// Origin: I.Belikov, CERN, Jouri.Belikov@cern.ch //
///////////////////////////////////////////////////////////////////////////////
#include <TMatrixDSym.h>
+#include <TPolyMarker3D.h>
+#include <TVector3.h>
+
#include "AliExternalTrackParam.h"
-#include "AliESDVertex.h"
+#include "AliVVertex.h"
#include "AliLog.h"
ClassImp(AliExternalTrackParam)
//_____________________________________________________________________________
AliExternalTrackParam::AliExternalTrackParam() :
- AliVParticle(),
+ AliVTrack(),
fX(0),
fAlpha(0)
{
//_____________________________________________________________________________
AliExternalTrackParam::AliExternalTrackParam(const AliExternalTrackParam &track):
- AliVParticle(track),
+ AliVTrack(track),
fX(track.fX),
fAlpha(track.fAlpha)
{
//
if (this!=&trkPar) {
- AliVParticle::operator=(trkPar);
+ AliVTrack::operator=(trkPar);
fX = trkPar.fX;
fAlpha = trkPar.fAlpha;
AliExternalTrackParam::AliExternalTrackParam(Double_t x, Double_t alpha,
const Double_t param[5],
const Double_t covar[15]) :
- AliVParticle(),
+ AliVTrack(),
fX(x),
fAlpha(alpha)
{
}
//_____________________________________________________________________________
-void AliExternalTrackParam::Set(Double_t x, Double_t alpha,
- const Double_t p[5], const Double_t cov[15]) {
+AliExternalTrackParam::AliExternalTrackParam(const AliVTrack *vTrack) :
+ AliVTrack(),
+ fX(0.),
+ fAlpha(0.)
+{
+ //
+ // Constructor from virtual track,
+ // This is not a copy contructor !
+ //
+
+ if (vTrack->InheritsFrom("AliExternalTrackParam")) {
+ AliError("This is not a copy constructor. Use AliExternalTrackParam(const AliExternalTrackParam &) !");
+ AliWarning("Calling the default constructor...");
+ AliExternalTrackParam();
+ return;
+ }
+
+ Double_t xyz[3],pxpypz[3],cv[21];
+ vTrack->GetXYZ(xyz);
+ pxpypz[0]=vTrack->Px();
+ pxpypz[1]=vTrack->Py();
+ pxpypz[2]=vTrack->Pz();
+ vTrack->GetCovarianceXYZPxPyPz(cv);
+ Short_t sign = (Short_t)vTrack->Charge();
+
+ Set(xyz,pxpypz,cv,sign);
+}
+
+//_____________________________________________________________________________
+AliExternalTrackParam::AliExternalTrackParam(Double_t xyz[3],Double_t pxpypz[3],
+ Double_t cv[21],Short_t sign) :
+ AliVTrack(),
+ fX(0.),
+ fAlpha(0.)
+{
+ //
+ // constructor from the global parameters
+ //
+
+ Set(xyz,pxpypz,cv,sign);
+}
+
+//_____________________________________________________________________________
+void AliExternalTrackParam::Set(Double_t xyz[3],Double_t pxpypz[3],
+ Double_t cv[21],Short_t sign)
+{
+ //
+ // create external track parameters from the global parameters
+ // x,y,z,px,py,pz and their 6x6 covariance matrix
+ // A.Dainese 10.10.08
+
+ // Calculate alpha: the rotation angle of the corresponding local system.
//
- // Sets the parameters
+ // For global radial position inside the beam pipe, alpha is the
+ // azimuthal angle of the momentum projected on (x,y).
