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 Revision 1.6 2002/10/14 14:57:43 hristov
19 Merging the VirtualMC branch to the main development branch (HEAD)
21 Revision 1.4.10.1 2002/08/28 15:06:52 alibrary
24 Revision 1.5 2002/08/25 15:54:29 kowal2
25 Protection against overflows in TMath::Nint.
27 Revision 1.4 2001/01/10 09:35:27 kowal2
28 Changes to obey the coding rules.
30 Revision 1.3 2000/11/02 10:22:50 kowal2
34 ///////////////////////////////////////////////////////////////////////////////
36 // Time Projection Chamber track hits object //
38 // Origin: Marian Ivanov , GSI Darmstadt
40 // Class for storing simulated AliTPCHits for given track //
41 // -average compression comparing to classical ClonesArray is //
42 // around 5-7 (depending on the required hit precision) //
46 <img src="gif/AliTPCTrackHits.gif">
51 ///////////////////////////////////////////////////////////////////////////////
54 #include "TClonesArray.h"
55 #include "AliTPCTrackHits.h"
58 #include <Riostream.h>
62 ClassImp(AliTPCTrackHits)
63 LClassImp(AliTrackHitsInfo)
64 LClassImp(AliTrackHitsParam)
67 Int_t AliTrackHitsInfo::fgCounter1 =0;
68 Int_t AliTrackHitsInfo::fgCounter2 =0;
69 Int_t AliTrackHitsParam::fgCounter1 =0;
70 Int_t AliTrackHitsParam::fgCounter2 =0;
71 Int_t AliHitInfo::fgCounter1 =0;
72 Int_t AliHitInfo::fgCounter2 =0;
73 Int_t AliTPCTrackHits::fgCounter1 =0;
74 Int_t AliTPCTrackHits::fgCounter2 =0;
75 const Double_t AliTPCTrackHits::fgkPrecision=1e-6; //precision
76 const Double_t AliTPCTrackHits::fgkPrecision2=1e-20; //precision
79 /************************************************************/
80 // Interface classes //
81 #include "AliTPCTrackHitsInterfaces.h"
86 struct AliTPCCurrentHit {
88 UInt_t fInfoIndex;// - current info pointer
89 UInt_t fParamIndex;// - current param pointer
90 UInt_t fStackIndex; // - current hit stack index
91 Double_t fR; //current Radius
92 Bool_t fStatus; //current status
96 struct AliTPCTempHitInfo {
97 enum { fkStackSize = 10000};
99 void NewParam(Double_t r, Double_t z, Double_t fi, Int_t q);
100 void SetHit(Double_t r, Double_t z, Double_t fi, Int_t q);
101 Double_t * GetPosition(Int_t index){return &fPositionStack[index*3];}
102 void UpdateParam(Double_t maxdelta); //recal
103 void Fit2(Double_t fSumY, Double_t fSumYX, Double_t fSumYX2,
104 Double_t fSumX, Double_t fSumX2, Double_t fSumX3,
105 Double_t fSumX4, Int_t n,
106 Double_t &a, Double_t &b, Double_t &c);
107 void Fit(AliTrackHitsParam * param);
113 Double_t fSumDFiDr; //
114 Double_t fSumDFiDr2;//
116 Double_t fSumDZDr; //
117 Double_t fSumDZDr2; //
118 Double_t fOldR; //previos r
119 Double_t fPositionStack[3*fkStackSize]; //position stack
120 UInt_t fQStack[fkStackSize]; //Q stack
121 UInt_t fStackIndex; //current stack index
122 UInt_t fInfoIndex; //current track info index
123 UInt_t fParamIndex; //current track parameters index
124 AliTrackHitsInfo * fInfo; //current track info
