = 1/y0
- // fParam[1] = -x0/y0
- // fParam[2] = - (R^2 - x0^2 - y0^2)/y0
- if (conv>1) fConv =kTRUE;
- else
- fConv=kFALSE;
-}
-
-Double_t AliTrackFitterRieman::GetYat(Double_t x){
- if (!fConv) return 0.;
- Double_t res2 = (x*fParams[0]+fParams[1]);
- res2*=res2;
- res2 = 1.-fParams[2]*fParams[0]+fParams[1]*fParams[1]-res2;
- if (res2<0) return 0;
- res2 = TMath::Sqrt(res2);
- res2 = (1-res2)/fParams[0];
- return res2;
-}
-
-Double_t AliTrackFitterRieman::GetDYat(Double_t x){
- if (!fConv) return 0.;
- Double_t x0 = -fParams[1]/fParams[0];
- if (-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1<0) return 0;
- Double_t Rm1 = fParams[0]/TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1);
- if ( 1./(Rm1*Rm1)-(x-x0)*(x-x0)<=0) return 0;
- Double_t res = (x-x0)/TMath::Sqrt(1./(Rm1*Rm1)-(x-x0)*(x-x0));
- if (fParams[0]<0) res*=-1.;
- return res;
-}
-
-
-
-Double_t AliTrackFitterRieman::GetZat(Double_t x){
- if (!fConv) return 0.;
- Double_t x0 = -fParams[1]/fParams[0];
- if (-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1<=0) return 0;
- Double_t Rm1 = fParams[0]/TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1);
- Double_t phi = TMath::ASin((x-x0)*Rm1);
- Double_t phi0 = TMath::ASin((0.-x0)*Rm1);
- Double_t dphi = (phi-phi0);
- Double_t res = fParams[3]+fParams[4]*dphi/Rm1;
- return res;
-}
-
-Double_t AliTrackFitterRieman::GetDZat(Double_t x){
- if (!fConv) return 0.;
- Double_t x0 = -fParams[1]/fParams[0];
- if (-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1<=0) return 0;
- Double_t Rm1 = fParams[0]/TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1);
- Double_t res = fParams[4]/TMath::Cos(TMath::ASin((x-x0)*Rm1));
- return res;
-}
-
-
-Double_t AliTrackFitterRieman::GetC(){
- return fParams[0]/TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1);
-}
-
-Bool_t AliTrackFitterRieman::GetXYZat(Double_t r, Float_t *xyz){
- if (!fConv) return kFALSE;
- Double_t res2 = (r*fParams[0]+fParams[1]);
- res2*=res2;
- res2 = 1.-fParams[2]*fParams[0]+fParams[1]*fParams[1]-res2;
- if (res2<0) return kFALSE;
- res2 = TMath::Sqrt(res2);
- res2 = (1-res2)/fParams[0];
-
- if (!fConv) return kFALSE;
- Double_t x0 = -fParams[1]/fParams[0];
- if (-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1<=0) return 0;
- Double_t Rm1 = fParams[0]/TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1);
- Double_t phi = TMath::ASin((r-x0)*Rm1);
- Double_t phi0 = TMath::ASin((0.-x0)*Rm1);
- Double_t dphi = (phi-phi0);
- Double_t res = fParams[3]+fParams[4]*dphi/Rm1;
-
- Double_t sin = TMath::Sin(fAlpha);
- Double_t cos = TMath::Cos(fAlpha);
- xyz[0] = r*cos - res2*sin;
- xyz[1] = res2*cos + r*sin;
- xyz[2] = res;
-
- return kTRUE;
}
+//_____________________________________________________________________________
Bool_t AliTrackFitterRieman::GetPCA(const AliTrackPoint &p, AliTrackPoint &p2) const
{
+ //
// Get the closest to a given spacepoint track trajectory point
// Look for details in the description of the Fit() method
