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51ad6848 | 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 | /* $Id$ */ | |
17 | ||
18 | /////////////////////////////////////////////////////////////////////////////// | |
19 | // // | |
49d13e89 | 20 | // Implementation of the external track parameterisation class. // |
51ad6848 | 21 | // // |
49d13e89 | 22 | // This parameterisation is used to exchange tracks between the detectors. // |
23 | // A set of functions returning the position and the momentum of tracks // | |
24 | // in the global coordinate system as well as the track impact parameters // | |
25 | // are implemented. | |
26 | // Origin: I.Belikov, CERN, Jouri.Belikov@cern.ch // | |
51ad6848 | 27 | /////////////////////////////////////////////////////////////////////////////// |
51ad6848 | 28 | #include "AliExternalTrackParam.h" |
29 | #include "AliKalmanTrack.h" | |
f76701bf | 30 | #include "AliESDVertex.h" |
5b77d93c | 31 | |
51ad6848 | 32 | |
33 | ClassImp(AliExternalTrackParam) | |
34 | ||
51ad6848 | 35 | //_____________________________________________________________________________ |
90e48c0c | 36 | AliExternalTrackParam::AliExternalTrackParam() : |
90e48c0c | 37 | fX(0), |
c9ec41e8 | 38 | fAlpha(0) |
51ad6848 | 39 | { |
90e48c0c | 40 | // |
41 | // default constructor | |
42 | // | |
c9ec41e8 | 43 | for (Int_t i = 0; i < 5; i++) fP[i] = 0; |
44 | for (Int_t i = 0; i < 15; i++) fC[i] = 0; | |
51ad6848 | 45 | } |
46 | ||
47 | //_____________________________________________________________________________ | |
48 | AliExternalTrackParam::AliExternalTrackParam(Double_t x, Double_t alpha, | |
49 | const Double_t param[5], | |
90e48c0c | 50 | const Double_t covar[15]) : |
90e48c0c | 51 | fX(x), |
c9ec41e8 | 52 | fAlpha(alpha) |
51ad6848 | 53 | { |
90e48c0c | 54 | // |
55 | // create external track parameters from given arguments | |
56 | // | |
c9ec41e8 | 57 | for (Int_t i = 0; i < 5; i++) fP[i] = param[i]; |
58 | for (Int_t i = 0; i < 15; i++) fC[i] = covar[i]; | |
51ad6848 | 59 | } |
60 | ||
90e48c0c | 61 | //_____________________________________________________________________________ |
62 | AliExternalTrackParam::AliExternalTrackParam(const AliKalmanTrack& track) : | |
fe12e09c | 63 | fX(0), |
c9ec41e8 | 64 | fAlpha(track.GetAlpha()) |
51ad6848 | 65 | { |
66 | // | |
67 | // | |
c9ec41e8 | 68 | track.GetExternalParameters(fX,fP); |
69 | track.GetExternalCovariance(fC); | |
51ad6848 | 70 | } |
71 | ||
51ad6848 | 72 | //_____________________________________________________________________________ |
c9ec41e8 | 73 | void AliExternalTrackParam::Set(const AliKalmanTrack& track) { |
74 | // | |
75 | // | |
76 | fAlpha=track.GetAlpha(); | |
77 | track.GetExternalParameters(fX,fP); | |
78 | track.GetExternalCovariance(fC); | |
51ad6848 | 79 | } |
80 | ||
81 | //_____________________________________________________________________________ | |
c9ec41e8 | 82 | void AliExternalTrackParam::Reset() { |
1530f89c | 83 | // |
84 | // Resets all the parameters to 0 | |
85 | // | |
c9ec41e8 | 86 | fX=fAlpha=0.; |
87 | for (Int_t i = 0; i < 5; i++) fP[i] = 0; | |
88 | for (Int_t i = 0; i < 15; i++) fC[i] = 0; | |
51ad6848 | 89 | } |
90 | ||
c9ec41e8 | 91 | Double_t AliExternalTrackParam::GetP() const { |
92 | //--------------------------------------------------------------------- | |
93 | // This function returns the track momentum | |
94 | // Results for (nearly) straight tracks are meaningless ! | |
95 | //--------------------------------------------------------------------- | |
06fb4a2f | 96 | if (TMath::Abs(fP[4])<=kAlmost0) return kVeryBig; |
c9ec41e8 | 97 | return TMath::Sqrt(1.+ fP[3]*fP[3])/TMath::Abs(fP[4]); |
51ad6848 | 98 | } |
99 | ||
1d99986f | 100 | Double_t AliExternalTrackParam::Get1P() const { |
101 | //--------------------------------------------------------------------- | |
102 | // This function returns the 1/(track momentum) | |
103 | //--------------------------------------------------------------------- | |
104 | return TMath::Abs(fP[4])/TMath::Sqrt(1.+ fP[3]*fP[3]); | |
105 | } | |
106 | ||
c9ec41e8 | 107 | //_______________________________________________________________________ |
c7bafca9 | 108 | Double_t AliExternalTrackParam::GetD(Double_t x,Double_t y,Double_t b) const { |
c9ec41e8 | 109 | //------------------------------------------------------------------ |
110 | // This function calculates the transverse impact parameter | |
111 | // with respect to a point with global coordinates (x,y) | |
112 | // in the magnetic field "b" (kG) | |
113 | //------------------------------------------------------------------ | |
