1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
16 //-------------------------------------------------------------------------
17 // Implementation of the ITS track class
19 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
20 //-------------------------------------------------------------------------
27 #include "AliCluster.h"
28 #include "AliTPCtrack.h"
29 #include "AliITStrackV2.h"
31 ClassImp(AliITStrackV2)
35 //____________________________________________________________________________
36 AliITStrackV2::AliITStrackV2(const AliTPCtrack& t) throw (const Char_t *) {
37 //------------------------------------------------------------------
38 //Conversion TPC track -> ITS track
39 //------------------------------------------------------------------
40 SetLabel(t.GetLabel());
42 SetNumberOfClusters(0);
43 //SetConvConst(t.GetConvConst());
46 fAlpha = t.GetAlpha();
47 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
48 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
50 //Conversion of the track parameters
51 Double_t x,p[5]; t.GetExternalParameters(x,p);
52 fX=x; x=GetConvConst();
59 //Conversion of the covariance matrix
60 Double_t c[15]; t.GetExternalCovariance(c);
63 fC10=c[1 ]; fC11=c[2 ];
64 fC20=c[3 ]; fC21=c[4 ]; fC22=c[5 ];
65 fC30=c[6 ]; fC31=c[7 ]; fC32=c[8 ]; fC33=c[9 ];
66 fC40=c[10]/x; fC41=c[11]/x; fC42=c[12]/x; fC43=c[13]/x; fC44=c[14]/x/x;
68 if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
71 //____________________________________________________________________________
72 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) {
73 //------------------------------------------------------------------
75 //------------------------------------------------------------------
80 fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;
83 fC10=t.fC10; fC11=t.fC11;
84 fC20=t.fC20; fC21=t.fC21; fC22=t.fC22;
85 fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33;
86 fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44;
88 Int_t n=GetNumberOfClusters();
89 for (Int_t i=0; i<n; i++) fIndex[i]=t.fIndex[i];
92 //_____________________________________________________________________________
93 Int_t AliITStrackV2::Compare(const TObject *o) const {
94 //-----------------------------------------------------------------
95 // This function compares tracks according to the their curvature
96 //-----------------------------------------------------------------
97 AliTPCtrack *t=(AliTPCtrack*)o;
98 Double_t co=TMath::Abs(t->Get1Pt());
99 Double_t c =TMath::Abs(Get1Pt());
101 else if (c<co) return -1;
105 //_____________________________________________________________________________
106 void AliITStrackV2::GetExternalCovariance(Double_t cc[15]) const {
107 //-------------------------------------------------------------------------
108 // This function returns an external representation of the covriance matrix.
109 // (See comments in AliTPCtrack.h about external track representation)
110 //-------------------------------------------------------------------------
111 Double_t a=GetConvConst();
114 cc[1 ]=fC10; cc[2 ]=fC11;
115 cc[3 ]=fC20; cc[4 ]=fC21; cc[5 ]=fC22;
116 cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=fC32; cc[9 ]=fC33;
117 cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=fC42*a; cc[13]=fC43*a; cc[14]=fC44*a*a;
120 //____________________________________________________________________________
121 Int_t AliITStrackV2::PropagateToVertex(Double_t x0,Double_t rho,Double_t pm) {
122 //------------------------------------------------------------------
123 //This function propagates a track to the minimal distance from the origin
124 //------------------------------------------------------------------
125 Double_t xv=fP2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2)); //linear approxim.
126 Propagate(fAlpha,xv,0.,0.,pm);
130 //____________________________________________________________________________
131 Int_t AliITStrackV2::
132 GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const {
133 //------------------------------------------------------------------
134 //This function returns a track position in the global system
135 //------------------------------------------------------------------
137 Double_t f1=fP2, f2=f1 + fP4*dx;
138 if (TMath::Abs(f2) >= 0.99999) {
139 Int_t n=GetNumberOfClusters();
140 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Propagation failed !\n";
144 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
146 Double_t yk = fP0 + dx*(f1+f2)/(r1+r2);
147 Double_t zk = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
149 Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha);
157 //_____________________________________________________________________________
158 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const
160 //-----------------------------------------------------------------
161 // This function calculates a predicted chi2 increment.
