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[u/mrichter/AliRoot.git] / ITS / AliITStrackV2.cxx
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006b5f7f 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
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 **************************************************************************/
15
16//-------------------------------------------------------------------------
17// Implementation of the ITS track class
18//
19// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
a9a2d814 20// dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
006b5f7f 21//-------------------------------------------------------------------------
22
23#include <TMatrixD.h>
24
25#include <TMath.h>
26#include <iostream.h>
27
28#include "AliCluster.h"
517b130f 29#include "AliTPCtrack.h"
006b5f7f 30#include "AliITStrackV2.h"
31
32ClassImp(AliITStrackV2)
33
7f6ddf58 34const Int_t kWARN=5;
006b5f7f 35
36//____________________________________________________________________________
37AliITStrackV2::AliITStrackV2(const AliTPCtrack& t) throw (const Char_t *) {
38 //------------------------------------------------------------------
9b280d80 39 //Conversion TPC track -> ITS track
006b5f7f 40 //------------------------------------------------------------------
41 SetLabel(t.GetLabel());
42 SetChi2(0.);
43 SetNumberOfClusters(0);
14825d5a 44 //SetConvConst(t.GetConvConst());
45
7f6ddf58 46 fdEdx = t.GetdEdx();
47 SetMass(t.GetMass());
48
006b5f7f 49 fAlpha = t.GetAlpha();
50 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
51 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
52
9b280d80 53 //Conversion of the track parameters
006b5f7f 54 Double_t x,p[5]; t.GetExternalParameters(x,p);
9b280d80 55 fX=x; x=GetConvConst();
006b5f7f 56 fP0=p[0];
57 fP1=p[1];
58 fP2=p[2];
59 fP3=p[3];
60 fP4=p[4]/x;
61
9b280d80 62 //Conversion of the covariance matrix
006b5f7f 63 Double_t c[15]; t.GetExternalCovariance(c);
64
65 fC00=c[0 ];
66 fC10=c[1 ]; fC11=c[2 ];
67 fC20=c[3 ]; fC21=c[4 ]; fC22=c[5 ];
68 fC30=c[6 ]; fC31=c[7 ]; fC32=c[8 ]; fC33=c[9 ];
69 fC40=c[10]/x; fC41=c[11]/x; fC42=c[12]/x; fC43=c[13]/x; fC44=c[14]/x/x;
70
71 if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
649ab0de 72
006b5f7f 73}
74
75//____________________________________________________________________________
76AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) {
77 //------------------------------------------------------------------
78 //Copy constructor
79 //------------------------------------------------------------------
80 fX=t.fX;
81 fAlpha=t.fAlpha;
82 fdEdx=t.fdEdx;
83
84 fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;
85
86 fC00=t.fC00;
87 fC10=t.fC10; fC11=t.fC11;
88 fC20=t.fC20; fC21=t.fC21; fC22=t.fC22;
89 fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33;
90 fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44;
91
92 Int_t n=GetNumberOfClusters();
23efe5f1 93 for (Int_t i=0; i<n; i++) {
a9a2d814 94 fIndex[i]=t.fIndex[i];
95 if (i<4) fdEdxSample[i]=t.fdEdxSample[i];
23efe5f1 96 }
006b5f7f 97}
a9a2d814 98
006b5f7f 99//_____________________________________________________________________________
100Int_t AliITStrackV2::Compare(const TObject *o) const {
101 //-----------------------------------------------------------------
102 // This function compares tracks according to the their curvature
103 //-----------------------------------------------------------------
7f6ddf58 104 AliITStrackV2 *t=(AliITStrackV2*)o;
a9a2d814 105 //Double_t co=TMath::Abs(t->Get1Pt());
106 //Double_t c =TMath::Abs(Get1Pt());
107 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
108 Double_t c =GetSigmaY2()*GetSigmaZ2();
006b5f7f 109 if (c>co) return 1;
110 else if (c<co) return -1;
111 return 0;
112}
113
114//_____________________________________________________________________________
115void AliITStrackV2::GetExternalCovariance(Double_t cc[15]) const {
116 //-------------------------------------------------------------------------
117 // This function returns an external representation of the covriance matrix.