125 AliTrackHitsParam * fParam; //current track param
129 AliTPCTempHitInfo::AliTPCTempHitInfo()
132 //set to default value
133 fSumDr=fSumDr2=fSumDr3=fSumDr4=
134 fSumDFi=fSumDFiDr=fSumDFiDr2=
135 fSumDZ=fSumDZDr=fSumDZDr2=0;
142 void AliTPCTempHitInfo::NewParam(Double_t r, Double_t z, Double_t fi, Int_t q)
145 //reset stack and sum parameters
146 //store line initial point
147 fSumDr=fSumDr2=fSumDr3=fSumDr4=
148 fSumDFi=fSumDFiDr=fSumDFiDr2=
149 fSumDZ=fSumDZDr=fSumDZDr2=0;
162 void AliTPCTempHitInfo::SetHit(Double_t r, Double_t z, Double_t fi, Int_t q)
165 //add hit to the stack
166 //recalculate new estimete of line parameters
167 Double_t *f = GetPosition(fStackIndex);
171 fQStack[fStackIndex]=q;
172 if (fStackIndex==0) return;
173 Double_t dr = (r-fParam->fR);
174 if (TMath::Abs(dr)<AliTPCTrackHits::fgkPrecision) dr =AliTPCTrackHits::fgkPrecision;
175 Double_t dfi = fi-fParam->fFi;
176 Double_t dz = z -fParam->fZ;
178 Double_t dr3 =dr2*dr;
179 Double_t dr4 =dr3*dr;
191 //update fit parameters
193 Double_t det = fSumDr2*fSumDr4-fSumDr3*fSumDr3;
194 if (TMath::Abs(det)<AliTPCTrackHits::fgkPrecision2) return;
195 if ( ( fStackIndex>1 ) ){
196 fParam->fAn = (fSumDr4*fSumDFiDr-fSumDr3*fSumDFiDr2)/det;
197 fParam->fAd = (fSumDr2*fSumDFiDr2-fSumDr3*fSumDFiDr)/det;
200 fParam->fAn = fSumDFiDr/fSumDr2;
201 if ( ( fStackIndex>1 ) ){
202 fParam->fTheta = (fSumDr4*fSumDZDr-fSumDr3*fSumDZDr2)/det;
203 fParam->fThetaD= (fSumDr2*fSumDZDr2-fSumDr3*fSumDZDr)/det;
206 fParam->fTheta = fSumDZDr/fSumDr2;
210 void AliTPCTempHitInfo::UpdateParam(Double_t maxdelta)
212 //recalc parameters not fixing origin point
216 Fit2(fSumDFi, fSumDFiDr, fSumDFiDr2, fSumDr,fSumDr2,fSumDr3,fSumDr4,
218 if (TMath::Abs(a)<maxdelta){
219 fParam->fFi +=a/fParam->fR;
223 Fit2(fSumDZ, fSumDZDr, fSumDZDr2, fSumDr,fSumDr2,fSumDr3,fSumDr4,
224 fStackIndex, a,b,c) ;
225 if (TMath::Abs(a)<maxdelta){
233 void AliTPCTempHitInfo::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)
238 //fit of second order
240 n* (fSumX2*fSumX4-fSumX3*fSumX3) -
241 fSumX* (fSumX*fSumX4-fSumX3*fSumX2)+
242 fSumX2* (fSumX*fSumX3-fSumX2*fSumX2);
244 if (TMath::Abs(det)> AliTPCTrackHits::fgkPrecision) {
246 (fSumY * (fSumX2*fSumX4-fSumX3*fSumX3)-
247 fSumX *(fSumYX*fSumX4-fSumYX2*fSumX3)+
248 fSumX2*(fSumYX*fSumX3-fSumYX2*fSumX2))/det;
250 (n*(fSumYX*fSumX4-fSumX3*fSumYX2)-
251 fSumY*(fSumX*fSumX4-fSumX3*fSumX2)+
252 fSumX2*(fSumX*fSumYX2-fSumYX*fSumX2))/det;
254 (n*(fSumX2*fSumYX2-fSumYX*fSumX3)-
255 fSumX*(fSumX*fSumYX2-fSumYX*fSumX2)+
256 fSumY*(fSumX*fSumX3-fSumX2*fSumX2))/det;
260 void AliTPCTempHitInfo::Fit(AliTrackHitsParam * param)
262 // fit fixing first and the last point
263 //result stored in new param
264 Double_t dx2 = (GetPosition(fStackIndex))[0]-fParam->fR;
265 Double_t det = fSumDr4+dx2*fSumDr2-2*dx2*fSumDr3;
266 if ( (TMath::Abs(det)> AliTPCTrackHits::fgkPrecision) &&
267 ((TMath::Abs(dx2)> AliTPCTrackHits::fgkPrecision))){
