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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 | // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch | |
21 | /////////////////////////////////////////////////////////////////////////// | |
22 | #include <TMath.h> | |
23 | ||
24 | #include "AliCluster.h" | |
25 | #include "AliESDtrack.h" | |
26 | #include "AliITStrackV2.h" | |
27 | #include "AliStrLine.h" | |
28 | ||
29 | ClassImp(AliITStrackV2) | |
30 | ||
31 | const Int_t kWARN=5; | |
32 | ||
33 | //____________________________________________________________________________ | |
34 | AliITStrackV2::AliITStrackV2():AliKalmanTrack(), | |
35 | fX(0), | |
36 | fAlpha(0), | |
37 | fdEdx(0), | |
38 | fP0(0), | |
39 | fP1(0), | |
40 | fP2(0), | |
41 | fP3(0), | |
42 | fP4(0), | |
43 | fC00(0), | |
44 | fC10(0), | |
45 | fC11(0), | |
46 | fC20(0), | |
47 | fC21(0), | |
48 | fC22(0), | |
49 | fC30(0), | |
50 | fC31(0), | |
51 | fC32(0), | |
52 | fC33(0), | |
53 | fC40(0), | |
54 | fC41(0), | |
55 | fC42(0), | |
56 | fC43(0), | |
57 | fC44(0), | |
58 | fESDtrack(0) | |
59 | { | |
60 | for(Int_t i=0; i<kMaxLayer; i++) fIndex[i]=0; | |
61 | for(Int_t i=0; i<4; i++) fdEdxSample[i]=0; | |
62 | } | |
63 | ||
64 | ||
65 | //____________________________________________________________________________ | |
66 | AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) : | |
67 | AliKalmanTrack() { | |
68 | //------------------------------------------------------------------ | |
69 | // Conversion ESD track -> ITS track. | |
70 | // If c==kTRUE, create the ITS track out of the constrained params. | |
71 | //------------------------------------------------------------------ | |
72 | SetNumberOfClusters(t.GetITSclusters(fIndex)); | |
73 | SetLabel(t.GetLabel()); | |
74 | SetMass(t.GetMass()); | |
75 | // | |
76 | // | |
77 | ||
78 | fdEdx=t.GetITSsignal(); | |
79 | fAlpha = t.GetAlpha(); | |
80 | if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi(); | |
81 | else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi(); | |
82 | ||
83 | //Conversion of the track parameters | |
84 | Double_t x,p[5]; | |
85 | if (c) t.GetConstrainedExternalParameters(fAlpha,x,p); | |
86 | else t.GetExternalParameters(x,p); | |
87 | fX=x; | |
88 | fP0=p[0]; | |
89 | fP1=p[1]; SaveLocalConvConst(); | |
90 | fP2=p[2]; | |
91 | fP3=p[3]; x=GetLocalConvConst(); | |
92 | fP4=p[4]/x; | |
93 | ||
94 | //Conversion of the covariance matrix | |
95 | Double_t cv[15]; | |
96 | if (c) t.GetConstrainedExternalCovariance(cv); | |
97 | else t.GetExternalCovariance(cv); | |
98 | fC00=cv[0 ]; | |
99 | fC10=cv[1 ]; fC11=cv[2 ]; | |
100 | fC20=cv[3 ]; fC21=cv[4 ]; fC22=cv[5 ]; | |
101 | fC30=cv[6 ]; fC31=cv[7 ]; fC32=cv[8 ]; fC33=cv[9 ]; | |
102 | fC40=cv[10]/x; fC41=cv[11]/x; fC42=cv[12]/x; fC43=cv[13]/x; fC44=cv[14]/x/x; | |
103 | ||
104 | if (t.GetStatus()&AliESDtrack::kTIME) { | |
105 | StartTimeIntegral(); | |
106 | Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times); | |
107 | SetIntegratedLength(t.GetIntegratedLength()); | |
108 | } | |
109 | fESDtrack=&t; | |
110 | ||
111 | // if (!Invariant()) throw "AliITStrackV2: conversion failed !\n"; | |
112 | for(Int_t i=0; i<4; i++) fdEdxSample[i]=0; | |
113 | } | |
114 | ||
115 | void AliITStrackV2::UpdateESDtrack(ULong_t flags) const { | |
116 | fESDtrack->UpdateTrackParams(this,flags); | |
117 | } | |
118 | ||
119 | //____________________________________________________________________________ | |
120 | AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) { | |
121 | //------------------------------------------------------------------ | |
