1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
17 /* History of cvs commits:
20 * Revision 1.93 2007/10/10 09:05:10 schutz
21 * Changing name QualAss to QA
23 * Revision 1.92 2007/08/28 12:55:08 policheh
24 * Loaders removed from the reconstruction code (C.Cheshkov)
26 * Revision 1.91 2007/08/07 14:12:03 kharlov
27 * Quality assurance added (Yves Schutz)
29 * Revision 1.90 2007/07/11 13:43:30 hristov
30 * New class AliESDEvent, backward compatibility with the old AliESD (Christian)
32 * Revision 1.89 2007/07/03 08:13:04 kharlov
33 * Bug fix in CPV local coordinates
35 * Revision 1.88 2007/06/27 09:11:07 kharlov
36 * Bug fix for CPV-EMC distance
38 * Revision 1.87 2007/05/04 14:49:29 policheh
39 * AliPHOSRecPoint inheritance from AliCluster
41 * Revision 1.86 2007/04/02 15:00:16 cvetan
42 * No more calls to gAlice in the reconstruction
44 * Revision 1.85 2007/03/28 19:18:15 kharlov
45 * RecPoints recalculation in TSM removed
47 * Revision 1.84 2007/03/07 07:01:21 hristov
48 * Fixing copy/paste erro. Additional protections
50 * Revision 1.83 2007/03/06 21:07:37 kharlov
51 * DP: xz CPV-EMC distance filled to TS
53 * Revision 1.82 2007/03/06 06:54:48 kharlov
54 * DP:Calculation of cluster properties dep. on vertex added
56 * Revision 1.81 2007/02/05 10:02:40 kharlov
57 * Module numbering is corrected
59 * Revision 1.80 2006/08/28 10:01:56 kharlov
60 * Effective C++ warnings fixed (Timur Pocheptsov)
62 * Revision 1.79 2006/04/25 12:41:15 hristov
63 * Moving non-persistent data to AliESDfriend (Yu.Belikov)
65 * Revision 1.78 2005/11/18 13:04:51 hristov
68 * Revision 1.77 2005/11/17 23:34:36 hristov
71 * Revision 1.76 2005/11/17 22:29:12 hristov
72 * Faster version, no attempt to match tracks outside the PHOS acceptance
74 * Revision 1.75 2005/11/17 12:35:27 hristov
75 * Use references instead of objects. Avoid to create objects when they are not really needed
77 * Revision 1.74 2005/07/08 14:01:36 hristov
78 * Tracking in non-uniform nmagnetic field (Yu.Belikov)
80 * Revision 1.73 2005/05/28 14:19:05 schutz
81 * Compilation warnings fixed by T.P.
85 //_________________________________________________________________________
86 // Implementation version 1 of algorithm class to construct PHOS track segments
87 // Track segment for PHOS is list of
88 // EMC RecPoint + (possibly) CPV RecPoint
89 // To find TrackSegments we do the following:
90 // for each EMC RecPoints we look at
91 // CPV RecPoints in the radious fRcpv.
92 // If there is such a CPV RecPoint,
93 // we make "Link" it is just indexes of EMC and CPV RecPoint and distance
94 // between them in the PHOS plane.
95 // Then we sort "Links" and starting from the
96 // least "Link" pointing to the unassined EMC and CPV RecPoints assing them to
98 // If there is no CPV RecPoint we make TrackSegment
99 // consisting from EMC alone. There is no TrackSegments without EMC RecPoint.
100 //// In principle this class should be called from AliPHOSReconstructor, but
101 // one can use it as well in standalone mode.