//
- fX=x;
- fAlpha=alpha;
- for (Int_t i = 0; i < 5; i++) fP[i] = p[i];
- for (Int_t i = 0; i < 15; i++) fC[i] = cov[i];
+ // For global radial position outside the beam pipe, alpha is the
+ // azimuthal angle of the centre of the TPC sector in which the point
+ // xyz lies
+ //
+ Double_t radPos2 = xyz[0]*xyz[0]+xyz[1]*xyz[1];
+ if (radPos2 < 3.*3.) { // inside beam pipe
+ fAlpha = TMath::ATan2(pxpypz[1],pxpypz[0]);
+ } else { // outside beam pipe
+ Float_t phiPos = TMath::Pi()+TMath::ATan2(-xyz[1], -xyz[0]);
+ fAlpha =
+ TMath::DegToRad()*(20*((((Int_t)(phiPos*TMath::RadToDeg()))/20))+10);
+ }
+
+ // Get the vertex of origin and the momentum
+ TVector3 ver(xyz[0],xyz[1],xyz[2]);
+ TVector3 mom(pxpypz[0],pxpypz[1],pxpypz[2]);
+
+ // Rotate to the local coordinate system
+ ver.RotateZ(-fAlpha);
+ mom.RotateZ(-fAlpha);
+
+ // x of the reference plane
+ fX = ver.X();
+
+ Double_t charge = (Double_t)sign;
+
+ fP[0] = ver.Y();
+ fP[1] = ver.Z();
+ fP[2] = TMath::Sin(mom.Phi());
+ fP[3] = mom.Pz()/mom.Pt();
+ fP[4] = TMath::Sign(1/mom.Pt(),charge);
+
+ // Covariance matrix (formulas to be simplified)
+
+ Double_t pt=1./TMath::Abs(fP[4]);
+ Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha);
+ Double_t r=TMath::Sqrt((1.-fP[2])*(1.+fP[2]));
+
+ Double_t m00=-sn;// m10=cs;
+ Double_t m23=-pt*(sn + fP[2]*cs/r), m43=-pt*pt*(r*cs - fP[2]*sn);
+ Double_t m24= pt*(cs - fP[2]*sn/r), m44=-pt*pt*(r*sn + fP[2]*cs);
+ Double_t m35=pt, m45=-pt*pt*fP[3];
+
+ m43*=GetSign();
+ m44*=GetSign();
+ m45*=GetSign();
+
+ Double_t cv34 = TMath::Sqrt(cv[3 ]*cv[3 ]+cv[4 ]*cv[4 ]);
+ Double_t a1=cv[13]-cv[9]*(m23*m44+m43*m24)/m23/m43;
+ Double_t a2=m23*m24-m23*(m23*m44+m43*m24)/m43;
+ Double_t a3=m43*m44-m43*(m23*m44+m43*m24)/m23;
+ Double_t a4=cv[14]-2.*cv[9]*m24*m44/m23/m43;
+ Double_t a5=m24*m24-2.*m24*m44*m23/m43;
+ Double_t a6=m44*m44-2.*m24*m44*m43/m23;
+
+ fC[0 ] = cv[0 ]+cv[2 ];
+ fC[1 ] = TMath::Sign(cv34,cv[3 ]/m00);
+ fC[2 ] = cv[5 ];
+ fC[3 ] = (cv[10]/m44-cv[6]/m43)/(m24/m44-m23/m43)/m00;
+ fC[10] = (cv[6]/m00-fC[3 ]*m23)/m43;
+ fC[6 ] = (cv[15]/m00-fC[10]*m45)/m35;
+ fC[4 ] = (cv[12]-cv[8]*m44/m43)/(m24-m23*m44/m43);
+ fC[11] = (cv[8]-fC[4]*m23)/m43;
+ fC[7 ] = cv[17]/m35-fC[11]*m45/m35;
+ fC[5 ] = TMath::Abs((a4-a6*a1/a3)/(a5-a6*a2/a3));
+ fC[14] = TMath::Abs(a1/a3-a2*fC[5]/a3);
+ fC[12] = (cv[9]-fC[5]*m23*m23-fC[14]*m43*m43)/m23/m43;
+ Double_t b1=cv[18]-fC[12]*m23*m45-fC[14]*m43*m45;
+ Double_t b2=m23*m35;
+ Double_t b3=m43*m35;
+ Double_t b4=cv[19]-fC[12]*m24*m45-fC[14]*m44*m45;
+ Double_t b5=m24*m35;
+ Double_t b6=m44*m35;
+ fC[8 ] = (b4-b6*b1/b3)/(b5-b6*b2/b3);
+ fC[13] = b1/b3-b2*fC[8]/b3;
+ fC[9 ] = TMath::Abs((cv[20]-fC[14]*(m45*m45)-fC[13]*2.*m35*m45)/(m35*m35));
+
+ return;
}
//_____________________________________________________________________________
for (Int_t i = 0; i < 15; i++) fC[i] = 0;
}
+//_____________________________________________________________________________
+void AliExternalTrackParam::AddCovariance(const Double_t c[15]) {
+ //
+ // Add "something" to the track covarince matrix.
