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c5555bc0 | 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 | // Class AliHelix | |
20 | // Representation and extrapolation of AliTracks in a magnetic field. | |
21 | // | |
22 | // This class is meant to provide a means to display and extrapolate | |
23 | // AliTrack objects in the presence of a constant homogeneous magnetic field. | |
24 | // | |
25 | // Examples : | |
26 | // ========== | |
27 | // | |
28 | // Display and extrapolation of individual tracks | |
29 | // ---------------------------------------------- | |
30 | // Float_t vec[3]; | |
31 | // AliPosition r1; | |
32 | // Ali3Vector p; | |
33 | // AliTrack t; | |
34 | // | |
35 | // vec[0]=0; | |
36 | // vec[1]=0; | |
37 | // vec[2]=0; | |
38 | // r1.SetVector(vec,"car"); | |
39 | // | |
40 | // vec[0]=1; | |
41 | // vec[1]=0; | |
42 | // vec[2]=0.3; | |
43 | // p.SetVector(vec,"car"); | |
44 | // | |
45 | // t.Set3Momentum(p); | |
46 | // t.SetBeginPoint(r1); | |
47 | // t.SetCharge(-1); | |
48 | // t.SetMass(0.139); | |
49 | // | |
50 | // // The magnetic field vector in Tesla | |
51 | // Ali3Vector b; | |
52 | // vec[0]=0; | |
53 | // vec[1]=0; | |
54 | // vec[2]=1; | |
55 | // b.SetVector(vec,"car"); | |
56 | // | |
57 | // AliHelix* helix=new AliHelix(); | |
58 | // helix->SetB(b); | |
59 | // helix->SetTofmax(1e-7); | |
60 | // | |
61 | // TCanvas* c1=new TCanvas("c1","c1"); | |
62 | // TView* view=new TView(1); | |
63 | // view->SetRange(-1000,-1000,-1000,1000,1000,1000); | |
64 | // view->ShowAxis(); | |
65 | // | |
66 | // // Track displays | |
67 | // Double_t range[2]={0,600}; | |
68 | // helix->Display(&t,range,3); | |
69 | // t.SetCharge(-t.GetCharge()); | |
70 | // helix->Display(&t); | |
71 | // | |
72 | // // Track extrapolation | |
73 | // Double_t pars[3]={550,0.001,3}; | |
74 | // AliPosition* rext=helix->Extrapolate(&t,pars); | |
75 | // if (rext) rext->Data(); | |
76 | // ====================================================================== | |
77 | // | |
78 | // Online display of events generated via AliCollider | |
79 | // -------------------------------------------------- | |
80 | // Int_t nevents=5; // Number of events to be generated | |
81 | // Int_t jrun=1; // The run number of this batch of generated events | |
82 | // | |
83 | // cout << " ***" << endl; | |
84 | // cout << " *** AliCollider run for " << nevents << " events." << endl; | |
85 | // cout << " ***" << endl; | |
86 | // | |
87 | // AliCollider* gen=new AliCollider(); | |
88 | // | |
89 | // gen->OpenFortranFile(6,"dump.log"); | |
90 | // | |
91 | // gen->SetVertexMode(2); | |
92 | // gen->SetResolution(1e-4); | |
93 | // | |
94 | // gen->SetRunNumber(jrun); | |
95 | // gen->SetPrintFreq(1); | |
96 | // | |
97 | // gen->SetSpectatorPmin(0.01); | |
98 | // | |
99 | // Int_t zp=1; | |
100 | // Int_t ap=1; | |
101 | // Int_t zt=2; | |
102 | // Int_t at=4; | |
103 | // | |
104 | // gen->Init("fixt",zp,ap,zt,at,158); | |
105 | // | |
106 | // AliHelix* helix=new AliHelix(); | |
107 | // Float_t vec[3]={0,2,0}; | |
108 | // Ali3Vector b; | |
109 | // b.SetVector(vec,"car"); | |
110 | // helix->SetB(b); | |
111 | // | |
112 | // helix->Refresh(-1); // Refresh display after each event | |
113 | // | |
114 | // TCanvas* c1=new TCanvas("c1","c1"); | |
115 | // TView* view=new TView(1); | |
116 | // view->SetRange(-200,-200,-200,200,200,200); | |
117 | // view->ShowAxis(); | |
118 | // | |
119 | // // Prepare random number sequence for this run | |
120 | // // to obtain the number of participants for each event | |
121 | // AliRandom rndm(abs(jrun)); | |
122 | // Float_t* rans=new Float_t[nevents]; | |
123 | // rndm.Uniform(rans,nevents,2,ap+at); | |
124 | // Int_t npart=0; | |
125 | // Int_t ntk=0; | |