118 // (See comments in AliTPCtrack.h about external track representation)
119 //-------------------------------------------------------------------------
9b280d80 120 Double_t a=GetConvConst();
006b5f7f 121
122 cc[0 ]=fC00;
123 cc[1 ]=fC10; cc[2 ]=fC11;
124 cc[3 ]=fC20; cc[4 ]=fC21; cc[5 ]=fC22;
125 cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=fC32; cc[9 ]=fC33;
126 cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=fC42*a; cc[13]=fC43*a; cc[14]=fC44*a*a;
127}
128
129//____________________________________________________________________________
a9a2d814 130Int_t AliITStrackV2::PropagateToVertex(Double_t d,Double_t x0) {
006b5f7f 131 //------------------------------------------------------------------
132 //This function propagates a track to the minimal distance from the origin
133 //------------------------------------------------------------------
134 Double_t xv=fP2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2)); //linear approxim.
a9a2d814 135 PropagateTo(xv,d,x0);
006b5f7f 136 return 0;
137}
138
139//____________________________________________________________________________
140Int_t AliITStrackV2::
141GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const {
142 //------------------------------------------------------------------
143 //This function returns a track position in the global system
144 //------------------------------------------------------------------
145 Double_t dx=xk-fX;
146 Double_t f1=fP2, f2=f1 + fP4*dx;
a9a2d814 147 if (TMath::Abs(f2) >= 0.9999) {
7f6ddf58 148 Int_t n=GetNumberOfClusters();
149 if (n>kWARN)
150 cerr<<n<<" AliITStrackV2::GetGlobalXYZat: Propagation failed !\n";
006b5f7f 151 return 0;
152 }
153
154 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
155
156 Double_t yk = fP0 + dx*(f1+f2)/(r1+r2);
157 Double_t zk = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
158
159 Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha);
160 x = xk*cs - yk*sn;
161 y = xk*sn + yk*cs;
162 z = zk;
163
164 return 1;
165}
166
167//_____________________________________________________________________________
168Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const
169{
170 //-----------------------------------------------------------------
171 // This function calculates a predicted chi2 increment.
172 //-----------------------------------------------------------------
173 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
174 r00+=fC00; r01+=fC10; r11+=fC11;
175
176 Double_t det=r00*r11 - r01*r01;
7f6ddf58 177 if (TMath::Abs(det) < 1.e-30) {
006b5f7f 178 Int_t n=GetNumberOfClusters();
7f6ddf58 179 if (n>kWARN)
180 cerr<<n<<" AliKalmanTrack::GetPredictedChi2: Singular matrix !\n";
006b5f7f 181 return 1e10;
182 }
183 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
184
185 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
186
187 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
188}
189
190//_____________________________________________________________________________
191Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c,Double_t *m,
7f6ddf58 192Double_t x0) const {
006b5f7f 193 //-----------------------------------------------------------------
194 // This function calculates a chi2 increment with a vertex contraint
195 //-----------------------------------------------------------------
196 TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4;
197 TMatrixD C(5,5);
198 C(0,0)=fC00;
199 C(1,0)=fC10; C(1,1)=fC11;
200 C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22;
201 C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33;
202 C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44;
203
204 C(0,1)=C(1,0);
205 C(0,2)=C(2,0); C(1,2)=C(2,1);