122 | //Copy constructor | |
123 | //------------------------------------------------------------------ | |
124 | fX=t.fX; | |
125 | fAlpha=t.fAlpha; | |
126 | fdEdx=t.fdEdx; | |
127 | ||
128 | fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4; | |
129 | ||
130 | fC00=t.fC00; | |
131 | fC10=t.fC10; fC11=t.fC11; | |
132 | fC20=t.fC20; fC21=t.fC21; fC22=t.fC22; | |
133 | fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33; | |
134 | fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44; | |
135 | ||
136 | Int_t n=GetNumberOfClusters(); | |
137 | for (Int_t i=0; i<n; i++) { | |
138 | fIndex[i]=t.fIndex[i]; | |
139 | if (i<4) fdEdxSample[i]=t.fdEdxSample[i]; | |
140 | } | |
141 | fESDtrack=t.fESDtrack; | |
142 | } | |
143 | ||
144 | //_____________________________________________________________________________ | |
145 | Int_t AliITStrackV2::Compare(const TObject *o) const { | |
146 | //----------------------------------------------------------------- | |
147 | // This function compares tracks according to the their curvature | |
148 | //----------------------------------------------------------------- | |
149 | AliITStrackV2 *t=(AliITStrackV2*)o; | |
150 | //Double_t co=TMath::Abs(t->Get1Pt()); | |
151 | //Double_t c =TMath::Abs(Get1Pt()); | |
152 | Double_t co=t->GetSigmaY2()*t->GetSigmaZ2(); | |
153 | Double_t c =GetSigmaY2()*GetSigmaZ2(); | |
154 | if (c>co) return 1; | |
155 | else if (c<co) return -1; | |
156 | return 0; | |
157 | } | |
158 | ||
159 | //_____________________________________________________________________________ | |
160 | void AliITStrackV2::GetExternalCovariance(Double_t cc[15]) const { | |
161 | //------------------------------------------------------------------------- | |
162 | // This function returns an external representation of the covriance matrix. | |
163 | // (See comments in AliTPCtrack.h about external track representation) | |
164 | //------------------------------------------------------------------------- | |
165 | Double_t a=GetLocalConvConst(); | |
166 | ||
167 | cc[0 ]=fC00; | |
168 | cc[1 ]=fC10; cc[2 ]=fC11; | |
169 | cc[3 ]=fC20; cc[4 ]=fC21; cc[5 ]=fC22; | |
170 | cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=fC32; cc[9 ]=fC33; | |
171 | cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=fC42*a; cc[13]=fC43*a; cc[14]=fC44*a*a; | |
172 | } | |
173 | ||
174 | //____________________________________________________________________________ | |
175 | Int_t AliITStrackV2::PropagateToVertex(Double_t d,Double_t x0) { | |
176 | //------------------------------------------------------------------ | |
177 | //This function propagates a track to the minimal distance from the origin | |
178 | //------------------------------------------------------------------ | |
179 | //Double_t xv=fP2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2)); //linear approxim. | |
180 | Double_t tgf=-(fP4*fX - fP2)/(fP4*fP0 + TMath::Sqrt(1 - fP2*fP2)); | |
181 | Double_t snf=tgf/TMath::Sqrt(1.+ tgf*tgf); | |
182 | Double_t xv=(snf - fP2)/fP4 + fX; | |
183 | return PropagateTo(xv,d,x0); | |
184 | } | |
185 | ||
186 | //____________________________________________________________________________ | |
187 | Int_t AliITStrackV2:: | |
188 | GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const { | |
189 | //------------------------------------------------------------------ | |
190 | //This function returns a track position in the global system | |
191 | //------------------------------------------------------------------ | |
192 | Double_t dx=xk-fX; | |
193 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
194 | if (TMath::Abs(f2) >= 0.9999) { | |
