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- bugfix: correct initialization of the AliTPCcalibDB to avoid out of bounds messages...
[u/mrichter/AliRoot.git] / HLT / TPCLib / AliHLTTPCFitter.cxx
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a6c02c85 1// @(#) $Id$
4aa41877 2// Original: AliHLTFitter.cxx,v 1.14 2005/06/14 10:55:21 cvetan
a6c02c85 3
6235cd38 4/**************************************************************************
9be2600f 5 * This file is property of and copyright by the ALICE HLT Project *
6 * ALICE Experiment at CERN, All rights reserved. *
6235cd38 7 * *
9be2600f 8 * Primary Authors: Anders Vestbo, maintained by *
9 * Matthias Richter <Matthias.Richter@ift.uib.no> *
10 * for The ALICE HLT Project. *
6235cd38 11 * *
12 * Permission to use, copy, modify and distribute this software and its *
13 * documentation strictly for non-commercial purposes is hereby granted *
14 * without fee, provided that the above copyright notice appears in all *
15 * copies and that both the copyright notice and this permission notice *
16 * appear in the supporting documentation. The authors make no claims *
17 * about the suitability of this software for any purpose. It is *
18 * provided "as is" without express or implied warranty. *
19 **************************************************************************/
20
21/** @file AliHLTTPCFitter.cxx
22 @author Anders Vestbo, maintained by Matthias Richter
23 @date
24 @brief Fit class HLT for helix
a6c02c85 25*/
26
27#include <math.h>
a6c02c85 28#include "AliHLTTPCLogging.h"
29#include "AliHLTTPCFitter.h"
30#include "AliHLTTPCVertex.h"
31#include "AliHLTTPCTrack.h"
32#include "AliHLTTPCSpacePointData.h"
33#include "AliHLTTPCMemHandler.h"
34#include "AliHLTTPCTransform.h"
a7c32962 35//#include "AliHLTTPC.h"
a6c02c85 36
37#if __GNUC__ >= 3
38using namespace std;
39#endif
40
41ClassImp(AliHLTTPCFitter)
42
43
44AliHLTTPCFitter::AliHLTTPCFitter()
6235cd38 45 :
46 fTrack(NULL),
47 fVertex(NULL),
48 fVertexConstraint(0)
a6c02c85 49{
50 //constructor
e419b223 51 // see header file for class documentation
52 // or
53 // refer to README to build package
54 // or
55 // visit http://web.ift.uib.no/~kjeks/doc/alice-hlt
a6c02c85 56 memset(fClusters,0,36*6*sizeof(AliHLTTPCSpacePointData*));
6235cd38 57 memset(fNcl,0,36*6*sizeof(UInt_t));
58}
59
a6c02c85 60AliHLTTPCFitter::AliHLTTPCFitter(AliHLTTPCVertex *vertex,Bool_t vertexconstraint)
e419b223 61 :
62 fTrack(NULL),
63 fVertex(vertex),
64 fVertexConstraint(vertexconstraint)
a6c02c85 65{
66 //constructor
67 fTrack=0;
a6c02c85 68 memset(fClusters,0,36*6*sizeof(AliHLTTPCSpacePointData*));
69}
70
71AliHLTTPCFitter::~AliHLTTPCFitter()
72{
73 //destructor
74 for(Int_t i=0; i<36; i++)
75 {
76 for(Int_t j=0; j<6; j++)
77 {
78 if(fClusters[i][j])
79 delete [] fClusters[i][j];
80 }
81 }
82}
83
84void AliHLTTPCFitter::LoadClusters(Char_t *path,Int_t event,Bool_t sp)
85{
86 //load clusters
87 Char_t fname[256];
88 AliHLTTPCMemHandler *clusterfile[36][6];
89 for(Int_t s=0; s<=35; s++)
90 {
91 for(Int_t p=0; p<6; p++)
92 {
93 Int_t patch;
94 if(sp==kTRUE)
95 patch=-1;
96 else
97 patch=p;
98 if(fClusters[s][p])
99 delete fClusters[s][p];
100 fClusters[s][p] = 0;
101 clusterfile[s][p] = new AliHLTTPCMemHandler();
102 sprintf(fname,"%s/points_%d_%d_%d.raw",path,event,s,patch);
103 if(!clusterfile[s][p]->SetBinaryInput(fname))
104 {
105 delete clusterfile[s][p];
106 clusterfile[s][p] = 0;
107 continue;
108 }
109 fClusters[s][p] = (AliHLTTPCSpacePointData*)clusterfile[s][p]->Allocate();
110 clusterfile[s][p]->Binary2Memory(fNcl[s][p],fClusters[s][p]);
111 clusterfile[s][p]->CloseBinaryInput();
112 if(sp==kTRUE)
113 break;
114 }
115 }
116}
117
118void AliHLTTPCFitter::SortTrackClusters(AliHLTTPCTrack *track) const
119{
120 //Sort the internal cluster list in each track with respect to row numbering.