103 // root [0] AliPHOSTrackSegmentMakerv1 * t = new AliPHOSTrackSegmentMaker("galice.root", "tracksegmentsname", "recpointsname")
104 // Warning in <TDatabasePDG::TDatabasePDG>: object already instantiated
105 // // reads gAlice from header file "galice.root", uses recpoints stored in the branch names "recpointsname" (default = "Default")
106 // // and saves recpoints in branch named "tracksegmentsname" (default = "recpointsname")
107 // root [1] t->ExecuteTask()
108 // root [3] t->SetTrackSegmentsBranch("max distance 5 cm")
109 // root [4] t->ExecuteTask("deb all time")
111 //*-- Author: Dmitri Peressounko (RRC Ki & SUBATECH) & Yves Schutz (SUBATECH)
114 // --- ROOT system ---
116 #include "AliTracker.h"
117 #include "AliGeomManager.h"
118 #include "AliCluster.h"
119 #include "AliKalmanTrack.h"
120 #include "AliGlobalQADataMaker.h"
122 #include "TVector3.h"
124 #include "TBenchmark.h"
126 // --- Standard library ---
127 #include "Riostream.h"
128 // --- AliRoot header files ---
129 #include "AliPHOSGeometry.h"
130 #include "AliPHOSTrackSegmentMakerv1.h"
131 #include "AliPHOSTrackSegment.h"
132 #include "AliPHOSLink.h"
133 #include "AliESDEvent.h"
134 #include "AliESDtrack.h"
135 #include "AliPHOSEmcRecPoint.h"
136 #include "AliPHOSCpvRecPoint.h"
140 ClassImp( AliPHOSTrackSegmentMakerv1)
143 //____________________________________________________________________________
144 AliPHOSTrackSegmentMakerv1::AliPHOSTrackSegmentMakerv1() :
145 AliPHOSTrackSegmentMaker(),
160 // default ctor (to be used mainly by Streamer)
164 //____________________________________________________________________________
165 AliPHOSTrackSegmentMakerv1::AliPHOSTrackSegmentMakerv1(AliPHOSGeometry *geom) :
166 AliPHOSTrackSegmentMaker(geom),
167 fDefaultInit(kFALSE),
188 AliPHOSTrackSegmentMakerv1::AliPHOSTrackSegmentMakerv1(const AliPHOSTrackSegmentMakerv1 & tsm) :
189 AliPHOSTrackSegmentMaker(tsm),
190 fDefaultInit(kFALSE),
204 // cpy ctor: no implementation yet
205 // requested by the Coding Convention
206 Fatal("cpy ctor", "not implemented") ;
210 //____________________________________________________________________________
211 AliPHOSTrackSegmentMakerv1::~AliPHOSTrackSegmentMakerv1()
214 // fDefaultInit = kTRUE if TrackSegmentMaker created by default ctor (to get just the parameters)
216 delete fLinkUpArray ;
217 if (fTrackSegments) {
218 fTrackSegments->Delete();
219 delete fTrackSegments;
223 //____________________________________________________________________________
224 void AliPHOSTrackSegmentMakerv1::FillOneModule()
226 // Finds first and last indexes between which
227 // clusters from one PHOS module are
230 Int_t totalEmc = fEMCRecPoints->GetEntriesFast() ;
231 for(fEmcFirst = fEmcLast; (fEmcLast < totalEmc) &&
232 ((dynamic_cast<AliPHOSRecPoint *>(fEMCRecPoints->At(fEmcLast)))->GetPHOSMod() == fModule );
236 Int_t totalCpv = fCPVRecPoints->GetEntriesFast() ;
238 for(fCpvFirst = fCpvLast; (fCpvLast < totalCpv) &&
239 ((dynamic_cast<AliPHOSRecPoint *>(fCPVRecPoints->At(fCpvLast)))->GetPHOSMod() == fModule );
244 //____________________________________________________________________________
245 void AliPHOSTrackSegmentMakerv1::GetDistanceInPHOSPlane(AliPHOSEmcRecPoint * emcClu,
246 AliPHOSCpvRecPoint * cpvClu,
248 Float_t &dx, Float_t &dz) const
250 // Calculates the distance between the EMC RecPoint and the CPV RecPoint
251 // If no CPV, calculates the distance between the EMC RecPoint and the track
252 // prolongation to the PHOS module plane.