195 | Int_t n=GetNumberOfClusters(); | |
196 | if (n>kWARN) | |
197 | Warning("GetGlobalXYZat","Propagation failed (%d) !\n",n); | |
198 | return 0; | |
199 | } | |
200 | ||
201 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); | |
202 | ||
203 | Double_t yk = fP0 + dx*(f1+f2)/(r1+r2); | |
204 | Double_t zk = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
205 | ||
206 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); | |
207 | x = xk*cs - yk*sn; | |
208 | y = xk*sn + yk*cs; | |
209 | z = zk; | |
210 | ||
211 | return 1; | |
212 | } | |
213 | ||
214 | //_____________________________________________________________________________ | |
215 | void AliITStrackV2::ApproximateHelixWithLine(Double_t xk, AliStrLine *line) | |
216 | { | |
217 | //------------------------------------------------------------ | |
218 | // Approximate the track (helix) with a straight line tangent to the | |
219 | // helix in the point defined by r (F. Prino, prino@to.infn.it) | |
220 | //------------------------------------------------------------ | |
221 | Double_t mom[3]; | |
222 | Double_t azim = TMath::ASin(fP2)+fAlpha; | |
223 | Double_t theta = TMath::Pi()/2. - TMath::ATan(fP3); | |
224 | mom[0] = TMath::Sin(theta)*TMath::Cos(azim); | |
225 | mom[1] = TMath::Sin(theta)*TMath::Sin(azim); | |
226 | mom[2] = TMath::Cos(theta); | |
227 | Double_t pos[3]; | |
228 | GetGlobalXYZat(xk,pos[0],pos[1],pos[2]); | |
229 | line->SetP0(pos); | |
230 | line->SetCd(mom); | |
231 | } | |
232 | //_____________________________________________________________________________ | |
233 | Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const | |
234 | { | |
235 | //----------------------------------------------------------------- | |
236 | // This function calculates a predicted chi2 increment. | |
237 | //----------------------------------------------------------------- | |
238 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
239 | r00+=fC00; r01+=fC10; r11+=fC11; | |
240 | // | |
241 | Double_t det=r00*r11 - r01*r01; | |
242 | if (TMath::Abs(det) < 1.e-30) { | |
243 | Int_t n=GetNumberOfClusters(); | |
244 | if (n>kWARN) | |
245 | Warning("GetPredictedChi2","Singular matrix (%d) !\n",n); | |
246 | return 1e10; | |
247 | } | |
248 | Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01; | |
249 | ||
250 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; | |
251 | ||
252 | return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det; | |
253 | } | |
254 | ||
255 | //____________________________________________________________________________ | |
256 | Int_t AliITStrackV2::CorrectForMaterial(Double_t d, Double_t x0) { | |
257 | //------------------------------------------------------------------ | |
258 | //This function corrects the track parameters for crossed material | |
259 | //------------------------------------------------------------------ | |
260 | Double_t p2=(1.+ fP3*fP3)/(Get1Pt()*Get1Pt()); | |
261 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); | |
262 | d*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2)); | |
263 | ||
264 | //Multiple scattering****************** | |
265 | if (d!=0) { | |
266 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d); | |
267 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33; | |
268 | fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3); | |
269 | fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3); | |
270 | fC43 += theta2*fP3*fP4*(1. + fP3*fP3); | |
271 | fC44 += theta2*fP3*fP4*fP3*fP4; | |
272 | } | |
273 | ||
274 | //Energy losses************************ | |
275 | if (x0!=0.) { | |
276 | d*=x0; | |
