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 **************************************************************************/
18 ///////////////////////////////////////////////////////////////////////////////
20 // Time Projection Chamber track hits object //
22 // Origin: Marian Ivanov , GSI Darmstadt
25 // Container for Track Hits - based on standard TClonesArray -
26 // fArray of AliTPCTrackHitsParamV2
27 // In AliTPCTrackHitsParamV2 - parameterization of the track segment is stored
28 // for each of the track segment - relative position ( distance between hits) and
29 // charge of the hits is stored - comparing to classical TClonesArray of AliTPChit -
30 // comperssion factor of 5-7 (depending on the required precision) -
31 // In future release AliTPCTrackHitsV2 - will replace old AliTPCTrackHits - which were not
32 // based on standard ROOT containers
34 // // during building Container
35 // AddHitKartez(Int_t volumeID, Int_t trackID, Double_t x, Double_t y, Double_t z,Int_t q)
36 // void SetHitPrecision(Double_t prec) {fPrecision=prec;}
37 // void SetStepPrecision(Double_t prec) {fStep=prec;}
38 // Bool_t FlushHitStack(Bool_t force=kTRUE);
39 // //at the end necessary to have Container in consistent state
41 // // looping over Container
42 // Bool_t First(), Bool_t Next() - iterators - return status of the operation
43 // AliTPChit * GetHit(); - return current hit
48 <img src="gif/AliTPCTrackHitsV2.gif">
53 ///////////////////////////////////////////////////////////////////////////////
56 #include "AliTPCTrackHitsV2.h"
57 #include "TClonesArray.h"
62 ClassImp(AliTPCTrackHitsV2)
63 ClassImp(AliTrackHitsParamV2)
66 Int_t AliTrackHitsParamV2::fgCounter1 =0;
67 Int_t AliTrackHitsParamV2::fgCounter2 =0;
69 Int_t AliTPCTrackHitsV2::fgCounter1 =0;
70 Int_t AliTPCTrackHitsV2::fgCounter2 =0;
72 const Double_t AliTPCTrackHitsV2::fgkPrecision=1e-6; //precision
73 const Double_t AliTPCTrackHitsV2::fgkPrecision2=1e-20; //precision
74 const Double_t AliTPCTrackHitsV2::fgkTimePrecision=20.e-9; //hit time precision
79 struct AliTPCTempHitInfoV2 {
80 friend class AliTPCTrackHitsV2;
82 enum { kStackSize = 10000};
83 AliTPCTempHitInfoV2();
84 AliTPCTempHitInfoV2(const AliTPCTempHitInfoV2 &hit)
86 AliTPCTempHitInfoV2& operator = (const AliTPCTempHitInfoV2 &hit)
87 {hit.Copy(*this); return (*this);}
88 void NewParam(Double_t r, Double_t z, Double_t fi, Int_t q, Float_t time);
89 void SetHit(Double_t r, Double_t z, Double_t fi, Int_t q, Float_t time);
90 Double_t * GetPosition(Int_t index){return &fPositionStack[index*3];}
91 void UpdateParam(Double_t maxdelta); //recal
92 void Fit2(Double_t fSumY, Double_t fSumYX, Double_t fSumYX2,
93 Double_t fSumX, Double_t fSumX2, Double_t fSumX3,
94 Double_t fSumX4, Int_t n,
95 Double_t &a, Double_t &b, Double_t &c);