121 //This may be necessary when no conventional track follower has been
122 //applied, in which the cluster list has been maintained in a more
123 //arbitrary fashion.
124
125 Int_t nhits = track->GetNHits();
126 Int_t *ids = (Int_t*)track->GetHitNumbers();
127 Int_t *origids = new Int_t[nhits];
128 Int_t *mk = new Int_t[nhits];
129 Int_t k;
130
131 for(k=0; k<nhits; k++) {origids[k] = ids[k]; mk[k] = -1;}
132
133 Int_t slice,patch,id,padrow,maxrow,maxk;
134 UInt_t pos;
135 for(Int_t j=0; j<nhits; j++)
136 {
137 maxrow=-1;
138 maxk=200;
139 for(k=0; k<nhits; k++)
140 {
141 id=ids[k];
142 if(id < 0) continue;
a371a266 143 slice = AliHLTTPCSpacePointData::GetSlice(id);
144 patch = AliHLTTPCSpacePointData::GetPatch(id);
145 pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 146 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
147 padrow = points[pos].fPadRow;
148 if(padrow > maxrow)
149 {
150 maxrow = padrow;
151 maxk=k;
152 }
153 }
154 mk[j]=maxk;
155 ids[maxk]=-1;
156 }
157
158 for(k=0; k<nhits; k++)
159 ids[k] = origids[mk[k]];
160 delete [] origids;
161 delete [] mk;
162}
163
164Int_t AliHLTTPCFitter::FitHelix(AliHLTTPCTrack *track)
165{
166 //fit helix parameters
167 fTrack = track;
168 if(FitCircle())
169 {
170 LOG(AliHLTTPCLog::kError,"AliHLTTPCFitter::FitHelix","TrackFit")<<AliHLTTPCLog::kDec<<
171 "Problems during circle fit"<<ENDLOG;
172 return 1;
173 }
174 if(FitLine())
175 {
176 LOG(AliHLTTPCLog::kError,"AliHLTTPCFitter::FitHelix","TrackFit")<<AliHLTTPCLog::kDec<<
177 "Problems during line fit"<<ENDLOG;
178 return 1;
179 }
180 return 0;
181}
182
183Int_t AliHLTTPCFitter::FitCircle()
184{
185 //-----------------------------------------------------------------
186 //Fits circle parameters using algorithm
187 //described by ChErnov and Oskov in Computer Physics
188 //Communications.
189 //
190 //Written in FORTRAN by Jawluen Tang, Physics department , UT-Austin
191 //Moved to C by Pablo Yepes
192 //Moved to AliROOT by ASV.