268 Double_t dfi2 = (GetPosition(fStackIndex))[1]-fParam->fFi;
269 param->fAd = (fSumDFiDr2+dfi2*fSumDr-dx2*fSumDFiDr-dfi2*fSumDr3/dx2)/det;
270 param->fAn = (dfi2-param->fAd*dx2*dx2)/dx2;
272 Double_t dz2 = (GetPosition(fStackIndex))[1]-fParam->fZ;
273 param->fTheta = (fSumDZDr2+dz2*fSumDr-dx2*fSumDZDr-dz2*fSumDr3/dx2)/det;
274 param->fTheta = (dz2-param->fAd*dx2*dx2)/dx2;
282 AliTPCTrackHits::AliTPCTrackHits()
285 //default constructor
287 const Float_t kHitPrecision=0.002; //default precision for hit position in cm
288 const Float_t kStep =0.003; //30 mum step
289 const UShort_t kMaxDistance =100; //maximum distance 100
291 fPrecision=kHitPrecision; //precision in cm
292 fStep = kStep; //step size
293 fMaxDistance = kMaxDistance; //maximum distance
295 fTrackHitsInfo = new AliObjectArray("AliTrackHitsInfo");
296 fTrackHitsParam = new AliObjectArray("AliTrackHitsParam");
297 fHitsPosAndQ = new TArrayOfArrayVStack("AliHitInfo");
298 fCurrentHit = new AliTPCCurrentHit;
304 AliTPCTrackHits::~AliTPCTrackHits()
309 if (fTrackHitsInfo) delete fTrackHitsInfo;
310 if (fTrackHitsParam) delete fTrackHitsParam;
311 if (fHitsPosAndQ) delete fHitsPosAndQ;
312 if (fCurrentHit) delete fCurrentHit;
313 if (fTempInfo) delete fTempInfo;
317 void AliTPCTrackHits::Clear()
321 fTrackHitsInfo->Clear();
322 fTrackHitsParam->Clear();
323 //fTrackHitsInfo->Resize(0);
324 //fTrackHitsParam->Resize(0);
325 fHitsPosAndQ->Clear();
334 void AliTPCTrackHits::AddHitKartez(Int_t volumeID, Int_t trackID, Double_t x,
335 Double_t y, Double_t z,Int_t q)
337 Double_t r = TMath::Sqrt(x*x+y*y);
338 Double_t fi = TMath::ACos(x/r);
340 AddHit(volumeID,trackID,r,z,fi,q);
343 void AliTPCTrackHits::AddHit(Int_t volumeID, Int_t trackID,
344 Double_t r, Double_t z, Double_t fi, Int_t q)
348 if (!fTempInfo) { //initialsation of track
349 fTempInfo = new AliTPCTempHitInfo;
351 if (fTrackHitsInfo->GetCapacity()<10) fTrackHitsInfo->Reserve(10);
352 fTrackHitsInfo->Resize(1);
353 fTempInfo->fInfoIndex =0;
354 if (fTrackHitsParam->GetCapacity()<100) fTrackHitsParam->Reserve(100);
355 fTrackHitsParam->Resize(1);
358 (AliTrackHitsInfo*) (fTrackHitsInfo->At(0));
359 fTempInfo->fInfo->fVolumeID = volumeID;
360 fTempInfo->fInfo->fTrackID = trackID;
361 fTempInfo->fInfo->fHitParamIndex =0;
362 fTempInfo->fInfoIndex = 0;
365 (AliTrackHitsParam*) (fTrackHitsParam->At(0));
366 fTempInfo->fParamIndex = 0;
367 fTempInfo->NewParam(r,z,fi,q);
371 Int_t size = fHitsPosAndQ->GetSize();
372 if (size>(Int_t)fTempInfo->fParamIndex) {
373 fTempInfo->fParamIndex++;
374 if (fTempInfo->fParamIndex+1>fTrackHitsParam->GetSize())
375 fTrackHitsParam->Resize(fTempInfo->fParamIndex+1);
377 (AliTrackHitsParam*) (fTrackHitsParam->At(fTempInfo->fParamIndex));
378 fTempInfo->NewParam(r,z,fi,q);
383 // if new volume or new trackID
384 if ( (volumeID!=fTempInfo->fInfo->fVolumeID) ||
385 (trackID!=fTempInfo->fInfo->fTrackID)){
388 FlushHitStack(kTRUE);
390 fTempInfo->fInfoIndex++;