253 // Clusters are sorted in "rows" and "columns" of width 1 cm
255 // Float_t delta = 1 ; // Width of the rows in sorting of RecPoints (in cm)
256 // // if you change this value, change it as well in xxxRecPoint::Compare()
268 // *** Start the matching
269 Int_t nt=fESD->GetNumberOfTracks();
270 Int_t iPHOSMod = emcClu->GetPHOSMod() ;
271 //Calculate actual distance to PHOS module
273 fGeom->Local2Global(iPHOSMod, 0.,0., globaPos) ;
274 const Double_t rPHOS = globaPos.Pt() ; //Distance to PHOS module
275 const Double_t kYmax = 72.+10. ; //Size of the module (with some reserve) in phi direction
276 const Double_t kZmax = 64.+10. ; //Size of the module (with some reserve) in z direction
277 const Double_t kAlpha= 20./180.*TMath::Pi() ; //TPC sector angular size
278 Double_t minDistance = 1.e6;
281 TVector3 gposRecPoint; // global (in ALICE frame) position of rec. point
282 emcClu->GetGlobalPosition(gposRecPoint,gmat);
283 Double_t gposTrack[3] ;
285 Double_t bz = GetBz() ; //B-Field for approximate matching
287 for (Int_t i=0; i<nt; i++) {
288 AliESDtrack *esdTrack=fESD->GetTrack(i);
290 // // Skip the tracks having "wrong" status (has to be checked/tuned)
291 // ULong_t status = esdTrack->GetStatus();
292 // if ((status & AliESDtrack::kTRDout) == 0) continue;
293 // if ((status & AliESDtrack::kTRDrefit) == 1) continue;
295 AliExternalTrackParam t(*esdTrack);
296 Int_t isec=Int_t(t.GetAlpha()/kAlpha);
297 Int_t imod=-isec-2; // PHOS module
299 Double_t y; // Some tracks do not reach the PHOS
300 if (!t.GetYAt(rPHOS,bz,y)) continue; // because of the bending
302 Double_t z; t.GetZAt(rPHOS,bz,z);
303 if (TMath::Abs(z) > kZmax) continue; // Some tracks miss the PHOS in Z
306 while (TMath::Abs(y) > kYmax) { // Find the matching module
307 Double_t alp=t.GetAlpha();
309 if (!t.Rotate(alp+kAlpha)) {ok=kFALSE; break;}
311 } else if (y < -kYmax) {
312 if (!t.Rotate(alp-kAlpha)) {ok=kFALSE; break;}
315 if (!t.GetYAt(rPHOS,bz,y)) {ok=kFALSE; break;}
317 if (!ok) continue; // Track rotation failed
320 if(imod!= iPHOSMod-1)
321 continue; //not even approximate coincidence
323 //t.CorrectForMaterial(...); // Correct for the TOF material, if needed
325 t.PropagateToBxByBz(rPHOS,b); // Propagate to the matching module
326 t.GetXYZ(gposTrack) ;
328 Double_t ddx = gposTrack[0] - gposRecPoint.X(), ddy = gposTrack[1] - gposRecPoint.Y(), ddz = gposTrack[2] - gposRecPoint.Z();
329 Double_t d2 = ddx*ddx + ddy*ddy + ddz*ddz;
330 if(d2 < minDistance) {
331 dx = TMath::Sign(TMath::Sqrt(ddx*ddx + ddy*ddy),ddx) ;
342 fGeom->GetGlobalPHOS((AliPHOSRecPoint*)emcClu,emcGlobal);
344 // Radius from IP to current point
345 Double_t rEMC = TMath::Abs(emcGlobal.Pt());
347 // Extrapolate the global track direction to EMC
348 // and find the closest track
350 Int_t nTracks = fESD->GetNumberOfTracks();
353 Double_t xyz[] = {-1,-1,-1};
360 Float_t minDistance = 1.e6;
363 for (Int_t iTrack=0; iTrack<nTracks; iTrack++) {