206 C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
207 C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
208
209 TMatrixD H(4,5); H.UnitMatrix();
210 Double_t dy=(c->GetY() - m[0]), dz=(c->GetZ() - m[1]);
211
212 Double_t dr=TMath::Sqrt(fX*fX + dy*dy);
213 Double_t r =TMath::Sqrt(4/dr/dr - fP4*fP4);
214 Double_t sn=0.5*(fP4*fX + dy*r);
215 Double_t tg=0.5*fP4*dz/TMath::ASin(0.5*fP4*dr);
216 TVectorD mm(4);
217 mm(0)=m[0]=c->GetY(); mm(1)=m[1]=c->GetZ(); mm(2)=m[2]=sn; mm(3)=m[3]=tg;
218
219 Double_t v22=0.,v33=0.;
220 //x0=0.;
221 if (x0!=0.) {
222 Double_t pp2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
7f6ddf58 223 Double_t beta2=pp2/(pp2 + GetMass()*GetMass());
006b5f7f 224 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
225 Double_t theta2=14.1*14.1/(beta2*pp2*1e6)*x0;
226 v22 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
227 v33 = theta2*(1.+ GetTgl()*GetTgl())*(1. + GetTgl()*GetTgl());
228 }
229 Double_t sy2=c->GetSigmaY2(), sz2=c->GetSigmaZ2();
230 v22+=kSigmaYV*kSigmaYV/dr/dr;
231 v22+=sy2/dr/dr;
232 Double_t v20=sy2/dr;
233
234 v33+=kSigmaZV*kSigmaZV/dr/dr;
235 v33+=sz2/dr/dr;
236 Double_t v31=sz2/dr;
237
238 TMatrixD V(4,4);
239 V(0,0)=m[4 ]=sy2; V(0,1)=m[5 ]=0.; V(0,2)=m[6 ]=v20; V(0,3)=m[7 ]=0.;
240 V(1,0)=m[8 ]=0.; V(1,1)=m[9 ]=sz2; V(1,2)=m[10]=0.; V(1,3)=m[11]=v31;
241 V(2,0)=m[12]=v20; V(2,1)=m[13]=0.; V(2,2)=m[14]=v22; V(2,3)=m[15]=0.;
242 V(3,0)=m[16]=0.; V(3,1)=m[17]=v31; V(3,2)=m[18]=0.; V(3,3)=m[19]=v33;
243
244 TVectorD res=x; res*=H; res-=mm; //res*=-1;
245 TMatrixD tmp(H,TMatrixD::kMult,C);
246 TMatrixD R(tmp,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed,H)); R+=V;
247
248 Double_t det=R.Determinant();
7f6ddf58 249 if (TMath::Abs(det) < 1.e-30) {
006b5f7f 250 Int_t n=GetNumberOfClusters();
7f6ddf58 251 if (n>kWARN)
252 cerr<<n<<" AliITStrackV2::GetPredictedChi2: Singular matrix !\n";
006b5f7f 253 return 1e10;
254 }
255
256 R.Invert();
257
258 TVectorD rs=res;
259 res*=R;
260 return rs*res;
261}
262
263//____________________________________________________________________________
a9a2d814 264Int_t AliITStrackV2::CorrectForMaterial(Double_t d, Double_t x0) {
265 //------------------------------------------------------------------
266 //This function corrects the track parameters for crossed material
267 //------------------------------------------------------------------
268 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
269 Double_t beta2=p2/(p2 + GetMass()*GetMass());
270 d*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2));
271
272 //Multiple scattering******************
273 if (d!=0) {
274 //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d);
649ab0de 275 Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
a9a2d814 276 fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3);
277 fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
278 fC43 += theta2*fP3*fP4*(1. + fP3*fP3);
279 fC44 += theta2*fP3*fP4*fP3*fP4;
280 }
281
282 //Energy losses************************
283 if (x0!=0.) {
284 d*=x0;
285 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d;
286 fP4*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
287 }
288
289 if (!Invariant()) return 0;
290
291 return 1;
292}
293
294//____________________________________________________________________________
295Int_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
006b5f7f 296 //------------------------------------------------------------------
297 //This function propagates a track
298 //------------------------------------------------------------------
299 Double_t x1=fX, x2=xk, dx=x2-x1;
300 Double_t f1=fP2, f2=f1 + fP4*dx;
a9a2d814 301 if (TMath::Abs(f2) >= 0.9999) {
006b5f7f 302 Int_t n=GetNumberOfClusters();