96 void Fit(AliTrackHitsParamV2 * param);
97 Double_t fSumDr; // Sum of Dr
98 Double_t fSumDr2; // Square of sum of Dr
99 Double_t fSumDr3; // Cube of sum of Dr
100 Double_t fSumDr4; // Fourth power of sum of Dr
101 Double_t fSumDFi; // Sum of DFi
102 Double_t fSumDFiDr; // Sum of DFiDr
103 Double_t fSumDFiDr2;// Sum of square of DFiDr
104 Double_t fSumDZ; // Sum of DZ
105 Double_t fSumDZDr; // Sum of DZDr
106 Double_t fSumDZDr2; // Sum of square of DZDr
107 Double_t fOldR; //previos r
108 Double_t fPositionStack[3*kStackSize]; //position stack
109 UInt_t fQStack[kStackSize]; //Q stack
110 Float_t fTimeStack[kStackSize]; //time stack
111 UInt_t fStackIndex; //current stack index
112 // UInt_t fInfoIndex; //current track info index
113 UInt_t fParamIndex; //current track parameters index
114 // AliTrackHitsInfo * fInfo; //current track info
115 AliTrackHitsParamV2 * fParam; //current track param
117 void Copy(AliTPCTempHitInfoV2 &) const
118 {printf("Not Implemented\n"); exit(1);}
122 AliTPCTempHitInfoV2::AliTPCTempHitInfoV2()
125 // Standard constructor
126 // set to default value
128 fSumDr=fSumDr2=fSumDr3=fSumDr4=
129 fSumDFi=fSumDFiDr=fSumDFiDr2=
130 fSumDZ=fSumDZDr=fSumDZDr2=0;
137 void AliTPCTempHitInfoV2::NewParam(Double_t r, Double_t z, Double_t fi, Int_t q, Float_t time)
140 //reset stack and sum parameters
141 //store line initial point
143 fSumDr=fSumDr2=fSumDr3=fSumDr4=
144 fSumDFi=fSumDFiDr=fSumDFiDr2=
145 fSumDZ=fSumDZDr=fSumDZDr2=0;
155 SetHit(r,z,fi,q,time);
158 void AliTPCTempHitInfoV2::SetHit(Double_t r, Double_t z, Double_t fi, Int_t q, Float_t time)
161 //add hit to the stack
162 //recalculate new estimete of line parameters
163 Double_t *f = GetPosition(fStackIndex);
167 fQStack[fStackIndex]=q;
168 fTimeStack[fStackIndex]=time;
169 if (fStackIndex==0) return;
170 Double_t dr = (r-fParam->fR);
171 if (TMath::Abs(dr)<AliTPCTrackHitsV2::fgkPrecision) dr =AliTPCTrackHitsV2::fgkPrecision;
172 Double_t dfi = fi-fParam->fFi;
173 Double_t dz = z -fParam->fZ;
175 Double_t dr3 =dr2*dr;
176 Double_t dr4 =dr3*dr;
188 //update fit parameters
190 Double_t det = fSumDr2*fSumDr4-fSumDr3*fSumDr3;
191 if (TMath::Abs(det)<AliTPCTrackHitsV2::fgkPrecision2) return;
192 if ( ( fStackIndex>1 ) ){
193 fParam->fAn = (fSumDr4*fSumDFiDr-fSumDr3*fSumDFiDr2)/det;
194 fParam->fAd = (fSumDr2*fSumDFiDr2-fSumDr3*fSumDFiDr)/det;
197 fParam->fAn = fSumDFiDr/fSumDr2;
198 if ( ( fStackIndex>1 ) ){
199 fParam->fTheta = (fSumDr4*fSumDZDr-fSumDr3*fSumDZDr2)/det;
200 fParam->fThetaD= (fSumDr2*fSumDZDr2-fSumDr3*fSumDZDr)/det;
203 fParam->fTheta = fSumDZDr/fSumDr2;
207 void AliTPCTempHitInfoV2::UpdateParam(Double_t maxdelta)
210 // recalc parameters not fixing origin point
215 Fit2(fSumDFi, fSumDFiDr, fSumDFiDr2, fSumDr,fSumDr2,fSumDr3,fSumDr4,
217 if (TMath::Abs(a)<maxdelta){