364 track = fESD->GetTrack(iTrack);
365 if (!track->GetXYZAt(rEMC, fESD->GetMagneticField(), xyz)) continue;
367 AliDebug(1,Form("Event %d, iTrack: %d, (%.3f,%.3f,%.3f)",
368 fESD->GetEventNumberInFile(),iTrack,xyz[0],xyz[1],xyz[2]));
370 if (track->GetPxPyPzAt(rEMC,fESD->GetMagneticField(),pxyz)) {
372 vecP.SetXYZ(pxyz[0],pxyz[1],pxyz[2]);
373 fGeom->ImpactOnEmc(xyz,vecP.Theta(),vecP.Phi(),module,zEMC,xEMC) ;
375 if(!module) continue;
376 AliDebug(1,Form("\t\tTrack hit PHOS! Module: %d, (x,z)=(%.3f,%.3f)",module,xEMC,zEMC));
378 if(emcClu->GetPHOSMod() != module) continue;
380 // match track to EMC cluster
381 emcClu->GetLocalPosition(locClu);
383 Float_t delta_x = xEMC - locClu.X();
384 Float_t delta_z = zEMC - locClu.Z();
385 dr = TMath::Sqrt(delta_x*delta_x + delta_z*delta_z);
386 AliDebug(1,Form("\tMatch iTrack=%d: (dx,dz)=(%.3f,%.3f)",iTrack,delta_x,delta_z));
399 AliDebug(1,Form("\t\tBest match for (xClu,zClu,eClu)=(%.3f,%.3f,%.3f): iTrack=%d, dR=%.3f",
400 locClu.X(),locClu.Z(),emcClu->GetEnergy(),
401 trackindex,TMath::Sqrt(dx*dx+dz*dz)));
404 Float_t distance2Track = fRtpc ;
406 trackindex = -1 ; // closest track within fRCpv
408 TVector3 vecEmc ; // Local position of EMC recpoint
409 TVector3 vecPloc ; // Momentum direction at CPV plain
412 if(emcClu->GetPHOSMod() != cpvClu->GetPHOSMod()){
418 emcClu->GetLocalPosition(vecEmc) ;
420 Double_t xCPV,zCPV ; //EMC-projected coordinates of CPV cluster
421 TVector3 cpvGlobal; // Global position of the CPV recpoint
422 fGeom->GetGlobalPHOS((AliPHOSRecPoint*)cpvClu,cpvGlobal);
423 Double_t vtxCPV[3]={cpvGlobal.X(),cpvGlobal.Y(),cpvGlobal.Z()} ;
427 //if no track information available, assume straight line from IP to emcal
428 fGeom->ImpactOnEmc(vtxCPV,cpvGlobal.Theta(),cpvGlobal.Phi(),dummyMod,zCPV,xCPV) ;
429 dx=xCPV - vecEmc.X() ;
430 dz=zCPV - vecEmc.Z() ;
434 //if there is ESD try to correct distance using TPC information on particle direct in CPV
437 Double_t rCPV = cpvGlobal.Pt() ;// Radius from IP to current point
439 // Extrapolate the global track direction if any to CPV and find the closest track
440 Int_t nTracks = fESD->GetNumberOfTracks();
441 Int_t iClosestTrack = -1;
442 Double_t minDistance = 1.e6;
448 for (Int_t iTrack=0; iTrack<nTracks; iTrack++) {
449 track = fESD->GetTrack(iTrack);
450 if (!track->GetXYZAt(rCPV, fESD->GetMagneticField(), xyz))
451 continue; //track coord on the cylinder of PHOS radius
452 if ((TMath::Abs(xyz[0])+TMath::Abs(xyz[1])+TMath::Abs(xyz[2]))<=0)
454 //Check if this track hits PHOS
455 inPHOS.SetXYZ(xyz[0],xyz[1],xyz[2]);
456 distance2Track = inPHOS.Angle(cpvGlobal) ;
457 // Find the closest track to the CPV recpoint
458 if (distance2Track < minDistance) {
459 minDistance = distance2Track;
460 iClosestTrack = iTrack;
464 if (iClosestTrack != -1) {
465 track = fESD->GetTrack(iClosestTrack);
466 if (track->GetPxPyPzAt(rCPV, fESD->GetMagneticField(), pxyz)) { // track momentum ibid.