7f6ddf58 303 if (n>kWARN)
304 cerr<<n<<" AliITStrackV2::PropagateTo: Propagation failed !\n";
006b5f7f 305 return 0;
306 }
307
308 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
309
310 fP0 += dx*(f1+f2)/(r1+r2);
311 fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
312 fP2 += dx*fP4;
313
314 //f = F - 1
315
316 Double_t f02= dx/(r1*r1*r1);
317 Double_t f04=0.5*dx*dx/(r1*r1*r1);
318 Double_t f12= dx*fP3*f1/(r1*r1*r1);
319 Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1);
320 Double_t f13= dx/r1;
321 Double_t f24= dx;
322
323 //b = C*ft
324 Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30;
325 Double_t b02=f24*fC40;
326 Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31;
327 Double_t b12=f24*fC41;
328 Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32;
329 Double_t b22=f24*fC42;
330 Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43;
331 Double_t b42=f24*fC44;
332 Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33;
333 Double_t b32=f24*fC43;
334
335 //a = f*b = f*C*ft
336 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42;
337 Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32;
338 Double_t a22=f24*b42;
339
340 //F*C*Ft = C + (b + bt + a)
341 fC00 += b00 + b00 + a00;
342 fC10 += b10 + b01 + a01;
343 fC20 += b20 + b02 + a02;
344 fC30 += b30;
345 fC40 += b40;
346 fC11 += b11 + b11 + a11;
347 fC21 += b21 + b12 + a12;
348 fC31 += b31;
349 fC41 += b41;
350 fC22 += b22 + b22 + a22;
351 fC32 += b32;
352 fC42 += b42;
353
354 fX=x2;
355
a9a2d814 356 if (!CorrectForMaterial(d,x0)) return 0;
006b5f7f 357
358 return 1;
359}
360
361//____________________________________________________________________________
362Int_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, UInt_t index) {
363 //------------------------------------------------------------------
364 //This function updates track parameters
365 //------------------------------------------------------------------
366 Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4;
367 Double_t c00=fC00;
368 Double_t c10=fC10, c11=fC11;
369 Double_t c20=fC20, c21=fC21, c22=fC22;
370 Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33;
371 Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44;
372
373
374 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
375 r00+=fC00; r01+=fC10; r11+=fC11;
376 Double_t det=r00*r11 - r01*r01;
377 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
378
379 Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11;
380 Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11;
381 Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11;
382 Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11;
383 Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11;
384
385 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
386 Double_t sf=fP2 + k20*dy + k21*dz;
7f6ddf58 387
006b5f7f 388 fP0 += k00*dy + k01*dz;
389 fP1 += k10*dy + k11*dz;
390 fP2 = sf;
391 fP3 += k30*dy + k31*dz;
392 fP4 += k40*dy + k41*dz;
393
394 Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
395 Double_t c12=fC21, c13=fC31, c14=fC41;
396
397 fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11;
398 fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13;
399 fC40-=k00*c04+k01*c14;
400
401 fC11-=k10*c01+k11*fC11;
402 fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13;
403 fC41-=k10*c04+k11*c14;
404
405 fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13;
406 fC42-=k20*c04+k21*c14;
407
408 fC33-=k30*c03+k31*c13;
409 fC43-=k30*c04+k31*c14;
410
411 fC44-=k40*c04+k41*c14;
412
413 if (!Invariant()) {
414 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
415 fC00=c00;
416 fC10=c10; fC11=c11;