126 | // for (Int_t i=0; i<nevents; i++) | |
127 | // { | |
128 | // npart=rans[i]; | |
129 | // gen->MakeEvent(npart); | |
130 | // AliEvent* evt=gen->GetEvent(); | |
131 | // if (evt) | |
132 | // { | |
133 | // helix->Display(evt); | |
134 | // c1->Update(); | |
135 | // gSystem->Sleep(5000); // Some delay to keep the display on screen | |
136 | // } | |
137 | // } | |
138 | // ====================================================================== | |
139 | // | |
140 | //--- Author: Nick van Eijndhoven 17-jun-2004 Utrecht University | |
141 | //- Modified: NvE $Date$ Utrecht University | |
142 | /////////////////////////////////////////////////////////////////////////// | |
143 | ||
144 | #include "AliHelix.h" | |
145 | #include "Riostream.h" | |
146 | ||
147 | ClassImp(AliHelix) // Class implementation to enable ROOT I/O | |
148 | ||
149 | AliHelix::AliHelix() : THelix() | |
150 | { | |
151 | // Default constructor | |
152 | fRefresh=0; | |
153 | fCurves=0; | |
154 | fExt=0; | |
155 | fTofmax=1e-8; | |
156 | } | |
157 | /////////////////////////////////////////////////////////////////////////// | |
158 | AliHelix::~AliHelix() | |
159 | { | |
160 | // Destructor to delete dynamically allocated memory. | |
161 | if (fCurves) | |
162 | { | |
163 | delete fCurves; | |
164 | fCurves=0; | |
165 | } | |
166 | if (fExt) | |
167 | { | |
168 | delete fExt; | |
169 | fExt=0; | |
170 | } | |
171 | } | |
172 | /////////////////////////////////////////////////////////////////////////// | |
173 | AliHelix::AliHelix(const AliHelix& h) : THelix(h) | |
174 | { | |
175 | // Copy constructor | |
176 | fB=h.fB; | |
177 | fRefresh=h.fRefresh; | |
178 | } | |
179 | /////////////////////////////////////////////////////////////////////////// | |
180 | void AliHelix::SetB(Ali3Vector& b) | |
181 | { | |
182 | // Set the magnetic field vector in Tesla. | |
183 | fB=b; | |
184 | ||
185 | if (fB.GetNorm()>0) | |
186 | { | |
187 | Double_t axis[3]; | |
188 | fB.GetVector(axis,"car"); | |
189 | SetAxis(axis); | |
190 | } | |
191 | } | |
192 | /////////////////////////////////////////////////////////////////////////// | |
193 | Ali3Vector& AliHelix::GetB() | |
194 | { | |
195 | // Provide the magnetic field vector in Tesla. | |
196 | return fB; | |
197 | } | |
198 | /////////////////////////////////////////////////////////////////////////// | |
199 | void AliHelix::SetTofmax(Float_t tof) | |
200 | { | |
201 | // Set the maximum time of flight for straight tracks in seconds. | |
202 | // This maximum tof will be used for drawing etc... in case no begin | |
203 | // and endpoints can be determined from the track info. | |
204 | // Notes : | |
205 | // ------- | |
206 | // 1) In case the user specifies an explicit range, it will override | |
207 | // the maximum tof limit. | |
208 | // 2) By default the tofmax is set to 10 ns in the AliHelix constructor. | |
209 | fTofmax=tof; | |
210 | } | |
211 | /////////////////////////////////////////////////////////////////////////// | |
212 | Float_t AliHelix::GetTofmax() const | |
213 | { | |
214 | // Provide the maximum time of flight for straight tracks in seconds. | |
215 | return fTofmax; | |
216 | } | |
217 | /////////////////////////////////////////////////////////////////////////// | |
218 | void AliHelix::MakeCurve(AliTrack* t,Double_t* range,Int_t iaxis,Double_t scale) | |
219 | { | |
220 | // Make the helix curve for the specified AliTrack. | |
221 | // Detailed information of all the helix points can be obtained via the | |
222 | // GetN() and GetP() memberfunctions of TPolyLine3D. | |
223 | // In case one wants to display or extrapolate an AliTrack it is preferable | |
224 | // to use the Display() or Extrapolate() memberfunctions. | |
225 | // It is assumed that the track charge is stored in elementary units | |