218 fParam->fFi +=a/fParam->fR;
222 Fit2(fSumDZ, fSumDZDr, fSumDZDr2, fSumDr,fSumDr2,fSumDr3,fSumDr4,
223 fStackIndex, a,b,c) ;
224 if (TMath::Abs(a)<maxdelta){
233 void AliTPCTempHitInfoV2::Fit2(Double_t fSumY, Double_t fSumYX, Double_t fSumYX2,
234 Double_t fSumX, Double_t fSumX2, Double_t fSumX3,
235 Double_t fSumX4, Int_t n,
236 Double_t &a, Double_t &b, Double_t &c)
239 // fit of second order
242 n* (fSumX2*fSumX4-fSumX3*fSumX3) -
243 fSumX* (fSumX*fSumX4-fSumX3*fSumX2)+
244 fSumX2* (fSumX*fSumX3-fSumX2*fSumX2);
246 if (TMath::Abs(det)> AliTPCTrackHitsV2::fgkPrecision) {
248 (fSumY * (fSumX2*fSumX4-fSumX3*fSumX3)-
249 fSumX *(fSumYX*fSumX4-fSumYX2*fSumX3)+
250 fSumX2*(fSumYX*fSumX3-fSumYX2*fSumX2))/det;
252 (n*(fSumYX*fSumX4-fSumX3*fSumYX2)-
253 fSumY*(fSumX*fSumX4-fSumX3*fSumX2)+
254 fSumX2*(fSumX*fSumYX2-fSumYX*fSumX2))/det;
256 (n*(fSumX2*fSumYX2-fSumYX*fSumX3)-
257 fSumX*(fSumX*fSumYX2-fSumYX*fSumX2)+
258 fSumY*(fSumX*fSumX3-fSumX2*fSumX2))/det;
262 void AliTPCTempHitInfoV2::Fit(AliTrackHitsParamV2 * param)
265 // fit fixing first and the last point
266 // result stored in new param
268 Double_t dx2 = (GetPosition(fStackIndex))[0]-fParam->fR;
269 Double_t det = fSumDr4+dx2*fSumDr2-2*dx2*fSumDr3;
270 if ( (TMath::Abs(det)> AliTPCTrackHitsV2::fgkPrecision) &&
271 ((TMath::Abs(dx2)> AliTPCTrackHitsV2::fgkPrecision))){
272 Double_t dfi2 = (GetPosition(fStackIndex))[1]-fParam->fFi;
273 param->fAd = (fSumDFiDr2+dfi2*fSumDr-dx2*fSumDFiDr-dfi2*fSumDr3/dx2)/det;
274 param->fAn = (dfi2-param->fAd*dx2*dx2)/dx2;
276 Double_t dz2 = (GetPosition(fStackIndex))[1]-fParam->fZ;
277 param->fTheta = (fSumDZDr2+dz2*fSumDr-dx2*fSumDZDr-dz2*fSumDr3/dx2)/det;
278 param->fTheta = (dz2-param->fAd*dx2*dx2)/dx2;
283 AliTrackHitsParamV2::AliTrackHitsParamV2()
286 // default constructor
296 AliTrackHitsParamV2::~AliTrackHitsParamV2()
299 // Standard destructor
303 delete[]fHitDistance;
316 Float_t AliTrackHitsParamV2::Eta() const
318 Float_t ctg = fZ / fR;
319 Float_t eta = -TMath::Log(TMath::Hypot(1,ctg)-TMath::Abs(ctg));
320 if(ctg < 0) eta = -eta;
325 AliTPCTrackHitsV2::AliTPCTrackHitsV2()
328 //default constructor
330 const Float_t kHitPrecision=0.002; //default precision for hit position in cm
331 const Float_t kStep =0.003; //30 mum step
332 const UShort_t kMaxDistance =100; //maximum distance 100
334 fPrecision=kHitPrecision; //precision in cm
335 fStep = kStep; //step size
336 fMaxDistance = kMaxDistance; //maximum distance
339 //fTrackHitsInfo = new AliObjectArray("AliTrackHitsInfo");
340 //fTrackHitsParam = new AliObjectArray("AliTrackHitsParamV2");
341 //fHitsPosAndQ = new TArrayOfArrayVStack("AliHitInfo");
342 fArray = new TClonesArray("AliTrackHitsParamV2");
343 fCurrentHit = new AliTPCCurrentHitV2;
352 AliTPCTrackHitsV2::~AliTPCTrackHitsV2()