162 //-----------------------------------------------------------------
163 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
164 r00+=fC00; r01+=fC10; r11+=fC11;
166 Double_t det=r00*r11 - r01*r01;
167 if (TMath::Abs(det) < 1.e-10) {
168 Int_t n=GetNumberOfClusters();
169 if (n>4) cerr<<n<<" AliKalmanTrack warning: Singular matrix !\n";
172 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
174 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
176 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
179 //_____________________________________________________________________________
180 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c,Double_t *m,
181 Double_t x0, Double_t pm) const {
182 //-----------------------------------------------------------------
183 // This function calculates a chi2 increment with a vertex contraint
184 //-----------------------------------------------------------------
185 TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4;
188 C(1,0)=fC10; C(1,1)=fC11;
189 C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22;
190 C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33;
191 C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44;
194 C(0,2)=C(2,0); C(1,2)=C(2,1);
195 C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
196 C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
198 TMatrixD H(4,5); H.UnitMatrix();
199 Double_t dy=(c->GetY() - m[0]), dz=(c->GetZ() - m[1]);
201 Double_t dr=TMath::Sqrt(fX*fX + dy*dy);
202 Double_t r =TMath::Sqrt(4/dr/dr - fP4*fP4);
203 Double_t sn=0.5*(fP4*fX + dy*r);
204 Double_t tg=0.5*fP4*dz/TMath::ASin(0.5*fP4*dr);
206 mm(0)=m[0]=c->GetY(); mm(1)=m[1]=c->GetZ(); mm(2)=m[2]=sn; mm(3)=m[3]=tg;
208 Double_t v22=0.,v33=0.;
211 Double_t pp2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
212 Double_t beta2=pp2/(pp2 + pm*pm);
213 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
214 Double_t theta2=14.1*14.1/(beta2*pp2*1e6)*x0;
215 v22 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
216 v33 = theta2*(1.+ GetTgl()*GetTgl())*(1. + GetTgl()*GetTgl());
218 Double_t sy2=c->GetSigmaY2(), sz2=c->GetSigmaZ2();
219 v22+=kSigmaYV*kSigmaYV/dr/dr;
223 v33+=kSigmaZV*kSigmaZV/dr/dr;
228 V(0,0)=m[4 ]=sy2; V(0,1)=m[5 ]=0.; V(0,2)=m[6 ]=v20; V(0,3)=m[7 ]=0.;
229 V(1,0)=m[8 ]=0.; V(1,1)=m[9 ]=sz2; V(1,2)=m[10]=0.; V(1,3)=m[11]=v31;
230 V(2,0)=m[12]=v20; V(2,1)=m[13]=0.; V(2,2)=m[14]=v22; V(2,3)=m[15]=0.;
231 V(3,0)=m[16]=0.; V(3,1)=m[17]=v31; V(3,2)=m[18]=0.; V(3,3)=m[19]=v33;
233 TVectorD res=x; res*=H; res-=mm; //res*=-1;
234 TMatrixD tmp(H,TMatrixD::kMult,C);
235 TMatrixD R(tmp,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed,H)); R+=V;
237 Double_t det=R.Determinant();
238 if (TMath::Abs(det) < 1.e-25) {
239 Int_t n=GetNumberOfClusters();
240 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Singular matrix !\n";
251 //____________________________________________________________________________
253 AliITStrackV2::PropagateTo(Double_t xk,Double_t x0,Double_t rho,Double_t pm) {
254 //------------------------------------------------------------------
255 //This function propagates a track
256 //------------------------------------------------------------------
257 Double_t x1=fX, x2=xk, dx=x2-x1;
258 Double_t f1=fP2, f2=f1 + fP4*dx;
259 if (TMath::Abs(f2) >= 0.99999) {
260 Int_t n=GetNumberOfClusters();
261 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Propagation failed !\n";
265 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
267 fP0 += dx*(f1+f2)/(r1+r2);
268 fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
273 Double_t f02= dx/(r1*r1*r1);
274 Double_t f04=0.5*dx*dx/(r1*r1*r1);
275 Double_t f12= dx*fP3*f1/(r1*r1*r1);
276 Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1);
281 Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30;
282 Double_t b02=f24*fC40;
283 Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31;