+ // May be needed to account for unknown mis-calibration/mis-alignment
+ //
+ fC[0] +=c[0];
+ fC[1] +=c[1]; fC[2] +=c[2];
+ fC[3] +=c[3]; fC[4] +=c[4]; fC[5] +=c[5];
+ fC[6] +=c[6]; fC[7] +=c[7]; fC[8] +=c[8]; fC[9] +=c[9];
+ fC[10]+=c[10]; fC[11]+=c[11]; fC[12]+=c[12]; fC[13]+=c[13]; fC[14]+=c[14];
+}
+
+
Double_t AliExternalTrackParam::GetP() const {
//---------------------------------------------------------------------
// This function returns the track momentum
}
Bool_t AliExternalTrackParam::CorrectForMeanMaterial
-(Double_t xOverX0, Double_t xTimesRho, Double_t mass,
-Double_t (*Bethe)(Double_t)) {
+(Double_t xOverX0, Double_t xTimesRho, Double_t mass, Bool_t anglecorr,
+ Double_t (*Bethe)(Double_t)) {
//------------------------------------------------------------------
// This function corrects the track parameters for the crossed material.
// "xOverX0" - X/X0, the thickness in units of the radiation length.
Double_t &fC43=fC[13];
Double_t &fC44=fC[14];
+ //Apply angle correction, if requested
+ if(anglecorr) {
+ Double_t angle=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
+ xOverX0 *=angle;
+ xTimesRho *=angle;
+ }
+
Double_t p=GetP();
Double_t p2=p*p;
Double_t beta2=p2/(p2 + mass*mass);
- //Multiple scattering******************
+ //Calculating the multiple scattering corrections******************
+ Double_t cC22 = 0.;
+ Double_t cC33 = 0.;
+ Double_t cC43 = 0.;
+ Double_t cC44 = 0.;
if (xOverX0 != 0) {
Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(xOverX0);
//Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
- fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
- fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
- fC43 += theta2*fP3*fP4*(1. + fP3*fP3);
- fC44 += theta2*fP3*fP4*fP3*fP4;
+ if(theta2>TMath::Pi()*TMath::Pi()) return kFALSE;
+ cC22 = theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
+ cC33 = theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
+ cC43 = theta2*fP3*fP4*(1. + fP3*fP3);
+ cC44 = theta2*fP3*fP4*fP3*fP4;
}
- //Energy losses************************
+ //Calculating the energy loss corrections************************
+ Double_t cP4=1.;
if ((xTimesRho != 0.) && (beta2 < 1.)) {
- Double_t dE=Bethe(beta2)*xTimesRho;
+ Double_t dE=Bethe(p/mass)*xTimesRho;
Double_t e=TMath::Sqrt(p2 + mass*mass);
if ( TMath::Abs(dE) > 0.3*e ) return kFALSE; //30% energy loss is too much!
- fP4*=(1.- e/p2*dE);
+ cP4 = (1.- e/p2*dE);
+ if (TMath::Abs(fP4*cP4)>100.) return kFALSE; //Do not track below 10 MeV/c
+
// Approximate energy loss fluctuation (M.Ivanov)
const Double_t knst=0.07; // To be tuned.
Double_t sigmadE=knst*TMath::Sqrt(TMath::Abs(dE));
- fC44+=((sigmadE*e/p2*fP4)*(sigmadE*e/p2*fP4));
+ cC44 += ((sigmadE*e/p2*fP4)*(sigmadE*e/p2*fP4));
}
+ //Applying the corrections*****************************
+ fC22 += cC22;
+ fC33 += cC33;
+ fC43 += cC43;
+ fC44 += cC44;
+ fP4 *= cP4;
+
return kTRUE;
}
d*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
//Multiple scattering******************
+ Double_t cC22 = 0.;
+ Double_t cC33 = 0.;
+ Double_t cC43 = 0.;
+ Double_t cC44 = 0.;
if (d!=0) {
Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d);
//Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
- fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
- fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
- fC43 += theta2*fP3*fP4*(1. + fP3*fP3);
- fC44 += theta2*fP3*fP4*fP3*fP4;
+ if(theta2>TMath::Pi()*TMath::Pi()) return kFALSE;
+ cC22 = theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
+ cC33 = theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
+ cC43 = theta2*fP3*fP4*(1. + fP3*fP3);
+ cC44 = theta2*fP3*fP4*fP3*fP4;
}
//Energy losses************************
+ Double_t cP4=1.;
if (x0!=0. && beta2<1) {
d*=x0;
- Double_t dE=Bethe(beta2)*d;
+ Double_t dE=Bethe(p/mass)*d;
Double_t e=TMath::Sqrt(p2 + mass*mass);
if ( TMath::Abs(dE) > 0.3*e ) return kFALSE; //30% energy loss is too much!