467 vecP.SetXYZ(pxyz[0],pxyz[1],pxyz[2]);
468 fGeom->ImpactOnEmc(vtxCPV,vecP.Theta(),vecP.Phi(),dummyMod,zCPV,xCPV) ;
472 if(minDistance < fRtpc ){
473 trackindex = iClosestTrack ;
477 // If the closest global track is found, calculate EMC-CPV distance from it
478 dx=xCPV - vecEmc.X() ;
479 dz=zCPV - vecEmc.Z() ;
482 // If no global track was found, just take the nearest CPV point
483 fGeom->ImpactOnEmc(vtxCPV,cpvGlobal.Theta(),cpvGlobal.Phi(),dummyMod,zCPV,xCPV) ;
484 dx=xCPV - vecEmc.X() ;
485 dz=zCPV - vecEmc.Z() ;
489 //____________________________________________________________________________
490 void AliPHOSTrackSegmentMakerv1::Init()
492 // Make all memory allocations that are not possible in default constructor
494 fLinkUpArray = new TClonesArray("AliPHOSLink", 1000);
495 fTrackSegments = new TClonesArray("AliPHOSTrackSegment",100);
496 fTrackSegments->SetName("TRACKS");
499 //____________________________________________________________________________
500 void AliPHOSTrackSegmentMakerv1::InitParameters()
502 //Initializes parameters
514 //____________________________________________________________________________
515 void AliPHOSTrackSegmentMakerv1::MakeLinks()const
517 // Finds distances (links) between all EMC and CPV clusters,
518 // which are not further apart from each other than fRcpv
519 // and sort them in accordance with this distance
521 fLinkUpArray->Clear() ;
523 AliPHOSCpvRecPoint * cpv ;
524 AliPHOSEmcRecPoint * emcclu ;
529 for(iEmcRP = fEmcFirst; iEmcRP < fEmcLast; iEmcRP++ ) {
530 emcclu = dynamic_cast<AliPHOSEmcRecPoint *>(fEMCRecPoints->At(iEmcRP)) ;
534 for(iCpv = fCpvFirst; iCpv < fCpvLast;iCpv++ ) {
536 cpv = dynamic_cast<AliPHOSCpvRecPoint *>(fCPVRecPoints->At(iCpv)) ;
539 GetDistanceInPHOSPlane(emcclu, cpv, track,dx,dz) ;
540 if(TMath::Sqrt(dx*dx+dz*dz) < fRcpv ){
541 new ((*fLinkUpArray)[iLinkUp++]) AliPHOSLink(dx, dz, iEmcRP, iCpv, track) ;
546 fLinkUpArray->Sort() ; //first links with smallest distances
549 //____________________________________________________________________________
550 void AliPHOSTrackSegmentMakerv1::MakePairs()
552 // Using the previously made list of "links", we found the smallest link - i.e.
553 // link with the least distance between EMC and CPV and pointing to still
554 // unassigned RecParticles. We assign these RecPoints to TrackSegment and
555 // remove them from the list of "unassigned".
557 //Make arrays to mark clusters already chosen
558 Int_t * emcExist = 0;
559 if(fEmcLast > fEmcFirst)
560 emcExist = new Int_t[fEmcLast-fEmcFirst] ;
563 for(index = 0; index <fEmcLast-fEmcFirst; index ++)
564 emcExist[index] = 1 ;
566 Bool_t * cpvExist = 0;
567 if(fCpvLast > fCpvFirst)
568 cpvExist = new Bool_t[fCpvLast-fCpvFirst] ;
569 for(index = 0; index <fCpvLast-fCpvFirst; index ++)
570 cpvExist[index] = kTRUE ;
573 // Finds the smallest links and makes pairs of CPV and EMC clusters with smallest distance
574 TIter nextUp(fLinkUpArray) ;
576 AliPHOSLink * linkUp ;
578 AliPHOSCpvRecPoint * nullpointer = 0 ;
580 while ( (linkUp = static_cast<AliPHOSLink *>(nextUp()) ) ){
582 if(emcExist[linkUp->GetEmc()-fEmcFirst] != -1){
584 if(cpvExist[linkUp->GetCpv()-fCpvFirst]){ //CPV still exist
586 linkUp->GetXZ(dx,dz) ;
587 new ((* fTrackSegments)[fNTrackSegments])
588 AliPHOSTrackSegment(dynamic_cast<AliPHOSEmcRecPoint *>(fEMCRecPoints->At(linkUp->GetEmc())) ,
589 dynamic_cast<AliPHOSCpvRecPoint *>(fCPVRecPoints->At(linkUp->GetCpv())) ,
590 linkUp->GetTrack(),dx,dz) ;
592 (dynamic_cast<AliPHOSTrackSegment *>(fTrackSegments->At(fNTrackSegments)))->SetIndexInList(fNTrackSegments);
594 emcExist[linkUp->GetEmc()-fEmcFirst] = -1 ; //Mark emc that Cpv was found
595 //mark CPV recpoint as already used
596 cpvExist[linkUp->GetCpv()-fCpvFirst] = kFALSE ;
597 } //if CpvUp still exist
601 //look through emc recPoints left without CPV
602 if(emcExist){ //if there is emc rec point
604 for(iEmcRP = 0; iEmcRP < fEmcLast-fEmcFirst ; iEmcRP++ ){
605 if(emcExist[iEmcRP] > 0 ){
608 AliPHOSEmcRecPoint *emcclu = dynamic_cast<AliPHOSEmcRecPoint *>(fEMCRecPoints->At(iEmcRP+fEmcFirst));
609 GetDistanceInPHOSPlane(emcclu, 0, track,dx,dz);
611 new ((*fTrackSegments)[fNTrackSegments]) AliPHOSTrackSegment(emcclu,nullpointer) ;
613 new ((*fTrackSegments)[fNTrackSegments]) AliPHOSTrackSegment(emcclu,0,track,dx,dz);
614 (dynamic_cast<AliPHOSTrackSegment *>(fTrackSegments->At(fNTrackSegments)))->SetIndexInList(fNTrackSegments);
623 //____________________________________________________________________________
624 void AliPHOSTrackSegmentMakerv1::Clusters2TrackSegments(Option_t *option)
626 // Steering method to perform track segment construction for the current event
627 // Returns an array with the found track-segments.