284 Double_t b12=f24*fC41;
285 Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32;
286 Double_t b22=f24*fC42;
287 Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43;
288 Double_t b42=f24*fC44;
289 Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33;
290 Double_t b32=f24*fC43;
293 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42;
294 Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32;
295 Double_t a22=f24*b42;
297 //F*C*Ft = C + (b + bt + a)
298 fC00 += b00 + b00 + a00;
299 fC10 += b10 + b01 + a01;
300 fC20 += b20 + b02 + a02;
303 fC11 += b11 + b11 + a11;
304 fC21 += b21 + b12 + a12;
307 fC22 += b22 + b22 + a22;
313 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
314 Double_t beta2=p2/(p2 + pm*pm);
316 //Multiple scattering******************
319 x0*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
320 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
321 fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
322 fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
323 fC43 += theta2*fP3*fP4*(1. + fP3*fP3);
324 fC44 += theta2*fP3*fP4*fP3*fP4;
327 //Energy losses************************
329 rho*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
330 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*rho;
332 fP4*=(1.- sqrt(p2+pm*pm)/p2*dE);
335 if (!Invariant()) {cout<<"Propagate !\n"; return 0;}
340 //____________________________________________________________________________
341 Int_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, UInt_t index) {
342 //------------------------------------------------------------------
343 //This function updates track parameters
344 //------------------------------------------------------------------
345 Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4;
347 Double_t c10=fC10, c11=fC11;
348 Double_t c20=fC20, c21=fC21, c22=fC22;
349 Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33;
350 Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44;
353 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
354 r00+=fC00; r01+=fC10; r11+=fC11;
355 Double_t det=r00*r11 - r01*r01;
356 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
358 Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11;
359 Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11;
360 Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11;
361 Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11;
362 Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11;
364 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
365 Double_t sf=fP2 + k20*dy + k21*dz;
367 if (TMath::Abs(sf) >= 0.99999) {
368 Int_t n=GetNumberOfClusters();
369 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Filtering failed !\n";
373 fP0 += k00*dy + k01*dz;
374 fP1 += k10*dy + k11*dz;
376 fP3 += k30*dy + k31*dz;
377 fP4 += k40*dy + k41*dz;
379 Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
380 Double_t c12=fC21, c13=fC31, c14=fC41;
382 fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11;
383 fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13;
384 fC40-=k00*c04+k01*c14;
386 fC11-=k10*c01+k11*fC11;
387 fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13;
388 fC41-=k10*c04+k11*c14;
390 fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13;
391 fC42-=k20*c04+k21*c14;
393 fC33-=k30*c03+k31*c13;
394 fC43-=k30*c04+k31*c14;
396 fC44-=k40*c04+k41*c14;
399 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
402 fC20=c20; fC21=c21; fC22=c22;
403 fC30=c30; fC31=c31; fC32=c32; fC33=c33;
404 fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44;
408 Int_t n=GetNumberOfClusters();
410 SetNumberOfClusters(n+1);
411 SetChi2(GetChi2()+chi2);
417 //____________________________________________________________________________
418 Int_t AliITStrackV2::Update(const Double_t* m, Double_t chi2, UInt_t index) {