- fP4*=(1.- e/p2*dE);
+ cP4 = (1.- e/p2*dE);
// Approximate energy loss fluctuation (M.Ivanov)
const Double_t knst=0.07; // To be tuned.
Double_t sigmadE=knst*TMath::Sqrt(TMath::Abs(dE));
- fC44+=((sigmadE*e/p2*fP4)*(sigmadE*e/p2*fP4));
+ cC44 += ((sigmadE*e/p2*fP4)*(sigmadE*e/p2*fP4));
}
+ fC22 += cC22;
+ fC33 += cC33;
+ fC43 += cC43;
+ fC44 += cC44;
+ fP4 *= cP4;
+
return kTRUE;
}
-Double_t ApproximateBetheBloch(Double_t beta2) {
+Double_t AliExternalTrackParam::BetheBlochAleph(Double_t bg,
+ Double_t kp1,
+ Double_t kp2,
+ Double_t kp3,
+ Double_t kp4,
+ Double_t kp5) {
+ //
+ // This is the empirical ALEPH parameterization of the Bethe-Bloch formula.
+ // It is normalized to 1 at the minimum.
+ //
+ // bg - beta*gamma
+ //
+ // The default values for the kp* parameters are for ALICE TPC.
+ // The returned value is in MIP units
+ //
+
+ Double_t beta = bg/TMath::Sqrt(1.+ bg*bg);
+
+ Double_t aa = TMath::Power(beta,kp4);
+ Double_t bb = TMath::Power(1./bg,kp5);
+
+ bb=TMath::Log(kp3+bb);
+
+ return (kp2-aa-bb)*kp1/aa;
+}
+
+Double_t AliExternalTrackParam::BetheBlochGeant(Double_t bg,
+ Double_t kp0,
+ Double_t kp1,
+ Double_t kp2,
+ Double_t kp3,
+ Double_t kp4) {
+ //
+ // This is the parameterization of the Bethe-Bloch formula inspired by Geant.
+ //
+ // bg - beta*gamma
+ // kp0 - density [g/cm^3]
+ // kp1 - density effect first junction point
+ // kp2 - density effect second junction point
+ // kp3 - mean excitation energy [GeV]
+ // kp4 - mean Z/A
+ //
+ // The default values for the kp* parameters are for silicon.
+ // The returned value is in [GeV/(g/cm^2)].
+ //
+
+ const Double_t mK = 0.307075e-3; // [GeV*cm^2/g]
+ const Double_t me = 0.511e-3; // [GeV/c^2]
+ const Double_t rho = kp0;
+ const Double_t x0 = kp1*2.303;
+ const Double_t x1 = kp2*2.303;
+ const Double_t mI = kp3;
+ const Double_t mZA = kp4;
+ const Double_t bg2 = bg*bg;
+ const Double_t maxT= 2*me*bg2; // neglecting the electron mass
+
+ //*** Density effect
+ Double_t d2=0.;
+ const Double_t x=TMath::Log(bg);
+ const Double_t lhwI=TMath::Log(28.816*1e-9*TMath::Sqrt(rho*mZA)/mI);
+ if (x > x1) {
+ d2 = lhwI + x - 0.5;
+ } else if (x > x0) {
+ const Double_t r=(x1-x)/(x1-x0);
+ d2 = lhwI + x - 0.5 + (0.5 - lhwI - x0)*r*r*r;
+ }
+
+ return mK*mZA*(1+bg2)/bg2*
+ (0.5*TMath::Log(2*me*bg2*maxT/(mI*mI)) - bg2/(1+bg2) - d2);
+}
+
+Double_t AliExternalTrackParam::BetheBlochSolid(Double_t bg) {
//------------------------------------------------------------------
- // This is an approximation of the Bethe-Bloch formula with
- // the density effect taken into account at beta*gamma > 3.5
- // (the approximation is reasonable only for solid materials)
+ // This is an approximation of the Bethe-Bloch formula,
+ // reasonable for solid materials.
+ // All the parameters are, in fact, for Si.