193 //------------------------------------------------------------------
194
195 Double_t wsum = 0.0 ;
196 Double_t xav = 0.0 ;
197 Double_t yav = 0.0 ;
198
199 //
200 // Loop over hits calculating average
201 Double_t * fXYWeight = new Double_t[(fTrack->GetNHits())];
202 UInt_t *hitnum = fTrack->GetHitNumbers();
203 for(Int_t i=0; i<fTrack->GetNHits(); i++)
204 {
205 UInt_t id = hitnum[i];
a371a266 206 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
207 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
208 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 209 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
210 fXYWeight[i] = 1./ (Double_t)(points[pos].fSigmaY2 + points[pos].fSigmaY2);
211 wsum += fXYWeight[i];
212 xav += fXYWeight[i]*points[pos].fX;
213 yav += fXYWeight[i]*points[pos].fY;
214 }
215 if (fVertexConstraint == kTRUE)
216 {
217 wsum += fVertex->GetXYWeight() ;
218 xav += fVertex->GetX() ;
219 yav += fVertex->GetY() ;
220 }
221
222 xav = xav / wsum ;
223 yav = yav / wsum ;
224//
225// CALCULATE <X**2>, <XY>, AND <Y**2> WITH <X> = 0, & <Y> = 0
226//
227 Double_t xxav = 0.0 ;
228 Double_t xyav = 0.0 ;
229 Double_t yyav = 0.0 ;
230 Double_t xi, yi ;
231
232 for(Int_t i=0; i<fTrack->GetNHits(); i++)
233 {
234 UInt_t id = hitnum[i];
a371a266 235 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
236 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
237 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 238 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
239
240 xi = points[pos].fX -xav;
241 yi = points[pos].fY - yav ;
242 xxav += xi * xi * fXYWeight[i];
243 xyav += xi * yi * fXYWeight[i];
244 yyav += yi * yi * fXYWeight[i];
245 }
246
247 if (fVertexConstraint == kTRUE)
248 {
249 xi = fVertex->GetX() - xav ;
250 yi = fVertex->GetY() - yav ;
251 xxav += xi * xi * fVertex->GetXYWeight() ;
252 xyav += xi * yi * fVertex->GetXYWeight() ;
253 yyav += yi * yi * fVertex->GetXYWeight() ;
254 }
255 xxav = xxav / wsum ;
256 xyav = xyav / wsum ;
257 yyav = yyav / wsum ;
258//
259//--> ROTATE COORDINATES SO THAT <XY> = 0
260//
261//--> SIGN(C**2 - S**2) = SIGN(XXAV - YYAV) >
262//--> & > ==> NEW : (XXAV-YYAV) > 0
263//--> SIGN(S) = SIGN(XYAV) >
264
265 Double_t a = fabs( xxav - yyav ) ;
266 Double_t b = 4.0 * xyav * xyav ;
267
268 Double_t asqpb = a * a + b ;
269 Double_t rasqpb = sqrt ( asqpb) ;
270
271 Double_t splus = 1.0 + a / rasqpb ;
272 Double_t sminus = b / (asqpb * splus) ;
273
274 splus = sqrt (0.5 * splus ) ;
275 sminus = sqrt (0.5 * sminus) ;
276//
277//-> FIRST REQUIRE : SIGN(C**2 - S**2) = SIGN(XXAV - YYAV)
278//
279 Double_t sinrot, cosrot ;
280 if ( xxav <= yyav ) {
281 cosrot = sminus ;
282 sinrot = splus ;
283 }
284 else {
285 cosrot = splus ;
286 sinrot = sminus ;
287 }
288//
289//-> REQUIRE : SIGN(S) = SIGN(XYAV) * SIGN(C) (ASSUMING SIGN(C) > 0)
290//
291 if ( xyav < 0.0 ) sinrot = - sinrot ;
292//
293//--> WE NOW HAVE THE SMALLEST ANGLE THAT GUARANTEES <X**2> > <Y**2>
294//--> TO GET THE SIGN OF THE CHARGE RIGHT, THE NEW X-AXIS MUST POINT
295//--> OUTWARD FROM THE ORGIN. WE ARE FREE TO CHANGE SIGNS OF BOTH
296//--> COSROT AND SINROT SIMULTANEOUSLY TO ACCOMPLISH THIS.
