return 0;
}
-
-static void External2Helix(const AliITStrackV2 *t, Double_t helix[6]) {
- //--------------------------------------------------------------------
- // External track parameters -> helix parameters
- //--------------------------------------------------------------------
- Double_t alpha,x,cs,sn;
- t->GetExternalParameters(x,helix); alpha=t->GetAlpha();
-
- cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
- helix[5]=x*cs - helix[0]*sn; // x0
- helix[0]=x*sn + helix[0]*cs; // y0
-//helix[1]= // z0
- helix[2]=TMath::ASin(helix[2]) + alpha; // phi0
-//helix[3]= // tgl
- helix[4]=helix[4]/t->GetConvConst(); // C
-}
-
-static void Evaluate(const Double_t *h, Double_t t,
- Double_t r[3], //radius vector
- Double_t g[3], //first defivatives
- Double_t gg[3]) //second derivatives
-{
- //--------------------------------------------------------------------
- // Calculate position of a point on a track and some derivatives
- //--------------------------------------------------------------------
- Double_t phase=h[4]*t+h[2];
- Double_t sn=TMath::Sin(phase), cs=TMath::Cos(phase);
-
- r[0] = h[5] + (sn - h[6])/h[4];
- r[1] = h[0] - (cs - h[7])/h[4];
- r[2] = h[1] + h[3]*t;
-
- g[0] = cs; g[1]=sn; g[2]=h[3];
-
- gg[0]=-h[4]*sn; gg[1]=h[4]*cs; gg[2]=0.;
-}
-
Double_t AliV0vertexer::PropagateToDCA(AliITStrackV2 *n, AliITStrackV2 *p) {
//--------------------------------------------------------------------
// This function returns the DCA between two tracks
// The tracks will be moved to the point of DCA !
//--------------------------------------------------------------------
- Double_t dy2=n->GetSigmaY2() + p->GetSigmaY2();
- Double_t dz2=n->GetSigmaZ2() + p->GetSigmaZ2();
- Double_t dx2=dy2;
-
- //dx2=dy2=dz2=1.;
-
- Double_t p1[8]; External2Helix(n,p1);
- p1[6]=TMath::Sin(p1[2]); p1[7]=TMath::Cos(p1[2]);
- Double_t p2[8]; External2Helix(p,p2);
- p2[6]=TMath::Sin(p2[2]); p2[7]=TMath::Cos(p2[2]);
-
-
- Double_t r1[3],g1[3],gg1[3]; Double_t t1=0.;
- Evaluate(p1,t1,r1,g1,gg1);
- Double_t r2[3],g2[3],gg2[3]; Double_t t2=0.;
- Evaluate(p2,t2,r2,g2,gg2);
-
- Double_t dx=r2[0]-r1[0], dy=r2[1]-r1[1], dz=r2[2]-r1[2];
- Double_t dm=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2;
-
- Int_t max=27;
- while (max--) {
- Double_t gt1=-(dx*g1[0]/dx2 + dy*g1[1]/dy2 + dz*g1[2]/dz2);
- Double_t gt2=+(dx*g2[0]/dx2 + dy*g2[1]/dy2 + dz*g2[2]/dz2);
- Double_t h11=(g1[0]*g1[0] - dx*gg1[0])/dx2 +
- (g1[1]*g1[1] - dy*gg1[1])/dy2 +
- (g1[2]*g1[2] - dz*gg1[2])/dz2;
- Double_t h22=(g2[0]*g2[0] + dx*gg2[0])/dx2 +
- (g2[1]*g2[1] + dy*gg2[1])/dy2 +
- (g2[2]*g2[2] + dz*gg2[2])/dz2;
- Double_t h12=-(g1[0]*g2[0]/dx2 + g1[1]*g2[1]/dy2 + g1[2]*g2[2]/dz2);
-
- Double_t det=h11*h22-h12*h12;
-
- Double_t dt1,dt2;
- if (TMath::Abs(det)<1.e-33) {
- //(quasi)singular Hessian
- dt1=-gt1; dt2=-gt2;
- } else {
- dt1=-(gt1*h22 - gt2*h12)/det;
- dt2=-(h11*gt2 - h12*gt1)/det;
- }
-
- if ((dt1*gt1+dt2*gt2)>0) {dt1=-dt1; dt2=-dt2;}
-
- //check delta(phase1) ?