357 // if (fTrackHitsInfo) delete fTrackHitsInfo;
362 //if (fHitsPosAndQ) delete fHitsPosAndQ;
363 if (fCurrentHit) delete fCurrentHit;
364 if (fTempInfo) delete fTempInfo;
377 void AliTPCTrackHitsV2::Clear(Option_t * /*option*/)
384 for (Int_t i=0;i<fArray->GetEntriesFast();i++){
385 AliTrackHitsParamV2 * par = (AliTrackHitsParamV2 *)fArray->UncheckedAt(i);
386 par->~AliTrackHitsParamV2(); // delete object
404 void AliTPCTrackHitsV2::AddHitKartez(Int_t volumeID, Int_t trackID, Double_t x,
405 Double_t y, Double_t z,Int_t q, Float_t time)
408 // add hit to the container - it add hit at the end - input in global coordinata
410 Double_t r = TMath::Sqrt(x*x+y*y);
411 Double_t fi = TMath::ACos(x/r);
413 AddHit(volumeID,trackID,r,z,fi,q,time);
417 void AliTPCTrackHitsV2::AddHit(Int_t volumeID, Int_t trackID,
418 Double_t r, Double_t z, Double_t fi, Int_t q, Float_t time)
425 if (!fTempInfo) { //initialisation of track - initialisation of parameters
426 fTempInfo = new AliTPCTempHitInfoV2;
427 fTempInfo->fParam = new((*fArray)[0]) AliTrackHitsParamV2;
428 fTempInfo->fParam->fVolumeID = volumeID;
429 fTempInfo->fParam->fTrackID = trackID;
432 fTempInfo->fParamIndex = 0;
433 fTempInfo->NewParam(r,z,fi,q,time);
437 // if new volume or new trackID
438 if ( (volumeID!=fTempInfo->fParam->fVolumeID) ||
439 (trackID!=fTempInfo->fParam->fTrackID)){
440 if (volumeID!=fTempInfo->fParam->fVolumeID) AddVolume(volumeID);
442 FlushHitStack(kTRUE);
444 fTempInfo->fParamIndex++;
445 fTempInfo->fParam = new((*fArray)[fTempInfo->fParamIndex]) AliTrackHitsParamV2;
446 fTempInfo->fParam->fVolumeID = volumeID;
447 fTempInfo->fParam->fTrackID = trackID;
448 fTempInfo->NewParam(r,z,fi,q,time);
452 //calculate current fit precission to next point
453 AliTrackHitsParamV2 ¶m = *(fTempInfo->fParam);
457 Double_t dr,dz,dfi,ddz,ddfi;
459 dr=dz=dfi=ddz=ddfi=0;
460 drhit = r-fTempInfo->fOldR;
462 //Double_t dfi2 = param.fAn+2*param.fAd*(r-param.fR);
463 Double_t dfi2 = param.fAn;
464 dfi2*=dfi2*fTempInfo->fOldR*fTempInfo->fOldR;
465 //Double_t ddz2 = param.fTheta+2*param.fThetaD*(r-param.fR);
466 Double_t ddz2 = param.fTheta;
468 ratio = TMath::Sqrt(1.+ dfi2+ ddz2);
471 // dl = fStep * Short_t(TMath::Nint(drhit*ratio/fStep)); // MI change - range check
472 dl = drhit*ratio/fStep;
473 if (TMath::Abs(dl)>32765) dl =0;
474 dl = fStep * Short_t(TMath::Nint(dl));
476 ddl = dl - drhit*ratio;
477 fTempInfo->fOldR += dl/ratio;
479 if (fTempInfo->fStackIndex>2){
483 ddz = dr*param.fTheta+dr*dr*param.fThetaD-dz;
484 ddfi= dr*param.fAn+dr*dr*param.fAd-dfi;
485 dd = TMath::Sqrt(ddz*ddz+r*r*ddfi*ddfi+ddl*ddl);
489 if ( ( (dd*1.25>fPrecision) ) ||
490 (fTempInfo->fStackIndex+4>fTempInfo->kStackSize) ||
491 (TMath::Abs(dl/fStep)>fMaxDistance) )
493 else{ // if precision OK
494 fTempInfo->fStackIndex++;