277 | Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d; | |
278 | if (beta2/(1-beta2)>3.5*3.5) | |
279 | dE=0.153e-3/beta2*(log(3.5*5940)+0.5*log(beta2/(1-beta2)) - beta2)*d; | |
280 | ||
281 | fP4*=(1.- TMath::Sqrt(p2+GetMass()*GetMass())/p2*dE); | |
282 | } | |
283 | ||
284 | if (!Invariant()) return 0; | |
285 | ||
286 | return 1; | |
287 | } | |
288 | ||
289 | //____________________________________________________________________________ | |
290 | Int_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) { | |
291 | //------------------------------------------------------------------ | |
292 | //This function propagates a track | |
293 | //------------------------------------------------------------------ | |
294 | Double_t x1=fX, x2=xk, dx=x2-x1; | |
295 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
296 | if (TMath::Abs(f2) >= 0.98) { | |
297 | // MI change - don't propagate highly inclined tracks | |
298 | // covariance matrix distorted | |
299 | //Int_t n=GetNumberOfClusters(); | |
300 | //if (n>kWARN) | |
301 | // Warning("PropagateTo","Propagation failed !\n",n); | |
302 | return 0; | |
303 | } | |
304 | Double_t lcc=GetLocalConvConst(); | |
305 | ||
306 | // old position [SR, GSI, 17.02.2003] | |
307 | Double_t oldX = fX, oldY = fP0, oldZ = fP1; | |
308 | ||
309 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); | |
310 | ||
311 | fP0 += dx*(f1+f2)/(r1+r2); | |
312 | fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
313 | fP2 += dx*fP4; | |
314 | ||
315 | //f = F - 1 | |
316 | ||
317 | Double_t f02= dx/(r1*r1*r1); | |
318 | Double_t f04=0.5*dx*dx/(r1*r1*r1); | |
319 | Double_t f12= dx*fP3*f1/(r1*r1*r1); | |
320 | Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1); | |
321 | Double_t f13= dx/r1; | |
322 | Double_t f24= dx; | |
323 | ||
324 | //b = C*ft | |
325 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; | |
326 | Double_t b02=f24*fC40; | |
327 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; | |
328 | Double_t b12=f24*fC41; | |
329 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; | |
330 | Double_t b22=f24*fC42; | |
331 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; | |
332 | Double_t b42=f24*fC44; | |
333 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; | |
334 | Double_t b32=f24*fC43; | |
335 | ||
336 | //a = f*b = f*C*ft | |
337 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42; | |
338 | Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32; | |
339 | Double_t a22=f24*b42; | |
340 | ||
341 | //F*C*Ft = C + (b + bt + a) | |
342 | fC00 += b00 + b00 + a00; | |
343 | fC10 += b10 + b01 + a01; | |
344 | fC20 += b20 + b02 + a02; | |
345 | fC30 += b30; | |
346 | fC40 += b40; | |
347 | fC11 += b11 + b11 + a11; | |
348 | fC21 += b21 + b12 + a12; | |
349 | fC31 += b31; | |
350 | fC41 += b41; | |
351 | fC22 += b22 + b22 + a22; | |
352 | fC32 += b32; | |
353 | fC42 += b42; | |
354 | ||
355 | fX=x2; | |
356 | ||
357 | //Change of the magnetic field ************* | |
358 | SaveLocalConvConst(); | |
359 | fP4*=lcc/GetLocalConvConst(); | |
360 | ||
361 | if (!CorrectForMaterial(d,x0)) return 0; | |
362 | ||
363 | // Integrated Time [SR, GSI, 17.02.2003] | |
364 | if (IsStartedTimeIntegral() && fX>oldX) { | |
365 | Double_t l2 = (fX-oldX)*(fX-oldX)+(fP0-oldY)*(fP0-oldY)+ | |
366 | (fP1-oldZ)*(fP1-oldZ); | |
367 | AddTimeStep(TMath::Sqrt(l2)); | |
368 | } | |
369 | // | |
370 | ||
371 | return 1; | |
372 | } | |
373 | ||
374 | //____________________________________________________________________________ | |
375 | Int_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, UInt_t index) { | |