- //check delta(phase2) ?
-
- if (TMath::Abs(dt1)/(TMath::Abs(t1)+1.e-3) < 1.e-4)
- if (TMath::Abs(dt2)/(TMath::Abs(t2)+1.e-3) < 1.e-4) {
- if ((gt1*gt1+gt2*gt2) > 1.e-4/dy2/dy2)
- cerr<<"AliV0vertexer::PropagateToDCA:"
- " stopped at not a stationary point !\n";
- Double_t lmb=h11+h22; lmb=lmb-TMath::Sqrt(lmb*lmb-4*det);
- if (lmb < 0.)
- cerr<<"AliV0vertexer::PropagateToDCA:"
- " stopped at not a minimum !\n";
- break;
- }
-
- Double_t dd=dm;
- for (Int_t div=1 ; ; div*=2) {
- Evaluate(p1,t1+dt1,r1,g1,gg1);
- Evaluate(p2,t2+dt2,r2,g2,gg2);
- dx=r2[0]-r1[0]; dy=r2[1]-r1[1]; dz=r2[2]-r1[2];
- dd=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2;
- if (dd<dm) break;
- dt1*=0.5; dt2*=0.5;
- if (div>512) {
- cerr<<"AliV0vertexer::PropagateToDCA: overshoot !\n"; break;
- }
- }
- dm=dd;
-
- t1+=dt1;
- t2+=dt2;
-
- }
-
- if (max<=0) cerr<<"AliV0vertexer::PropagateToDCA: too many iterations !\n";
-
- //propagate tracks to the points of DCA
- Double_t cs=TMath::Cos(n->GetAlpha());
- Double_t sn=TMath::Sin(n->GetAlpha());
- Double_t x=r1[0]*cs + r1[1]*sn;
- if (!n->PropagateTo(x,0.,0.)) {
- //cerr<<"AliV0vertexer::PropagateToDCA: propagation failed !\n";
- return 1.e+33;
- }
-
- cs=TMath::Cos(p->GetAlpha());
- sn=TMath::Sin(p->GetAlpha());
- x=r2[0]*cs + r2[1]*sn;
- if (!p->PropagateTo(x,0.,0.)) {
- //cerr<<"AliV0vertexer::PropagateToDCA: propagation failed !\n";
- return 1.e+33;
- }
-
- return TMath::Sqrt(dm*TMath::Sqrt(dy2*dz2));
- //return TMath::Sqrt(dx*dx + dy*dy + dz*dz);
+ return n->PropagateToDCA(p);
}
//_______________________________________________________________________
void AliKalmanTrack::StartTimeIntegral()
{
+ // Sylwester Radomski, GSI
+ // S.Radomski@gsi.de
//
// Start time integration
// To be called at Vertex by ITS tracker
Double_t AliKalmanTrack::GetIntegratedTime(Int_t pdg) const
{
+ // Sylwester Radomski, GSI
+ // S.Radomski@gsi.de
//
// Return integrated time hypothesis for a given particle
// type assumption.