5773defd | 114 | if (TMath::Abs(b) < kAlmost0Field) return GetLinearD(x,y); |
1530f89c | 115 | Double_t rp4=GetC(b); |
c9ec41e8 | 116 | |
117 | Double_t xt=fX, yt=fP[0]; | |
118 | ||
119 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); | |
120 | Double_t a = x*cs + y*sn; | |
121 | y = -x*sn + y*cs; x=a; | |
122 | xt-=x; yt-=y; | |
123 | ||
124 | sn=rp4*xt - fP[2]; cs=rp4*yt + TMath::Sqrt(1.- fP[2]*fP[2]); | |
125 | a=2*(xt*fP[2] - yt*TMath::Sqrt(1.- fP[2]*fP[2]))-rp4*(xt*xt + yt*yt); | |
1530f89c | 126 | return -a/(1 + TMath::Sqrt(sn*sn + cs*cs)); |
127 | } | |
128 | ||
129 | //_______________________________________________________________________ | |
130 | void AliExternalTrackParam:: | |
131 | GetDZ(Double_t x, Double_t y, Double_t z, Double_t b, Float_t dz[2]) const { | |
132 | //------------------------------------------------------------------ | |
133 | // This function calculates the transverse and longitudinal impact parameters | |
134 | // with respect to a point with global coordinates (x,y) | |
135 | // in the magnetic field "b" (kG) | |
136 | //------------------------------------------------------------------ | |
137 | Double_t f1 = fP[2], r1 = TMath::Sqrt(1. - f1*f1); | |
138 | Double_t xt=fX, yt=fP[0]; | |
139 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); | |
140 | Double_t a = x*cs + y*sn; | |
141 | y = -x*sn + y*cs; x=a; | |
142 | xt-=x; yt-=y; | |
143 | ||
144 | Double_t rp4=GetC(b); | |
145 | if ((TMath::Abs(b) < kAlmost0Field) || (TMath::Abs(rp4) < kAlmost0)) { | |
146 | dz[0] = -(xt*f1 - yt*r1); | |
147 | dz[1] = fP[1] + (dz[0]*f1 - xt)/r1*fP[3] - z; | |
148 | return; | |
149 | } | |
150 | ||
151 | sn=rp4*xt - f1; cs=rp4*yt + r1; | |
152 | a=2*(xt*f1 - yt*r1)-rp4*(xt*xt + yt*yt); | |
153 | Double_t rr=TMath::Sqrt(sn*sn + cs*cs); | |
154 | dz[0] = -a/(1 + rr); | |
155 | Double_t f2 = -sn/rr, r2 = TMath::Sqrt(1. - f2*f2); | |
156 | dz[1] = fP[1] + fP[3]/rp4*TMath::ASin(f2*r1 - f1*r2) - z; | |
51ad6848 | 157 | } |
158 | ||
49d13e89 | 159 | //_______________________________________________________________________ |
160 | Double_t AliExternalTrackParam::GetLinearD(Double_t xv,Double_t yv) const { | |
161 | //------------------------------------------------------------------ | |
162 | // This function calculates the transverse impact parameter | |
163 | // with respect to a point with global coordinates (xv,yv) | |
164 | // neglecting the track curvature. | |
165 | //------------------------------------------------------------------ | |
166 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); | |
167 | Double_t x= xv*cs + yv*sn; | |
168 | Double_t y=-xv*sn + yv*cs; | |
169 | ||
170 | Double_t d = (fX-x)*fP[2] - (fP[0]-y)*TMath::Sqrt(1.- fP[2]*fP[2]); | |
171 | ||
1530f89c | 172 | return -d; |
49d13e89 | 173 | } |
174 | ||
c7bafca9 | 175 | Bool_t AliExternalTrackParam:: |
176 | CorrectForMaterial(Double_t d, Double_t x0, Double_t mass) { | |
177 | //------------------------------------------------------------------ | |
178 | // This function corrects the track parameters for the crossed material | |
179 | // "d" - the thickness (fraction of the radiation length) | |
180 | // "x0" - the radiation length (g/cm^2) | |
181 | // "mass" - the mass of this particle (GeV/c^2) | |
182 | //------------------------------------------------------------------ | |
183 | Double_t &fP2=fP[2]; | |
184 | Double_t &fP3=fP[3]; | |
185 | Double_t &fP4=fP[4]; | |
186 | ||
187 | Double_t &fC22=fC[5]; | |
188 | Double_t &fC33=fC[9]; | |
189 | Double_t &fC43=fC[13]; | |
190 | Double_t &fC44=fC[14]; | |
191 | ||
192 | Double_t p2=(1.+ fP3*fP3)/(fP4*fP4); | |
193 | Double_t beta2=p2/(p2 + mass*mass); | |
194 | d*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2)); | |
195 | ||
196 | //Multiple scattering****************** | |
197 | if (d!=0) { | |
198 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d); | |
199 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33; | |
200 | fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3); | |
201 | fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3); | |
202 | fC43 += theta2*fP3*fP4*(1. + fP3*fP3); | |
203 | fC44 += theta2*fP3*fP4*fP3*fP4; | |
204 | } | |
205 | ||
206 | //Energy losses************************ | |
8fc1985d | 207 | if (x0!=0. && beta2<1) { |
c7bafca9 | 208 | d*=x0; |
209 | Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d; | |
210 | if (beta2/(1-beta2)>3.5*3.5) | |
211 | dE=0.153e-3/beta2*(log(3.5*5940)+0.5*log(beta2/(1-beta2)) - beta2)*d; | |
212 | ||
213 | fP4*=(1.- TMath::Sqrt(p2 + mass*mass)/p2*dE); | |
214 | } | |