629 if(strstr(option,"tim"))
630 gBenchmark->Start("PHOSTSMaker");
632 if(strstr(option,"print")) {
637 //Make some initializations
638 fNTrackSegments = 0 ;
644 fTrackSegments->Clear();
646 // if(!ReadRecPoints(ievent)) continue; //reads RecPoints for event ievent
648 for(fModule = 1; fModule <= fGeom->GetNModules() ; fModule++ ) {
654 if(strstr(option,"deb"))
655 PrintTrackSegments(option);
657 if(strstr(option,"tim")){
658 gBenchmark->Stop("PHOSTSMaker");
659 Info("Exec", "took %f seconds for making TS",
660 gBenchmark->GetCpuTime("PHOSTSMaker"));
664 //____________________________________________________________________________
665 void AliPHOSTrackSegmentMakerv1::Print(const Option_t *)const
667 // Print TrackSegmentMaker parameters
669 TString message("") ;
670 if( strcmp(GetName(), "") != 0 ) {
671 message = "\n======== AliPHOSTrackSegmentMakerv1 ========\n" ;
672 message += "Making Track segments\n" ;
673 message += "with parameters:\n" ;
674 message += " Maximal EMC - CPV distance (cm) %f\n" ;
675 message += "============================================\n" ;
676 Info("Print", message.Data(),fRcpv) ;
679 Info("Print", "AliPHOSTrackSegmentMakerv1 not initialized ") ;
682 //____________________________________________________________________________
683 void AliPHOSTrackSegmentMakerv1::PrintTrackSegments(Option_t * option)
685 // option deb - prints # of found TrackSegments
686 // option deb all - prints as well indexed of found RecParticles assigned to the TS
688 Info("PrintTrackSegments", "Results from TrackSegmentMaker:") ;
689 printf(" Found %d TrackSegments\n", fTrackSegments->GetEntriesFast() );
691 if(strstr(option,"all")) { // printing found TS
692 printf("TrackSegment # EMC RP# CPV RP#\n") ;
694 for (index = 0 ; index <fTrackSegments->GetEntriesFast() ; index++) {
695 AliPHOSTrackSegment * ts = (AliPHOSTrackSegment * )fTrackSegments->At(index) ;
696 printf(" %d %d %d \n", ts->GetIndexInList(), ts->GetEmcIndex(), ts->GetCpvIndex() ) ;
700 //__________________________________________________________________________
701 Double_t AliPHOSTrackSegmentMakerv1::GetBz()const
703 Double_t kAlmost0Field=1.e-13;
704 AliMagF* fld = (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
705 if (!fld) return 0.5*kAlmost0Field;
706 Double_t bz = fld->SolenoidField();
707 return TMath::Sign(0.5*kAlmost0Field,bz) + bz;
709 //__________________________________________________________________________
710 void AliPHOSTrackSegmentMakerv1::GetBxByBz(const Double_t r[3], Double_t b[3])const {
711 //------------------------------------------------------------------
712 // Returns Bx, By and Bz (kG) at the point "r" .
713 //------------------------------------------------------------------
714 Double_t kAlmost0Field=1.e-13;
715 AliMagF* fld = (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
718 b[2] = 0.5*kAlmost0Field;
722 if (fld->IsUniform()) {
724 b[2] = fld->SolenoidField();
728 b[2] = (TMath::Sign(0.5*kAlmost0Field,b[2]) + b[2]);