226 | // (i.e. charge=1 for a proton) and that the track energy is stored in GeV. | |
227 | // The input argument "scale" specifies the unit scale for the various | |
228 | // locations where scale=0.01 indicates unit scales in cm etc... | |
229 | // In case scale<=0, the unit scale for locations is determined from the | |
230 | // begin, reference or endpoint of the track. If neither of these | |
231 | // positions is present, all locations are assumed to be given in cm. | |
232 | // The lower and upper bounds for the range are specified by range[0] and | |
233 | // range[1] and the argument "iaxis" indicates along which axis this range | |
234 | // is specified. | |
235 | // The range can be specified either in the LAB frame or in the Helix frame. | |
236 | // The latter is the frame in which the Z axis points in the B direction. | |
237 | // | |
238 | // The conventions for the "iaxis" argument are the following : | |
239 | // iaxis = 1 ==> X axis in the LAB frame | |
240 | // 2 ==> Y axis in the LAB frame | |
241 | // 3 ==> Z axis in the LAB frame | |
242 | // -1 ==> X axis in the Helix frame | |
243 | // -2 ==> Y axis in the Helix frame | |
244 | // -3 ==> Z axis in the Helix frame | |
245 | // | |
246 | // In case range=0 the begin/end/reference points of the AliTrack and the | |
247 | // maximum time of flight (see the SetTofmax() memberfunction) will be used | |
248 | // and an appropriate choice for the iaxis parameter will be made automatically | |
249 | // based on the track kinematics. | |
250 | // In case the reference point is not present, the begin or endpoint will be used | |
251 | // as reference point for the 3-momentum specification. If neither of these positions | |
252 | // is present, (0,0,0) will be taken as the reference point. | |
253 | // | |
254 | // The default values are range=0, iaxis=3 and scale=-1. | |
255 | ||
256 | SetPolyLine(0); // Reset the polyline data points | |
257 | ||
258 | if (!t || (range && !iaxis)) return; | |
259 | ||
260 | Double_t energy=t->GetEnergy(); | |
261 | Double_t betanorm=t->GetBeta(); | |
262 | ||
263 | if (energy<=0 || betanorm<=0) return; | |
264 | ||
265 | AliPosition* rbeg=t->GetBeginPoint(); | |
266 | AliPosition* rend=t->GetEndPoint(); | |
267 | AliPosition* rref=t->GetReferencePoint(); | |
268 | ||
269 | // Magnetic field vector or default Z-direction | |
270 | Double_t bvec[3]={0,0,1}; | |
271 | if (fB.GetNorm()>0) fB.GetVector(bvec,"car"); | |
272 | ||
273 | // The unit scale for locations if not specified by the user | |
274 | if (scale<=0) | |
275 | { | |
276 | scale=0.01; // Set default to cm | |
277 | if (rbeg) | |
278 | { | |
279 | scale=rbeg->GetUnitScale(); | |
280 | } | |
281 | else if (rend) | |
282 | { | |
283 | scale=rend->GetUnitScale(); | |
284 | } | |
285 | else if (rref) | |
286 | { | |
287 | scale=rref->GetUnitScale(); | |
288 | } | |
289 | } | |
290 | ||
291 | Double_t c=2.99792458e8/scale; // Lightspeed in the selected unit scale | |
292 | ||
293 | // The helix angular frequency | |
294 | Double_t w=9e7*(t->GetCharge()*fB.GetNorm())/energy; | |
295 | ||
296 | // The particle velocity in the LAB frame | |
297 | Ali3Vector beta=t->GetBetaVector(); | |
298 | Ali3Vector v=beta*c; | |
299 | Double_t vel[3]; | |
300 | v.GetVector(vel,"car"); | |
301 | ||
302 | // The particle velocity in the Helix frame | |
303 | Ali3Vector betaprim=beta.GetPrimed(fRotMat); | |
304 | v=v.GetPrimed(fRotMat); | |
305 | Double_t velprim[3]; | |
306 | v.GetVector(velprim,"car"); | |
307 | ||
308 | // Check compatibility of velocity and range specification. | |
309 | if (range) | |
310 | { | |
311 | Double_t betavec[3]; | |
312 | if (iaxis>0) beta.GetVector(betavec,"car"); | |
313 | if (iaxis<0) betaprim.GetVector(betavec,"car"); | |