215 | ||
216 | return kTRUE; | |
217 | } | |
218 | ||
49d13e89 | 219 | Bool_t AliExternalTrackParam::Rotate(Double_t alpha) { |
220 | //------------------------------------------------------------------ | |
221 | // Transform this track to the local coord. system rotated | |
222 | // by angle "alpha" (rad) with respect to the global coord. system. | |
223 | //------------------------------------------------------------------ | |
dfcef74c | 224 | if (TMath::Abs(fP[2]) >= kAlmost1) { |
225 | AliError(Form("Precondition is not satisfied: |sin(phi)|>1 ! %f",fP[2])); | |
226 | return kFALSE; | |
227 | } | |
228 | ||
49d13e89 | 229 | if (alpha < -TMath::Pi()) alpha += 2*TMath::Pi(); |
230 | else if (alpha >= TMath::Pi()) alpha -= 2*TMath::Pi(); | |
231 | ||
232 | Double_t &fP0=fP[0]; | |
233 | Double_t &fP2=fP[2]; | |
234 | Double_t &fC00=fC[0]; | |
235 | Double_t &fC10=fC[1]; | |
236 | Double_t &fC20=fC[3]; | |
237 | Double_t &fC21=fC[4]; | |
238 | Double_t &fC22=fC[5]; | |
239 | Double_t &fC30=fC[6]; | |
240 | Double_t &fC32=fC[8]; | |
241 | Double_t &fC40=fC[10]; | |
242 | Double_t &fC42=fC[12]; | |
243 | ||
244 | Double_t x=fX; | |
245 | Double_t ca=TMath::Cos(alpha-fAlpha), sa=TMath::Sin(alpha-fAlpha); | |
246 | Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2); | |
247 | ||
dfcef74c | 248 | Double_t tmp=sf*ca - cf*sa; |
249 | if (TMath::Abs(tmp) >= kAlmost1) return kFALSE; | |
250 | ||
49d13e89 | 251 | fAlpha = alpha; |
252 | fX = x*ca + fP0*sa; | |
253 | fP0= -x*sa + fP0*ca; | |
dfcef74c | 254 | fP2= tmp; |
49d13e89 | 255 | |
06fb4a2f | 256 | if (TMath::Abs(cf)<kAlmost0) { |
257 | AliError(Form("Too small cosine value %f",cf)); | |
258 | cf = kAlmost0; | |
259 | } | |
260 | ||
49d13e89 | 261 | Double_t rr=(ca+sf/cf*sa); |
262 | ||
263 | fC00 *= (ca*ca); | |
264 | fC10 *= ca; | |
265 | fC20 *= ca*rr; | |
266 | fC21 *= rr; | |
267 | fC22 *= rr*rr; | |
268 | fC30 *= ca; | |
269 | fC32 *= rr; | |
270 | fC40 *= ca; | |
271 | fC42 *= rr; | |
272 | ||
273 | return kTRUE; | |
274 | } | |
275 | ||
276 | Bool_t AliExternalTrackParam::PropagateTo(Double_t xk, Double_t b) { | |
277 | //---------------------------------------------------------------- | |
278 | // Propagate this track to the plane X=xk (cm) in the field "b" (kG) | |
279 | //---------------------------------------------------------------- | |
49d13e89 | 280 | Double_t dx=xk-fX; |
e421f556 | 281 | if (TMath::Abs(dx)<=kAlmost0) return kTRUE; |
18ebc5ef | 282 | |
1530f89c | 283 | Double_t crv=GetC(b); |
5773defd | 284 | if (TMath::Abs(b) < kAlmost0Field) crv=0.; |
285 | ||
49d13e89 | 286 | Double_t f1=fP[2], f2=f1 + crv*dx; |
bbefa4c4 | 287 | if (TMath::Abs(f1) >= kAlmost1) return kFALSE; |
49d13e89 | 288 | if (TMath::Abs(f2) >= kAlmost1) return kFALSE; |
289 | ||
290 | Double_t &fP0=fP[0], &fP1=fP[1], &fP2=fP[2], &fP3=fP[3], &fP4=fP[4]; | |
291 | Double_t | |
292 | &fC00=fC[0], | |
293 | &fC10=fC[1], &fC11=fC[2], | |
294 | &fC20=fC[3], &fC21=fC[4], &fC22=fC[5], | |
295 | &fC30=fC[6], &fC31=fC[7], &fC32=fC[8], &fC33=fC[9], | |
296 | &fC40=fC[10], &fC41=fC[11], &fC42=fC[12], &fC43=fC[13], &fC44=fC[14]; | |
297 | ||
298 | Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2); | |
299 | ||
300 | fX=xk; | |
301 | fP0 += dx*(f1+f2)/(r1+r2); | |
18ebc5ef | 302 | fP1 += dx*(r2 + f2*(f1+f2)/(r1+r2))*fP3; // Many thanks to P.Hristov ! |
49d13e89 | 303 | fP2 += dx*crv; |
304 | ||
305 | //f = F - 1 | |
306 | ||
307 | Double_t f02= dx/(r1*r1*r1); Double_t cc=crv/fP4; | |
308 | Double_t f04=0.5*dx*dx/(r1*r1*r1); f04*=cc; | |
309 | Double_t f12= dx*fP3*f1/(r1*r1*r1); | |
310 | Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1); f14*=cc; | |
311 | Double_t f13= dx/r1; | |
312 | Double_t f24= dx; f24*=cc; | |
313 | ||
314 | //b = C*ft | |
315 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; | |
316 | Double_t b02=f24*fC40; | |
317 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; | |
318 | Double_t b12=f24*fC41; | |
319 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; | |
320 | Double_t b22=f24*fC42; | |
321 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; | |
322 | Double_t b42=f24*fC44; | |
323 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; | |
324 | Double_t b32=f24*fC43; | |
325 | ||
326 | //a = f*b = f*C*ft | |
327 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42; | |
328 | Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32; | |
329 | Double_t a22=f24*b42; | |
330 | ||
331 | //F*C*Ft = C + (b + bt + a) | |
332 | fC00 += b00 + b00 + a00; | |
333 | fC10 += b10 + b01 + a01; | |
334 | fC20 += b20 + b02 + a02; | |
335 | fC30 += b30; | |