297//
298//--> CHOOSE SIGN OF C WISELY TO BE ABLE TO GET THE SIGN OF THE CHARGE
299//
300 if ( cosrot*xav+sinrot*yav < 0.0 ) {
301 cosrot = -cosrot ;
302 sinrot = -sinrot ;
303 }
304//
305//-> NOW GET <R**2> AND RSCALE= SQRT(<R**2>)
306//
307 Double_t rrav = xxav + yyav ;
308 Double_t rscale = sqrt(rrav) ;
309
310 xxav = 0.0 ;
311 yyav = 0.0 ;
312 xyav = 0.0 ;
313 Double_t xrrav = 0.0 ;
314 Double_t yrrav = 0.0 ;
315 Double_t rrrrav = 0.0 ;
316
317 Double_t xixi, yiyi, riri, wiriri, xold, yold ;
318
319 for(Int_t i=0; i<fTrack->GetNHits(); i++)
320 {
321 UInt_t id = hitnum[i];
a371a266 322 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
323 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
324 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 325 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
326
327 xold = points[pos].fX - xav ;
328 yold = points[pos].fY - yav ;
329 //
330 //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
331 //
332 xi = ( cosrot * xold + sinrot * yold ) / rscale ;
333 yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
334
335 xixi = xi * xi ;
336 yiyi = yi * yi ;
337 riri = xixi + yiyi ;
338 wiriri = fXYWeight[i] * riri ;
339
340 xyav += fXYWeight[i] * xi * yi ;
341 xxav += fXYWeight[i] * xixi ;
342 yyav += fXYWeight[i] * yiyi ;
343
344 xrrav += wiriri * xi ;
345 yrrav += wiriri * yi ;
346 rrrrav += wiriri * riri ;
347 }
348//
349// Include vertex if required
350//
351 if (fVertexConstraint == kTRUE)
352 {
353 xold = fVertex->GetX() - xav ;
354 yold = fVertex->GetY() - yav ;
355 //
356 //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
357 //
358 xi = ( cosrot * xold + sinrot * yold ) / rscale ;
359 yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
360
361 xixi = xi * xi ;
362 yiyi = yi * yi ;
363 riri = xixi + yiyi ;
364 wiriri = fVertex->GetXYWeight() * riri ;
365
366 xyav += fVertex->GetXYWeight() * xi * yi ;
367 xxav += fVertex->GetXYWeight() * xixi ;
368 yyav += fVertex->GetXYWeight() * yiyi ;
369
370 xrrav += wiriri * xi ;
371 yrrav += wiriri * yi ;
372 rrrrav += wiriri * riri ;
373 }
374 //
375 //
376 //
377 //--> DIVIDE BY WSUM TO MAKE AVERAGES
378 //
379 xxav = xxav / wsum ;
380 yyav = yyav / wsum ;
381 xrrav = xrrav / wsum ;
382 yrrav = yrrav / wsum ;
383 rrrrav = rrrrav / wsum ;
384 xyav = xyav / wsum ;
385
386 Int_t const kntry = 5 ;
387//
388//--> USE THESE TO GET THE COEFFICIENTS OF THE 4-TH ORDER POLYNIMIAL
389//--> DON'T PANIC - THE THIRD ORDER TERM IS ZERO !
390//
391 Double_t xrrxrr = xrrav * xrrav ;
392 Double_t yrryrr = yrrav * yrrav ;
393 Double_t rrrrm1 = rrrrav - 1.0 ;
394 Double_t xxyy = xxav * yyav ;
395
396 Double_t c0 = rrrrm1*xxyy - xrrxrr*yyav - yrryrr*xxav ;
397 Double_t c1 = - rrrrm1 + xrrxrr + yrryrr - 4.0*xxyy ;
398 Double_t c2 = 4.0 + rrrrm1 - 4.0*xxyy ;
399 Double_t c4 = - 4.0 ;
400//
401//--> COEFFICIENTS OF THE DERIVATIVE - USED IN NEWTON-RAPHSON ITERATIONS
402//
403 Double_t c2d = 2.0 * c2 ;
404 Double_t c4d = 4.0 * c4 ;
405//
406//--> 0'TH VALUE OF LAMDA - LINEAR INTERPOLATION BETWEEN P(0) & P(YYAV)
407//
408// LAMDA = YYAV * C0 / (C0 + YRRSQ * (XXAV-YYAV))
409 Double_t lamda = 0.0 ;
410 Double_t dlamda = 0.0 ;
411//
412 Double_t chiscl = wsum * rscale * rscale ;
413 Double_t dlamax = 0.001 / chiscl ;
414
415 Double_t p, pd ;
416 for ( int itry = 1 ; itry <= kntry ; itry++ ) {
417 p = c0 + lamda * (c1 + lamda * (c2 + lamda * lamda * c4 )) ;
418 pd = (c1 + lamda * (c2d + lamda * lamda * c4d)) ;
419 dlamda = -p / pd ;
420 lamda = lamda + dlamda ;
421 if (fabs(dlamda)< dlamax) break ;
422 }
423
424 //Double_t chi2 = (Double_t)(chiscl * lamda) ;
425 //fTrack->SetChiSq1(chi2);
426 // Double_t dchisq = chiscl * dlamda ;
427 //
428 //--> NOW CALCULATE THE MATRIX ELEMENTS FOR ALPHA, BETA & KAPPA
429 //
430 Double_t h11 = xxav - lamda ;
431 Double_t h14 = xrrav ;
432 Double_t h22 = yyav - lamda ;
433 Double_t h24 = yrrav ;
434 Double_t h34 = 1.0 + 2.0*lamda ;
435 if ( h11 == 0.0 || h22 == 0.0 ){
436 LOG(AliHLTTPCLog::kError,"AliHLTTPCFitter::FitCircle","TrackFit")<<AliHLTTPCLog::kDec<<
437 "Problems fitting circle"<<ENDLOG;
438 return 1 ;
439 }
440 Double_t rootsq = (h14*h14)/(h11*h11) + 4.0*h34 ;
441
442 Double_t ratio, kappa, beta ;
443 if ( fabs(h22) > fabs(h24) ) {
444 ratio = h24 / h22 ;
445 rootsq = ratio * ratio + rootsq ;
446 kappa = 1.0 / sqrt(rootsq) ;
447 beta = - ratio * kappa ;
448 }
449 else {
450 ratio = h22 / h24 ;
451 rootsq = 1.0 + ratio * ratio * rootsq ;
452 beta = 1.0 / sqrt(rootsq) ;
453 if ( h24 > 0 ) beta = - beta ;
454 kappa = -ratio * beta ;
455 }
456 Double_t alpha = - (h14/h11) * kappa ;
457//
458//--> transform these into the lab coordinate system
459//--> first get kappa and back to real dimensions
460//
461 Double_t kappa1 = kappa / rscale ;
462 Double_t dbro = 0.5 / kappa1 ;
463//
464//--> next rotate alpha and beta and scale
465//
466 Double_t alphar = (cosrot * alpha - sinrot * beta)* dbro ;
467 Double_t betar = (sinrot * alpha + cosrot * beta)* dbro ;
468//
469//--> then translate by (xav,yav)
470//
471 Double_t acent = (double)(xav - alphar) ;
472 Double_t bcent = (double)(yav - betar ) ;
473 Double_t radius = (double)dbro ;
474//
475// Get charge
476//
477 Int_t q = ( ( yrrav < 0 ) ? 1 : -1 ) ;
478 fTrack->SetCharge(q);
479
480 //Set the first point on the track to the space point coordinates of the innermost track
481 //This will be updated to lie on the fit later on (AliHLTTPCTrack::UpdateToFirstPoint).