376 | //------------------------------------------------------------------ | |
377 | //This function updates track parameters | |
378 | //------------------------------------------------------------------ | |
379 | Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4; | |
380 | Double_t c00=fC00; | |
381 | Double_t c10=fC10, c11=fC11; | |
382 | Double_t c20=fC20, c21=fC21, c22=fC22; | |
383 | Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33; | |
384 | Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44; | |
385 | ||
386 | ||
387 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
388 | r00+=fC00; r01+=fC10; r11+=fC11; | |
389 | Double_t det=r00*r11 - r01*r01; | |
390 | Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det; | |
391 | ||
392 | ||
393 | Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11; | |
394 | Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11; | |
395 | Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11; | |
396 | Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11; | |
397 | Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11; | |
398 | ||
399 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; | |
400 | Double_t sf=fP2 + k20*dy + k21*dz; | |
401 | ||
402 | fP0 += k00*dy + k01*dz; | |
403 | fP1 += k10*dy + k11*dz; | |
404 | fP2 = sf; | |
405 | fP3 += k30*dy + k31*dz; | |
406 | fP4 += k40*dy + k41*dz; | |
407 | ||
408 | Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40; | |
409 | Double_t c12=fC21, c13=fC31, c14=fC41; | |
410 | ||
411 | fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11; | |
412 | fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13; | |
413 | fC40-=k00*c04+k01*c14; | |
414 | ||
415 | fC11-=k10*c01+k11*fC11; | |
416 | fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13; | |
417 | fC41-=k10*c04+k11*c14; | |
418 | ||
419 | fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13; | |
420 | fC42-=k20*c04+k21*c14; | |
421 | ||
422 | fC33-=k30*c03+k31*c13; | |
423 | fC43-=k30*c04+k31*c14; | |
424 | ||
425 | fC44-=k40*c04+k41*c14; | |
426 | ||
427 | if (!Invariant()) { | |
428 | fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4; | |
429 | fC00=c00; | |
430 | fC10=c10; fC11=c11; | |
431 | fC20=c20; fC21=c21; fC22=c22; | |
432 | fC30=c30; fC31=c31; fC32=c32; fC33=c33; | |
433 | fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44; | |
434 | return 0; | |
435 | } | |
436 | ||
437 | if (chi2<0) return 1; | |
438 | ||
439 | Int_t n=GetNumberOfClusters(); | |
440 | fIndex[n]=index; | |
441 | SetNumberOfClusters(n+1); | |
442 | SetChi2(GetChi2()+chi2); | |
443 | ||
444 | return 1; | |
445 | } | |
446 | ||
447 | Int_t AliITStrackV2::Invariant() const { | |
448 | //------------------------------------------------------------------ | |
449 | // This function is for debugging purpose only | |
450 | //------------------------------------------------------------------ | |
451 | Int_t n=GetNumberOfClusters(); | |
452 | ||
453 | if (TMath::Abs(fP2)>=0.9999){ | |
454 | if (n>kWARN) Warning("Invariant","fP2=%f\n",fP2); | |
455 | return 0; | |
456 | } | |
457 | if (fC00<=0 || fC00>9.) { | |
458 | if (n>kWARN) Warning("Invariant","fC00=%f\n",fC00); | |
459 | return 0; | |
460 | } | |
461 | if (fC11<=0 || fC11>9.) { | |
462 | if (n>kWARN) Warning("Invariant","fC11=%f\n",fC11); | |
463 | return 0; | |
464 | } | |
465 | if (fC22<=0 || fC22>1.) { | |
466 | if (n>kWARN) Warning("Invariant","fC22=%f\n",fC22); | |
467 | return 0; | |
468 | } | |
469 | if (fC33<=0 || fC33>1.) { | |
470 | if (n>kWARN) Warning("Invariant","fC33=%f\n",fC33); | |
471 | return 0; | |
472 | } | |
473 | if (fC44<=0 || fC44>6e-5) { | |