419 //------------------------------------------------------------------
420 //This function updates track parameters with a vertex constraint
421 //------------------------------------------------------------------
422 Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4;
424 Double_t c10=fC10, c11=fC11;
425 Double_t c20=fC20, c21=fC21, c22=fC22;
426 Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33;
427 Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44;
430 TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4;
433 C(1,0)=fC10; C(1,1)=fC11;
434 C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22;
435 C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33;
436 C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44;
439 C(0,2)=C(2,0); C(1,2)=C(2,1);
440 C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
441 C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
443 TMatrixD H(4,5); H.UnitMatrix();
444 TMatrixD Ht(TMatrixD::kTransposed,H);
445 TVectorD mm(4); mm(0)=m[0]; mm(1)=m[1]; mm(2)=m[2]; mm(3)=m[3];
447 V(0,0)=m[4 ]; V(0,1)=m[5 ]; V(0,2)=m[6 ]; V(0,3)=m[7 ];
448 V(1,0)=m[8 ]; V(1,1)=m[9 ]; V(1,2)=m[10]; V(1,3)=m[11];
449 V(2,0)=m[12]; V(2,1)=m[13]; V(2,2)=m[14]; V(2,3)=m[15];
450 V(3,0)=m[16]; V(3,1)=m[17]; V(3,2)=m[18]; V(3,3)=m[19];
452 TMatrixD tmp(H,TMatrixD::kMult,C);
453 TMatrixD R(tmp,TMatrixD::kMult,Ht); R+=V;
457 TMatrixD K(C,TMatrixD::kMult,Ht); K*=R;
460 x*=H; x-=mm; x*=-1; x*=K; x+=savex;
463 C.Mult(K,tmp); C-=saveC; C*=-1;
465 fP0=x(0); fP1=x(1); fP2=x(2); fP3=x(3); fP4=x(4);
467 fC10=C(1,0); fC11=C(1,1);
468 fC20=C(2,0); fC21=C(2,1); fC22=C(2,2);
469 fC30=C(3,0); fC31=C(3,1); fC32=C(3,2); fC33=C(3,3);
470 fC40=C(4,0); fC41=C(4,1); fC42=C(4,2); fC43=C(4,3); fC44=C(4,4);
474 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
477 fC20=c20; fC21=c21; fC22=c22;
478 fC30=c30; fC31=c31; fC32=c32; fC33=c33;
479 fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44;
483 Int_t n=GetNumberOfClusters();
485 SetNumberOfClusters(n+1);
486 SetChi2(GetChi2()+chi2);
491 Int_t AliITStrackV2::Invariant() const {
492 //------------------------------------------------------------------
493 // This function is for debugging purpose only
494 //------------------------------------------------------------------
495 //if (TMath::Abs(fP1)>11.5)
496 //if (fP1*fP4<0) {cout<<"fP1*fP4="<<fP1*fP4<<' '<<fP1<<endl; return 0;}
497 if (TMath::Abs(fP2)>=1) {cout<<"fP2="<<fP2<<endl; return 0;}
499 if (fC00<=0) {cout<<"fC00="<<fC00<<endl; return 0;}
500 if (fC11<=0) {cout<<"fC11="<<fC11<<endl; return 0;}
501 if (fC22<=0) {cout<<"fC22="<<fC22<<endl; return 0;}
502 if (fC33<=0) {cout<<"fC33="<<fC33<<endl; return 0;}
503 if (fC44<=0) {cout<<"fC44="<<fC44<<endl; return 0;}
507 m(1,0)=fC10; m(1,1)=fC11;
508 m(2,0)=fC20; m(2,1)=fC21; m(2,2)=fC22;
509 m(3,0)=fC30; m(3,1)=fC31; m(3,2)=fC32; m(3,3)=fC33;
510 m(4,0)=fC40; m(4,1)=fC41; m(4,2)=fC42; m(4,3)=fC43; m(4,4)=fC44;
513 m(0,2)=m(2,0); m(1,2)=m(2,1);
514 m(0,3)=m(3,0); m(1,3)=m(3,1); m(2,3)=m(3,2);
515 m(0,4)=m(4,0); m(1,4)=m(4,1); m(2,4)=m(4,2); m(3,4)=m(4,3);
517 Double_t det=m.Determinant();
520 cout<<" bad determinant "<<det<<endl;
528 //____________________________________________________________________________
529 Int_t AliITStrackV2::Propagate(Double_t alp, Double_t xk,
530 Double_t x0,Double_t rho,Double_t pm) {
531 //------------------------------------------------------------------
532 //This function propagates a track
533 //------------------------------------------------------------------
534 Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4;
536 Double_t c10=fC10, c11=fC11;
537 Double_t c20=fC20, c21=fC21, c22=fC22;
538 Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33;
539 Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44;
542 Double_t dalp=alp-fAlpha;
544 Double_t ca=TMath::Cos(dalp), sa=TMath::Sin(dalp);
545 Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2);