495 fTempInfo->SetHit(r,z,fi,q,time);
500 //if parameter changed
501 if (FlushHitStack(kFALSE)){ //if full buffer flushed
502 fTempInfo->fParamIndex++;
503 fTempInfo->fParam = new((*fArray)[fTempInfo->fParamIndex]) AliTrackHitsParamV2;
504 fTempInfo->fParam->fVolumeID = volumeID;
505 fTempInfo->fParam->fTrackID = trackID;
506 fTempInfo->NewParam(r,z,fi,q,time);
509 fTempInfo->fStackIndex++;
510 fTempInfo->SetHit(r,z,fi,q,time);
514 Bool_t AliTPCTrackHitsV2::FlushHitStack(Bool_t force)
517 // write fHitsPosAndQ information from the stack to te arrays
519 if (!fTempInfo) return kFALSE;
521 AliTrackHitsParamV2 & param = *(fTempInfo->fParam);
522 //recalculate track parameter not fixing first point
523 fTempInfo->UpdateParam(fStep/4.);
524 //fTempInfo->Fit(fTempInfo->fParam); //- fixing the first and the last point
526 Double_t oldr = param.fR;
529 param.fNHits = fTempInfo->fStackIndex+1;
530 if (param.fHitDistance) delete []param.fHitDistance;
531 if (param.fCharge) delete []param.fCharge;
532 if (param.fTime) delete []param.fTime;
533 param.fHitDistance = new Short_t[param.fNHits];
534 param.fCharge = new Short_t[param.fNHits];
535 param.fTime = new Short_t[param.fNHits];
538 for (i=0; i <= fTempInfo->fStackIndex; i++){
539 Double_t * position = fTempInfo->GetPosition(i);
540 Double_t dr = position[0]-oldr;
543 //Double_t dfi2 = param.fAn+2*param.fAd*(position[0]-param.fR);
544 Double_t dfi2 = param.fAn;
545 dfi2*=dfi2*oldr*oldr;
546 //Double_t ddz2 = param.fTheta+2*param.fThetaD*(position[0]-param.fR);
547 Double_t ddz2 = param.fTheta;
549 ratio = TMath::Sqrt(1.+ dfi2+ ddz2);
552 // Double_t dl = fStep*(Short_t)TMath::Nint(dr*ratio/fStep); //MI change
553 Double_t dl = dr*ratio/fStep;
554 if (TMath::Abs(dl)>32765) dl =0;
555 dl = fStep * Short_t(TMath::Nint(dl));
559 //calculate precission
560 AliTrackHitsParamV2 ¶m = *(fTempInfo->fParam);
562 Double_t dr1= position[0]-param.fR;
563 Double_t dz = position[1]-param.fZ;
564 Double_t dfi = position[2]-param.fFi;
565 //extrapolated deltas
566 Double_t dr2 = oldr-param.fR;
567 Double_t ddr = dr2-dr1;
568 Double_t ddz = dr2*param.fTheta+dr2*dr2*param.fThetaD-dz;
569 Double_t ddfi= dr2*param.fAn+dr2*dr2*param.fAd-dfi;
570 dd = TMath::Sqrt(ddz*ddz+oldr*oldr*ddfi*ddfi+ddr*ddr);
573 if ( (dd>fPrecision) ){
580 Double_t ddz = dr2*param.fTheta+dr2*dr2*param.fThetaD-dz;
581 Double_t ddfi= dr2*param.fAn+dr2*dr2*param.fAd-dfi;
583 dd = TMath::Sqrt(ddz*ddz+oldr*oldr*ddfi*ddfi+ddr*ddr);
589 param.fHitDistance[i]= Short_t(TMath::Nint(dl/fStep));
590 param.fCharge[i]= Short_t(fTempInfo->fQStack[i]);
591 param.fTime[i]= Short_t(fTempInfo->fTimeStack[i]/AliTPCTrackHitsV2::fgkTimePrecision);
594 if (i<=fTempInfo->fStackIndex){ //if previous iteration not succesfull
595 Short_t * charge = new Short_t[i];
596 Short_t * time = new Short_t[i];