7a086578 | 314 | if (fabs(betavec[abs(iaxis)-1])/betanorm<1e-10) return; |
c5555bc0 | 315 | } |
316 | ||
317 | // The LAB location in which the velocity of the particle is defined | |
318 | Double_t loc[3]={0,0,0}; | |
319 | Ali3Vector* rx=0; | |
320 | Double_t scalex=0; | |
321 | if (rref) | |
322 | { | |
323 | rx=(Ali3Vector*)rref; | |
324 | scalex=rref->GetUnitScale(); | |
325 | } | |
326 | else if (rbeg) | |
327 | { | |
328 | rx=(Ali3Vector*)rbeg; | |
329 | scalex=rbeg->GetUnitScale(); | |
330 | } | |
331 | else if (rend) | |
332 | { | |
333 | rx=(Ali3Vector*)rend; | |
334 | scalex=rend->GetUnitScale(); | |
335 | } | |
336 | ||
337 | if (rx) | |
338 | { | |
339 | if (scalex/scale>1.1 || scale/scalex>1.1) (*rx)*=scalex/scale; | |
340 | rx->GetVector(loc,"car"); | |
341 | } | |
342 | ||
343 | // Initialisation of Helix kinematics | |
344 | SetHelix(loc,vel,w,0,kUnchanged,bvec); | |
345 | ||
346 | Int_t bend=0; | |
7a086578 | 347 | if (fabs(w)>0 && fabs(fVt)>0) bend=1; |
c5555bc0 | 348 | |
349 | // Flight time boundaries. | |
350 | // The time origin t=0 is chosen to indicate the position in which | |
351 | // the particle velocity was defined. | |
352 | // The total flight time is initialised to the (user specified) tofmax. | |
353 | Double_t tmin=0,tmax=0; | |
354 | Double_t tof=fTofmax; | |
355 | Double_t dum=0; | |
356 | ||
357 | // The trajectory begin and end points | |
358 | Double_t vec1[3]={0,0,0}; | |
359 | Double_t vec2[3]={0,0,0}; | |
360 | Ali3Vector r1; | |
361 | Ali3Vector r2; | |
362 | Double_t scale1=0.01; | |
363 | Double_t scale2=0.01; | |
364 | ||
365 | if (!bend) | |
366 | { | |
367 | //////////////////////////////////////// | |
368 | // Treatment of straight trajectories // | |
369 | //////////////////////////////////////// | |
370 | Ali3Vector r; | |
371 | if (range) // Specified range allows for exact flight time boundaries | |
372 | { | |
373 | if (iaxis>0) | |
374 | { | |
375 | tmin=(range[0]-loc[iaxis-1])/vel[iaxis-1]; | |
376 | tmax=(range[1]-loc[iaxis-1])/vel[iaxis-1]; | |
377 | } | |
378 | else | |
379 | { | |
380 | loc[0]=fX0; | |
381 | loc[1]=fY0; | |
382 | loc[2]=fZ0; | |
7a086578 | 383 | tmin=(range[0]-loc[abs(iaxis)-1])/velprim[abs(iaxis)-1]; |
384 | tmax=(range[1]-loc[abs(iaxis)-1])/velprim[abs(iaxis)-1]; | |
c5555bc0 | 385 | } |
386 | if (tmax<tmin) | |
387 | { | |
388 | dum=tmin; | |
389 | tmin=tmax; | |
390 | tmax=dum; | |
391 | } | |
392 | // Make the 'curve' in the LAB frame and exit. | |
393 | // Use the parametrisation : r(t)=r0+t*v | |
394 | // using the range based flight time boundaries. | |
395 | // An additional point in the middle of the trajectory is | |
396 | // generated in view of accuracy in the case of extrapolations. | |
397 | tof=tmax-tmin; | |
398 | v=beta*c; | |
399 | if (rx) r1=(*rx); | |
400 | r=v*tmin; | |
401 | r1=r1+r; | |
402 | r1.GetVector(vec1,"car"); | |
403 | SetNextPoint(float(vec1[0]),float(vec1[1]),float(vec1[2])); | |
404 | r=v*(tof/2.); | |
405 | r2=r1+r; | |
406 | r2.GetVector(vec2,"car"); | |
407 | SetNextPoint(float(vec2[0]),float(vec2[1]),float(vec2[2])); | |
408 | r=v*tof; | |
409 | r2=r1+r; | |
410 | r2.GetVector(vec2,"car"); | |
411 | SetNextPoint(float(vec2[0]),float(vec2[1]),float(vec2[2])); | |
412 | } | |
413 | else // Automatic range determination | |
414 | { | |
415 | // Initially the point with Z=0 in the Helix frame is taken as a starting point. | |
416 | // In case this point can't be reached, the point in which the particle velocity | |
417 | // was defined is taken as the starting point. | |
418 | // The endpoint is initially obtained by applying the tofmax from the start point. | |
419 | tmin=0; | |
7a086578 | 420 | if (fabs(fVz)>0) tmin=-fZ0/fVz; |
c5555bc0 | 421 | v=beta*c; |
422 | if (rx) r1=(*rx); | |
423 | r=v*tmin; | |
424 | r1=r1+r; | |