547 Double_t pp2=fP2*ca - cf*sa;
548 if (TMath::Abs(pp2) >= 0.99999) {
549 Int_t n=GetNumberOfClusters();
550 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Rotation failed !\n";
555 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
556 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
558 Double_t x1=fX, y1=fP0;
566 if (!Invariant()) {cout<<dalp<<" Rotate !\n"; return 0;}
568 x1=fX; Double_t x2=xk, dx=x2-x1;
569 Double_t f1=fP2, f2=f1 + fP4*dx;
570 if (TMath::Abs(f2) >= 0.99999) {
571 Int_t n=GetNumberOfClusters();
572 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Propagation failed !\n";
576 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
578 fP0 += dx*(f1+f2)/(r1+r2);
579 fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
583 Double_t f02= dx/(r1*r1*r1);
584 Double_t f04=0.5*dx*dx/(r1*r1*r1);
585 Double_t f12= dx*fP3*f1/(r1*r1*r1);
586 Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1);
591 Double_t b00=f02*fC20 + f03*fC30, b01=f12*fC20 + f13*fC30 + f14*fC40;
592 Double_t b02=f23*fC30;
593 Double_t b10=f02*fC21 + f03*fC31, b11=f12*fC21 + f13*fC31 + f14*fC41;
594 Double_t b12=f23*fC31;
595 Double_t b20=f02*fC22 + f03*fC32, b21=f12*fC22 + f13*fC32 + f14*fC42;
596 Double_t b22=f23*fC32;
597 Double_t b30=f02*fC32 + f03*fC33, b31=f12*fC32 + f13*fC33 + f14*fC43;
598 Double_t b32=f23*fC33;
599 Double_t b40=f02*fC42 + f03*fC43, b41=f12*fC42 + f13*fC43 + f14*fC44;
600 Double_t b42=f23*fC43;
603 Double_t a00=f02*b20+f03*b30,a01=f02*b21+f03*b31,a02=f02*b22+f03*b32;
604 Double_t a11=f12*b21+f13*b31+f14*b41,a12=f12*b22+f13*b32+f14*b42;
605 Double_t a22=f23*b32;
607 //F*C*Ft = C + (b + bt + a)
608 fC00 += b00 + b00 + a00;
609 fC10 += b10 + b01 + a01;
610 fC20 += b20 + b02 + a02;
613 fC11 += b11 + b11 + a11;
614 fC21 += b21 + b12 + a12;
617 fC22 += b22 + b22 + a22;
622 TMatrixD F(5,5); F.UnitMatrix();
623 F(0,0)=-(f1+f2)/(r1+r2)*sa + ca; F(0,2)=f02*cf; F(0,4)=f04;
624 F(1,0)=-(f1+f2)/(f1*r2 + f2*r1)*fP3*sa; F(1,2)=f12*cf; F(1,4)=f14; F(1,3)=f13;
625 F(2,0)=-fP4*sa; F(2,2)=cf; F(2,4)=f24;
629 C(1,0)=fC10; C(1,1)=fC11;
630 C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22;
631 C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33;
632 C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44;
635 C(0,2)=C(2,0); C(1,2)=C(2,1);
636 C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
637 C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
639 TMatrixD tmp(C,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F));
643 fC10=C(1,0); fC11=C(1,1);
644 fC20=C(2,0); fC21=C(2,1); fC22=C(2,2);
645 fC30=C(3,0); fC31=C(3,1); fC32=C(3,2); fC33=C(3,3);
646 fC40=C(4,0); fC41=C(4,1); fC42=C(4,2); fC43=C(4,3); fC44=C(4,4);
648 pp2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
649 Double_t beta2=pp2/(pp2 + pm*pm);
651 //Multiple scattering******************
654 x0*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
655 Double_t theta2=14.1*14.1/(beta2*pp2*1e6)*x0;
656 fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
657 fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
658 fC43 += theta2*fP3*fP4*(1. + fP3*fP3);
659 fC44 += theta2*fP3*fP4*fP3*fP4;
662 //Energy losses************************
664 rho*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
665 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*rho;
667 fP4*=(1.- sqrt(pp2+pm*pm)/pp2*dE);
671 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
674 fC20=c20; fC21=c21; fC22=c22;
675 fC30=c30; fC31=c31; fC32=c32; fC33=c33;
676 fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44;
685 Double_t AliITStrackV2::GetD() const {
686 //------------------------------------------------------------------
687 //This function calculates the transverse impact parameter
688 //------------------------------------------------------------------
689 Double_t sn=fP4*fX - fP2, cs=fP4*fP0 + TMath::Sqrt(1.- fP2*fP2);