391 if (fTempInfo->fInfoIndex+1>fTrackHitsInfo->GetSize())
392 fTrackHitsInfo->Resize(fTempInfo->fInfoIndex+1);
394 (AliTrackHitsInfo*) (fTrackHitsInfo->At(fTempInfo->fInfoIndex));
395 fTempInfo->fInfo->fVolumeID = volumeID;
396 fTempInfo->fInfo->fTrackID = trackID;
397 fTempInfo->fInfo->fHitParamIndex =fTempInfo->fParamIndex+1;
398 // FlushHitStack(kTRUE);
400 fTempInfo->fParamIndex++;
401 if (fTempInfo->fParamIndex+1>fTrackHitsParam->GetSize())
402 fTrackHitsParam->Resize(fTempInfo->fParamIndex+1);
404 (AliTrackHitsParam*) (fTrackHitsParam->At(fTempInfo->fParamIndex));
405 fTempInfo->NewParam(r,z,fi,q);
409 //calculate current fit precission to next point
410 AliTrackHitsParam ¶m = *(fTempInfo->fParam);
414 Double_t dr,dz,dfi,ddz,ddfi;
416 dr=dz=dfi=ddz=ddfi=0;
417 drhit = r-fTempInfo->fOldR;
419 //Double_t dfi2 = param.fAn+2*param.fAd*(r-param.fR);
420 Double_t dfi2 = param.fAn;
421 dfi2*=dfi2*fTempInfo->fOldR*fTempInfo->fOldR;
422 //Double_t ddz2 = param.fTheta+2*param.fThetaD*(r-param.fR);
423 Double_t ddz2 = param.fTheta;
425 ratio = TMath::Sqrt(1.+ dfi2+ ddz2);
430 dl = (TMath::Abs(drhit*ratio/fStep)<32000) ? fStep * Short_t(TMath::Nint(drhit*ratio/fStep)):0;
431 ddl = dl - drhit*ratio;
432 fTempInfo->fOldR += dl/ratio;
434 if (fTempInfo->fStackIndex>2){
438 ddz = dr*param.fTheta+dr*dr*param.fThetaD-dz;
439 ddfi= dr*param.fAn+dr*dr*param.fAd-dfi;
440 dd = TMath::Sqrt(ddz*ddz+r*r*ddfi*ddfi+ddl*ddl);
444 if ( ( (dd*1.25>fPrecision) ) ||
445 (fTempInfo->fStackIndex+4>fTempInfo->fkStackSize) ||
446 (TMath::Abs(dl/fStep)>fMaxDistance) )
449 fTempInfo->fStackIndex++;
450 fTempInfo->SetHit(r,z,fi,q);
453 //if parameter changed
454 if (FlushHitStack(kFALSE)){ //if full buffer flushed
455 fTempInfo->fParamIndex++;
456 if (fTempInfo->fParamIndex+1>fTrackHitsParam->GetSize())
457 fTrackHitsParam->Resize(fTempInfo->fParamIndex+1);
459 (AliTrackHitsParam*) (fTrackHitsParam->At(fTempInfo->fParamIndex));
460 fTempInfo->NewParam(r,z,fi,q);
463 fTempInfo->fStackIndex++;
464 fTempInfo->SetHit(r,z,fi,q);
468 Bool_t AliTPCTrackHits::FlushHitStack(Bool_t force)
471 //write fHitsPosAndQ information from the stack to te arrays
472 if (!fTempInfo) return kFALSE;
473 Int_t size = fHitsPosAndQ->GetSize();
475 if ( (size>0)&&(size!=(Int_t)fTempInfo->fParamIndex)) return kFALSE;
477 if (fHitsPosAndQ->Push(fTempInfo->fStackIndex+1)!=fTempInfo->fParamIndex){
478 cout<<"internal error - contact MI\n";
483 AliTrackHitsParam & param = *(fTempInfo->fParam);
484 //recalculate track parameter not fixing first point
485 fTempInfo->UpdateParam(fStep/4.);
486 //fTempInfo->Fit(fTempInfo->fParam); //- fixing the first and the last point
488 Double_t oldr = param.fR;
489 //cout<<"C3"<<fTempInfo->fStackIndex<<"\n"<<flush;
492 for (i=0; i <= fTempInfo->fStackIndex; i++){
493 Double_t * position = fTempInfo->GetPosition(i);
494 Double_t dr = position[0]-oldr;
497 //Double_t dfi2 = param.fAn+2*param.fAd*(position[0]-param.fR);