+ // The returned value is in [GeV]
//------------------------------------------------------------------
- if (beta2/(1-beta2)>3.5*3.5)
- return 0.153e-3/beta2*(log(3.5*5940)+0.5*log(beta2/(1-beta2)) - beta2);
- return 0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2);
+ return BetheBlochGeant(bg);
+}
+
+Double_t AliExternalTrackParam::BetheBlochGas(Double_t bg) {
+ //------------------------------------------------------------------
+ // This is an approximation of the Bethe-Bloch formula,
+ // reasonable for gas materials.
+ // All the parameters are, in fact, for Ne.
+ // The returned value is in [GeV]
+ //------------------------------------------------------------------
+
+ const Double_t rho = 0.9e-3;
+ const Double_t x0 = 2.;
+ const Double_t x1 = 4.;
+ const Double_t mI = 140.e-9;
+ const Double_t mZA = 0.49555;
+
+ return BetheBlochGeant(bg,rho,x0,x1,mI,mZA);
}
Bool_t AliExternalTrackParam::Rotate(Double_t alpha) {
return kTRUE;
}
+Bool_t
+AliExternalTrackParam::Propagate(Double_t alpha, Double_t x, Double_t b) {
+ //------------------------------------------------------------------
+ // Transform this track to the local coord. system rotated
+ // by angle "alpha" (rad) with respect to the global coord. system,
+ // and propagate this track to the plane X=xk (cm) in the field "b" (kG)
+ //------------------------------------------------------------------
+
+ //Save the parameters
+ Double_t as=fAlpha;
+ Double_t xs=fX;
+ Double_t ps[5], cs[15];
+ for (Int_t i=0; i<5; i++) ps[i]=fP[i];
+ for (Int_t i=0; i<15; i++) cs[i]=fC[i];
+
+ if (Rotate(alpha))
+ if (PropagateTo(x,b)) return kTRUE;
+
+ //Restore the parameters, if the operation failed
+ fAlpha=as;
+ fX=xs;
+ for (Int_t i=0; i<5; i++) fP[i]=ps[i];
+ for (Int_t i=0; i<15; i++) fC[i]=cs[i];
+ return kFALSE;
+}
+
+
void AliExternalTrackParam::Propagate(Double_t len, Double_t x[3],
Double_t p[3], Double_t bz) const {
//+++++++++++++++++++++++++++++++++++++++++
//+++++++++++++++++++++++++++++++++++++++++
GetXYZ(x);
- if (OneOverPt() < kAlmost0 || TMath::Abs(bz) < kAlmost0Field ){ //straight-line tracks
+ if (OneOverPt() < kAlmost0 || TMath::Abs(bz) < kAlmost0Field || GetC(bz) < kAlmost0){ //straight-line tracks
Double_t unit[3]; GetDirection(unit);
x[0]+=unit[0]*len;
x[1]+=unit[1]*len;
return kTRUE;
}
+Double_t *AliExternalTrackParam::GetResiduals(
+Double_t *p,Double_t *cov,Bool_t updated) const {
+ //------------------------------------------------------------------
+ // Returns the track residuals with the space point "p" having
+ // the covariance matrix "cov".
+ // If "updated" is kTRUE, the track parameters expected to be updated,
+ // otherwise they must be predicted.
+ //------------------------------------------------------------------
+ static Double_t res[2];
+
+ Double_t r00=cov[0], r01=cov[1], r11=cov[2];
+ if (updated) {
+ r00-=fC[0]; r01-=fC[1]; r11-=fC[2];
+ } else {
+ r00+=fC[0]; r01+=fC[1]; r11+=fC[2];
+ }
+ Double_t det=r00*r11 - r01*r01;
+
+ if (TMath::Abs(det) < kAlmost0) return 0;
+
+ Double_t tmp=r00; r00=r11/det; r11=tmp/det;
+
+ if (r00 < 0.) return 0;
+ if (r11 < 0.) return 0;
+
+ Double_t dy = fP[0] - p[0];
+ Double_t dz = fP[1] - p[1];
+
+ res[0]=dy*TMath::Sqrt(r00);
+ res[1]=dz*TMath::Sqrt(r11);
+
+ return res;
+}
+
Bool_t AliExternalTrackParam::Update(Double_t p[2], Double_t cov[3]) {
//------------------------------------------------------------------
// Update the track parameters with the space point "p" having
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[0] = h[5];
+ r[1] = h[0];
+ if (TMath::Abs(h[4])>kAlmost0) {
+ r[0] += (sn - h[6])/h[4];
+ r[1] -= (cs - h[7])/h[4];
+ }
r[2] = h[1] + h[3]*t;
g[0] = cs; g[1]=sn; g[2]=h[3];
Double_t dz2=GetSigmaZ2() + p->GetSigmaZ2();
Double_t dx2=dy2;
- //dx2=dy2=dz2=1.;
-
Double_t p1[8]; GetHelixParameters(p1,b);
p1[6]=TMath::Sin(p1[2]); p1[7]=TMath::Cos(p1[2]);
Double_t p2[8]; p->GetHelixParameters(p2,b);
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)
- AliWarning(" stopped at not a stationary point !");
+ AliDebug(1," stopped at not a stationary point !");
Double_t lmb=h11+h22; lmb=lmb-TMath::Sqrt(lmb*lmb-4*det);
if (lmb < 0.)