336 | fC40 += b40; | |
337 | fC11 += b11 + b11 + a11; | |
338 | fC21 += b21 + b12 + a12; | |
339 | fC31 += b31; | |
340 | fC41 += b41; | |
341 | fC22 += b22 + b22 + a22; | |
342 | fC32 += b32; | |
343 | fC42 += b42; | |
344 | ||
345 | return kTRUE; | |
346 | } | |
347 | ||
348 | Double_t | |
349 | AliExternalTrackParam::GetPredictedChi2(Double_t p[2],Double_t cov[3]) const { | |
350 | //---------------------------------------------------------------- | |
351 | // Estimate the chi2 of the space point "p" with the cov. matrix "cov" | |
352 | //---------------------------------------------------------------- | |
353 | Double_t sdd = fC[0] + cov[0]; | |
354 | Double_t sdz = fC[1] + cov[1]; | |
355 | Double_t szz = fC[2] + cov[2]; | |
356 | Double_t det = sdd*szz - sdz*sdz; | |
357 | ||
358 | if (TMath::Abs(det) < kAlmost0) return kVeryBig; | |
359 | ||
360 | Double_t d = fP[0] - p[0]; | |
361 | Double_t z = fP[1] - p[1]; | |
362 | ||
363 | return (d*szz*d - 2*d*sdz*z + z*sdd*z)/det; | |
364 | } | |
365 | ||
366 | Bool_t AliExternalTrackParam::Update(Double_t p[2], Double_t cov[3]) { | |
367 | //------------------------------------------------------------------ | |
368 | // Update the track parameters with the space point "p" having | |
369 | // the covariance matrix "cov" | |
370 | //------------------------------------------------------------------ | |
371 | Double_t &fP0=fP[0], &fP1=fP[1], &fP2=fP[2], &fP3=fP[3], &fP4=fP[4]; | |
372 | Double_t | |
373 | &fC00=fC[0], | |
374 | &fC10=fC[1], &fC11=fC[2], | |
375 | &fC20=fC[3], &fC21=fC[4], &fC22=fC[5], | |
376 | &fC30=fC[6], &fC31=fC[7], &fC32=fC[8], &fC33=fC[9], | |
377 | &fC40=fC[10], &fC41=fC[11], &fC42=fC[12], &fC43=fC[13], &fC44=fC[14]; | |
378 | ||
379 | Double_t r00=cov[0], r01=cov[1], r11=cov[2]; | |
380 | r00+=fC00; r01+=fC10; r11+=fC11; | |
381 | Double_t det=r00*r11 - r01*r01; | |
382 | ||
383 | if (TMath::Abs(det) < kAlmost0) return kFALSE; | |
384 | ||
385 | ||
386 | Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det; | |
387 | ||
388 | Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11; | |
389 | Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11; | |
390 | Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11; | |
391 | Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11; | |
392 | Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11; | |
393 | ||
394 | Double_t dy=p[0] - fP0, dz=p[1] - fP1; | |
395 | Double_t sf=fP2 + k20*dy + k21*dz; | |
396 | if (TMath::Abs(sf) > kAlmost1) return kFALSE; | |
397 | ||
398 | fP0 += k00*dy + k01*dz; | |
399 | fP1 += k10*dy + k11*dz; | |
400 | fP2 = sf; | |
401 | fP3 += k30*dy + k31*dz; | |
402 | fP4 += k40*dy + k41*dz; | |
403 | ||
404 | Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40; | |
405 | Double_t c12=fC21, c13=fC31, c14=fC41; | |
406 | ||
407 | fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11; | |
408 | fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13; | |
409 | fC40-=k00*c04+k01*c14; | |
410 | ||
411 | fC11-=k10*c01+k11*fC11; | |
412 | fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13; | |
413 | fC41-=k10*c04+k11*c14; | |
414 | ||
415 | fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13; | |
416 | fC42-=k20*c04+k21*c14; | |
417 | ||
418 | fC33-=k30*c03+k31*c13; | |
419 | fC43-=k30*c04+k31*c14; | |
420 | ||
421 | fC44-=k40*c04+k41*c14; | |
422 | ||
423 | return kTRUE; | |
424 | } | |
425 | ||
c7bafca9 | 426 | void |
427 | AliExternalTrackParam::GetHelixParameters(Double_t hlx[6], Double_t b) const { | |
428 | //-------------------------------------------------------------------- | |
429 | // External track parameters -> helix parameters | |
430 | // "b" - magnetic field (kG) | |
431 | //-------------------------------------------------------------------- | |
432 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); | |
433 | ||
1530f89c | 434 | hlx[0]=fP[0]; hlx[1]=fP[1]; hlx[2]=fP[2]; hlx[3]=fP[3]; |
c7bafca9 | 435 | |
436 | hlx[5]=fX*cs - hlx[0]*sn; // x0 | |
437 | hlx[0]=fX*sn + hlx[0]*cs; // y0 | |
438 | //hlx[1]= // z0 | |
439 | hlx[2]=TMath::ASin(hlx[2]) + fAlpha; // phi0 | |
440 | //hlx[3]= // tgl | |
1530f89c | 441 | hlx[4]=GetC(b); // C |
c7bafca9 | 442 | } |
443 | ||
444 | ||
445 | static void Evaluate(const Double_t *h, Double_t t, | |
446 | Double_t r[3], //radius vector | |
447 | Double_t g[3], //first defivatives | |
448 | Double_t gg[3]) //second derivatives | |
449 | { | |
450 | //-------------------------------------------------------------------- | |
451 | // Calculate position of a point on a track and some derivatives | |
452 | //-------------------------------------------------------------------- | |
453 | Double_t phase=h[4]*t+h[2]; | |
454 | Double_t sn=TMath::Sin(phase), cs=TMath::Cos(phase); | |
455 | ||
456 | r[0] = h[5] + (sn - h[6])/h[4]; | |
457 | r[1] = h[0] - (cs - h[7])/h[4]; | |
458 | r[2] = h[1] + h[3]*t; | |
459 | ||
460 | g[0] = cs; g[1]=sn; g[2]=h[3]; | |
461 | ||
462 | gg[0]=-h[4]*sn; gg[1]=h[4]*cs; gg[2]=0.; | |
463 | } | |
464 | ||
465 | Double_t AliExternalTrackParam::GetDCA(const AliExternalTrackParam *p, | |
466 | Double_t b, Double_t &xthis, Double_t &xp) const { | |
467 | //------------------------------------------------------------ | |
468 | // Returns the (weighed !) distance of closest approach between | |
469 | // this track and the track "p". | |
470 | // Other returned values: | |
471 | // xthis, xt - coordinates of tracks' reference planes at the DCA | |
472 | //----------------------------------------------------------- | |
473 | Double_t dy2=GetSigmaY2() + p->GetSigmaY2(); | |
474 | Double_t dz2=GetSigmaZ2() + p->GetSigmaZ2(); | |
475 | Double_t dx2=dy2; | |
476 | ||
477 | //dx2=dy2=dz2=1.; | |
478 | ||
479 | Double_t p1[8]; GetHelixParameters(p1,b); | |
480 | p1[6]=TMath::Sin(p1[2]); p1[7]=TMath::Cos(p1[2]); | |
481 | Double_t p2[8]; p->GetHelixParameters(p2,b); | |
482 | p2[6]=TMath::Sin(p2[2]); p2[7]=TMath::Cos(p2[2]); | |
483 | ||
484 | ||
485 | Double_t r1[3],g1[3],gg1[3]; Double_t t1=0.; | |
486 | Evaluate(p1,t1,r1,g1,gg1); | |
487 | Double_t r2[3],g2[3],gg2[3]; Double_t t2=0.; | |
488 | Evaluate(p2,t2,r2,g2,gg2); | |
489 | ||
490 | Double_t dx=r2[0]-r1[0], dy=r2[1]-r1[1], dz=r2[2]-r1[2]; | |
491 | Double_t dm=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2; | |
492 | ||
493 | Int_t max=27; | |
494 | while (max--) { | |
495 | Double_t gt1=-(dx*g1[0]/dx2 + dy*g1[1]/dy2 + dz*g1[2]/dz2); | |
496 | Double_t gt2=+(dx*g2[0]/dx2 + dy*g2[1]/dy2 + dz*g2[2]/dz2); | |
497 | Double_t h11=(g1[0]*g1[0] - dx*gg1[0])/dx2 + | |
498 | (g1[1]*g1[1] - dy*gg1[1])/dy2 + | |
499 | (g1[2]*g1[2] - dz*gg1[2])/dz2; | |
500 | Double_t h22=(g2[0]*g2[0] + dx*gg2[0])/dx2 + | |
501 | (g2[1]*g2[1] + dy*gg2[1])/dy2 + | |
502 | (g2[2]*g2[2] + dz*gg2[2])/dz2; | |
503 | Double_t h12=-(g1[0]*g2[0]/dx2 + g1[1]*g2[1]/dy2 + g1[2]*g2[2]/dz2); | |
504 | ||
505 | Double_t det=h11*h22-h12*h12; | |
506 | ||
507 | Double_t dt1,dt2; | |
508 | if (TMath::Abs(det)<1.e-33) { | |
509 | //(quasi)singular Hessian | |
510 | dt1=-gt1; dt2=-gt2; | |
511 | } else { | |
512 | dt1=-(gt1*h22 - gt2*h12)/det; | |
513 | dt2=-(h11*gt2 - h12*gt1)/det; | |
514 | } | |
515 | ||
516 | if ((dt1*gt1+dt2*gt2)>0) {dt1=-dt1; dt2=-dt2;} | |
517 | ||
518 | //check delta(phase1) ? | |
519 | //check delta(phase2) ? | |
520 | ||
521 | if (TMath::Abs(dt1)/(TMath::Abs(t1)+1.e-3) < 1.e-4) | |
522 | if (TMath::Abs(dt2)/(TMath::Abs(t2)+1.e-3) < 1.e-4) { | |
523 | if ((gt1*gt1+gt2*gt2) > 1.e-4/dy2/dy2) | |
524 | AliWarning(" stopped at not a stationary point !"); | |
525 | Double_t lmb=h11+h22; lmb=lmb-TMath::Sqrt(lmb*lmb-4*det); | |
526 | if (lmb < 0.) | |
527 | AliWarning(" stopped at not a minimum !"); | |
528 | break; | |
529 | } | |
530 | ||
531 | Double_t dd=dm; | |
532 | for (Int_t div=1 ; ; div*=2) { | |
533 | Evaluate(p1,t1+dt1,r1,g1,gg1); | |
534 | Evaluate(p2,t2+dt2,r2,g2,gg2); | |
535 | dx=r2[0]-r1[0]; dy=r2[1]-r1[1]; dz=r2[2]-r1[2]; | |
536 | dd=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2; | |
537 | if (dd<dm) break; | |
538 | dt1*=0.5; dt2*=0.5; | |
539 | if (div>512) { | |
540 | AliWarning(" overshoot !"); break; | |
541 | } | |
542 | } | |
543 | dm=dd; | |
544 | ||
545 | t1+=dt1; | |
546 | t2+=dt2; | |
547 | ||
548 | } | |
549 | ||
550 | if (max<=0) AliWarning(" too many iterations !"); | |
551 | ||
552 | Double_t cs=TMath::Cos(GetAlpha()); | |
553 | Double_t sn=TMath::Sin(GetAlpha()); | |
554 | xthis=r1[0]*cs + r1[1]*sn; | |
555 | ||
556 | cs=TMath::Cos(p->GetAlpha()); | |
557 | sn=TMath::Sin(p->GetAlpha()); | |
558 | xp=r2[0]*cs + r2[1]*sn; | |
559 | ||
560 | return TMath::Sqrt(dm*TMath::Sqrt(dy2*dz2)); | |
561 | } | |
562 | ||
563 | Double_t AliExternalTrackParam:: | |
564 | PropagateToDCA(AliExternalTrackParam *p, Double_t b) { | |
565 | //-------------------------------------------------------------- | |
566 | // Propagates this track and the argument track to the position of the | |
567 | // distance of closest approach. | |
568 | // Returns the (weighed !) distance of closest approach. | |
569 | //-------------------------------------------------------------- | |
570 | Double_t xthis,xp; | |
571 | Double_t dca=GetDCA(p,b,xthis,xp); | |
572 | ||
573 | if (!PropagateTo(xthis,b)) { | |
574 | //AliWarning(" propagation failed !"); | |
575 | return 1e+33; | |
576 | } | |
577 | ||
578 | if (!p->PropagateTo(xp,b)) { | |
579 | //AliWarning(" propagation failed !"; | |
580 | return 1e+33; | |
581 | } | |
582 | ||
583 | return dca; | |
584 | } | |
585 | ||
586 | ||
587 | ||
f76701bf | 588 | |
589 | Bool_t AliExternalTrackParam::PropagateToDCA(const AliESDVertex *vtx, Double_t b, Double_t maxd){ | |
590 | // | |
591 | // Try to relate this track to the vertex "vtx", | |
592 | // if the (rough) transverse impact parameter is not bigger then "maxd". | |
593 | // Magnetic field is "b" (kG). | |
594 | // | |
595 | // a) The track gets extapolated to the DCA to the vertex. | |
596 | // b) The impact parameters and their covariance matrix are calculated. | |
597 | // | |
598 | // In the case of success, the returned value is kTRUE | |
599 | // (otherwise, it's kFALSE) | |
600 | // | |
601 | Double_t alpha=GetAlpha(); | |
602 | Double_t sn=TMath::Sin(alpha), cs=TMath::Cos(alpha); | |
603 | Double_t x=GetX(), y=GetParameter()[0], snp=GetParameter()[2]; | |
604 | Double_t xv= vtx->GetXv()*cs + vtx->GetYv()*sn; | |
29fbcc93 | 605 | Double_t yv=-vtx->GetXv()*sn + vtx->GetYv()*cs; |
f76701bf | 606 | x-=xv; y-=yv; |
607 | ||
608 | //Estimate the impact parameter neglecting the track curvature | |
609 | Double_t d=TMath::Abs(x*snp - y*TMath::Sqrt(1.- snp*snp)); | |
610 | if (d > maxd) return kFALSE; | |
611 | ||
612 | //Propagate to the DCA | |
613 | Double_t crv=0.299792458e-3*b*GetParameter()[4]; | |
614 | Double_t tgfv=-(crv*x - snp)/(crv*y + TMath::Sqrt(1.-snp*snp)); | |
615 | sn=tgfv/TMath::Sqrt(1.+ tgfv*tgfv); cs=TMath::Sqrt(1.- sn*sn); | |
616 | ||
617 | x = xv*cs + yv*sn; | |
618 | yv=-xv*sn + yv*cs; xv=x; | |
619 | ||
620 | if (!Propagate(alpha+TMath::ASin(sn),xv,b)) return kFALSE; | |
29fbcc93 | 621 | return kTRUE; |
f76701bf | 622 | } |
623 | ||
624 | ||
625 | ||
626 | ||
c9ec41e8 | 627 | Bool_t Local2GlobalMomentum(Double_t p[3],Double_t alpha) { |
628 | //---------------------------------------------------------------- | |
629 | // This function performs local->global transformation of the | |
630 | // track momentum. | |
631 | // When called, the arguments are: | |
632 | // p[0] = 1/pt of the track; | |
633 | // p[1] = sine of local azim. angle of the track momentum; | |
634 | // p[2] = tangent of the track momentum dip angle; | |
635 | // alpha - rotation angle. | |
636 | // The result is returned as: | |
637 | // p[0] = px | |
638 | // p[1] = py | |
639 | // p[2] = pz | |
640 | // Results for (nearly) straight tracks are meaningless ! | |
641 | //---------------------------------------------------------------- | |
e421f556 | 642 | if (TMath::Abs(p[0])<=kAlmost0) return kFALSE; |
49d13e89 | 643 | if (TMath::Abs(p[1])> kAlmost1) return kFALSE; |
c9ec41e8 | 644 | |
645 | Double_t pt=1./TMath::Abs(p[0]); | |
646 | Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha); | |
647 | Double_t r=TMath::Sqrt(1 - p[1]*p[1]); | |
648 | p[0]=pt*(r*cs - p[1]*sn); p[1]=pt*(p[1]*cs + r*sn); p[2]=pt*p[2]; | |
a5e407e9 | 649 | |
650 | return kTRUE; | |
651 | } | |
652 | ||
c9ec41e8 | 653 | Bool_t Local2GlobalPosition(Double_t r[3],Double_t alpha) { |
654 | //---------------------------------------------------------------- | |
655 | // This function performs local->global transformation of the | |
656 | // track position. | |
657 | // When called, the arguments are: | |
658 | // r[0] = local x | |
659 | // r[1] = local y | |
660 | // r[2] = local z | |
661 | // alpha - rotation angle. | |
662 | // The result is returned as: | |
663 | // r[0] = global x | |
664 | // r[1] = global y | |
665 | // r[2] = global z | |
666 | //---------------------------------------------------------------- | |
667 | Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha), x=r[0]; | |
668 | r[0]=x*cs - r[1]*sn; r[1]=x*sn + r[1]*cs; | |
a5e407e9 | 669 | |
a5e407e9 | 670 | return kTRUE; |
51ad6848 | 671 | } |
672 | ||
c9ec41e8 | 673 | Bool_t AliExternalTrackParam::GetPxPyPz(Double_t *p) const { |
674 | //--------------------------------------------------------------------- | |
675 | // This function returns the global track momentum components | |
676 | // Results for (nearly) straight tracks are meaningless ! | |
677 | //--------------------------------------------------------------------- | |
678 | p[0]=fP[4]; p[1]=fP[2]; p[2]=fP[3]; | |
679 | return Local2GlobalMomentum(p,fAlpha); | |
680 | } | |
a5e407e9 | 681 | |
c9ec41e8 | 682 | Bool_t AliExternalTrackParam::GetXYZ(Double_t *r) const { |
683 | //--------------------------------------------------------------------- | |