498 Double_t dfi2 = param.fAn;
499 dfi2*=dfi2*oldr*oldr;
500 //Double_t ddz2 = param.fTheta+2*param.fThetaD*(position[0]-param.fR);
501 Double_t ddz2 = param.fTheta;
503 ratio = TMath::Sqrt(1.+ dfi2+ ddz2);
506 Double_t dl = (TMath::Abs(dr*ratio/fStep)<32000) ? fStep*(Short_t)TMath::Nint(dr*ratio/fStep):0;
509 //calculate precission
510 AliTrackHitsParam ¶m = *(fTempInfo->fParam);
512 Double_t dr1= position[0]-param.fR;
513 Double_t dz = position[1]-param.fZ;
515 Double_t dfi = position[2]-param.fFi;
516 //extrapolated deltas
517 Double_t dr2 = oldr-param.fR;
518 Double_t ddr = dr2-dr1;
519 Double_t ddz = dr2*param.fTheta+dr2*dr2*param.fThetaD-dz;
520 Double_t ddfi= dr2*param.fAn+dr2*dr2*param.fAd-dfi;
521 dd = TMath::Sqrt(ddz*ddz+oldr*oldr*ddfi*ddfi+ddr*ddr);
523 if ( (dd>fPrecision) ){
529 Double_t ddz = dr2*param.fTheta+dr2*dr2*param.fThetaD-dz;
530 Double_t ddfi= dr2*param.fAn+dr2*dr2*param.fAd-dfi;
532 dd = TMath::Sqrt(ddz*ddz+oldr*oldr*ddfi*ddfi+ddr*ddr);
538 info = (AliHitInfo*)(fHitsPosAndQ->At(fTempInfo->fParamIndex,i));
539 info->fHitDistance = (TMath::Abs(dl/fStep)<32000) ?Short_t(TMath::Nint(dl/fStep)):0;
540 info->fCharge = Short_t(fTempInfo->fQStack[i]);
543 cout<<" "<<fTempInfo->fStackIndex<<" \t";
545 cout<<position[0]<<"\t";
546 cout<<position[1]<<"\t";
547 cout<<position[2]<<"\t";
548 cout<<param.fAn<<"\t";
549 cout<<param.fTheta<<"\t";
550 cout<<dr1<<"\t"<<ddr<<"\t"<<ddz<<"\t"<<ddfi<<"\t"<<dd<<"\n"<<flush;
554 if (i<=fTempInfo->fStackIndex){ //if previous iteration not succesfull
555 fHitsPosAndQ->Resize(fTempInfo->fParamIndex,i);
557 fTempInfo->fParamIndex++;
558 if (fTempInfo->fParamIndex+1>fTrackHitsParam->GetSize())
559 fTrackHitsParam->Resize(fTempInfo->fParamIndex+1);
561 (AliTrackHitsParam*) (fTrackHitsParam->At(fTempInfo->fParamIndex));
562 Double_t * p = fTempInfo->GetPosition(i);
563 UInt_t index2 = fTempInfo->fStackIndex;
564 fTempInfo->NewParam(p[0],p[1],p[2],fTempInfo->fQStack[i]);
565 if (i+1<=index2) FlushHitStack2(i+1,index2);
567 if (force) return FlushHitStack(kTRUE);
574 void AliTPCTrackHits::FlushHitStack2(Int_t index1, Int_t index2)
577 // second iteration flush stack
578 // call only for hits where first iteration were not succesfully interpolated
579 Double_t * positionstack = new Double_t[3*(index2-index1+1)];
580 UInt_t * qstack = new UInt_t[index2-index1+1];
581 memcpy(positionstack, &fTempInfo->fPositionStack[3*index1],
582 (3*(index2-index1+1))*sizeof(Double_t));
583 memcpy(qstack, &fTempInfo->fQStack[index1],(index2-index1+1)*sizeof(UInt_t));
584 Double_t *p = positionstack;
585 for (Int_t j=0; j<=index2-index1;j++){
586 fTempInfo->fStackIndex++;
587 fTempInfo->SetHit(p[3*j+0],p[3*j+1],p[3*j+2],qstack[j]);
589 delete []positionstack;
601 Bool_t AliTPCTrackHits::First()
604 //set Current hit for the first hit
606 AliTrackHitsInfo *info = (AliTrackHitsInfo *)fTrackHitsInfo->At(0);
607 AliTrackHitsParam *param = (AliTrackHitsParam *)fTrackHitsParam->At(0);