417 fC20=c20; fC21=c21; fC22=c22;
418 fC30=c30; fC31=c31; fC32=c32; fC33=c33;
419 fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44;
420 return 0;
421 }
422
423 Int_t n=GetNumberOfClusters();
424 fIndex[n]=index;
425 SetNumberOfClusters(n+1);
426 SetChi2(GetChi2()+chi2);
427
428 return 1;
429}
430
006b5f7f 431Int_t AliITStrackV2::Invariant() const {
432 //------------------------------------------------------------------
433 // This function is for debugging purpose only
434 //------------------------------------------------------------------
7f6ddf58 435 Int_t n=GetNumberOfClusters();
436
a9a2d814 437 if (TMath::Abs(fP2)>=0.9999){
438 if (n>kWARN) cout<<"AliITStrackV2::Invariant : fP2="<<fP2<<endl;
439 return 0;
440 }
441 if (fC00<=0 || fC00>9.) {
442 if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC00="<<fC00<<endl;
443 return 0;
444 }
445 if (fC11<=0 || fC11>9.) {
446 if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC11="<<fC11<<endl;
447 return 0;
448 }
449 if (fC22<=0 || fC22>1.) {
450 if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC22="<<fC22<<endl;
451 return 0;
452 }
453 if (fC33<=0 || fC33>1.) {
454 if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC33="<<fC33<<endl;
455 return 0;
456 }
457 if (fC44<=0 || fC44>6e-5) {
458 if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC44="<<fC44<<endl;
459 return 0;
14825d5a 460 }
14825d5a 461 return 1;
006b5f7f 462}
463
464//____________________________________________________________________________
a9a2d814 465Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
006b5f7f 466 //------------------------------------------------------------------
467 //This function propagates a track
468 //------------------------------------------------------------------
469 Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4;
470 Double_t c00=fC00;
471 Double_t c10=fC10, c11=fC11;
472 Double_t c20=fC20, c21=fC21, c22=fC22;
473 Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33;
474 Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44;
475
476
477 Double_t dalp=alp-fAlpha;
478
479 Double_t ca=TMath::Cos(dalp), sa=TMath::Sin(dalp);
480 Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2);
481
482 Double_t pp2=fP2*ca - cf*sa;
a9a2d814 483 if (TMath::Abs(pp2) >= 0.9999) {
006b5f7f 484 Int_t n=GetNumberOfClusters();
7f6ddf58 485 if (n>kWARN)
486 cerr<<n<<" AliITStrackV2::Propagate: Rotation failed !\n";
006b5f7f 487 return 0;
488 }
489
490 fAlpha = alp;
491 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
492 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
493
494 Double_t x1=fX, y1=fP0;
495
496 fX = x1*ca + y1*sa;
497 fP0=-x1*sa + y1*ca;
498 fP2 = pp2;
499
500 cf=ca + sf*sa/cf;
501
a9a2d814 502 if (!Invariant()) return 0;
006b5f7f 503
504 x1=fX; Double_t x2=xk, dx=x2-x1;
505 Double_t f1=fP2, f2=f1 + fP4*dx;
a9a2d814 506 if (TMath::Abs(f2) >= 0.9999) {
006b5f7f 507 Int_t n=GetNumberOfClusters();
7f6ddf58 508 if (n>kWARN)
509 cerr<<n<<" AliITStrackV2::Propagate: Propagation failed !\n";
006b5f7f 510 return 0;
511 }
512
513 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
514
515 fP0 += dx*(f1+f2)/(r1+r2);
516 fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
517 fP2 += dx*fP4;
518
519 //f = F - 1
520 Double_t f02= dx/(r1*r1*r1);
521 Double_t f04=0.5*dx*dx/(r1*r1*r1);
522 Double_t f12= dx*fP3*f1/(r1*r1*r1);
523 Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1);
524 Double_t f13= dx/r1;
525 Double_t f24= dx;
526 /*
527 //b = C*ft
528 Double_t b00=f02*fC20 + f03*fC30, b01=f12*fC20 + f13*fC30 + f14*fC40;
529 Double_t b02=f23*fC30;
530 Double_t b10=f02*fC21 + f03*fC31, b11=f12*fC21 + f13*fC31 + f14*fC41;
531 Double_t b12=f23*fC31;