- AliWarning(" stopped at not a minimum !");
+ AliDebug(1," stopped at not a minimum !");
break;
}
if (dd<dm) break;
dt1*=0.5; dt2*=0.5;
if (div>512) {
- AliWarning(" overshoot !"); break;
+ AliDebug(1," overshoot !"); break;
}
}
dm=dd;
}
- if (max<=0) AliWarning(" too many iterations !");
+ if (max<=0) AliDebug(1," too many iterations !");
Double_t cs=TMath::Cos(GetAlpha());
Double_t sn=TMath::Sin(GetAlpha());
}
-
-
-Bool_t AliExternalTrackParam::PropagateToDCA(const AliESDVertex *vtx, Double_t b, Double_t maxd){
+Bool_t AliExternalTrackParam::PropagateToDCA(const AliVVertex *vtx,
+Double_t b, Double_t maxd, Double_t dz[2], Double_t covar[3]) {
//
- // Try to relate this track to the vertex "vtx",
+ // Propagate this track to the DCA to vertex "vtx",
// if the (rough) transverse impact parameter is not bigger then "maxd".
// Magnetic field is "b" (kG).
//
Double_t alpha=GetAlpha();
Double_t sn=TMath::Sin(alpha), cs=TMath::Cos(alpha);
Double_t x=GetX(), y=GetParameter()[0], snp=GetParameter()[2];
- Double_t xv= vtx->GetXv()*cs + vtx->GetYv()*sn;
- Double_t yv=-vtx->GetXv()*sn + vtx->GetYv()*cs;
+ Double_t xv= vtx->GetX()*cs + vtx->GetY()*sn;
+ Double_t yv=-vtx->GetX()*sn + vtx->GetY()*cs, zv=vtx->GetZ();
x-=xv; y-=yv;
//Estimate the impact parameter neglecting the track curvature
if (d > maxd) return kFALSE;
//Propagate to the DCA
- Double_t crv=0.299792458e-3*b*GetParameter()[4];
+ Double_t crv=GetC(b);
+ if (TMath::Abs(b) < kAlmost0Field) crv=0.;
+
Double_t tgfv=-(crv*x - snp)/(crv*y + TMath::Sqrt(1.-snp*snp));
sn=tgfv/TMath::Sqrt(1.+ tgfv*tgfv); cs=TMath::Sqrt(1.- sn*sn);
+ if (TMath::Abs(tgfv)>0.) cs = sn/tgfv;
+ else cs=1.;
x = xv*cs + yv*sn;
yv=-xv*sn + yv*cs; xv=x;
if (!Propagate(alpha+TMath::ASin(sn),xv,b)) return kFALSE;
- return kTRUE;
-}
-
-
+ if (dz==0) return kTRUE;
+ dz[0] = GetParameter()[0] - yv;
+ dz[1] = GetParameter()[1] - zv;
+
+ if (covar==0) return kTRUE;
+ Double_t cov[6]; vtx->GetCovarianceMatrix(cov);
-Bool_t Local2GlobalMomentum(Double_t p[3],Double_t alpha) {
- //----------------------------------------------------------------
- // This function performs local->global transformation of the
- // track momentum.
- // When called, the arguments are:
- // p[0] = 1/pt of the track;
- // p[1] = sine of local azim. angle of the track momentum;
- // p[2] = tangent of the track momentum dip angle;
- // alpha - rotation angle.
- // The result is returned as:
- // p[0] = px
- // p[1] = py
- // p[2] = pz
- // Results for (nearly) straight tracks are meaningless !