690 Double_t a=2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2))-fP4*(fX*fX + fP0*fP0);
692 return a/(1 + TMath::Sqrt(sn*sn + cs*cs));
696 Int_t AliITStrackV2::Improve(Double_t x0,Double_t yv,Double_t zv) {
697 //------------------------------------------------------------------
698 //This function improves angular track parameters
699 //------------------------------------------------------------------
700 Double_t dy=fP0-yv, dz=fP1-zv;
701 Double_t r2=fX*fX+dy*dy;
702 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
703 Double_t beta2=p2/(p2 + 0.14*0.14);
704 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
705 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
707 Double_t par=0.5*(fP4*fX + dy*TMath::Sqrt(4/r2-fP4*fP4));
708 Double_t sigma2 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
709 sigma2 += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
710 sigma2 += kSigmaYV*kSigmaYV/r2;
711 sigma2 += 0.25*fC44*fX*fX;
712 Double_t eps2=sigma2/(fC22+sigma2), eps=TMath::Sqrt(eps2);
713 if (10*r2*fC44<fC22) {
714 fP2 = eps2*fP2 + (1-eps2)*par;
715 fC22*=eps2; fC21*=eps; fC20*=eps; fC32*=eps; fC42*=eps;
718 par=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2));
720 sigma2 += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2);
721 sigma2 += kSigmaZV*kSigmaZV/r2;
722 eps2=sigma2/(fC33+sigma2); eps=TMath::Sqrt(eps2);
724 fP3 = eps2*fP3 + (1-eps2)*par;
725 fC33*=eps2; fC32*=eps; fC31*=eps; fC30*=eps; fC43*=eps;
727 eps=TMath::Sqrt((1+fP3*fP3)/(1+tgl*tgl));
729 fC44*=eps*eps; fC43*=eps;fC42*=eps; fC41*=eps; fC40*=eps;
731 if (!Invariant()) return 0;
736 Int_t AliITStrackV2::Improve(Double_t x0,Double_t xv,Double_t yv) {
737 //------------------------------------------------------------------
738 //This function improves angular track parameters
739 //------------------------------------------------------------------
741 TVectorD v(5); v(0)=fP0; v(1)=fP1; v(2)=fP2; v(3)=fP3; v(4)=fP4;
743 Double_t r2=fX*fX+fP0*fP0;
744 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
745 Double_t beta2=p2/(p2 + 0.14*0.14);
746 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
747 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
749 v(2)=0.5*(fP4*fX + fP0*TMath::Sqrt(4/r2-fP4*fP4));
750 Double_t sigma2 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
751 sigma2 += fC00/r2*(1.- fP0*fP0/r2)*(1.- fP0*fP0/r2);
752 sigma2 += kSigmaYV*kSigmaYV/r2;
755 v(3)=0.5*fP4*fP1/TMath::ASin(0.5*fP4*TMath::Sqrt(r2));
757 sigma2 += fC11/r2+fC00*fP0*fP0*fP1*fP1/(r2*r2*r2);
758 sigma2 += kSigmaZV*kSigmaZV/r2;
763 TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4;
766 C(1,0)=fC10; C(1,1)=fC11;
767 C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22;
768 C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33;
769 C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44;
772 C(0,2)=C(2,0); C(1,2)=C(2,1);
773 C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
774 C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
776 TMatrixD tmp(I,TMatrixD::kMult,C),U(5,5); U.UnitMatrix();
780 TMatrixD W2(tmp,TMatrixD::kMult,W1);
787 fP0=x(0); fP1=x(1); fP2=x(2); fP3=x(3); fP4=x(4);
789 fC10=C(1,0); fC11=C(1,1);
790 fC20=C(2,0); fC21=C(2,1); fC22=C(2,2);
791 fC30=C(3,0); fC31=C(3,1); fC32=C(3,2); fC33=C(3,3);
792 fC40=C(4,0); fC41=C(4,1); fC42=C(4,2); fC43=C(4,3); fC44=C(4,4);
794 eps=TMath::Sqrt((1+fP3*fP3)/(1+tgl*tgl));
796 fC44*=eps*eps; fC43*=eps;fC42*=eps; fC41*=eps; fC40*=eps;
798 if (!Invariant()) return 0;
803 void AliITStrackV2::ResetCovariance() {
804 //------------------------------------------------------------------
805 //This function makes a track forget its history :)
806 //------------------------------------------------------------------
810 fC20=0.; fC21=0.; fC22*=10.;
811 fC30=0.; fC31=0.; fC32=0.; fC33*=10.;
812 fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.;