532 Double_t b20=f02*fC22 + f03*fC32, b21=f12*fC22 + f13*fC32 + f14*fC42;
533 Double_t b22=f23*fC32;
534 Double_t b30=f02*fC32 + f03*fC33, b31=f12*fC32 + f13*fC33 + f14*fC43;
535 Double_t b32=f23*fC33;
536 Double_t b40=f02*fC42 + f03*fC43, b41=f12*fC42 + f13*fC43 + f14*fC44;
537 Double_t b42=f23*fC43;
538
539 //a = f*b = f*C*ft
540 Double_t a00=f02*b20+f03*b30,a01=f02*b21+f03*b31,a02=f02*b22+f03*b32;
541 Double_t a11=f12*b21+f13*b31+f14*b41,a12=f12*b22+f13*b32+f14*b42;
542 Double_t a22=f23*b32;
543
544 //F*C*Ft = C + (b + bt + a)
545 fC00 += b00 + b00 + a00;
546 fC10 += b10 + b01 + a01;
547 fC20 += b20 + b02 + a02;
548 fC30 += b30;
549 fC40 += b40;
550 fC11 += b11 + b11 + a11;
551 fC21 += b21 + b12 + a12;
552 fC31 += b31;
553 fC41 += b41;
554 fC22 += b22 + b22 + a22;
555 fC32 += b32;
556 fC42 += b42;
557*/
558
559 TMatrixD F(5,5); F.UnitMatrix();
560 F(0,0)=-(f1+f2)/(r1+r2)*sa + ca; F(0,2)=f02*cf; F(0,4)=f04;
561 F(1,0)=-(f1+f2)/(f1*r2 + f2*r1)*fP3*sa; F(1,2)=f12*cf; F(1,4)=f14; F(1,3)=f13;
562 F(2,0)=-fP4*sa; F(2,2)=cf; F(2,4)=f24;
563
564 TMatrixD C(5,5);
565 C(0,0)=fC00;
566 C(1,0)=fC10; C(1,1)=fC11;
567 C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22;
568 C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33;
569 C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44;
570
571 C(0,1)=C(1,0);
572 C(0,2)=C(2,0); C(1,2)=C(2,1);
573 C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2);
574 C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3);
575
576 TMatrixD tmp(C,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F));
577 C.Mult(F,tmp);
578
579 fC00=C(0,0);
580 fC10=C(1,0); fC11=C(1,1);
581 fC20=C(2,0); fC21=C(2,1); fC22=C(2,2);
582 fC30=C(3,0); fC31=C(3,1); fC32=C(3,2); fC33=C(3,3);
583 fC40=C(4,0); fC41=C(4,1); fC42=C(4,2); fC43=C(4,3); fC44=C(4,4);
584
006b5f7f 585 if (!Invariant()) {
586 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
587 fC00=c00;
588 fC10=c10; fC11=c11;
589 fC20=c20; fC21=c21; fC22=c22;
590 fC30=c30; fC31=c31; fC32=c32; fC33=c33;
591 fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44;
592 return 0;
593 }
594
595 fX=x2;
596
597 return 1;
598}
599
600Double_t AliITStrackV2::GetD() const {
601 //------------------------------------------------------------------
602 //This function calculates the transverse impact parameter
603 //------------------------------------------------------------------
604 Double_t sn=fP4*fX - fP2, cs=fP4*fP0 + TMath::Sqrt(1.- fP2*fP2);
605 Double_t a=2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2))-fP4*(fX*fX + fP0*fP0);
606 if (fP4<0) a=-a;
607 return a/(1 + TMath::Sqrt(sn*sn + cs*cs));
a9a2d814 608}
006b5f7f 609
a9a2d814 610Int_t AliITStrackV2::Improve(Double_t x0,Double_t yv,Double_t zv) {
611 //------------------------------------------------------------------
612 //This function improves angular track parameters
613 //------------------------------------------------------------------
614 Double_t dy=fP0-yv, dz=fP1-zv;
615 Double_t r2=fX*fX+dy*dy;
616 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
617 Double_t beta2=p2/(p2 + GetMass()*GetMass());
618 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
619 //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
620 Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
621 {
622 Double_t parp=0.5*(fP4*fX + dy*TMath::Sqrt(4/r2-fP4*fP4));
623 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
624 sigma2p += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
625 sigma2p += kSigmaYV*kSigmaYV/r2;
626 sigma2p += 0.25*fC44*fX*fX;
627 Double_t eps2p=sigma2p/(fC22+sigma2p);
628 fP0 += fC20/(fC22+sigma2p)*(parp-fP2);
629 fP2 = eps2p*fP2 + (1-eps2p)*parp;
630 fC22 *= eps2p;
631 fC20 *= eps2p;
632 }
633 {