597 Short_t * hitDistance= new Short_t[i];
598 memcpy(charge, param.fCharge,sizeof(Short_t)*i);
599 memcpy(time, param.fTime,sizeof(Short_t)*i);
600 memcpy(hitDistance, param.fHitDistance,sizeof(Short_t)*i);
601 delete [] param.fCharge;
602 delete [] param.fTime;
603 delete [] param.fHitDistance;
605 param.fCharge = charge;
607 param.fHitDistance = hitDistance;
609 Int_t volumeID = fTempInfo->fParam->fVolumeID;
610 Int_t trackID =fTempInfo->fParam->fTrackID;
611 fTempInfo->fParamIndex++;
612 fTempInfo->fParam = new((*fArray)[fTempInfo->fParamIndex]) AliTrackHitsParamV2;
613 Double_t * p = fTempInfo->GetPosition(i);
614 UInt_t index2 = fTempInfo->fStackIndex;
615 fTempInfo->NewParam(p[0],p[1],p[2],fTempInfo->fQStack[i],fTempInfo->fTimeStack[i]);
616 fTempInfo->fParam->fVolumeID= volumeID;
617 fTempInfo->fParam->fTrackID= trackID;
618 if (i+1<=index2) FlushHitStack2(i+1,index2);
620 if (force) return FlushHitStack(kTRUE);
627 void AliTPCTrackHitsV2::FlushHitStack2(Int_t index1, Int_t index2)
630 // second iteration flush stack
631 // call only for hits where first iteration were not succesfully interpolated
633 Double_t * positionstack = new Double_t[3*(index2-index1+1)];
634 UInt_t * qstack = new UInt_t[index2-index1+1];
635 Float_t * timestack = new Float_t[index2-index1+1];
636 memcpy(positionstack, &fTempInfo->fPositionStack[3*index1],
637 (3*(index2-index1+1))*sizeof(Double_t));
638 memcpy(qstack, &fTempInfo->fQStack[index1],(index2-index1+1)*sizeof(UInt_t));
639 memcpy(timestack, &fTempInfo->fTimeStack[index1],(index2-index1+1)*sizeof(Float_t));
640 Double_t *p = positionstack;
641 for (Int_t j=0; j<=index2-index1;j++){
642 fTempInfo->fStackIndex++;
643 fTempInfo->SetHit(p[3*j+0],p[3*j+1],p[3*j+2],qstack[j],timestack[j]);
645 delete []positionstack;
651 void AliTPCTrackHitsV2::AddVolume(Int_t volume)
654 //add volumes to tthe list of volumes
656 Int_t * volumes = new Int_t[fNVolumes+1];
657 if (fVolumes) memcpy(volumes,fVolumes,(fNVolumes)*sizeof(Int_t));
658 volumes[fNVolumes]=volume;
660 if (fVolumes) delete []fVolumes;
665 Bool_t AliTPCTrackHitsV2::First()
668 //set Current hit for the first hit
671 if (fArray->GetSize()<=0) {
672 fCurrentHit->fStatus = kFALSE;
676 AliTrackHitsParamV2 *param = (AliTrackHitsParamV2 *)fArray->At(0);
677 if (!fHit) fHit = new AliTPChit;
679 fCurrentHit->fStatus = kFALSE;
683 fCurrentHit->fParamIndex = 0;
684 fCurrentHit->fStackIndex = 0;
687 ((AliTPChit*)fHit)->fSector = param->fVolumeID;
688 ((AliTPChit*)fHit)->SetTrack(param->fTrackID);
689 ((AliTPChit*)fHit)->SetX(param->fR*TMath::Cos(param->fFi));
690 ((AliTPChit*)fHit)->SetY(param->fR*TMath::Sin(param->fFi));
691 ((AliTPChit*)fHit)->SetZ(param->fZ);
692 ((AliTPChit*)fHit)->fQ = param->fCharge[0];
693 ((AliTPChit*)fHit)->fTime = (Float_t)(param->fTime[0]*AliTPCTrackHitsV2::fgkTimePrecision);