425 | ||
426 | // Override the initial begin and endpoint settings by the track data | |
427 | if (rbeg) | |
428 | { | |
429 | r1=(Ali3Vector)(*rbeg); | |
430 | scale1=rbeg->GetUnitScale(); | |
431 | // All coordinates in the selected unit scale | |
432 | if (scale1/scale>1.1 || scale/scale1>1.1) r1*=scale1/scale; | |
433 | } | |
434 | ||
435 | r=v*fTofmax; | |
436 | r2=r1+r; | |
437 | if (rend) | |
438 | { | |
439 | r2=(Ali3Vector)(*rend); | |
440 | scale2=rend->GetUnitScale(); | |
441 | // All coordinates in the selected unit scale | |
442 | if (scale2/scale>1.1 || scale/scale2>1.1) r2*=scale2/scale; | |
443 | } | |
444 | ||
445 | r1.GetVector(vec1,"car"); | |
446 | r2.GetVector(vec2,"car"); | |
447 | ||
448 | // Make the 'curve' in the LAB frame and exit. | |
449 | SetNextPoint(float(vec1[0]),float(vec1[1]),float(vec1[2])); | |
450 | SetNextPoint(float(vec2[0]),float(vec2[1]),float(vec2[2])); | |
451 | } | |
452 | } | |
453 | else | |
454 | { | |
455 | ////////////////////////////////////// | |
456 | // Treatment of curved trajectories // | |
457 | ////////////////////////////////////// | |
458 | ||
459 | // Initialisation of the flight time boundaries. | |
460 | // Based on the constant motion of the particle along the Helix Z-axis, | |
461 | // the parametrisation z(t)=z0+fVz*t in the Helix frame is used. | |
462 | // If possible the point with Z=0 in the Helix frame is taken as a starting point. | |
463 | // In case this point can't be reached, the point in which the particle velocity | |
464 | // was defined is taken as the starting point. | |
465 | tmin=0; | |
7a086578 | 466 | if (fabs(fVz)>0) tmin=-fZ0/fVz; |
c5555bc0 | 467 | tmax=tmin+fTofmax; |
468 | ||
469 | if (tmax<tmin) | |
470 | { | |
471 | dum=tmin; | |
472 | tmin=tmax; | |
473 | tmax=dum; | |
474 | } | |
475 | ||
476 | // Determination of the range in the helix frame | |
477 | ||
478 | if (!range) // Automatic range determination | |
479 | { | |
480 | scale1=0.01; | |
481 | scale2=0.01; | |
482 | if (rbeg) | |
483 | { | |
484 | r1=rbeg->GetPrimed(fRotMat); | |
485 | scale1=rbeg->GetUnitScale(); | |
486 | // All coordinates in the selected unit scale | |
487 | if (scale1/scale>1.1 || scale/scale1>1.1) r1*=scale1/scale; | |
488 | // Re-calculate the tmin for this new starting point | |
489 | r1.GetVector(vec1,"car"); | |
7a086578 | 490 | if (fabs(fVz)>0) tmin=(vec1[2]-fZ0)/fVz; |
c5555bc0 | 491 | tmax=tmin+fTofmax; |
492 | } | |
493 | if (rend) | |
494 | { | |
495 | r2=rend->GetPrimed(fRotMat); | |
496 | scale2=rend->GetUnitScale(); | |
497 | // All coordinates in the selected unit scale | |
498 | if (scale2/scale>1.1 || scale/scale2>1.1) r2*=scale2/scale; | |
499 | r2.GetVector(vec2,"car"); | |
7a086578 | 500 | if (fabs(fVz)>0) tmax=(vec2[2]-fZ0)/fVz; |
c5555bc0 | 501 | } |
502 | // Make the curve on basis of the flight time boundaries and exit | |
503 | if (tmax<tmin) | |
504 | { | |
505 | dum=tmin; | |
506 | tmin=tmax; | |
507 | tmax=dum; | |
508 | } | |
509 | SetRange(tmin,tmax,kHelixT); | |
510 | } | |
511 | else // User explicitly specified range | |
512 | { | |
7a086578 | 513 | vec1[abs(iaxis)-1]=range[0]; |
514 | vec2[abs(iaxis)-1]=range[1]; | |
c5555bc0 | 515 | r1.SetVector(vec1,"car"); |
516 | r2.SetVector(vec2,"car"); | |
517 | if (iaxis>0) // Range specified in LAB frame | |
518 | { | |
519 | r1=r1.GetPrimed(fRotMat); | |
520 | r1.GetVector(vec1,"car"); | |
521 | r2=r2.GetPrimed(fRotMat); | |
522 | r2.GetVector(vec2,"car"); | |
523 | } | |
524 | // Determination of the axis component with the | |
525 | // largest range difference | |
526 | Double_t dmax=0; | |
527 | Int_t imax=0; | |
528 | Double_t test=0; | |
529 | for (Int_t i=0; i<3; i++) | |
530 | { | |
7a086578 | 531 | test=fabs(vec1[i]-vec2[i]); |
c5555bc0 | 532 | if (test>dmax) |