474 | if (n>kWARN) Warning("Invariant","fC44=%f\n",fC44); | |
475 | return 0; | |
476 | } | |
477 | return 1; | |
478 | } | |
479 | ||
480 | //____________________________________________________________________________ | |
481 | Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) { | |
482 | //------------------------------------------------------------------ | |
483 | //This function propagates a track | |
484 | //------------------------------------------------------------------ | |
485 | Double_t alpha=fAlpha, x=fX; | |
486 | Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4; | |
487 | Double_t c00=fC00; | |
488 | Double_t c10=fC10, c11=fC11; | |
489 | Double_t c20=fC20, c21=fC21, c22=fC22; | |
490 | Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33; | |
491 | Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44; | |
492 | ||
493 | if (alp < -TMath::Pi()) alp += 2*TMath::Pi(); | |
494 | else if (alp >= TMath::Pi()) alp -= 2*TMath::Pi(); | |
495 | Double_t ca=TMath::Cos(alp-fAlpha), sa=TMath::Sin(alp-fAlpha); | |
496 | Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2); | |
497 | ||
498 | // **** rotation ********************** | |
499 | { | |
500 | fAlpha = alp; | |
501 | fX = x*ca + p0*sa; | |
502 | fP0= -x*sa + p0*ca; | |
503 | fP2= sf*ca - cf*sa; | |
504 | ||
505 | Double_t rr=(ca+sf/cf*sa); | |
506 | ||
507 | fC00 *= (ca*ca); | |
508 | fC10 *= ca; | |
509 | fC20 *= ca*rr; | |
510 | fC30 *= ca; | |
511 | fC40 *= ca; | |
512 | //fC11 = fC11; | |
513 | fC21 *= rr; | |
514 | //fC31 = fC31; | |
515 | //fC41 = fC41; | |
516 | fC22 *= rr*rr; | |
517 | fC32 *= rr; | |
518 | fC42 *= rr; | |
519 | //fC33=fC33; | |
520 | //fC43=fC43; | |
521 | //fC44=fC44; | |
522 | ||
523 | } | |
524 | ||
525 | // **** translation ****************** | |
526 | { | |
527 | Double_t dx=xk-fX; | |
528 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
529 | if (TMath::Abs(f2) >= 0.98) { | |
530 | // don't propagate highly inclined tracks MI | |
531 | return 0; | |
532 | } | |
533 | // Int_t n=GetNumberOfClusters(); | |
534 | // if (n>kWARN) | |
535 | // Warning("Propagate","Propagation failed (%d) !\n",n); | |
536 | // return 0; | |
537 | //} | |
538 | Double_t lcc=GetLocalConvConst(); | |
539 | ||
540 | Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2); | |
541 | ||
542 | fX=xk; | |
543 | fP0 += dx*(f1+f2)/(r1+r2); | |
544 | fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
545 | fP2 += dx*fP4; | |
546 | ||
547 | //Change of the magnetic field ************* | |
548 | SaveLocalConvConst(); | |
549 | fP4*=lcc/GetLocalConvConst(); | |
550 | ||
551 | //f = F - 1 | |
552 | ||
553 | Double_t f02= dx/(r1*r1*r1); | |
554 | Double_t f04=0.5*dx*dx/(r1*r1*r1); | |
555 | Double_t f12= dx*fP3*f1/(r1*r1*r1); | |
556 | Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1); | |
557 | Double_t f13= dx/r1; | |
558 | Double_t f24= dx; | |
559 | ||
560 | //b = C*ft | |
561 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; | |
562 | Double_t b02=f24*fC40; | |
563 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; | |
564 | Double_t b12=f24*fC41; | |
565 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; | |
566 | Double_t b22=f24*fC42; | |
567 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; | |
568 | Double_t b42=f24*fC44; | |
569 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; | |
570 | Double_t b32=f24*fC43; | |
571 | ||
572 | //a = f*b = f*C*ft | |
573 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42; | |
574 | Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32; | |
575 | Double_t a22=f24*b42; | |
576 | ||
577 | //F*C*Ft = C + (b + bt + a) | |