void AliKalmanTrack::PrintTime() const
{
+ // Sylwester Radomski, GSI
+ // S.Radomski@gsi.de
+ //
// For testing
// Prints time for all hypothesis
//
printf("\n");
}
-//_______________________________________________________________________
+static void External2Helix(const AliKalmanTrack *t, Double_t helix[6]) {
+ //--------------------------------------------------------------------
+ // External track parameters -> helix parameters
+ //--------------------------------------------------------------------
+ Double_t alpha,x,cs,sn;
+ t->GetExternalParameters(x,helix); alpha=t->GetAlpha();
+
+ cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
+ helix[5]=x*cs - helix[0]*sn; // x0
+ helix[0]=x*sn + helix[0]*cs; // y0
+//helix[1]= // z0
+ helix[2]=TMath::ASin(helix[2]) + alpha; // phi0
+//helix[3]= // tgl
+ helix[4]=helix[4]/t->GetConvConst(); // C
+}
+
+static void Evaluate(const Double_t *h, Double_t t,
+ Double_t r[3], //radius vector
+ Double_t g[3], //first defivatives
+ Double_t gg[3]) //second derivatives
+{
+ //--------------------------------------------------------------------
+ // Calculate position of a point on a track and some derivatives
+ //--------------------------------------------------------------------
+ Double_t phase=h[4]*t+h[2];
+ Double_t sn=TMath::Sin(phase), cs=TMath::Cos(phase);
+
+ r[0] = h[5] + (sn - h[6])/h[4];
+ r[1] = h[0] - (cs - h[7])/h[4];
+ r[2] = h[1] + h[3]*t;
+
+ g[0] = cs; g[1]=sn; g[2]=h[3];
+
+ gg[0]=-h[4]*sn; gg[1]=h[4]*cs; gg[2]=0.;
+}
+
+Double_t AliKalmanTrack::
+GetDCA(const AliKalmanTrack *p, Double_t &xthis, Double_t &xp) const {
+ //------------------------------------------------------------
+ // Returns the (weighed !) distance of closest approach between
+ // this track and the track passed as the argument.
+ // Other returned values:
+ // xthis, xt - coordinates of tracks' reference planes at the DCA
+ //-----------------------------------------------------------
+ Double_t dy2=GetSigmaY2() + p->GetSigmaY2();
+ Double_t dz2=GetSigmaZ2() + p->GetSigmaZ2();
+ Double_t dx2=dy2;
+
+ //dx2=dy2=dz2=1.;
+
+ Double_t p1[8]; External2Helix(this,p1);
+ p1[6]=TMath::Sin(p1[2]); p1[7]=TMath::Cos(p1[2]);
+ Double_t p2[8]; External2Helix(p,p2);
+ p2[6]=TMath::Sin(p2[2]); p2[7]=TMath::Cos(p2[2]);
+
+
+ Double_t r1[3],g1[3],gg1[3]; Double_t t1=0.;
+ Evaluate(p1,t1,r1,g1,gg1);
+ Double_t r2[3],g2[3],gg2[3]; Double_t t2=0.;
+ Evaluate(p2,t2,r2,g2,gg2);
+ Double_t dx=r2[0]-r1[0], dy=r2[1]-r1[1], dz=r2[2]-r1[2];
+ Double_t dm=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2;
+
+ Int_t max=27;
+ while (max--) {
+ Double_t gt1=-(dx*g1[0]/dx2 + dy*g1[1]/dy2 + dz*g1[2]/dz2);
+ Double_t gt2=+(dx*g2[0]/dx2 + dy*g2[1]/dy2 + dz*g2[2]/dz2);
+ Double_t h11=(g1[0]*g1[0] - dx*gg1[0])/dx2 +
+ (g1[1]*g1[1] - dy*gg1[1])/dy2 +
+ (g1[2]*g1[2] - dz*gg1[2])/dz2;
+ Double_t h22=(g2[0]*g2[0] + dx*gg2[0])/dx2 +
+ (g2[1]*g2[1] + dy*gg2[1])/dy2 +
+ (g2[2]*g2[2] + dz*gg2[2])/dz2;
+ Double_t h12=-(g1[0]*g2[0]/dx2 + g1[1]*g2[1]/dy2 + g1[2]*g2[2]/dz2);
+
+ Double_t det=h11*h22-h12*h12;
+
+ Double_t dt1,dt2;
+ if (TMath::Abs(det)<1.e-33) {
+ //(quasi)singular Hessian
+ dt1=-gt1; dt2=-gt2;
+ } else {
+ dt1=-(gt1*h22 - gt2*h12)/det;
+ dt2=-(h11*gt2 - h12*gt1)/det;
+ }
+
+ if ((dt1*gt1+dt2*gt2)>0) {dt1=-dt1; dt2=-dt2;}
+
+ //check delta(phase1) ?
+ //check delta(phase2) ?