533 | { | |
534 | dmax=test; | |
535 | imax=i; | |
536 | } | |
537 | } | |
538 | ||
539 | Double_t rmin=vec1[imax]; | |
540 | Double_t rmax=vec2[imax]; | |
541 | if (rmax<rmin) | |
542 | { | |
543 | dum=rmin; | |
544 | rmin=rmax; | |
545 | rmax=dum; | |
546 | } | |
547 | ||
548 | // The kinematic range boundaries in the helix frame | |
549 | Double_t xmin=fX0-fVt/fW; | |
550 | Double_t xmax=fX0+fVt/fW; | |
551 | Double_t ymin=fY0-fVt/fW; | |
552 | Double_t ymax=fY0+fVt/fW; | |
553 | ||
554 | if (xmax<xmin) | |
555 | { | |
556 | dum=xmin; | |
557 | xmin=xmax; | |
558 | xmax=dum; | |
559 | } | |
560 | if (ymax<ymin) | |
561 | { | |
562 | dum=ymin; | |
563 | ymin=ymax; | |
564 | ymax=dum; | |
565 | } | |
566 | ||
567 | // Set the range for the helix | |
568 | if (imax==2 && dmax>0) SetRange(rmin,rmax,kHelixZ); | |
569 | if (imax==1) | |
570 | { | |
571 | // Limit range to kinematic boundaries if needed | |
572 | if (rmin<=ymin) rmin=ymin+1e-6*dmax; | |
573 | if (rmax>=ymax) rmax=ymax-1e-6*dmax; | |
574 | if (rmin<rmax) SetRange(rmin,rmax,kHelixY); | |
575 | } | |
576 | if (imax==0) | |
577 | { | |
578 | // Limit range to kinematic boundaries if needed | |
579 | if (rmin<=xmin) rmin=xmin+1e-6*dmax; | |
580 | if (rmax>=xmax) rmax=xmax-1e-6*dmax; | |
581 | if (rmin<rmax) SetRange(rmin,rmax,kHelixX); | |
582 | } | |
583 | } | |
584 | } | |
585 | return; | |
586 | } | |
587 | /////////////////////////////////////////////////////////////////////////// | |
588 | void AliHelix::Display(AliTrack* t,Double_t* range,Int_t iaxis,Double_t scale) | |
589 | { | |
590 | // Display the helix curve of an AliTrack. | |
591 | // Various curves can be displayed together or individually; please refer to | |
592 | // the memberfunction Refresh() for further details. | |
593 | // It is assumed that the track charge is stored in elementary units | |
594 | // (i.e. charge=1 for a proton) and that the track energy is stored in GeV. | |
595 | // The input argument "scale" specifies the unit scale for the various | |
596 | // locations where scale=0.01 indicates unit scales in cm etc... | |
597 | // In case scale<=0, the unit scale for locations is determined from the | |
598 | // begin, reference or endpoint of the track. If neither of these | |
599 | // positions is present, all locations are assumed to be given in cm. | |
600 | // The lower and upper bounds for the range are specified by range[0] and | |
601 | // range[1] and the argument "iaxis" indicates along which axis this range | |
602 | // is specified. | |
603 | // The range can be specified either in the LAB frame or in the Helix frame. | |
604 | // The latter is the frame in which the Z axis points in the B direction. | |
605 | // | |
606 | // The conventions for the "iaxis" argument are the following : | |
607 | // iaxis = 1 ==> X axis in the LAB frame | |
608 | // 2 ==> Y axis in the LAB frame | |
609 | // 3 ==> Z axis in the LAB frame | |
610 | // -1 ==> X axis in the Helix frame | |
611 | // -2 ==> Y axis in the Helix frame | |
612 | // -3 ==> Z axis in the Helix frame | |
613 | // | |
614 | // In case range=0 the begin/end/reference points of the AliTrack and the | |
615 | // maximum time of flight (see the SetTofmax() memberfunction) will be used | |
616 | // and an appropriate choice for the iaxis parameter will be made automatically | |
617 | // based on the track kinematics. | |
618 | // In case the reference point is not present, the begin or endpoint will be used | |
619 | // as reference point for the 3-momentum specification. If neither of these positions | |
620 | // is present, (0,0,0) will be taken as the reference point. | |
621 | // | |
622 | // The default values are range=0, iaxis=3 and scale=-1. | |
623 | // | |
624 | // Note : | |
625 | // ------ | |