608 AliHitInfo * hinfo = (AliHitInfo *)fHitsPosAndQ->At(0,0);
610 if (!(info) || !(param) || !(hinfo) ) {
611 fCurrentHit->fStatus = kFALSE;
615 fCurrentHit->fInfoIndex = 0;
616 fCurrentHit->fParamIndex = 0;
617 fCurrentHit->fStackIndex = 0;
619 fCurrentHit->fHit.fSector = info->fVolumeID;
620 fCurrentHit->fHit.SetTrack(info->fTrackID);
621 fCurrentHit->fHit.SetX(param->fR*TMath::Cos(param->fFi));
622 fCurrentHit->fHit.SetY(param->fR*TMath::Sin(param->fFi));
623 fCurrentHit->fHit.SetZ(param->fZ);
624 fCurrentHit->fHit.fQ = hinfo->fCharge;
626 fCurrentHit->fR = param->fR;
628 return fCurrentHit->fStatus = kTRUE;
631 Bool_t AliTPCTrackHits::Next()
635 if (!(fCurrentHit->fStatus))
638 fCurrentHit->fStackIndex++;
639 AliHitInfo * hinfo = (AliHitInfo *)fHitsPosAndQ->At(fCurrentHit->fParamIndex,
640 fCurrentHit->fStackIndex);
641 AliTrackHitsInfo *info = (AliTrackHitsInfo *)fTrackHitsInfo->At(fCurrentHit->fInfoIndex);
642 AliTrackHitsParam *param = (AliTrackHitsParam *)fTrackHitsParam->At(fCurrentHit->fParamIndex);
645 hinfo = (AliHitInfo *)fHitsPosAndQ->At(fCurrentHit->fParamIndex+1, 0);
647 return fCurrentHit->fStatus = kFALSE;
649 fCurrentHit->fParamIndex++;
650 fCurrentHit->fStackIndex = 0;
651 param = (AliTrackHitsParam *)fTrackHitsParam->At(fCurrentHit->fParamIndex);
653 return fCurrentHit->fStatus = kFALSE;
654 fCurrentHit->fR = param->fR;
656 if ((fCurrentHit->fInfoIndex+1<fTrackHitsInfo->GetSize())
657 &&((info+1)->fHitParamIndex<=fCurrentHit->fParamIndex)){
658 fCurrentHit->fInfoIndex++;
659 info = (AliTrackHitsInfo *)fTrackHitsInfo->At(fCurrentHit->fInfoIndex);
661 return fCurrentHit->fStatus = kFALSE;
662 fCurrentHit->fHit.fSector = info->fVolumeID;
663 fCurrentHit->fHit.SetTrack(info->fTrackID);
669 // Double_t dfi2 = param->fAn+2*param->fAd*(fCurrentHit->fR-param->fR);
670 Double_t dfi2 = param->fAn;
671 dfi2*=dfi2*fCurrentHit->fR*fCurrentHit->fR;
672 // Double_t ddz2 = param->fTheta+2*param->fThetaD*(fCurrentHit->fR-param->fR);
673 Double_t ddz2 = param->fTheta;
675 ratio = TMath::Sqrt(1.+ dfi2+ ddz2);
678 fCurrentHit->fHit.fQ = hinfo->fCharge;
679 fCurrentHit->fR += fStep*hinfo->fHitDistance/ratio;
680 Double_t dR = fCurrentHit->fR - param->fR;
682 Double_t fi = param->fFi + (param->fAn*dR+param->fAd*dR*dR);
683 Double_t z = param->fZ + (param->fTheta*dR+param->fThetaD*dR*dR);
685 fCurrentHit->fHit.SetX(fCurrentHit->fR*TMath::Cos(fi));
686 fCurrentHit->fHit.SetY(fCurrentHit->fR*TMath::Sin(fi));
687 fCurrentHit->fHit.SetZ(z);
691 AliTPChit * AliTPCTrackHits::GetHit()
694 return (fCurrentHit->fStatus)? &fCurrentHit->fHit:0;
695 //return &fCurrentHit->fHit;
699 AliTrackHitsParam * AliTPCTrackHits::GetParam()
702 return (fCurrentHit->fStatus)? (AliTrackHitsParam *)fTrackHitsParam->At(fCurrentHit->fParamIndex) :0;
705 AliHitInfo * AliTPCTrackHits::GetHitInfo()
708 return (fCurrentHit->fStatus)?
709 (AliHitInfo *)fHitsPosAndQ->At(fCurrentHit->fParamIndex,fCurrentHit->fStackIndex) :0;