634 Double_t parl=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2));
635 Double_t sigma2l=theta2;
636 sigma2l += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2);
637 sigma2l += kSigmaZV*kSigmaZV/r2;
638 Double_t eps2l=sigma2l/(fC33+sigma2l);
639 fP1 += fC31/(fC33+sigma2l)*(parl-fP3);
640 fP4 += fC43/(fC33+sigma2l)*(parl-fP3);
641 fP3 = eps2l*fP3 + (1-eps2l)*parl;
642 fC33 *= eps2l; fC43 *= eps2l;
643 fC31 *= eps2l;
644 }
645 if (!Invariant()) return 0;
646 return 1;
647}
006b5f7f 648
a9a2d814 649/*
006b5f7f 650Int_t AliITStrackV2::Improve(Double_t x0,Double_t yv,Double_t zv) {
651 //------------------------------------------------------------------
652 //This function improves angular track parameters
653 //------------------------------------------------------------------
654 Double_t dy=fP0-yv, dz=fP1-zv;
655 Double_t r2=fX*fX+dy*dy;
656 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
7f6ddf58 657 Double_t beta2=p2/(p2 + GetMass()*GetMass());
006b5f7f 658 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
a9a2d814 659 //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
660 Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
006b5f7f 661
662 Double_t par=0.5*(fP4*fX + dy*TMath::Sqrt(4/r2-fP4*fP4));
663 Double_t sigma2 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
664 sigma2 += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
665 sigma2 += kSigmaYV*kSigmaYV/r2;
666 sigma2 += 0.25*fC44*fX*fX;
667 Double_t eps2=sigma2/(fC22+sigma2), eps=TMath::Sqrt(eps2);
668 if (10*r2*fC44<fC22) {
669 fP2 = eps2*fP2 + (1-eps2)*par;
670 fC22*=eps2; fC21*=eps; fC20*=eps; fC32*=eps; fC42*=eps;
671 }
672
673 par=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2));
674 sigma2=theta2;
675 sigma2 += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2);
676 sigma2 += kSigmaZV*kSigmaZV/r2;
677 eps2=sigma2/(fC33+sigma2); eps=TMath::Sqrt(eps2);
678 Double_t tgl=fP3;
679 fP3 = eps2*fP3 + (1-eps2)*par;
680 fC33*=eps2; fC32*=eps; fC31*=eps; fC30*=eps; fC43*=eps;
681
682 eps=TMath::Sqrt((1+fP3*fP3)/(1+tgl*tgl));
683 fP4*=eps;
684 fC44*=eps*eps; fC43*=eps;fC42*=eps; fC41*=eps; fC40*=eps;
685
686 if (!Invariant()) return 0;
687 return 1;
688}
006b5f7f 689*/
14825d5a 690void AliITStrackV2::ResetCovariance() {
691 //------------------------------------------------------------------
692 //This function makes a track forget its history :)
693 //------------------------------------------------------------------
694
695 fC00*=10.;
696 fC10=0.; fC11*=10.;
697 fC20=0.; fC21=0.; fC22*=10.;
698 fC30=0.; fC31=0.; fC32=0.; fC33*=10.;
699 fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.;
700
701}
23efe5f1 702
703void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
704 //-----------------------------------------------------------------
a9a2d814 705 // This function calculates dE/dX within the "low" and "up" cuts.
706 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
23efe5f1 707 //-----------------------------------------------------------------
708 Int_t i;
a9a2d814 709 Int_t nc=4;
23efe5f1 710 // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1
711 // Take only SSD and SDD
23efe5f1 712
a9a2d814 713 Int_t swap;//stupid sorting
23efe5f1 714 do {
715 swap=0;
716 for (i=0; i<nc-1; i++) {
717 if (fdEdxSample[i]<=fdEdxSample[i+1]) continue;
718 Float_t tmp=fdEdxSample[i];
719 fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp;
720 swap++;
721 }
722 } while (swap);
723
a9a2d814 724 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX
725 // values from four ones choose
726 // nu=2
23efe5f1 727 Float_t dedx=0;
a9a2d814 728 for (i=nl; i<nu; i++) dedx += fdEdxSample[i];
729 dedx /= (nu-nl);
23efe5f1 730
23efe5f1 731 SetdEdx(dedx);
732}