626 | // Before any display activity, a TCanvas and a TView have to be initiated | |
627 | // first by the user like for instance | |
628 | // | |
629 | // TCanvas* c1=new TCanvas("c1","c1"); | |
630 | // TView* view=new TView(1); | |
631 | // view->SetRange(-1000,-1000,-1000,1000,1000,1000); | |
632 | // view->ShowAxis(); | |
633 | ||
634 | if (!t || (range && !iaxis)) return; | |
635 | ||
636 | MakeCurve(t,range,iaxis,scale); | |
637 | ||
638 | if (fRefresh>0) Refresh(fRefresh); | |
639 | ||
640 | Int_t np=GetN(); | |
641 | if (!np) return; | |
642 | ||
643 | Float_t* points=GetP(); | |
644 | TPolyLine3D* curve=new TPolyLine3D(np,points); | |
645 | ||
646 | curve->SetLineWidth(2); | |
647 | Float_t q=t->GetCharge(); | |
648 | curve->SetLineColor(kGreen); | |
649 | if (q>0) curve->SetLineColor(kRed); | |
650 | if (q<0) curve->SetLineColor(kBlue); | |
651 | curve->Draw(); | |
652 | ||
653 | if (!fCurves) | |
654 | { | |
655 | fCurves=new TObjArray(); | |
656 | fCurves->SetOwner(); | |
657 | } | |
658 | fCurves->Add(curve); | |
659 | } | |
660 | /////////////////////////////////////////////////////////////////////////// | |
661 | void AliHelix::Refresh(Int_t mode) | |
662 | { | |
663 | // Refresh the display screen before showing the next curve. | |
664 | // | |
665 | // mode = 0 : refreshing fully under user control. | |
666 | // 1 : the display screen will be refreshed automatically | |
667 | // at each individual track display. | |
668 | // -1 : the display screen will be refreshed automatically | |
669 | // at each event display. | |
670 | // | |
671 | // The default is mode=0. | |
672 | ||
7a086578 | 673 | if (abs(mode)<2) fRefresh=mode; |
c5555bc0 | 674 | if (fCurves) fCurves->Delete(); |
675 | } | |
676 | /////////////////////////////////////////////////////////////////////////// | |
677 | void AliHelix::Display(AliEvent* evt,Double_t* range,Int_t iaxis,Double_t scale) | |
678 | { | |
679 | // Display the helix curves of all tracks of the specified event. | |
680 | // Various events can be displayed together or individually; please refer to | |
681 | // the memberfunction Refresh() for further details. | |
682 | // Please refer to the track display memberfunction for further details | |
683 | // on the input arguments. | |
684 | // | |
685 | // The default values are range=0, iaxis=3 and scale=-1. | |
686 | // | |
687 | // Note : | |
688 | // ------ | |
689 | // Before any display activity, a TCanvas and a TView have to be initiated | |
690 | // first by the user like for instance | |
691 | // | |
692 | // TCanvas* c1=new TCanvas("c1","c1"); | |
693 | // TView* view=new TView(1); | |
694 | // view->SetRange(-1000,-1000,-1000,1000,1000,1000); | |
695 | // view->ShowAxis(); | |
696 | ||
697 | if (!evt) return; | |
698 | ||
699 | if (fRefresh<0) Refresh(fRefresh); | |
700 | ||
701 | Int_t ntk=evt->GetNtracks(); | |
702 | for (Int_t jtk=1; jtk<=ntk; jtk++) | |
703 | { | |
704 | AliTrack* tx=evt->GetTrack(jtk); | |
705 | if (tx) Display(tx,range,iaxis,scale); | |
706 | } | |
707 | } | |
708 | /////////////////////////////////////////////////////////////////////////// | |
709 | AliPosition* AliHelix::Extrapolate(AliTrack* t,Double_t* pars,Double_t scale) | |
710 | { | |
711 | // Extrapolate an AliTrack according to the corresponding helix curve | |
712 | // and provide a pointer to the impact position w.r.t. a specified plane. | |
713 | // In case the track can never reach the specified plane, the returned | |
714 | // position pointer is zero. | |
715 | // Detailed information of all the helix points used in the extrapolation | |
716 | // can be obtained via the GetN() and GetP() memberfunctions of TPolyLine3D. | |
717 | // It is assumed that the track charge is stored in elementary units | |