- //----------------------------------------------------------------
- if (TMath::Abs(p[0])<=kAlmost0) return kFALSE;
- if (TMath::Abs(p[1])> kAlmost1) return kFALSE;
-
- Double_t pt=1./TMath::Abs(p[0]);
- Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha);
- Double_t r=TMath::Sqrt(1 - p[1]*p[1]);
- p[0]=pt*(r*cs - p[1]*sn); p[1]=pt*(p[1]*cs + r*sn); p[2]=pt*p[2];
+ //***** Improvements by A.Dainese
+ alpha=GetAlpha(); sn=TMath::Sin(alpha); cs=TMath::Cos(alpha);
+ Double_t s2ylocvtx = cov[0]*sn*sn + cov[2]*cs*cs - 2.*cov[1]*cs*sn;
+ covar[0] = GetCovariance()[0] + s2ylocvtx; // neglecting correlations
+ covar[1] = GetCovariance()[1]; // between (x,y) and z
+ covar[2] = GetCovariance()[2] + cov[5]; // in vertex's covariance matrix
+ //*****
return kTRUE;
}
-Bool_t Local2GlobalPosition(Double_t r[3],Double_t alpha) {
- //----------------------------------------------------------------
- // This function performs local->global transformation of the
- // track position.
- // When called, the arguments are:
- // r[0] = local x
- // r[1] = local y
- // r[2] = local z
- // alpha - rotation angle.
- // The result is returned as:
- // r[0] = global x
- // r[1] = global y
- // r[2] = global z
- //----------------------------------------------------------------
- Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha), x=r[0];
- r[0]=x*cs - r[1]*sn; r[1]=x*sn + r[1]*cs;
-
- return kTRUE;
-}
void AliExternalTrackParam::GetDirection(Double_t d[3]) const {
//----------------------------------------------------------------
d[2]=fP[3]/norm;
}
-Bool_t AliExternalTrackParam::GetPxPyPz(Double_t *p) const {
+Bool_t AliExternalTrackParam::GetPxPyPz(Double_t p[3]) const {
//---------------------------------------------------------------------
// This function returns the global track momentum components
// Results for (nearly) straight tracks are meaningless !
return p[2];
}
+Double_t AliExternalTrackParam::Xv() const {
+ //---------------------------------------------------------------------
+ // Returns x-component of first track point
+ //---------------------------------------------------------------------
+
+ Double_t r[3]={0.,0.,0.};
+ GetXYZ(r);
+
+ return r[0];
+}
+
+Double_t AliExternalTrackParam::Yv() const {
+ //---------------------------------------------------------------------
+ // Returns y-component of first track point
+ //---------------------------------------------------------------------
+
+ Double_t r[3]={0.,0.,0.};
+ GetXYZ(r);
+
+ return r[1];
+}
+
+Double_t AliExternalTrackParam::Zv() const {
+ //---------------------------------------------------------------------
+ // Returns z-component of first track point
+ //---------------------------------------------------------------------
+
+ Double_t r[3]={0.,0.,0.};
+ GetXYZ(r);
+
+ return r[2];
+}
+
Double_t AliExternalTrackParam::Theta() const {
// return theta angle of momentum
- return TMath::ATan2(Pt(), Pz());
+ return 0.5*TMath::Pi() - TMath::ATan(fP[3]);
}
Double_t AliExternalTrackParam::Phi() const {
if (TMath::Abs(f1) >= kAlmost1) return kFALSE;
if (TMath::Abs(f2) >= kAlmost1) return kFALSE;
- Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2);
+ Double_t r1=TMath::Sqrt((1.-f1)*(1.+f1)), r2=TMath::Sqrt((1.-f2)*(1.+f2));
y = fP[0] + dx*(f1+f2)/(r1+r2);
return kTRUE;
}
Double_t dx=x-fX;
if(TMath::Abs(dx)<=kAlmost0) {z=fP[1]; return kTRUE;}
- Double_t f1=fP[2], f2=f1 + dx*fP[4]*b*kB2C;
+ Double_t f1=fP[2], f2=f1 + dx*GetC(b);
if (TMath::Abs(f1) >= kAlmost1) return kFALSE;
if (TMath::Abs(f2) >= kAlmost1) return kFALSE;
- Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
+ Double_t r1=sqrt((1.-f1)*(1.+f1)), r2=sqrt((1.-f2)*(1.+f2));
z = fP[1] + dx*(r2 + f2*(f1+f2)/(r1+r2))*fP[3]; // Many thanks to P.Hristov !