695 fCurrentHit->fHit.fSector = param->fVolumeID;
696 fCurrentHit->fHit.SetTrack(param->fTrackID);
697 fCurrentHit->fHit.SetX(param->fR*TMath::Cos(param->fFi));
698 fCurrentHit->fHit.SetY(param->fR*TMath::Sin(param->fFi));
699 fCurrentHit->fHit.SetZ(param->fZ);
700 fCurrentHit->fHit.fQ = param->fCharge[0];
701 fCurrentHit->fHit.fTime = (Float_t)(param->fTime[0]*AliTPCTrackHitsV2::fgkTimePrecision);
703 fCurrentHit->fR = param->fR;
705 return fCurrentHit->fStatus = kTRUE;
708 Bool_t AliTPCTrackHitsV2::Next()
713 if (!(fCurrentHit->fStatus))
716 fCurrentHit->fStackIndex++;
718 AliTrackHitsParamV2 *param = (AliTrackHitsParamV2 *)fArray->At(fCurrentHit->fParamIndex);
719 if (fCurrentHit->fStackIndex>=param->fNHits){
720 fCurrentHit->fParamIndex++;
721 if (fCurrentHit->fParamIndex>=fArray->GetEntriesFast()){
722 fCurrentHit->fStatus=kFALSE;
725 param = (AliTrackHitsParamV2 *)fArray->At(fCurrentHit->fParamIndex);
726 fCurrentHit->fStackIndex=0;
727 fCurrentHit->fR = param->fR;
734 // Double_t dfi2 = param->fAn+2*param->fAd*(fCurrentHit->fR-param->fR);
735 Double_t dfi2 = param->fAn;
736 dfi2*=dfi2*fCurrentHit->fR*fCurrentHit->fR;
737 // Double_t ddz2 = param->fTheta+2*param->fThetaD*(fCurrentHit->fR-param->fR);
738 Double_t ddz2 = param->fTheta;
740 ratio = TMath::Sqrt(1.+ dfi2+ ddz2);
743 fCurrentHit->fR += fStep*param->fHitDistance[fCurrentHit->fStackIndex]/ratio;
745 Double_t dR = fCurrentHit->fR - param->fR;
746 Double_t fi = param->fFi + (param->fAn*dR+param->fAd*dR*dR);
747 Double_t z = param->fZ + (param->fTheta*dR+param->fThetaD*dR*dR);
749 fCurrentHit->fHit.fQ = param->fCharge[fCurrentHit->fStackIndex];
750 fCurrentHit->fHit.fTime = (Float_t)(param->fTime[fCurrentHit->fStackIndex]*AliTPCTrackHitsV2::fgkTimePrecision);
751 fCurrentHit->fHit.SetX(fCurrentHit->fR*TMath::Cos(fi));
752 fCurrentHit->fHit.SetY(fCurrentHit->fR*TMath::Sin(fi));
753 fCurrentHit->fHit.SetZ(z);
754 fCurrentHit->fHit.fSector = param->fVolumeID;
755 fCurrentHit->fHit.SetTrack(param->fTrackID);
757 ((AliTPChit*)fHit)->fQ = param->fCharge[fCurrentHit->fStackIndex];
758 ((AliTPChit*)fHit)->fTime = (Float_t)(param->fTime[fCurrentHit->fStackIndex]*AliTPCTrackHitsV2::fgkTimePrecision);
759 ((AliTPChit*)fHit)->SetX(fCurrentHit->fR*TMath::Cos(fi));
760 ((AliTPChit*)fHit)->SetY(fCurrentHit->fR*TMath::Sin(fi));
761 ((AliTPChit*)fHit)->SetZ(z);
762 ((AliTPChit*)fHit)->fSector = param->fVolumeID;
763 ((AliTPChit*)fHit)->SetTrack(param->fTrackID);
768 AliHit * AliTPCTrackHitsV2::GetHit() const
773 return (fCurrentHit->fStatus)? fHit:0;
774 //return &fCurrentHit->fHit;
778 AliTrackHitsParamV2 * AliTPCTrackHitsV2::GetParam()
781 // Return current parameters
783 return (fCurrentHit->fStatus)?
784 (AliTrackHitsParamV2 *)fArray->At(fCurrentHit->fParamIndex):0;