718 | // (i.e. charge=1 for a proton) and that the track energy is stored in GeV. | |
719 | // The input argument "scale" specifies the unit scale for the various | |
720 | // locations where scale=0.01 indicates unit scales in cm etc... | |
721 | // In case scale<=0, the unit scale for locations is determined from the | |
722 | // begin, reference or endpoint of the track. If neither of these | |
723 | // positions is present, all locations are assumed to be given in cm. | |
724 | // The extrapolation parameters for the impact plane and required accuracy | |
725 | // are specified by pars[0], pars[1] and pars[2], respectively. | |
726 | // pars[0] = coordinate value of the plane for the impact point | |
727 | // pars[1] = required accuracy on the specified impact plane coordinate | |
728 | // pars[2] = the axis along which the value of par[0] is specified | |
729 | // | |
730 | // The parameters can be specified either w.r.t. the LAB frame or the Helix frame. | |
731 | // The latter is the frame in which the Z axis points in the B direction. | |
732 | // | |
733 | // The conventions for the par[2] argument are the following : | |
734 | // par[2] = 1 ==> X axis in the LAB frame | |
735 | // 2 ==> Y axis in the LAB frame | |
736 | // 3 ==> Z axis in the LAB frame | |
737 | // -1 ==> X axis in the Helix frame | |
738 | // -2 ==> Y axis in the Helix frame | |
739 | // -3 ==> Z axis in the Helix frame | |
740 | // | |
741 | // Example : | |
742 | // --------- | |
743 | // To obtain an extrapolation to the plane Z=0 in the LAB frame | |
744 | // with an accuracy of 0.001 cm the input arguments would be | |
745 | // pars[0]=0 pars[1]=0.001 pars[2]=3 scale=0.01 | |
746 | // | |
747 | // Note : The default value for the scale is -1. | |
748 | ||
749 | if (fExt) | |
750 | { | |
751 | delete fExt; | |
752 | fExt=0; | |
753 | } | |
754 | ||
755 | if (!t || !pars) return fExt; | |
756 | ||
757 | AliPosition* rbeg=t->GetBeginPoint(); | |
758 | AliPosition* rend=t->GetEndPoint(); | |
759 | AliPosition* rref=t->GetReferencePoint(); | |
760 | ||
761 | // The unit scale for locations if not specified by the user | |
762 | if (scale<=0) | |
763 | { | |
764 | scale=0.01; // Set default to cm | |
765 | if (rbeg) | |
766 | { | |
767 | scale=rbeg->GetUnitScale(); | |
768 | } | |
769 | else if (rend) | |
770 | { | |
771 | scale=rend->GetUnitScale(); | |
772 | } | |
773 | else if (rref) | |
774 | { | |
775 | scale=rref->GetUnitScale(); | |
776 | } | |
777 | } | |
778 | ||
779 | Double_t range[2]; | |
7a086578 | 780 | range[0]=pars[0]-fabs(pars[1])/2.; |
781 | range[1]=pars[0]+fabs(pars[1])/2.; | |
c5555bc0 | 782 | |
783 | Int_t iaxis=int(pars[2]); | |
784 | ||
785 | MakeCurve(t,range,iaxis,scale); | |
786 | ||
787 | Int_t np=GetN(); | |
788 | if (!np) return fExt; | |
789 | ||
790 | Float_t* points=GetP(); | |
791 | ||
792 | // First point of the curve around the impact | |
793 | Int_t ip=0; | |
794 | Float_t first[3]={points[3*ip],points[3*ip+1],points[3*ip+2]}; | |
795 | ||
796 | // Last point of the curve around the impact | |
797 | ip=np-1; | |
798 | Float_t last[3]={points[3*ip],points[3*ip+1],points[3*ip+2]}; | |
799 | ||
800 | // The accuracy on the impact point | |
801 | Float_t err[3]; | |
7a086578 | 802 | err[0]=fabs(first[0]-last[0]); |
803 | err[1]=fabs(first[1]-last[1]); | |
804 | err[2]=fabs(first[2]-last[2]); | |
c5555bc0 | 805 | |
806 | // Take the middle point as impact location | |
807 | ip=np/2; | |
808 | Float_t imp[3]={points[3*ip],points[3*ip+1],points[3*ip+2]}; | |
809 | ||
810 | fExt=new AliPosition(); | |
811 | fExt->SetUnitScale(scale); | |
812 | fExt->SetPosition(imp,"car"); | |
813 | fExt->SetPositionErrors(err,"car"); | |
814 | ||
815 | return fExt; | |
816 | } | |
817 | /////////////////////////////////////////////////////////////////////////// |