+
+ if (TMath::Abs(dt1)/(TMath::Abs(t1)+1.e-3) < 1.e-4)
+ if (TMath::Abs(dt2)/(TMath::Abs(t2)+1.e-3) < 1.e-4) {
+ if ((gt1*gt1+gt2*gt2) > 1.e-4/dy2/dy2)
+ Warning("GetDCA"," stopped at not a stationary point !\n");
+ Double_t lmb=h11+h22; lmb=lmb-TMath::Sqrt(lmb*lmb-4*det);
+ if (lmb < 0.)
+ Warning("GetDCA"," stopped at not a minimum !\n");
+ break;
+ }
+
+ Double_t dd=dm;
+ for (Int_t div=1 ; ; div*=2) {
+ Evaluate(p1,t1+dt1,r1,g1,gg1);
+ Evaluate(p2,t2+dt2,r2,g2,gg2);
+ dx=r2[0]-r1[0]; dy=r2[1]-r1[1]; dz=r2[2]-r1[2];
+ dd=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2;
+ if (dd<dm) break;
+ dt1*=0.5; dt2*=0.5;
+ if (div>512) {
+ Warning("GetDCA"," overshoot !\n"); break;
+ }
+ }
+ dm=dd;
+
+ t1+=dt1;
+ t2+=dt2;
+
+ }
+
+ if (max<=0) Warning("GetDCA"," too many iterations !\n");
+
+ Double_t cs=TMath::Cos(GetAlpha());
+ Double_t sn=TMath::Sin(GetAlpha());
+ xthis=r1[0]*cs + r1[1]*sn;
+
+ cs=TMath::Cos(p->GetAlpha());
+ sn=TMath::Sin(p->GetAlpha());
+ xp=r2[0]*cs + r2[1]*sn;
+
+ return TMath::Sqrt(dm*TMath::Sqrt(dy2*dz2));
+}
+
+Double_t AliKalmanTrack::
+PropagateToDCA(AliKalmanTrack *p, Double_t d, Double_t x0) {
+ //--------------------------------------------------------------
+ // Propagates this track and the argument track to the position of the
+ // distance of closest approach.
+ // Returns the (weighed !) distance of closest approach.
+ //--------------------------------------------------------------
+ Double_t xthis,xp;
+ Double_t dca=GetDCA(p,xthis,xp);
+
+ if (!PropagateTo(xthis,d,x0)) {
+ //Warning("PropagateToDCA"," propagation failed !\n");
+ return 1e+33;
+ }
+
+ if (!p->PropagateTo(xp,d,x0)) {
+ //Warning("PropagateToDCA"," propagation failed !\n";
+ return 1e+33;
+ }
+
+ return dca;
+}
return 0;
}
+ virtual Double_t GetDCA(const AliKalmanTrack *,Double_t &,Double_t &) const;
+ virtual
+ Double_t PropagateToDCA(AliKalmanTrack *, Double_t d=0., Double_t x0=0.);
+ virtual Double_t GetAlpha() const {
+ Warning("GetAlpha()","Method must be overloaded !\n");
+ return 0.;
+ }
+ virtual Double_t GetSigmaY2() const {
+ Warning("GetSigmaY2()","Method must be overloaded !\n");
+ return 0.;
+ }
+ virtual Double_t GetSigmaZ2() const {
+ Warning("GetSigmaZ2()","Method must be overloaded !\n");
+ return 0.;
+ }
+
virtual Int_t Compare(const TObject *) const {return 0;}
virtual void GetExternalParameters(Double_t &/*xr*/, Double_t /*x*/[5]) const {}
}
Double_t GetMagneticField() const {return 100/0.299792458/fgConvConst;}
- // Time integration
+ // Time integration (S.Radomski@gsi.de)
void StartTimeIntegral();
Bool_t IsStartedTimeIntegral() const {return fStartTimeIntegral;}
void AddTimeStep(Double_t length);
static Double_t fgConvConst; //conversion constant cm -> GeV/c
- // variables for time integration
+ // variables for time integration (S.Radomski@gsi.de)
static const Int_t fgkTypes = 5; // Number of track types (e,mu,pi,k,p)
Bool_t fStartTimeIntegral; // indicator wether integrate time
Float_t fIntegratedTime[5]; // intgrated time
git://git.uio.no / u / mrichter / AliRoot.git / commitdiff