return kTRUE;
}
if (TMath::Abs(f1) >= kAlmost1) return kFALSE;
if (TMath::Abs(f2) >= kAlmost1) return kFALSE;
- Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2);
+ Double_t r1=TMath::Sqrt((1.-f1)*(1.+f1)), r2=TMath::Sqrt((1.-f2)*(1.+f2));
r[0] = x;
r[1] = fP[0] + dx*(f1+f2)/(r1+r2);
- r[2] = fP[1] + dx*(f1+f2)/(f1*r2 + f2*r1)*fP[3];
+ r[2] = fP[1] + dx*(r2 + f2*(f1+f2)/(r1+r2))*fP[3];//Thanks to Andrea & Peter
+
return Local2GlobalPosition(r,fAlpha);
}
Double_t res = fP[2]+dx*crv;
return res;
}
+
+Bool_t AliExternalTrackParam::GetDistance(AliExternalTrackParam *param2, Double_t x, Double_t dist[3], Double_t bz){
+ //------------------------------------------------------------------------
+ // Get the distance between two tracks at the local position x
+ // working in the local frame of this track.
+ // Origin : Marian.Ivanov@cern.ch
+ //-----------------------------------------------------------------------
+ Double_t xyz[3];
+ Double_t xyz2[3];
+ xyz[0]=x;
+ if (!GetYAt(x,bz,xyz[1])) return kFALSE;
+ if (!GetZAt(x,bz,xyz[2])) return kFALSE;
+ //
+ //
+ if (TMath::Abs(GetAlpha()-param2->GetAlpha())<kAlmost0){
+ xyz2[0]=x;
+ if (!param2->GetYAt(x,bz,xyz2[1])) return kFALSE;
+ if (!param2->GetZAt(x,bz,xyz2[2])) return kFALSE;
+ }else{
+ //
+ Double_t xyz1[3];
+ Double_t dfi = param2->GetAlpha()-GetAlpha();
+ Double_t ca = TMath::Cos(dfi), sa = TMath::Sin(dfi);
+ xyz2[0] = xyz[0]*ca+xyz[1]*sa;
+ xyz2[1] = -xyz[0]*sa+xyz[1]*ca;
+ //
+ xyz1[0]=xyz2[0];
+ if (!param2->GetYAt(xyz2[0],bz,xyz1[1])) return kFALSE;
+ if (!param2->GetZAt(xyz2[0],bz,xyz1[2])) return kFALSE;
+ //
+ xyz2[0] = xyz1[0]*ca-xyz1[1]*sa;
+ xyz2[1] = +xyz1[0]*sa+xyz1[1]*ca;
+ xyz2[2] = xyz1[2];
+ }
+ dist[0] = xyz[0]-xyz2[0];
+ dist[1] = xyz[1]-xyz2[1];
+ dist[2] = xyz[2]-xyz2[2];
+
+ return kTRUE;
+}
+
+
+//
+// Draw functionality.
+// Origin: Marian Ivanov, Marian.Ivanov@cern.ch
+//
+
+void AliExternalTrackParam::DrawTrack(Float_t magf, Float_t minR, Float_t maxR, Float_t stepR){
+ //
+ // Draw track line
+ //
+ if (minR>maxR) return ;
+ if (stepR<=0) return ;
+ Int_t npoints = TMath::Nint((maxR-minR)/stepR)+1;
+ if (npoints<1) return;
+ TPolyMarker3D *polymarker = new TPolyMarker3D(npoints);
+ FillPolymarker(polymarker, magf,minR,maxR,stepR);
+ polymarker->Draw();
+}
+
+//
+void AliExternalTrackParam::FillPolymarker(TPolyMarker3D *pol, Float_t magF, Float_t minR, Float_t maxR, Float_t stepR){
+ //
+ // Fill points in the polymarker
+ //
+ Int_t counter=0;
+ for (Double_t r=minR; r<maxR; r+=stepR){
+ Double_t point[3];
+ GetXYZAt(r,magF,point);
+ pol->SetPoint(counter,point[0],point[1], point[2]);
+ printf("xyz\t%f\t%f\t%f\n",point[0], point[1],point[2]);
+ counter++;
+ }
+}
+
+Int_t AliExternalTrackParam::GetIndex(Int_t i, Int_t j) const {
+ //
+ Int_t min = TMath::Min(i,j);
+ Int_t max = TMath::Max(i,j);
+
+ return min+(max+1)*max/2;
+}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff