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87594435 | 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 | ||
acd84897 | 16 | /* $Id$ */ |
fb17acd4 | 17 | |
87594435 | 18 | //------------------------------------------------------------------------- |
19 | // Implementation of the AliKalmanTrack class | |
066782e8 | 20 | // that is the base for AliTPCtrack, AliITStrackV2 and AliTRDtrack |
87594435 | 21 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch |
22 | //------------------------------------------------------------------------- | |
23 | ||
24 | #include "AliKalmanTrack.h" | |
74f9526e | 25 | #include "AliPDG.h" |
26 | #include "TPDGCode.h" | |
27 | #include "TDatabasePDG.h" | |
87594435 | 28 | |
29 | ClassImp(AliKalmanTrack) | |
30 | ||
116cbefd | 31 | Double_t AliKalmanTrack::fgConvConst; |
9b280d80 | 32 | |
e2afb3b6 | 33 | //_______________________________________________________________________ |
34 | AliKalmanTrack::AliKalmanTrack(): | |
35 | fLab(-3141593), | |
36 | fChi2(0), | |
37 | fMass(0.13957), | |
38 | fN(0) | |
39 | { | |
116cbefd | 40 | // |
41 | // Default constructor | |
42 | // | |
43 | if (fgConvConst==0) | |
e2afb3b6 | 44 | Fatal("AliKalmanTrack()","The magnetic field has not been set !\n"); |
74f9526e | 45 | |
46 | fStartTimeIntegral = kFALSE; | |
47 | fIntegratedLength = 0; | |
48 | for(Int_t i=0; i<5; i++) fIntegratedTime[i] = 0; | |
e2afb3b6 | 49 | } |
50 | ||
51 | //_______________________________________________________________________ | |
52 | AliKalmanTrack::AliKalmanTrack(const AliKalmanTrack &t): | |
53 | TObject(t), | |
54 | fLab(t.fLab), | |
55 | fChi2(t.fChi2), | |
56 | fMass(t.fMass), | |
57 | fN(t.fN) | |
58 | { | |
116cbefd | 59 | // |
60 | // Copy constructor | |
61 | // | |
62 | if (fgConvConst==0) | |
e2afb3b6 | 63 | Fatal("AliKalmanTrack(const AliKalmanTrack&)", |
64 | "The magnetic field has not been set !\n"); | |
74f9526e | 65 | |
66 | fStartTimeIntegral = t.fStartTimeIntegral; | |
67 | fIntegratedLength = t.fIntegratedLength; | |
68 | ||
69 | for (Int_t i=0; i<5; i++) | |
70 | fIntegratedTime[i] = t.fIntegratedTime[i]; | |
71 | } | |
c5507f6d | 72 | |
73 | //_______________________________________________________________________ | |
74 | Double_t AliKalmanTrack::GetX() const | |
75 | { | |
76 | Warning("GetX()","Method must be overloaded !\n"); | |
77 | return 0.; | |
78 | } | |
79 | //_______________________________________________________________________ | |
80 | Double_t AliKalmanTrack::GetdEdx() const | |
81 | { | |
82 | Warning("GetdEdx()","Method must be overloaded !\n"); | |
83 | return 0.; | |
84 | } | |
85 | ||
86 | //_______________________________________________________________________ | |
87 | Double_t AliKalmanTrack::GetY() const | |
88 | { | |
89 | Double_t par[5]; | |
90 | Double_t localX = GetX(); | |
91 | GetExternalParameters(localX, par); | |
92 | return par[0]; | |
93 | } | |
94 | //_______________________________________________________________________ | |
95 | Double_t AliKalmanTrack::GetZ() const | |
96 | { | |
97 | Double_t par[5]; | |
98 | Double_t localX = GetX(); | |
99 | GetExternalParameters(localX, par); | |
100 | return par[1]; | |
101 | } | |
102 | //_______________________________________________________________________ | |
103 | Double_t AliKalmanTrack::GetSnp() const | |
104 | { | |
105 | Double_t par[5]; | |
106 | Double_t localX = GetX(); | |
107 | GetExternalParameters(localX, par); | |
108 | return par[2]; | |
109 | } | |
110 | //_______________________________________________________________________ | |
111 | Double_t AliKalmanTrack::GetTgl() const | |
112 | { | |
113 | Double_t par[5]; | |
114 | Double_t localX = GetX(); | |
115 | GetExternalParameters(localX, par); | |
116 | return par[3]; | |
117 | } | |
118 | //_______________________________________________________________________ | |
119 | Double_t AliKalmanTrack::Get1Pt() const | |
120 | { | |
121 | Double_t par[5]; | |
122 | Double_t localX = GetX(); | |
123 | GetExternalParameters(localX, par); | |
124 | return par[4]; | |
125 | } | |
126 | ||
127 | //_______________________________________________________________________ | |
128 | Double_t AliKalmanTrack::Phi() const | |
129 | { | |
130 | // return global phi of track | |
131 | ||
132 | Double_t par[5]; | |
133 | Double_t localX = GetX(); | |
134 | GetExternalParameters(localX, par); | |
79e94bf8 | 135 | if (par[2] > 1.) par[2] = 1.; |
136 | if (par[2] < -1.) par[2] = -1.; | |
c5507f6d | 137 | Double_t phi = TMath::ASin(par[2]) + GetAlpha(); |
138 | while (phi < 0) phi += TMath::TwoPi(); | |
139 | while (phi > TMath::TwoPi()) phi -= TMath::TwoPi(); | |
140 | return phi; | |
141 | } | |
142 | //_______________________________________________________________________ | |
143 | Double_t AliKalmanTrack::SigmaPhi() const | |
144 | { | |
145 | // return error of global phi of track | |
146 | ||
147 | Double_t par[5]; | |
148 | Double_t cov[15]; | |
149 | Double_t localX = GetX(); | |
150 | GetExternalParameters(localX, par); | |
151 | GetExternalCovariance(cov); | |
152 | return TMath::Sqrt(TMath::Abs(cov[5] / (1. - par[2]*par[2]))); | |
153 | } | |
154 | //_______________________________________________________________________ | |
155 | Double_t AliKalmanTrack::Theta() const | |
156 | { | |
157 | // return global theta of track | |
158 | ||
159 | Double_t par[5]; | |
160 | Double_t localX = GetX(); | |
161 | GetExternalParameters(localX, par); | |
162 | return TMath::Pi()/2. - TMath::ATan(par[3]); | |
163 | } | |
164 | //_______________________________________________________________________ | |
165 | Double_t AliKalmanTrack::SigmaTheta() const | |
166 | { | |
167 | // return error of global theta of track | |
168 | ||
169 | Double_t par[5]; | |
170 | Double_t cov[15]; | |
171 | Double_t localX = GetX(); | |
172 | GetExternalParameters(localX, par); | |
173 | GetExternalCovariance(cov); | |
174 | return TMath::Sqrt(TMath::Abs(cov[5])) / (1. + par[3]*par[3]); | |
175 | } | |
176 | //_______________________________________________________________________ | |
177 | Double_t AliKalmanTrack::Px() const | |
178 | { | |
179 | // return x component of track momentum | |
180 | ||
181 | Double_t par[5]; | |
182 | Double_t localX = GetX(); | |
183 | GetExternalParameters(localX, par); | |
184 | Double_t phi = TMath::ASin(par[2]) + GetAlpha(); | |
185 | return TMath::Cos(phi) / TMath::Abs(par[4]); | |
186 | } | |
187 | //_______________________________________________________________________ | |
188 | Double_t AliKalmanTrack::Py() const | |
189 | { | |
190 | // return y component of track momentum | |
191 | ||
192 | Double_t par[5]; | |
193 | Double_t localX = GetX(); | |
194 | GetExternalParameters(localX, par); | |
195 | Double_t phi = TMath::ASin(par[2]) + GetAlpha(); | |
196 | return TMath::Sin(phi) / TMath::Abs(par[4]); | |
197 | } | |
198 | //_______________________________________________________________________ | |
199 | Double_t AliKalmanTrack::Pz() const | |
200 | { | |
201 | // return z component of track momentum | |
202 | ||
203 | Double_t par[5]; | |
204 | Double_t localX = GetX(); | |
205 | GetExternalParameters(localX, par); | |
206 | return par[3] / TMath::Abs(par[4]); | |
207 | } | |
208 | //_______________________________________________________________________ | |
209 | Double_t AliKalmanTrack::Pt() const | |
210 | { | |
211 | // return transverse component of track momentum | |
212 | ||
213 | Double_t par[5]; | |
214 | Double_t localX = GetX(); | |
215 | GetExternalParameters(localX, par); | |
216 | return 1. / TMath::Abs(par[4]); | |
217 | } | |
218 | //_______________________________________________________________________ | |
219 | Double_t AliKalmanTrack::SigmaPt() const | |
220 | { | |
221 | // return error of transverse component of track momentum | |
222 | ||
223 | Double_t par[5]; | |
224 | Double_t cov[15]; | |
225 | Double_t localX = GetX(); | |
226 | GetExternalParameters(localX, par); | |
227 | GetExternalCovariance(cov); | |
228 | return TMath::Sqrt(cov[14]) / TMath::Abs(par[4]); | |
229 | } | |
230 | //_______________________________________________________________________ | |
231 | Double_t AliKalmanTrack::P() const | |
232 | { | |
233 | // return total track momentum | |
234 | ||
235 | Double_t par[5]; | |
236 | Double_t localX = GetX(); | |
237 | GetExternalParameters(localX, par); | |
79e94bf8 | 238 | return 1. / TMath::Abs(par[4] * TMath::Cos(TMath::ATan(par[3]))); |
c5507f6d | 239 | } |
74f9526e | 240 | //_______________________________________________________________________ |
241 | void AliKalmanTrack::StartTimeIntegral() | |
242 | { | |
49a7a79a | 243 | // Sylwester Radomski, GSI |
244 | // S.Radomski@gsi.de | |
74f9526e | 245 | // |
246 | // Start time integration | |
247 | // To be called at Vertex by ITS tracker | |
248 | // | |
249 | ||
250 | //if (fStartTimeIntegral) | |
251 | // Warning("StartTimeIntegral", "Reseting Recorded Time."); | |
252 | ||
253 | fStartTimeIntegral = kTRUE; | |
5d8718b8 | 254 | for(Int_t i=0; i<fgkTypes; i++) fIntegratedTime[i] = 0; |
74f9526e | 255 | fIntegratedLength = 0; |
256 | } | |
257 | //_______________________________________________________________________ | |
258 | void AliKalmanTrack:: AddTimeStep(Double_t length) | |
259 | { | |
260 | // | |
261 | // Add step to integrated time | |
262 | // this method should be called by a sublasses at the end | |
263 | // of the PropagateTo function or by a tracker | |
264 | // each time step is made. | |
265 | // | |
266 | // If integration not started function does nothing | |
267 | // | |
268 | // Formula | |
269 | // dt = dl * sqrt(p^2 + m^2) / p | |
270 | // p = pT * (1 + tg^2 (lambda) ) | |
271 | // | |
272 | // pt = 1/external parameter [4] | |
273 | // tg lambda = external parameter [3] | |
274 | // | |
275 | // | |
276 | // Sylwester Radomski, GSI | |
277 | // S.Radomski@gsi.de | |
278 | // | |
279 | ||
5d8718b8 | 280 | static const Double_t kcc = 2.99792458e-2; |
74f9526e | 281 | |
282 | if (!fStartTimeIntegral) return; | |
283 | ||
284 | fIntegratedLength += length; | |
285 | ||
5d8718b8 | 286 | static Int_t pdgCode[fgkTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton}; |
74f9526e | 287 | TDatabasePDG *db = TDatabasePDG::Instance(); |
288 | ||
289 | Double_t xr, param[5]; | |
290 | Double_t pt, tgl; | |
291 | ||
292 | GetExternalParameters(xr, param); | |
293 | pt = 1/param[4] ; | |
294 | tgl = param[3]; | |
295 | ||
296 | Double_t p = TMath::Abs(pt * TMath::Sqrt(1+tgl*tgl)); | |
297 | ||
298 | if (length > 100) return; | |
299 | ||
5d8718b8 | 300 | for (Int_t i=0; i<fgkTypes; i++) { |
74f9526e | 301 | |
302 | Double_t mass = db->GetParticle(pdgCode[i])->Mass(); | |
303 | Double_t correction = TMath::Sqrt( pt*pt * (1 + tgl*tgl) + mass * mass ) / p; | |
5d8718b8 | 304 | Double_t time = length * correction / kcc; |
74f9526e | 305 | |
306 | //cout << mass << "\t" << pt << "\t" << p << "\t" | |
307 | // << correction << endl; | |
308 | ||
309 | fIntegratedTime[i] += time; | |
310 | } | |
e2afb3b6 | 311 | } |
312 | ||
74f9526e | 313 | //_______________________________________________________________________ |
314 | ||
315 | Double_t AliKalmanTrack::GetIntegratedTime(Int_t pdg) const | |
316 | { | |
49a7a79a | 317 | // Sylwester Radomski, GSI |
318 | // S.Radomski@gsi.de | |
74f9526e | 319 | // |
320 | // Return integrated time hypothesis for a given particle | |
321 | // type assumption. | |
322 | // | |
323 | // Input parameter: | |
324 | // pdg - Pdg code of a particle type | |
325 | // | |
326 | ||
327 | ||
328 | if (!fStartTimeIntegral) { | |
329 | Warning("GetIntegratedTime","Time integration not started"); | |
330 | return 0.; | |
331 | } | |
332 | ||
5d8718b8 | 333 | static Int_t pdgCode[fgkTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton}; |
74f9526e | 334 | |
5d8718b8 | 335 | for (Int_t i=0; i<fgkTypes; i++) |
74f9526e | 336 | if (pdgCode[i] == TMath::Abs(pdg)) return fIntegratedTime[i]; |
337 | ||
338 | Warning(":GetIntegratedTime","Particle type [%d] not found", pdg); | |
339 | return 0; | |
340 | } | |
ae982df3 | 341 | |
342 | void AliKalmanTrack::GetIntegratedTimes(Double_t *times) const { | |
343 | for (Int_t i=0; i<fgkTypes; i++) times[i]=fIntegratedTime[i]; | |
344 | } | |
345 | ||
346 | void AliKalmanTrack::SetIntegratedTimes(const Double_t *times) { | |
347 | for (Int_t i=0; i<fgkTypes; i++) fIntegratedTime[i]=times[i]; | |
348 | } | |
349 | ||
74f9526e | 350 | //_______________________________________________________________________ |
351 | ||
352 | void AliKalmanTrack::PrintTime() const | |
353 | { | |
49a7a79a | 354 | // Sylwester Radomski, GSI |
355 | // S.Radomski@gsi.de | |
356 | // | |
74f9526e | 357 | // For testing |
358 | // Prints time for all hypothesis | |
359 | // | |
360 | ||
5d8718b8 | 361 | static Int_t pdgCode[fgkTypes] = {kElectron, kMuonMinus, kPiPlus, kKPlus, kProton}; |
74f9526e | 362 | |
5d8718b8 | 363 | for (Int_t i=0; i<fgkTypes; i++) |
74f9526e | 364 | printf("%d: %.2f ", pdgCode[i], fIntegratedTime[i]); |
365 | printf("\n"); | |
366 | } | |
367 | ||
49a7a79a | 368 | static void External2Helix(const AliKalmanTrack *t, Double_t helix[6]) { |
369 | //-------------------------------------------------------------------- | |
370 | // External track parameters -> helix parameters | |
371 | //-------------------------------------------------------------------- | |
372 | Double_t alpha,x,cs,sn; | |
373 | t->GetExternalParameters(x,helix); alpha=t->GetAlpha(); | |
374 | ||
375 | cs=TMath::Cos(alpha); sn=TMath::Sin(alpha); | |
376 | helix[5]=x*cs - helix[0]*sn; // x0 | |
377 | helix[0]=x*sn + helix[0]*cs; // y0 | |
378 | //helix[1]= // z0 | |
379 | helix[2]=TMath::ASin(helix[2]) + alpha; // phi0 | |
380 | //helix[3]= // tgl | |
381 | helix[4]=helix[4]/t->GetConvConst(); // C | |
382 | } | |
383 | ||
384 | static void Evaluate(const Double_t *h, Double_t t, | |
385 | Double_t r[3], //radius vector | |
386 | Double_t g[3], //first defivatives | |
387 | Double_t gg[3]) //second derivatives | |
388 | { | |
389 | //-------------------------------------------------------------------- | |
390 | // Calculate position of a point on a track and some derivatives | |
391 | //-------------------------------------------------------------------- | |
392 | Double_t phase=h[4]*t+h[2]; | |
393 | Double_t sn=TMath::Sin(phase), cs=TMath::Cos(phase); | |
394 | ||
395 | r[0] = h[5] + (sn - h[6])/h[4]; | |
396 | r[1] = h[0] - (cs - h[7])/h[4]; | |
397 | r[2] = h[1] + h[3]*t; | |
398 | ||
399 | g[0] = cs; g[1]=sn; g[2]=h[3]; | |
400 | ||
401 | gg[0]=-h[4]*sn; gg[1]=h[4]*cs; gg[2]=0.; | |
402 | } | |
403 | ||
404 | Double_t AliKalmanTrack:: | |
405 | GetDCA(const AliKalmanTrack *p, Double_t &xthis, Double_t &xp) const { | |
406 | //------------------------------------------------------------ | |
407 | // Returns the (weighed !) distance of closest approach between | |
408 | // this track and the track passed as the argument. | |
409 | // Other returned values: | |
410 | // xthis, xt - coordinates of tracks' reference planes at the DCA | |
411 | //----------------------------------------------------------- | |
412 | Double_t dy2=GetSigmaY2() + p->GetSigmaY2(); | |
413 | Double_t dz2=GetSigmaZ2() + p->GetSigmaZ2(); | |
414 | Double_t dx2=dy2; | |
415 | ||
416 | //dx2=dy2=dz2=1.; | |
417 | ||
418 | Double_t p1[8]; External2Helix(this,p1); | |
419 | p1[6]=TMath::Sin(p1[2]); p1[7]=TMath::Cos(p1[2]); | |
420 | Double_t p2[8]; External2Helix(p,p2); | |
421 | p2[6]=TMath::Sin(p2[2]); p2[7]=TMath::Cos(p2[2]); | |
422 | ||
423 | ||
424 | Double_t r1[3],g1[3],gg1[3]; Double_t t1=0.; | |
425 | Evaluate(p1,t1,r1,g1,gg1); | |
426 | Double_t r2[3],g2[3],gg2[3]; Double_t t2=0.; | |
427 | Evaluate(p2,t2,r2,g2,gg2); | |
74f9526e | 428 | |
49a7a79a | 429 | Double_t dx=r2[0]-r1[0], dy=r2[1]-r1[1], dz=r2[2]-r1[2]; |
430 | Double_t dm=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2; | |
431 | ||
432 | Int_t max=27; | |
433 | while (max--) { | |
434 | Double_t gt1=-(dx*g1[0]/dx2 + dy*g1[1]/dy2 + dz*g1[2]/dz2); | |
435 | Double_t gt2=+(dx*g2[0]/dx2 + dy*g2[1]/dy2 + dz*g2[2]/dz2); | |
436 | Double_t h11=(g1[0]*g1[0] - dx*gg1[0])/dx2 + | |
437 | (g1[1]*g1[1] - dy*gg1[1])/dy2 + | |
438 | (g1[2]*g1[2] - dz*gg1[2])/dz2; | |
439 | Double_t h22=(g2[0]*g2[0] + dx*gg2[0])/dx2 + | |
440 | (g2[1]*g2[1] + dy*gg2[1])/dy2 + | |
441 | (g2[2]*g2[2] + dz*gg2[2])/dz2; | |
442 | Double_t h12=-(g1[0]*g2[0]/dx2 + g1[1]*g2[1]/dy2 + g1[2]*g2[2]/dz2); | |
443 | ||
444 | Double_t det=h11*h22-h12*h12; | |
445 | ||
446 | Double_t dt1,dt2; | |
447 | if (TMath::Abs(det)<1.e-33) { | |
448 | //(quasi)singular Hessian | |
449 | dt1=-gt1; dt2=-gt2; | |
450 | } else { | |
451 | dt1=-(gt1*h22 - gt2*h12)/det; | |
452 | dt2=-(h11*gt2 - h12*gt1)/det; | |
453 | } | |
454 | ||
455 | if ((dt1*gt1+dt2*gt2)>0) {dt1=-dt1; dt2=-dt2;} | |
456 | ||
457 | //check delta(phase1) ? | |
458 | //check delta(phase2) ? | |
459 | ||
460 | if (TMath::Abs(dt1)/(TMath::Abs(t1)+1.e-3) < 1.e-4) | |
461 | if (TMath::Abs(dt2)/(TMath::Abs(t2)+1.e-3) < 1.e-4) { | |
462 | if ((gt1*gt1+gt2*gt2) > 1.e-4/dy2/dy2) | |
463 | Warning("GetDCA"," stopped at not a stationary point !\n"); | |
464 | Double_t lmb=h11+h22; lmb=lmb-TMath::Sqrt(lmb*lmb-4*det); | |
465 | if (lmb < 0.) | |
466 | Warning("GetDCA"," stopped at not a minimum !\n"); | |
467 | break; | |
468 | } | |
469 | ||
470 | Double_t dd=dm; | |
471 | for (Int_t div=1 ; ; div*=2) { | |
472 | Evaluate(p1,t1+dt1,r1,g1,gg1); | |
473 | Evaluate(p2,t2+dt2,r2,g2,gg2); | |
474 | dx=r2[0]-r1[0]; dy=r2[1]-r1[1]; dz=r2[2]-r1[2]; | |
475 | dd=dx*dx/dx2 + dy*dy/dy2 + dz*dz/dz2; | |
476 | if (dd<dm) break; | |
477 | dt1*=0.5; dt2*=0.5; | |
478 | if (div>512) { | |
479 | Warning("GetDCA"," overshoot !\n"); break; | |
480 | } | |
481 | } | |
482 | dm=dd; | |
483 | ||
484 | t1+=dt1; | |
485 | t2+=dt2; | |
486 | ||
487 | } | |
488 | ||
489 | if (max<=0) Warning("GetDCA"," too many iterations !\n"); | |
490 | ||
491 | Double_t cs=TMath::Cos(GetAlpha()); | |
492 | Double_t sn=TMath::Sin(GetAlpha()); | |
493 | xthis=r1[0]*cs + r1[1]*sn; | |
494 | ||
495 | cs=TMath::Cos(p->GetAlpha()); | |
496 | sn=TMath::Sin(p->GetAlpha()); | |
497 | xp=r2[0]*cs + r2[1]*sn; | |
498 | ||
499 | return TMath::Sqrt(dm*TMath::Sqrt(dy2*dz2)); | |
500 | } | |
501 | ||
502 | Double_t AliKalmanTrack:: | |
503 | PropagateToDCA(AliKalmanTrack *p, Double_t d, Double_t x0) { | |
504 | //-------------------------------------------------------------- | |
505 | // Propagates this track and the argument track to the position of the | |
506 | // distance of closest approach. | |
507 | // Returns the (weighed !) distance of closest approach. | |
508 | //-------------------------------------------------------------- | |
509 | Double_t xthis,xp; | |
510 | Double_t dca=GetDCA(p,xthis,xp); | |
511 | ||
512 | if (!PropagateTo(xthis,d,x0)) { | |
513 | //Warning("PropagateToDCA"," propagation failed !\n"); | |
514 | return 1e+33; | |
515 | } | |
516 | ||
517 | if (!p->PropagateTo(xp,d,x0)) { | |
518 | //Warning("PropagateToDCA"," propagation failed !\n"; | |
519 | return 1e+33; | |
520 | } | |
521 | ||
522 | return dca; | |
523 | } |