578 | fC00 += b00 + b00 + a00; | |
579 | fC10 += b10 + b01 + a01; | |
580 | fC20 += b20 + b02 + a02; | |
581 | fC30 += b30; | |
582 | fC40 += b40; | |
583 | fC11 += b11 + b11 + a11; | |
584 | fC21 += b21 + b12 + a12; | |
585 | fC31 += b31; | |
586 | fC41 += b41; | |
587 | fC22 += b22 + b22 + a22; | |
588 | fC32 += b32; | |
589 | fC42 += b42; | |
590 | ||
591 | if (!Invariant()) { | |
592 | fAlpha=alpha; | |
593 | fX=x; | |
594 | fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4; | |
595 | fC00=c00; | |
596 | fC10=c10; fC11=c11; | |
597 | fC20=c20; fC21=c21; fC22=c22; | |
598 | fC30=c30; fC31=c31; fC32=c32; fC33=c33; | |
599 | fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44; | |
600 | return 0; | |
601 | } | |
602 | } | |
603 | ||
604 | return 1; | |
605 | } | |
606 | ||
607 | ||
608 | Double_t AliITStrackV2::GetD(Double_t x, Double_t y) const { | |
609 | //------------------------------------------------------------------ | |
610 | // This function calculates the transverse impact parameter | |
611 | // with respect to a point with global coordinates (x,y) | |
612 | //------------------------------------------------------------------ | |
613 | Double_t xt=fX, yt=fP0; | |
614 | ||
615 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); | |
616 | Double_t a = x*cs + y*sn; | |
617 | y = -x*sn + y*cs; x=a; | |
618 | xt-=x; yt-=y; | |
619 | ||
620 | sn=fP4*xt - fP2; cs=fP4*yt + TMath::Sqrt(1.- fP2*fP2); | |
621 | a=2*(xt*fP2 - yt*TMath::Sqrt(1.- fP2*fP2))-fP4*(xt*xt + yt*yt); | |
622 | if (fP4<0) a=-a; | |
623 | return a/(1 + TMath::Sqrt(sn*sn + cs*cs)); | |
624 | } | |
625 | ||
626 | Double_t AliITStrackV2::GetZat(Double_t x) const { | |
627 | //------------------------------------------------------------------ | |
628 | // This function calculates the z at given x point - in current coordinate system | |
629 | //------------------------------------------------------------------ | |
630 | Double_t x1=fX, x2=x, dx=x2-x1; | |
631 | // | |
632 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
633 | if (TMath::Abs(f2) >= 0.9999) { | |
634 | return 10000000; | |
635 | } | |
636 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); | |
637 | Double_t z = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
638 | return z; | |
639 | } | |
640 | ||
641 | ||
642 | ||
643 | ||
644 | Int_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) { | |
645 | //------------------------------------------------------------------ | |
646 | //This function improves angular track parameters | |
647 | //------------------------------------------------------------------ | |
648 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); | |
649 | //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex | |
650 | Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the | |
651 | Double_t zv = xyz[2]; // local frame | |
652 | Double_t dy=fP0-yv, dz=fP1-zv; | |
653 | Double_t r2=fX*fX+dy*dy; | |
654 | Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); | |
655 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); | |
656 | x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp())); | |
657 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0; | |
658 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33; | |
659 | { | |
660 | Double_t dummy=4/r2-fP4*fP4; | |
661 | if (dummy < 0) return 0; | |
662 | Double_t parp=0.5*(fP4*fX + dy*TMath::Sqrt(dummy)); | |
663 | Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl()); | |
664 | sigma2p += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2); | |
665 | sigma2p += ers[1]*ers[1]/r2; | |
666 | sigma2p += 0.25*fC44*fX*fX; | |
