X-Git-Url: http://git.uio.no/git/?a=blobdiff_plain;f=STEER%2FAliKalmanTrack.cxx;h=7bbc416d423df42a5e8f0791a23bacd4a96fbf83;hb=fc7be9e323c3ca1ce3d624d2dd3f96c28c5be37f;hp=7fb0e857abeebdd380f8f9dbbcdef1fc9db15264;hpb=74f9526e5af6bf8990075f5a079f4d9cbeeded09;p=u%2Fmrichter%2FAliRoot.git

diff --git a/STEER/AliKalmanTrack.cxx b/STEER/AliKalmanTrack.cxx
index 7fb0e857abe..7bbc416d423 100644
--- a/STEER/AliKalmanTrack.cxx
+++ b/STEER/AliKalmanTrack.cxx
@@ -17,7 +17,7 @@
 
 //-------------------------------------------------------------------------
 //                Implementation of the AliKalmanTrack class
-//
+//   that is the base for AliTPCtrack, AliITStrackV2 and AliTRDtrack
 //        Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
 //-------------------------------------------------------------------------
 
@@ -25,6 +25,9 @@
 #include "AliPDG.h"
 #include "TPDGCode.h"
 #include "TDatabasePDG.h"
+#include "AliRunLoader.h"
+#include "AliRun.h"
+#include "AliMagF.h"
 
 ClassImp(AliKalmanTrack)
 
@@ -40,8 +43,10 @@ AliKalmanTrack::AliKalmanTrack():
   //
   // Default constructor
   //
-    if (fgConvConst==0) 
-      Fatal("AliKalmanTrack()","The magnetic field has not been set !\n"); 
+    if (fgConvConst==0) {
+      Warning("AliKalmanTrack()", "The magnetic field has not been set!");
+      SetConvConst();
+    }
     
     fStartTimeIntegral = kFALSE;
     fIntegratedLength = 0;
@@ -59,9 +64,11 @@ AliKalmanTrack::AliKalmanTrack(const AliKalmanTrack &t):
   //
   // Copy constructor
   //
-  if (fgConvConst==0) 
-    Fatal("AliKalmanTrack(const AliKalmanTrack&)",
-          "The magnetic field has not been set !\n"); 
+  if (fgConvConst==0) {
+    Warning("AliKalmanTrack(const AliKalmanTrack&)", 
+	    "The magnetic field has not been set!");
+    SetConvConst();
+  }
 
   fStartTimeIntegral = t.fStartTimeIntegral;
   fIntegratedLength = t.fIntegratedLength;
@@ -69,9 +76,213 @@ AliKalmanTrack::AliKalmanTrack(const AliKalmanTrack &t):
   for (Int_t i=0; i<5; i++) 
     fIntegratedTime[i] = t.fIntegratedTime[i];
 }
+
+
+//_______________________________________________________________________
+void AliKalmanTrack::SetConvConst()
+{
+  // Sets the conversion constants for the magnetic field 
+  // (Momentum in GeV/c -> curvature in mm)
+  ::Info("SetConvConst()", "tryinig to get the magnetic field from the AliRun object..."); 
+  AliRunLoader* loader = AliRunLoader::GetRunLoader();
+  if (!loader) ::Fatal("SetConvConst()", "No run loader found"); 
+  if (!loader->GetAliRun()) loader->LoadgAlice();
+  AliRun* alirun = loader->GetAliRun();
+  if (!alirun) ::Fatal("SetConvConst()", "No AliRun object found");
+
+  Double_t field = alirun->Field()->SolenoidField();
+  SetConvConst(1000/0.299792458/field);
+  ::Info("SetConvConst()", "Magnetic field set to %f kGauss\n", field);
+}
+
+//_______________________________________________________________________
+Double_t AliKalmanTrack::GetX() const
+{
+  // Returns the X coordinate of the current track position
+  Warning("GetX()","Method must be overloaded !\n");
+  return 0.;
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::GetdEdx() const
+{
+  // Returns the dE/dx of the track
+  Warning("GetdEdx()","Method must be overloaded !\n");
+  return 0.;
+}
+
+//_______________________________________________________________________
+Double_t AliKalmanTrack::GetY() const
+{
+  // Returns the Y coordinate of the current track position
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return par[0];
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::GetZ() const
+{
+  // Returns the Z coordinate of the current track position
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return par[1];
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::GetSnp() const
+{
+  // Returns the Sin(phi), where phi is the angle between the transverse
+  // momentum (in xOy plane) and the X axis
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return par[2];
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::GetTgl() const
+{
+  // Returns the Tan(lambda), where lambda is the dip angle (between 
+  // the bending plane (xOy) and the momentum of the track
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return par[3];
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Get1Pt() const
+{
+  // Returns 1/pT
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return par[4];
+}
+
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Phi() const
+{
+// return global phi of track
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  if (par[2] >  1.) par[2] =  1.;
+  if (par[2] < -1.) par[2] = -1.;
+  Double_t phi = TMath::ASin(par[2]) + GetAlpha();
+  while (phi < 0) phi += TMath::TwoPi();
+  while (phi > TMath::TwoPi()) phi -= TMath::TwoPi();
+  return phi;
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::SigmaPhi() const
+{
+// return error of global phi of track
+
+  Double_t par[5];
+  Double_t cov[15];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  GetExternalCovariance(cov);
+  return TMath::Sqrt(TMath::Abs(cov[5] / (1. - par[2]*par[2])));
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Theta() const
+{
+// return global theta of track
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return TMath::Pi()/2. - TMath::ATan(par[3]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::SigmaTheta() const
+{
+// return error of global theta of track
+
+  Double_t par[5];
+  Double_t cov[15];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  GetExternalCovariance(cov);
+  return TMath::Sqrt(TMath::Abs(cov[5])) / (1. + par[3]*par[3]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Eta() const
+{
+// return global eta of track
+
+  return -TMath::Log(TMath::Tan(Theta()/2.));
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Px() const
+{
+// return x component of track momentum
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  Double_t phi = TMath::ASin(par[2]) + GetAlpha();
+  return TMath::Cos(phi) / TMath::Abs(par[4]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Py() const
+{
+// return y component of track momentum
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  Double_t phi = TMath::ASin(par[2]) + GetAlpha();
+  return TMath::Sin(phi) / TMath::Abs(par[4]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Pz() const
+{
+// return z component of track momentum
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return par[3] / TMath::Abs(par[4]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::Pt() const
+{
+// return transverse component of track momentum
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return 1. / TMath::Abs(par[4]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::SigmaPt() const
+{
+// return error of transverse component of track momentum
+
+  Double_t par[5];
+  Double_t cov[15];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  GetExternalCovariance(cov);
+  return TMath::Sqrt(cov[14]) / TMath::Abs(par[4]);
+}
+//_______________________________________________________________________
+Double_t AliKalmanTrack::P() const
+{
+// return total track momentum
+
+  Double_t par[5];
+  Double_t localX = GetX();
+  GetExternalParameters(localX, par);
+  return 1. / TMath::Abs(par[4] * TMath::Cos(TMath::ATan(par[3])));
+}
 //_______________________________________________________________________
 void AliKalmanTrack::StartTimeIntegral() 
 {
+  // Sylwester Radomski, GSI
+  // S.Radomski@gsi.de
   //
   // Start time integration
   // To be called at Vertex by ITS tracker
@@ -81,7 +292,7 @@ void AliKalmanTrack::StartTimeIntegral()
   //  Warning("StartTimeIntegral", "Reseting Recorded Time.");
 
   fStartTimeIntegral = kTRUE;
-  for(Int_t i=0; i<fTypes; i++) fIntegratedTime[i] = 0;  
+  for(Int_t i=0; i<fgkTypes; i++) fIntegratedTime[i] = 0;  
   fIntegratedLength = 0;
 }
 //_______________________________________________________________________
@@ -107,13 +318,13 @@ void AliKalmanTrack:: AddTimeStep(Double_t length)
   // S.Radomski@gsi.de
   // 
   
-  static const Double_t cc = 2.99792458e-2;
+  static const Double_t kcc = 2.99792458e-2;
 
   if (!fStartTimeIntegral) return;
   
   fIntegratedLength += length;
 
-  static Int_t pdgCode[fTypes]  = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton};
+  static Int_t pdgCode[fgkTypes]  = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton};
   TDatabasePDG *db = TDatabasePDG::Instance();
 
   Double_t xr, param[5];
@@ -127,11 +338,11 @@ void AliKalmanTrack:: AddTimeStep(Double_t length)
 
   if (length > 100) return;
 
-  for (Int_t i=0; i<fTypes; i++) {
+  for (Int_t i=0; i<fgkTypes; i++) {
     
     Double_t mass = db->GetParticle(pdgCode[i])->Mass();
     Double_t correction = TMath::Sqrt( pt*pt * (1 + tgl*tgl) + mass * mass ) / p;
-    Double_t time = length * correction / cc;
+    Double_t time = length * correction / kcc;
 
     //cout << mass << "\t" << pt << "\t" << p << "\t" 
     //     << correction << endl;
@@ -144,6 +355,8 @@ void AliKalmanTrack:: AddTimeStep(Double_t length)
 
 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.
@@ -158,28 +371,194 @@ Double_t AliKalmanTrack::GetIntegratedTime(Int_t pdg) const
     return 0.;
   }
 
-  static Int_t pdgCode[fTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton};
+  static Int_t pdgCode[fgkTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton};
 
-  for (Int_t i=0; i<fTypes; i++)
+  for (Int_t i=0; i<fgkTypes; i++)
     if (pdgCode[i] == TMath::Abs(pdg)) return fIntegratedTime[i];
 
   Warning(":GetIntegratedTime","Particle type [%d] not found", pdg);
   return 0;
 }
+
+void AliKalmanTrack::GetIntegratedTimes(Double_t *times) const {
+  for (Int_t i=0; i<fgkTypes; i++) times[i]=fIntegratedTime[i];
+}
+
+void AliKalmanTrack::SetIntegratedTimes(const Double_t *times) {
+  for (Int_t i=0; i<fgkTypes; i++) fIntegratedTime[i]=times[i];
+}
+
 //_______________________________________________________________________
 
 void AliKalmanTrack::PrintTime() const
 {
+  // Sylwester Radomski, GSI
+  // S.Radomski@gsi.de
+  //
   // For testing
   // Prints time for all hypothesis
   //
 
-  static Int_t pdgCode[fTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton};
+  static Int_t pdgCode[fgkTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton};
 
-  for (Int_t i=0; i<fTypes; i++)
+  for (Int_t i=0; i<fgkTypes; i++)
     printf("%d: %.2f  ", pdgCode[i], fIntegratedTime[i]);
   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;
+}