Added check for ppad[1] range
[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
20//-------------------------------------------------------------------------
21
22#include <TMatrixD.h>
23
24#include <TMath.h>
25#include <iostream.h>
26
27#include "AliCluster.h"
517b130f 28#include "AliTPCtrack.h"
006b5f7f 29#include "AliITStrackV2.h"
30
31ClassImp(AliITStrackV2)
32
33const Int_t kWARN=1;
34
35//____________________________________________________________________________
36AliITStrackV2::AliITStrackV2(const AliTPCtrack& t) throw (const Char_t *) {
37 //------------------------------------------------------------------
9b280d80 38 //Conversion TPC track -> ITS track
006b5f7f 39 //------------------------------------------------------------------
40 SetLabel(t.GetLabel());
41 SetChi2(0.);
42 SetNumberOfClusters(0);
14825d5a 43 //SetConvConst(t.GetConvConst());
44
006b5f7f 45 fdEdx = 0.;
46 fAlpha = t.GetAlpha();
47 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
48 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
49
9b280d80 50 //Conversion of the track parameters
006b5f7f 51 Double_t x,p[5]; t.GetExternalParameters(x,p);
9b280d80 52 fX=x; x=GetConvConst();
006b5f7f 53 fP0=p[0];
54 fP1=p[1];
55 fP2=p[2];
56 fP3=p[3];
57 fP4=p[4]/x;
58
9b280d80 59 //Conversion of the covariance matrix
006b5f7f 60 Double_t c[15]; t.GetExternalCovariance(c);
61
62 fC00=c[0 ];
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;
67
68 if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
69}
70
71//____________________________________________________________________________
72AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) {
73 //------------------------------------------------------------------
74 //Copy constructor
75 //------------------------------------------------------------------
76 fX=t.fX;
77 fAlpha=t.fAlpha;
78 fdEdx=t.fdEdx;
79
80 fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;
81
82 fC00=t.fC00;
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;
87
88 Int_t n=GetNumberOfClusters();
89 for (Int_t i=0; i<n; i++) fIndex[i]=t.fIndex[i];
90}
91
92//_____________________________________________________________________________
93Int_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());
100 if (c>co) return 1;
101 else if (c<co) return -1;
102 return 0;
103}
104
105//_____________________________________________________________________________
106void 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 //-------------------------------------------------------------------------
9b280d80 111 Double_t a=GetConvConst();
006b5f7f 112
113 cc[0 ]=fC00;
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;
118}
119
120//____________________________________________________________________________
121Int_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);
127 return 0;
128}
129
130//____________________________________________________________________________
131Int_t AliITStrackV2::
132GetGlobalXYZat(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 //------------------------------------------------------------------
136 Double_t dx=xk-fX;
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";
141 return 0;
142 }
143
144 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
145
146 Double_t yk = fP0 + dx*(f1+f2)/(r1+r2);
147 Double_t zk = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
148
149 Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha);
150 x = xk*cs - yk*sn;
151 y = xk*sn + yk*cs;
152 z = zk;
153
154 return 1;
155}
156
157//_____________________________________________________________________________
158Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const
159{
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;
165
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";
170 return 1e10;
171 }
172 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
173
174 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
175
176 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
177}
178
179//_____________________________________________________________________________
180Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c,Double_t *m,
60e5fcc3 181Double_t x0, Double_t pm) const {
006b5f7f 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;
186 TMatrixD C(5,5);
187 C(0,0)=fC00;
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;
192
193 C(0,1)=C(1,0);
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);
197
198 TMatrixD H(4,5); H.UnitMatrix();
199 Double_t dy=(c->GetY() - m[0]), dz=(c->GetZ() - m[1]);
200
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);
205 TVectorD mm(4);
206 mm(0)=m[0]=c->GetY(); mm(1)=m[1]=c->GetZ(); mm(2)=m[2]=sn; mm(3)=m[3]=tg;
207
208 Double_t v22=0.,v33=0.;
209 //x0=0.;
210 if (x0!=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());
217 }
218 Double_t sy2=c->GetSigmaY2(), sz2=c->GetSigmaZ2();
219 v22+=kSigmaYV*kSigmaYV/dr/dr;
220 v22+=sy2/dr/dr;
221 Double_t v20=sy2/dr;
222
223 v33+=kSigmaZV*kSigmaZV/dr/dr;
224 v33+=sz2/dr/dr;
225 Double_t v31=sz2/dr;
226
227 TMatrixD V(4,4);
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;
232
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;
236
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";
241 return 1e10;
242 }
243
244 R.Invert();
245
246 TVectorD rs=res;
247 res*=R;
248 return rs*res;
249}
250
251//____________________________________________________________________________
252Int_t
253AliITStrackV2::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";
262 return 0;
263 }
264
265 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
266
267 fP0 += dx*(f1+f2)/(r1+r2);
268 fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
269 fP2 += dx*fP4;
270
271 //f = F - 1
272
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);
277 Double_t f13= dx/r1;
278 Double_t f24= dx;
279
280 //b = C*ft
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;
291
292 //a = f*b = f*C*ft
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;
296
297 //F*C*Ft = C + (b + bt + a)
298 fC00 += b00 + b00 + a00;
299 fC10 += b10 + b01 + a01;
300 fC20 += b20 + b02 + a02;
301 fC30 += b30;
302 fC40 += b40;
303 fC11 += b11 + b11 + a11;
304 fC21 += b21 + b12 + a12;
305 fC31 += b31;
306 fC41 += b41;
307 fC22 += b22 + b22 + a22;
308 fC32 += b32;
309 fC42 += b42;
310
311 fX=x2;
312
313 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
314 Double_t beta2=p2/(p2 + pm*pm);
315
316 //Multiple scattering******************
317 //x0=0.;
318 if (x0!=0) {
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;
325 }
326
327 //Energy losses************************
328 if (rho!=0.) {
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;
331 if (x1 < x2) dE=-dE;
332 fP4*=(1.- sqrt(p2+pm*pm)/p2*dE);
333 }
334
335 if (!Invariant()) {cout<<"Propagate !\n"; return 0;}
336
337 return 1;
338}
339
340//____________________________________________________________________________
341Int_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;
346 Double_t c00=fC00;
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;
351
352
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;
357
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;
363
364 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
365 Double_t sf=fP2 + k20*dy + k21*dz;
366 /*
367 if (TMath::Abs(sf) >= 0.99999) {
368 Int_t n=GetNumberOfClusters();
369 if (n>kWARN) cerr<<n<<" AliITStrackV2 warning: Filtering failed !\n";
370 return 0;
371 }
372 */
373 fP0 += k00*dy + k01*dz;
374 fP1 += k10*dy + k11*dz;
375 fP2 = sf;
376 fP3 += k30*dy + k31*dz;
377 fP4 += k40*dy + k41*dz;
378
379 Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
380 Double_t c12=fC21, c13=fC31, c14=fC41;
381
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;
385
386 fC11-=k10*c01+k11*fC11;
387 fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13;
388 fC41-=k10*c04+k11*c14;
389
390 fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13;
391 fC42-=k20*c04+k21*c14;
392
393 fC33-=k30*c03+k31*c13;
394 fC43-=k30*c04+k31*c14;
395
396 fC44-=k40*c04+k41*c14;
397
398 if (!Invariant()) {
399 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
400 fC00=c00;
401 fC10=c10; fC11=c11;
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;
405 return 0;
406 }
407
408 Int_t n=GetNumberOfClusters();
409 fIndex[n]=index;
410 SetNumberOfClusters(n+1);
411 SetChi2(GetChi2()+chi2);
412
413 return 1;
414}
415
416
417//____________________________________________________________________________
418Int_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;
423 Double_t c00=fC00;
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;
428
429
430 TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4;
431 TMatrixD C(5,5);
432 C(0,0)=fC00;
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;
437
438 C(0,1)=C(1,0);
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);
442
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];
446 TMatrixD V(4,4);
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];
451
452 TMatrixD tmp(H,TMatrixD::kMult,C);
453 TMatrixD R(tmp,TMatrixD::kMult,Ht); R+=V;
454
455 R.Invert();
456
457 TMatrixD K(C,TMatrixD::kMult,Ht); K*=R;
458
459 TVectorD savex=x;
460 x*=H; x-=mm; x*=-1; x*=K; x+=savex;
461
462 TMatrixD saveC=C;
463 C.Mult(K,tmp); C-=saveC; C*=-1;
464
465 fP0=x(0); fP1=x(1); fP2=x(2); fP3=x(3); fP4=x(4);
466 fC00=C(0,0);
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);
471
472
473 if (!Invariant()) {
474 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
475 fC00=c00;
476 fC10=c10; fC11=c11;
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;
480 return 0;
481 }
482
483 Int_t n=GetNumberOfClusters();
484 fIndex[n]=index;
485 SetNumberOfClusters(n+1);
486 SetChi2(GetChi2()+chi2);
487
488 return 1;
489}
490
491Int_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;}
498
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;}
14825d5a 504 /*
505 TMatrixD m(5,5);
506 m(0,0)=fC00;
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;
511
512 m(0,1)=m(1,0);
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);
516
517 Double_t det=m.Determinant();
518
519 if (det <= 0) {
520 cout<<" bad determinant "<<det<<endl;
521 m.Print();
522 return 0;
523 }
524 */
525 return 1;
006b5f7f 526}
527
528//____________________________________________________________________________
529Int_t AliITStrackV2::Propagate(Double_t alp, Double_t xk,
530Double_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;
535 Double_t c00=fC00;
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;
540
541
542 Double_t dalp=alp-fAlpha;
543
544 Double_t ca=TMath::Cos(dalp), sa=TMath::Sin(dalp);
545 Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2);
546
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";
551 return 0;
552 }
553
554 fAlpha = alp;
555 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
556 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
557
558 Double_t x1=fX, y1=fP0;
559
560 fX = x1*ca + y1*sa;
561 fP0=-x1*sa + y1*ca;
562 fP2 = pp2;
563
564 cf=ca + sf*sa/cf;
565
566 if (!Invariant()) {cout<<dalp<<" Rotate !\n"; return 0;}
567
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";
573 return 0;
574 }
575
576 Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2);
577
578 fP0 += dx*(f1+f2)/(r1+r2);
579 fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3;
580 fP2 += dx*fP4;
581
582 //f = F - 1
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);
587 Double_t f13= dx/r1;
588 Double_t f24= dx;
589 /*
590 //b = C*ft
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;
601
602 //a = f*b = f*C*ft
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;
606
607 //F*C*Ft = C + (b + bt + a)
608 fC00 += b00 + b00 + a00;
609 fC10 += b10 + b01 + a01;
610 fC20 += b20 + b02 + a02;
611 fC30 += b30;
612 fC40 += b40;
613 fC11 += b11 + b11 + a11;
614 fC21 += b21 + b12 + a12;
615 fC31 += b31;
616 fC41 += b41;
617 fC22 += b22 + b22 + a22;
618 fC32 += b32;
619 fC42 += b42;
620*/
621
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;
626
627 TMatrixD C(5,5);
628 C(0,0)=fC00;
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;
633
634 C(0,1)=C(1,0);
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);
638
639 TMatrixD tmp(C,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F));
640 C.Mult(F,tmp);
641
642 fC00=C(0,0);
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);
647
648 pp2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
649 Double_t beta2=pp2/(pp2 + pm*pm);
650
651 //Multiple scattering******************
652 //x0=0.;
653 if (x0!=0.) {
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;
660 }
661
662 //Energy losses************************
663 if (rho!=0.) {
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;
666 if (x1 < x2) dE=-dE;
667 fP4*=(1.- sqrt(pp2+pm*pm)/pp2*dE);
668 }
669
670 if (!Invariant()) {
671 fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4;
672 fC00=c00;
673 fC10=c10; fC11=c11;
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;
677 return 0;
678 }
679
680 fX=x2;
681
682 return 1;
683}
684
685Double_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);
691 if (fP4<0) a=-a;
692 return a/(1 + TMath::Sqrt(sn*sn + cs*cs));
693}
694
695
696Int_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;
706
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;
716 }
717
718 par=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2));
719 sigma2=theta2;
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);
723 Double_t tgl=fP3;
724 fP3 = eps2*fP3 + (1-eps2)*par;
725 fC33*=eps2; fC32*=eps; fC31*=eps; fC30*=eps; fC43*=eps;
726
727 eps=TMath::Sqrt((1+fP3*fP3)/(1+tgl*tgl));
728 fP4*=eps;
729 fC44*=eps*eps; fC43*=eps;fC42*=eps; fC41*=eps; fC40*=eps;
730
731 if (!Invariant()) return 0;
732 return 1;
733}
734
735/*
736Int_t AliITStrackV2::Improve(Double_t x0,Double_t xv,Double_t yv) {
737 //------------------------------------------------------------------
738 //This function improves angular track parameters
739 //------------------------------------------------------------------
740 TMatrixD I(5,5);
741 TVectorD v(5); v(0)=fP0; v(1)=fP1; v(2)=fP2; v(3)=fP3; v(4)=fP4;
742
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;
748
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;
753 I(2,2)=1/sigma2;
754
755 v(3)=0.5*fP4*fP1/TMath::ASin(0.5*fP4*TMath::Sqrt(r2));
756 sigma2=theta2;
757 sigma2 += fC11/r2+fC00*fP0*fP0*fP1*fP1/(r2*r2*r2);
758 sigma2 += kSigmaZV*kSigmaZV/r2;
759 I(3,3)=1/sigma2;
760
761 Double_t tgl=fP3;
762
763 TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4;
764 TMatrixD C(5,5);
765 C(0,0)=fC00;
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;
770
771 C(0,1)=C(1,0);
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);
775
776 TMatrixD tmp(I,TMatrixD::kMult,C),U(5,5); U.UnitMatrix();
777 U+=tmp;
778 U.Invert();
779 TMatrixD W1(U);
780 TMatrixD W2(tmp,TMatrixD::kMult,W1);
781
782 v*=W2; x*=W1; x+=v;
783
784 C*=W1;
785
786
787 fP0=x(0); fP1=x(1); fP2=x(2); fP3=x(3); fP4=x(4);
788 fC00=C(0,0);
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);
793
794 eps=TMath::Sqrt((1+fP3*fP3)/(1+tgl*tgl));
795 fP4*=eps;
796 fC44*=eps*eps; fC43*=eps;fC42*=eps; fC41*=eps; fC40*=eps;
797
798 if (!Invariant()) return 0;
799 return 1;
800}
801*/
802
14825d5a 803void AliITStrackV2::ResetCovariance() {
804 //------------------------------------------------------------------
805 //This function makes a track forget its history :)
806 //------------------------------------------------------------------
807
808 fC00*=10.;
809 fC10=0.; fC11*=10.;
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.;
813
814}