667 | Double_t eps2p=sigma2p/(fC22+sigma2p); | |
668 | fP0 += fC20/(fC22+sigma2p)*(parp-fP2); | |
669 | fP2 = eps2p*fP2 + (1-eps2p)*parp; | |
670 | fC22 *= eps2p; | |
671 | fC20 *= eps2p; | |
672 | } | |
673 | { | |
674 | Double_t parl=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2)); | |
675 | Double_t sigma2l=theta2; | |
676 | sigma2l += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2); | |
677 | sigma2l += ers[2]*ers[2]/r2; | |
678 | Double_t eps2l=sigma2l/(fC33+sigma2l); | |
679 | fP1 += fC31/(fC33+sigma2l)*(parl-fP3); | |
680 | fP4 += fC43/(fC33+sigma2l)*(parl-fP3); | |
681 | fP3 = eps2l*fP3 + (1-eps2l)*parl; | |
682 | fC33 *= eps2l; fC43 *= eps2l; | |
683 | fC31 *= eps2l; | |
684 | } | |
685 | if (!Invariant()) return 0; | |
686 | return 1; | |
687 | } | |
688 | ||
689 | void AliITStrackV2::ResetCovariance() { | |
690 | //------------------------------------------------------------------ | |
691 | //This function makes a track forget its history :) | |
692 | //------------------------------------------------------------------ | |
693 | ||
694 | fC00*=10.; | |
695 | fC10=0.; fC11*=10.; | |
696 | fC20=0.; fC21=0.; fC22*=10.; | |
697 | fC30=0.; fC31=0.; fC32=0.; fC33*=10.; | |
698 | fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.; | |
699 | ||
700 | } | |
701 | ||
702 | void AliITStrackV2::CookdEdx(Double_t low, Double_t up) { | |
703 | //----------------------------------------------------------------- | |
704 | // This function calculates dE/dX within the "low" and "up" cuts. | |
705 | // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch | |
706 | //----------------------------------------------------------------- | |
707 | // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1 | |
708 | ||
709 | Int_t i; | |
710 | Int_t nc=0; | |
711 | for (i=0; i<GetNumberOfClusters(); i++) { | |
712 | Int_t idx=GetClusterIndex(i); | |
713 | idx=(idx&0xf0000000)>>28; | |
714 | if (idx>1) nc++; // Take only SSD and SDD | |
715 | } | |
716 | ||
717 | Int_t swap;//stupid sorting | |
718 | do { | |
719 | swap=0; | |
720 | for (i=0; i<nc-1; i++) { | |
721 | if (fdEdxSample[i]<=fdEdxSample[i+1]) continue; | |
722 | Float_t tmp=fdEdxSample[i]; | |
723 | fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp; | |
724 | swap++; | |
725 | } | |
726 | } while (swap); | |
727 | ||
728 | Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX | |
729 | // values from four ones choose | |
730 | // nu=2 | |
731 | Float_t dedx=0; | |
732 | for (i=nl; i<nu; i++) dedx += fdEdxSample[i]; | |
733 | if (nu-nl>0) dedx /= (nu-nl); | |
734 | ||
735 | SetdEdx(dedx); | |
736 | } | |
737 | ||
738 | Double_t AliITStrackV2:: | |
739 | PropagateToDCA(AliKalmanTrack *p, Double_t d, Double_t x0) { | |
740 | //-------------------------------------------------------------- | |
741 | // Propagates this track and the argument track to the position of the | |
742 | // distance of closest approach. | |
743 | // Returns the (weighed !) distance of closest approach. | |
744 | //-------------------------------------------------------------- | |
745 | Double_t xthis, xp, dca; | |
746 | { | |
747 | //Temporary solution | |
748 | Double_t b=1./GetLocalConvConst()/kB2C; | |
749 | AliExternalTrackParam dummy1(*this), dummy2(*p); | |
750 | dca=dummy1.GetDCA(&dummy2,b,xthis,xp); | |
751 | } | |
752 | if (!PropagateTo(xthis,d,x0)) { | |
753 | //AliWarning(" propagation failed !"); | |
754 | return 1e+33; | |
755 | } | |
756 | ||
757 | if (!p->PropagateTo(xp,d,x0)) { | |
758 | //AliWarning(" propagation failed !"; | |
759 | return 1e+33; | |
760 | } | |
761 | ||
762 | return dca; | |
763 | } |