684 | // This function returns the global track position | |
685 | //--------------------------------------------------------------------- | |
686 | r[0]=fX; r[1]=fP[0]; r[2]=fP[1]; | |
687 | return Local2GlobalPosition(r,fAlpha); | |
51ad6848 | 688 | } |
689 | ||
c9ec41e8 | 690 | Bool_t AliExternalTrackParam::GetCovarianceXYZPxPyPz(Double_t cv[21]) const { |
691 | //--------------------------------------------------------------------- | |
692 | // This function returns the global covariance matrix of the track params | |
693 | // | |
694 | // Cov(x,x) ... : cv[0] | |
695 | // Cov(y,x) ... : cv[1] cv[2] | |
696 | // Cov(z,x) ... : cv[3] cv[4] cv[5] | |
697 | // Cov(px,x)... : cv[6] cv[7] cv[8] cv[9] | |
698 | // Cov(py,x)... : cv[10] cv[11] cv[12] cv[13] cv[14] | |
699 | // Cov(pz,x)... : cv[15] cv[16] cv[17] cv[18] cv[19] cv[20] | |
a5e407e9 | 700 | // |
c9ec41e8 | 701 | // Results for (nearly) straight tracks are meaningless ! |
702 | //--------------------------------------------------------------------- | |
e421f556 | 703 | if (TMath::Abs(fP[4])<=kAlmost0) { |
c9ec41e8 | 704 | for (Int_t i=0; i<21; i++) cv[i]=0.; |
705 | return kFALSE; | |
a5e407e9 | 706 | } |
49d13e89 | 707 | if (TMath::Abs(fP[2]) > kAlmost1) { |
c9ec41e8 | 708 | for (Int_t i=0; i<21; i++) cv[i]=0.; |
709 | return kFALSE; | |
710 | } | |
711 | Double_t pt=1./TMath::Abs(fP[4]); | |
712 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); | |
713 | Double_t r=TMath::Sqrt(1-fP[2]*fP[2]); | |
714 | ||
715 | Double_t m00=-sn, m10=cs; | |
716 | Double_t m23=-pt*(sn + fP[2]*cs/r), m43=-pt*pt*(r*cs - fP[2]*sn); | |
717 | Double_t m24= pt*(cs - fP[2]*sn/r), m44=-pt*pt*(r*sn + fP[2]*cs); | |
718 | Double_t m35=pt, m45=-pt*pt*fP[3]; | |
719 | ||
720 | cv[0 ] = fC[0]*m00*m00; | |
721 | cv[1 ] = fC[0]*m00*m10; | |
722 | cv[2 ] = fC[0]*m10*m10; | |
723 | cv[3 ] = fC[1]*m00; | |
724 | cv[4 ] = fC[1]*m10; | |
725 | cv[5 ] = fC[2]; | |
726 | cv[6 ] = m00*(fC[3]*m23 + fC[10]*m43); | |
727 | cv[7 ] = m10*(fC[3]*m23 + fC[10]*m43); | |
728 | cv[8 ] = fC[4]*m23 + fC[11]*m43; | |
729 | cv[9 ] = m23*(fC[5]*m23 + fC[12]*m43) + m43*(fC[12]*m23 + fC[14]*m43); | |
730 | cv[10] = m00*(fC[3]*m24 + fC[10]*m44); | |
731 | cv[11] = m10*(fC[3]*m24 + fC[10]*m44); | |
732 | cv[12] = fC[4]*m24 + fC[11]*m44; | |
733 | cv[13] = m23*(fC[5]*m24 + fC[12]*m44) + m43*(fC[12]*m24 + fC[14]*m44); | |
734 | cv[14] = m24*(fC[5]*m24 + fC[12]*m44) + m44*(fC[12]*m24 + fC[14]*m44); | |
735 | cv[15] = m00*(fC[6]*m35 + fC[10]*m45); | |
736 | cv[16] = m10*(fC[6]*m35 + fC[10]*m45); | |
737 | cv[17] = fC[7]*m35 + fC[11]*m45; | |
738 | cv[18] = m23*(fC[8]*m35 + fC[12]*m45) + m43*(fC[13]*m35 + fC[14]*m45); | |
739 | cv[19] = m24*(fC[8]*m35 + fC[12]*m45) + m44*(fC[13]*m35 + fC[14]*m45); | |
740 | cv[20] = m35*(fC[9]*m35 + fC[13]*m45) + m45*(fC[13]*m35 + fC[14]*m45); | |
51ad6848 | 741 | |
c9ec41e8 | 742 | return kTRUE; |
51ad6848 | 743 | } |
744 | ||
51ad6848 | 745 | |
c9ec41e8 | 746 | Bool_t |
747 | AliExternalTrackParam::GetPxPyPzAt(Double_t x, Double_t b, Double_t *p) const { | |
748 | //--------------------------------------------------------------------- | |
749 | // This function returns the global track momentum extrapolated to | |
750 | // the radial position "x" (cm) in the magnetic field "b" (kG) | |
751 | //--------------------------------------------------------------------- | |
c9ec41e8 | 752 | p[0]=fP[4]; |
1530f89c | 753 | p[1]=fP[2]+(x-fX)*GetC(b); |
c9ec41e8 | 754 | p[2]=fP[3]; |
755 | return Local2GlobalMomentum(p,fAlpha); | |
51ad6848 | 756 | } |
757 | ||
7cf7bb6c | 758 | Bool_t |
759 | AliExternalTrackParam::GetYAt(Double_t x, Double_t b, Double_t &y) const { | |
760 | //--------------------------------------------------------------------- | |
761 | // This function returns the local Y-coordinate of the intersection | |
762 | // point between this track and the reference plane "x" (cm). | |
763 | // Magnetic field "b" (kG) | |
764 | //--------------------------------------------------------------------- | |
765 | Double_t dx=x-fX; | |
766 | if(TMath::Abs(dx)<=kAlmost0) {y=fP[0]; return kTRUE;} | |
767 | ||
1530f89c | 768 | Double_t f1=fP[2], f2=f1 + dx*GetC(b); |
7cf7bb6c | 769 | |
770 | if (TMath::Abs(f1) >= kAlmost1) return kFALSE; | |
771 | if (TMath::Abs(f2) >= kAlmost1) return kFALSE; | |
772 | ||
773 | Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2); | |
774 | y = fP[0] + dx*(f1+f2)/(r1+r2); | |
775 | return kTRUE; | |
776 | } | |
777 | ||
c9ec41e8 | 778 | Bool_t |
779 | AliExternalTrackParam::GetXYZAt(Double_t x, Double_t b, Double_t *r) const { | |
780 | //--------------------------------------------------------------------- | |
781 | // This function returns the global track position extrapolated to | |
782 | // the radial position "x" (cm) in the magnetic field "b" (kG) | |
783 | //--------------------------------------------------------------------- | |
c9ec41e8 | 784 | Double_t dx=x-fX; |
e421f556 | 785 | if(TMath::Abs(dx)<=kAlmost0) return GetXYZ(r); |
786 | ||
1530f89c | 787 | Double_t f1=fP[2], f2=f1 + dx*GetC(b); |
c9ec41e8 | 788 | |
e421f556 | 789 | if (TMath::Abs(f1) >= kAlmost1) return kFALSE; |
49d13e89 | 790 | if (TMath::Abs(f2) >= kAlmost1) return kFALSE; |
c9ec41e8 | 791 | |
792 | Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2); | |
793 | r[0] = x; | |
794 | r[1] = fP[0] + dx*(f1+f2)/(r1+r2); | |
1ce63cae | 795 | r[2] = fP[1] + dx*(r2 + f2*(f1+f2)/(r1+r2))*fP[3];//Many thanks to P.Hristov ! |
c9ec41e8 | 796 | return Local2GlobalPosition(r,fAlpha); |
51ad6848 | 797 | } |
798 | ||
51ad6848 | 799 | //_____________________________________________________________________________ |
800 | void AliExternalTrackParam::Print(Option_t* /*option*/) const | |
801 | { | |
802 | // print the parameters and the covariance matrix | |
803 | ||
804 | printf("AliExternalTrackParam: x = %-12g alpha = %-12g\n", fX, fAlpha); | |
805 | printf(" parameters: %12g %12g %12g %12g %12g\n", | |
c9ec41e8 | 806 | fP[0], fP[1], fP[2], fP[3], fP[4]); |
807 | printf(" covariance: %12g\n", fC[0]); | |
808 | printf(" %12g %12g\n", fC[1], fC[2]); | |
809 | printf(" %12g %12g %12g\n", fC[3], fC[4], fC[5]); | |
51ad6848 | 810 | printf(" %12g %12g %12g %12g\n", |
c9ec41e8 | 811 | fC[6], fC[7], fC[8], fC[9]); |
51ad6848 | 812 | printf(" %12g %12g %12g %12g %12g\n", |
c9ec41e8 | 813 | fC[10], fC[11], fC[12], fC[13], fC[14]); |
51ad6848 | 814 | } |
5b77d93c | 815 | |
c194ba83 | 816 | Double_t AliExternalTrackParam::GetSnpAt(Double_t x,Double_t b) const { |
817 | // | |
818 | // Get sinus at given x | |
819 | // | |
1530f89c | 820 | Double_t crv=GetC(b); |
c194ba83 | 821 | if (TMath::Abs(b) < kAlmost0Field) crv=0.; |
822 | Double_t dx = x-fX; | |
823 | Double_t res = fP[2]+dx*crv; | |
824 | return res; | |
825 | } | |
5b77d93c | 826 | |
c194ba83 | 827 | Bool_t AliExternalTrackParam::PropagateTo(Double_t xToGo, Double_t b, Double_t mass, Double_t maxStep, Bool_t rotateTo, Double_t maxSnp){ |
5b77d93c | 828 | //---------------------------------------------------------------- |
08df6187 | 829 | // |
830 | // Very expensive function ! Don't abuse it ! | |
831 | // | |
832 | // Propagates this track to the plane X=xk (cm) | |
833 | // in the magnetic field "b" (kG), | |
5b77d93c | 834 | // the correction for the material is included |
835 | // | |
08df6187 | 836 | // Requires acces to geomanager |
5b77d93c | 837 | // |
838 | // mass - mass used in propagation - used for energy loss correction | |
839 | // maxStep - maximal step for propagation | |
840 | //---------------------------------------------------------------- | |
841 | const Double_t kEpsilon = 0.00001; | |
842 | Double_t xpos = GetX(); | |
843 | Double_t dir = (xpos<xToGo) ? 1.:-1.; | |
844 | // | |
845 | while ( (xToGo-xpos)*dir > kEpsilon){ | |
846 | Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep); | |
847 | Double_t x = xpos+step; | |
848 | Double_t xyz0[3],xyz1[3],param[7]; | |
849 | GetXYZ(xyz0); //starting global position | |
08df6187 | 850 | if (!GetXYZAt(x,b,xyz1)) return kFALSE; // no prolongation |
20e5d17c | 851 | xyz1[2]+=kEpsilon; // waiting for bug correction in geo |
5b77d93c | 852 | AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param); |
c194ba83 | 853 | if (TMath::Abs(GetSnpAt(x,b)) >= maxSnp) return kFALSE; |
08df6187 | 854 | if (!PropagateTo(x,b)) return kFALSE; |
855 | ||
856 | Double_t rho=param[0],x0=param[1],distance=param[4]; | |
857 | Double_t d=distance*rho/x0; | |
858 | ||
859 | if (!CorrectForMaterial(d,x0,mass)) return kFALSE; | |
5b77d93c | 860 | if (rotateTo){ |
c194ba83 | 861 | if (TMath::Abs(fP[2]) >= maxSnp) return kFALSE; |
5b77d93c | 862 | GetXYZ(xyz0); // global position |
c194ba83 | 863 | Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]); |
864 | // | |
865 | Double_t ca=TMath::Cos(alphan-fAlpha), sa=TMath::Sin(alphan-fAlpha); | |
866 | Double_t sf=fP[2], cf=TMath::Sqrt(1.- fP[2]*fP[2]); | |
867 | Double_t sinNew = sf*ca - cf*sa; | |
868 | if (TMath::Abs(sinNew) >= maxSnp) return kFALSE; | |
5b77d93c | 869 | if (!Rotate(alphan)) return kFALSE; |
870 | } | |
871 | xpos = GetX(); | |
872 | } | |
873 | return kTRUE; | |
874 | } | |
875 | ||
5b77d93c | 876 | |
5b77d93c | 877 | |
878 |