-
+ //
if (!fConv) return kFALSE;
// First X and Y coordinates
// fParam[1] = -x0/y0
// fParam[2] = - (R^2 - x0^2 - y0^2)/y0
if (fParams[0] == 0) return kFALSE;
+ // Track parameters in the global coordinate system
Double_t x0 = -fParams[1]/fParams[0]*cos - 1./fParams[0]*sin;
Double_t y0 = 1./fParams[0]*cos - fParams[1]/fParams[0]*sin;
if ((-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1) <= 0) return kFALSE;
- Double_t R = TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1)/
+ Double_t r = TMath::Sqrt(-fParams[2]*fParams[0]+fParams[1]*fParams[1]+1)/
fParams[0];
- Double_t x = p.GetX();
- Double_t y = p.GetY();
- Double_t dR = TMath::Sqrt((x-x0)*(x-x0)+(y-y0)*(y-y0));
- Double_t xprime = TMath::Abs(R)*(x-x0)/dR + x0;
- Double_t yprime = TMath::Abs(R)*(y-y0)/dR + y0;
-
- // Now Z coordinate
- Double_t phi = TMath::ASin((x-x0)/R);
- Double_t phi0 = TMath::ASin((0.-x0)/R);
- Double_t dphi = (phi-phi0);
- Double_t zprime = fParams[3]+fParams[4]*dphi*R;
-
- p2.SetXYZ(xprime,yprime,zprime);
-
+ // Define space-point refence plane
+ Double_t alphap = p.GetAngle();
+ Double_t sinp = TMath::Sin(alphap);
+ Double_t cosp = TMath::Cos(alphap);
+ Double_t x = p.GetX()*cosp + p.GetY()*sinp;
+ Double_t y = p.GetY()*cosp - p.GetX()*sinp;
+ Double_t x0p= x0*cosp + y0*sinp;
+ Double_t y0p= y0*cosp - x0*sinp;
+ if ((r*r - (x-x0p)*(x-x0p))<0) {
+ AliWarning(Form("Track extrapolation failed ! (Track radius = %f, track circle x = %f, space-point x = %f, reference plane angle = %f\n",r,x0p,x,alphap));
+ return kFALSE;
+ }
+ Double_t temp = TMath::Sqrt(r*r - (x-x0p)*(x-x0p));
+ Double_t y1 = y0p + temp;
+ Double_t y2 = y0p - temp;
+ Double_t yprime = y1;
+ if(TMath::Abs(y2-y) < TMath::Abs(y1-y)) yprime = y2;
+
+ // Back to the global coordinate system
+ Double_t xsecond = x*cosp - yprime*sinp;
+ Double_t ysecond = yprime*cosp + x*sinp;
+
+ // Now Z coordinate and track angles
+ Double_t x2 = xsecond*cos + ysecond*sin;
+ Double_t zsecond = GetZat(x2);
+ Double_t dydx = GetDYat(x2);
+ Double_t dzdx = GetDZat(x2);
+
+ // Fill the cov matrix of the track extrapolation point
+ Double_t cov[6] = {0,0,0,0,0,0};
+ Double_t sigmax = 100*100.;
+ cov[0] = sigmax; cov[1] = sigmax*dydx; cov[2] = sigmax*dzdx;
+ cov[3] = sigmax*dydx*dydx; cov[4] = sigmax*dydx*dzdx;
+ cov[5] = sigmax*dzdx*dzdx;
+
+ Float_t newcov[6];
+ newcov[0] = cov[0]*cos*cos-
+ 2*cov[1]*sin*cos+
+ cov[3]*sin*sin;
+ newcov[1] = cov[1]*(cos*cos-sin*sin)-
+ (cov[3]-cov[0])*sin*cos;
+ newcov[2] = cov[2]*cos-
+ cov[4]*sin;
+ newcov[3] = cov[0]*sin*sin+
+ 2*cov[1]*sin*cos+
+ cov[3]*cos*cos;
+ newcov[4] = cov[4]*cos+
+ cov[2]*sin;
+ newcov[5] = cov[5];
+
+ p2.SetXYZ(xsecond,ysecond,zsecond,newcov);
+ if (AliLog::GetDebugLevel("","AliTrackFitterRieman")>1){
+ AliTrackPoint lp0(p);
+ AliTrackPoint lp2(p2);
+ if (0)(*fDebugStream)<<"PCA"<<
+ "P0.="<<&lp0<<
+ "P2.="<<&lp2<<
+ "\n";
+ }
return kTRUE;
}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff