X-Git-Url: http://git.uio.no/git/?p=u%2Fmrichter%2FAliRoot.git;a=blobdiff_plain;f=ITS%2FAliITStrackV2.cxx;h=60834d30969a9ff5fecc2df77163e79ee2bfa672;hp=35cfdccd8b544ac244441af1dcc7f4b5354db978;hb=559d0c87ae779c3681ae7486db74297306ad8138;hpb=15dd636fe2589363908aa2f48504ba5fab2d5763

diff --git a/ITS/AliITStrackV2.cxx b/ITS/AliITStrackV2.cxx
index 35cfdccd8b5..60834d30969 100644
--- a/ITS/AliITStrackV2.cxx
+++ b/ITS/AliITStrackV2.cxx
@@ -13,20 +13,18 @@
  * provided "as is" without express or implied warranty.                  *
  **************************************************************************/
 
-//-------------------------------------------------------------------------
+///////////////////////////////////////////////////////////////////////////
 //                Implementation of the ITS track class
 //
 //          Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
 //     dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
-//-------------------------------------------------------------------------
-
-#include <TMatrixD.h>
-
+///////////////////////////////////////////////////////////////////////////
 #include <TMath.h>
 
 #include "AliCluster.h"
 #include "AliESDtrack.h"
 #include "AliITStrackV2.h"
+#include "AliStrLine.h"
 
 ClassImp(AliITStrackV2)
 
@@ -59,7 +57,7 @@ AliITStrackV2::AliITStrackV2():AliKalmanTrack(),
   fC44(0),
   fESDtrack(0)
 {
-    for(Int_t i=0; i<kMaxLayer; i++) fIndex[i]=0;
+    for(Int_t i=0; i<2*kMaxLayer; i++) fIndex[i]=-1;
     for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
 }
 
@@ -84,13 +82,13 @@ AliKalmanTrack() {
 
   //Conversion of the track parameters
   Double_t x,p[5]; 
-  if (c) t.GetConstrainedExternalParameters(x,p);
+  if (c) t.GetConstrainedExternalParameters(fAlpha,x,p);
   else t.GetExternalParameters(x,p);
-  fX=x;    x=GetConvConst();
+  fX=x;   
   fP0=p[0]; 
-  fP1=p[1]; 
+  fP1=p[1];   SaveLocalConvConst(); 
   fP2=p[2];
-  fP3=p[3];
+  fP3=p[3];   x=GetLocalConvConst();
   fP4=p[4]/x; 
 
   //Conversion of the covariance matrix
@@ -110,15 +108,13 @@ AliKalmanTrack() {
   }
   fESDtrack=&t;
 
-  if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
+  //  if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
+  for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
 }
 
 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
   fESDtrack->UpdateTrackParams(this,flags);
 }
-void AliITStrackV2::SetConstrainedESDtrack(Double_t chi2) const {
-  fESDtrack->SetConstrainedTrackParams(this,chi2);
-}
 
 //____________________________________________________________________________
 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) {
@@ -137,11 +133,10 @@ AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) {
   fC30=t.fC30;  fC31=t.fC31;  fC32=t.fC32;  fC33=t.fC33;
   fC40=t.fC40;  fC41=t.fC41;  fC42=t.fC42;  fC43=t.fC43;  fC44=t.fC44;
 
-  Int_t n=GetNumberOfClusters();
-  for (Int_t i=0; i<n; i++) {
-    fIndex[i]=t.fIndex[i];
-    if (i<4) fdEdxSample[i]=t.fdEdxSample[i];
-  }
+  Int_t i;
+  for (i=0; i<2*kMaxLayer; i++) fIndex[i]=t.fIndex[i];
+  for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
+
   fESDtrack=t.fESDtrack;
 }
 
@@ -166,7 +161,7 @@ void AliITStrackV2::GetExternalCovariance(Double_t cc[15]) const {
   // This function returns an external representation of the covriance matrix.
   //   (See comments in AliTPCtrack.h about external track representation)
   //-------------------------------------------------------------------------
-  Double_t a=GetConvConst();
+  Double_t a=GetLocalConvConst();
 
   cc[0 ]=fC00;
   cc[1 ]=fC10;   cc[2 ]=fC11;
@@ -215,6 +210,24 @@ GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const {
   return 1;
 }
 
+//_____________________________________________________________________________
+void AliITStrackV2::ApproximateHelixWithLine(Double_t xk, AliStrLine *line)
+{
+  //------------------------------------------------------------
+  // Approximate the track (helix) with a straight line tangent to the
+  // helix in the point defined by r (F. Prino, prino@to.infn.it)
+  //------------------------------------------------------------
+  Double_t mom[3];
+  Double_t azim = TMath::ASin(fP2)+fAlpha;
+  Double_t theta = TMath::Pi()/2. - TMath::ATan(fP3);
+  mom[0] = TMath::Sin(theta)*TMath::Cos(azim);
+  mom[1] = TMath::Sin(theta)*TMath::Sin(azim);
+  mom[2] = TMath::Cos(theta);
+  Double_t pos[3];
+  GetGlobalXYZat(xk,pos[0],pos[1],pos[2]);
+  line->SetP0(pos);
+  line->SetCd(mom);
+}
 //_____________________________________________________________________________
 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const 
 {
@@ -279,12 +292,15 @@ Int_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
   //------------------------------------------------------------------
   Double_t x1=fX, x2=xk, dx=x2-x1;
   Double_t f1=fP2, f2=f1 + fP4*dx;
-  if (TMath::Abs(f2) >= 0.9999) {
-    Int_t n=GetNumberOfClusters();
-    if (n>kWARN) 
-       Warning("PropagateTo","Propagation failed !\n",n);
+  if (TMath::Abs(f2) >= 0.98) {
+    // MI change  - don't propagate highly inclined tracks
+    //              covariance matrix distorted
+    //Int_t n=GetNumberOfClusters();
+    //if (n>kWARN) 
+    //   Warning("PropagateTo","Propagation failed !\n",n);
     return 0;
   }
+  Double_t lcc=GetLocalConvConst();  
 
   // old position [SR, GSI, 17.02.2003]
   Double_t oldX = fX, oldY = fP0, oldZ = fP1;
@@ -337,6 +353,10 @@ Int_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
 
   fX=x2;
 
+  //Change of the magnetic field *************
+  SaveLocalConvConst();
+  fP4*=lcc/GetLocalConvConst();
+
   if (!CorrectForMaterial(d,x0)) return 0;
 
   // Integrated Time [SR, GSI, 17.02.2003]
@@ -474,7 +494,6 @@ Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
   Double_t ca=TMath::Cos(alp-fAlpha), sa=TMath::Sin(alp-fAlpha);
   Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2);
 
-  TMatrixD *T=0;
   // **** rotation **********************
   {
   fAlpha = alp;
@@ -482,74 +501,91 @@ Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
   fP0= -x*sa + p0*ca;
   fP2=  sf*ca - cf*sa;
 
-  static TMatrixD C(5,5); 
-  C(0,0)=c00;
-  C(1,0)=c10; C(1,1)=c11;
-  C(2,0)=c20; C(2,1)=c21; C(2,2)=c22;
-  C(3,0)=c30; C(3,1)=c31; C(3,2)=c32; C(3,3)=c33;
-  C(4,0)=c40; C(4,1)=c41; C(4,2)=c42; C(4,3)=c43; C(4,4)=c44;
-  C(0,1)=C(1,0);
-  C(0,2)=C(2,0); C(1,2)=C(2,1);
-  C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
-  C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
-
-  
-  static TMatrixD F(6,5);
-  F(0,0)=sa; 
-  F(1,0)=ca;
-  F(2,1)=F(4,3)=F(5,4)=1; 
-  F(3,2)=ca + sf/cf*sa;
-
-  //TMatrixD tmp(C,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F)); 
-  
-  static TMatrixD Ft(5,6);
-  Ft(0,0)=sa; 
-  Ft(0,1)=ca;
-  Ft(1,2)=Ft(3,4)=Ft(4,5)=1; 
-  Ft(2,3)=ca + sf/cf*sa;
-
-  TMatrixD tmp(C,TMatrixD::kMult,Ft); 
-  T=new TMatrixD(F,TMatrixD::kMult,tmp); 
+  Double_t rr=(ca+sf/cf*sa);  
+
+  fC00 *= (ca*ca);
+  fC10 *= ca; 
+  fC20 *= ca*rr;
+  fC30 *= ca;
+  fC40 *= ca;
+  //fC11 = fC11;
+  fC21 *= rr;
+  //fC31 = fC31; 
+  //fC41 = fC41;
+  fC22 *= rr*rr;
+  fC32 *= rr;
+  fC42 *= rr;
+  //fC33=fC33;
+  //fC43=fC43;
+  //fC44=fC44;
+ 
   }
 
   // **** translation ******************
   {
   Double_t dx=xk-fX;
   Double_t f1=fP2, f2=f1 + fP4*dx;
-  if (TMath::Abs(f2) >= 0.9999) {
-    Int_t n=GetNumberOfClusters();
-    if (n>kWARN) 
-       Warning("Propagate","Propagation failed (%d) !\n",n);
+  if (TMath::Abs(f2) >= 0.98) {
+    // don't propagate highly inclined tracks MI
     return 0;
   }
+  //    Int_t n=GetNumberOfClusters();
+  //  if (n>kWARN) 
+  //     Warning("Propagate","Propagation failed (%d) !\n",n);
+  //  return 0;
+  //}
+  Double_t lcc=GetLocalConvConst();  
+
   Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2);
-  
+
   fX=xk;
   fP0 += dx*(f1+f2)/(r1+r2);
   fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
   fP2 += dx*fP4;
 
-  static TMatrixD F(5,6);
-  F(0,1)=F(1,2)=F(2,3)=F(3,4)=F(4,5)=1; 
-  F(0,3)=dx/(r1+r2)*(2+(f1+f2)*(f2/r2+f1/r1)/(r1+r2)); 
-  F(0,5)=dx*dx/(r1+r2)*(1+(f1+f2)*f2/(r1+r2));
-  F(1,3)=dx*fP3/(f1*r2 + f2*r1)*(2-(f1+f2)*(r2-f1*f2/r2+r1-f2*f1/r1)/(f1*r2 + f2*r1));
-  F(1,4)=dx*(f1+f2)/(f1*r2 + f2*r1);
-  F(1,5)=dx*dx*fP3/(f1*r2 + f2*r1)*(1-(f1+f2)*(-f1*f2/r2+r1)/(f1*r2 + f2*r1));
-  F(2,5)=dx;
-  F(0,0)=-1/(r1+r2)*((f1+f2)+dx*fP4*(1+(f1+f2)/(r1+r2)*f2/r2));
-  F(1,0)=-fP3/(f1*r2 + f2*r1)*((f1+f2)+dx*fP4*(1+(f1+f2)/(f1*r2 + f2*r1)*(f1*f2/r2-r1)));
-  F(2,0)=-fP4;
-
-  TMatrixD tmp(*T,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F)); 
-  delete T;
-  TMatrixD C(F,TMatrixD::kMult,tmp);
-
-  fC00=C(0,0); 
-  fC10=C(1,0); fC11=C(1,1); 
-  fC20=C(2,0); fC21=C(2,1); fC22=C(2,2);
-  fC30=C(3,0); fC31=C(3,1); fC32=C(3,2); fC33=C(3,3);
-  fC40=C(4,0); fC41=C(4,1); fC42=C(4,2); fC43=C(4,3); fC44=C(4,4);
+  //Change of the magnetic field *************
+  SaveLocalConvConst();
+  fP4*=lcc/GetLocalConvConst();
+
+  //f = F - 1
+  
+  Double_t f02=    dx/(r1*r1*r1);
+  Double_t f04=0.5*dx*dx/(r1*r1*r1);
+  Double_t f12=    dx*fP3*f1/(r1*r1*r1);
+  Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1);
+  Double_t f13=    dx/r1;
+  Double_t f24=    dx; 
+  
+  //b = C*ft
+  Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30;
+  Double_t b02=f24*fC40;
+  Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31;
+  Double_t b12=f24*fC41;
+  Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32;
+  Double_t b22=f24*fC42;
+  Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43;
+  Double_t b42=f24*fC44;
+  Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33;
+  Double_t b32=f24*fC43;
+  
+  //a = f*b = f*C*ft
+  Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42;
+  Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32;
+  Double_t a22=f24*b42;
+
+  //F*C*Ft = C + (b + bt + a)
+  fC00 += b00 + b00 + a00;
+  fC10 += b10 + b01 + a01; 
+  fC20 += b20 + b02 + a02;
+  fC30 += b30;
+  fC40 += b40;
+  fC11 += b11 + b11 + a11;
+  fC21 += b21 + b12 + a12;
+  fC31 += b31; 
+  fC41 += b41;
+  fC22 += b22 + b22 + a22;
+  fC32 += b32;
+  fC42 += b42;
 
   if (!Invariant()) {
      fAlpha=alpha; 
@@ -567,6 +603,7 @@ Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
   return 1;
 }
 
+
 Double_t AliITStrackV2::GetD(Double_t x, Double_t y) const {
   //------------------------------------------------------------------
   // This function calculates the transverse impact parameter
@@ -619,7 +656,9 @@ Int_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
   Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
   //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
   {
-  Double_t parp=0.5*(fP4*fX + dy*TMath::Sqrt(4/r2-fP4*fP4));
+  Double_t dummy=4/r2-fP4*fP4;
+  if (dummy < 0) return 0;
+  Double_t parp=0.5*(fP4*fX + dy*TMath::Sqrt(dummy));
   Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
   sigma2p += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
   sigma2p += ers[1]*ers[1]/r2;
@@ -694,3 +733,40 @@ void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
 
   SetdEdx(dedx);
 }
+
+Double_t AliITStrackV2::
+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, dca;
+  {
+  //Temporary solution
+  Double_t b=1./GetLocalConvConst()/kB2C;
+  AliExternalTrackParam dummy1(*this), dummy2(*p); 
+  dca=dummy1.GetDCA(&dummy2,b,xthis,xp);
+  }
+  if (!PropagateTo(xthis,d,x0)) {
+    //AliWarning(" propagation failed !");
+    return 1e+33;
+  }  
+
+  if (!p->PropagateTo(xp,d,x0)) {
+    //AliWarning(" propagation failed !";
+    return 1e+33;
+  }  
+
+  return dca;
+} 
+
+Double_t AliITStrackV2::Get1Pt() const {
+  //--------------------------------------------------------------
+  // Returns the inverse Pt (1/GeV/c)
+  // (or 1/"most probable pt", if the field is too weak)
+  //--------------------------------------------------------------
+  if (TMath::Abs(GetLocalConvConst()) > kVeryBigConvConst)
+      return 1./kMostProbableMomentum/TMath::Sqrt(1.+ GetTgl()*GetTgl());
+  return (TMath::Sign(1e-9,fP4) + fP4)*GetLocalConvConst();
+}