482 Double_t x0,y0,psi,pt ;
483 Int_t lastid=fTrack->GetNHits()-1;
484 UInt_t id = hitnum[lastid];
a371a266 485 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
486 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
487 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 488 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
489 x0 = points[pos].fX;
490 y0 = points[pos].fY;
491 fTrack->SetFirstPoint(x0,y0,0); //Z-value is set in FitLine
492
493 //Set the remaining fit parameters
494 psi = (Double_t)atan2(bcent-y0,acent-x0) ;
495 psi = psi + q * 0.5F * AliHLTTPCTransform::Pi() ;
496 if ( psi < 0 ) psi = psi + 2*AliHLTTPCTransform::Pi();
497
498 pt = (Double_t)(AliHLTTPCTransform::GetBFact() * AliHLTTPCTransform::GetBField() * radius ) ;
499 fTrack->SetPsi(psi);
500 fTrack->SetPt(pt);
501 fTrack->SetRadius(radius);
502 fTrack->SetCenterX(acent);
503 fTrack->SetCenterY(bcent);
504//
505// Get errors from fast fit
506//
507 //if ( getPara()->getErrors ) getErrorsCircleFit ( acent, bcent, radius ) ;
508//
509 delete [] fXYWeight;
510 return 0 ;
511}
512
513//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
514// Fit Line in s-z plane
515//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
516Int_t AliHLTTPCFitter::FitLine ( )
517{
518 //
519 //Initialization
520 //
521 Double_t sum = 0.F ;
522 Double_t ss = 0.F ;
523 Double_t sz = 0.F ;
524 Double_t sss = 0.F ;
525 Double_t ssz = 0.F ;
526 //
527 //find sum , sums ,sumz, sumss
528 //
529 Double_t dx, dy ;
530 Double_t radius = (Double_t)(fTrack->GetPt() / ( AliHLTTPCTransform::GetBFact() * AliHLTTPCTransform::GetBField() ) ) ;
531
532 Double_t * fS = new Double_t[(fTrack->GetNHits())];
533 Double_t *fZWeight = new Double_t[fTrack->GetNHits()];
534 UInt_t *hitnum = fTrack->GetHitNumbers();
535 if (0)//fVertexConstraint==kTRUE)
536 {
537 UInt_t id = hitnum[0];
a371a266 538 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
539 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
540 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 541 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
542
543 dx = points[pos].fX - fVertex->GetX();
544 dy = points[pos].fY - fVertex->GetY();
545 }
546 else
547 {
548 UInt_t id = hitnum[0];
a371a266 549 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
550 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
551 UInt_t posf = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 552 AliHLTTPCSpacePointData *pointsf = fClusters[slice][patch];
553 id = hitnum[(fTrack->GetNHits()-1)];
a371a266 554 slice = AliHLTTPCSpacePointData::GetSlice(id);
555 patch = AliHLTTPCSpacePointData::GetPatch(id);
556 UInt_t posl = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 557 AliHLTTPCSpacePointData *pointsl = fClusters[slice][patch];
558 dx = pointsf[posf].fX - pointsl[posl].fX;
559 dy = pointsf[posf].fY - pointsl[posl].fY;
560 }
561
562 Double_t localPsi = 0.5F * sqrt ( dx*dx + dy*dy ) / radius ;
563 Double_t totals ;
564
565 if ( fabs(localPsi) < 1. )
566 {
567 totals = 2.0 * radius * asin ( localPsi ) ;
568 }
569 else
570 {
571 totals = 2.0 * radius * AliHLTTPCTransform::Pi() ;
572 }
573
574 Double_t dpsi,s;
575
576 for(Int_t i=0; i<fTrack->GetNHits(); i++)
577 {
578 UInt_t id = hitnum[i];
a371a266 579 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
580 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
581 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 582 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
583
584 fZWeight[i] = 1./(Double_t)(points[pos].fSigmaZ2);
585 if(i>0)
586 {
587 id = hitnum[i-1];
a371a266 588 slice = AliHLTTPCSpacePointData::GetSlice(id);
589 patch = AliHLTTPCSpacePointData::GetPatch(id);
590 UInt_t lastpos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 591 AliHLTTPCSpacePointData *lastpoints = fClusters[slice][patch];
592 dx = points[pos].fX -lastpoints[lastpos].fX;
593 dy = points[pos].fY -lastpoints[lastpos].fY;
594 dpsi = 0.5 * (Double_t)sqrt ( dx*dx + dy*dy ) / radius ;
595 if(fabs(dpsi) > 1)
596 return 1;
597 fTrack->SetPsierr(dpsi);
598 s = fS[i-1] - 2.0 * radius * (Double_t)asin ( dpsi ) ;
599 fS[i]=s;
600 }
601 else
602 fS[i]=totals;
603
604 sum += fZWeight[i];
605 ss += fZWeight[i] * fS[i];
606 sz += fZWeight[i] * points[pos].fZ;
607 sss += fZWeight[i] * fS[i] * fS[i];
608 ssz += fZWeight[i] * fS[i] * points[pos].fZ;
609
610 }
611
612
613 Double_t chi2,det = sum * sss - ss * ss;
614 if ( fabs(det) < 1e-20)
615 {
616 chi2 = 99999.F ;
617 //fTrack->SetChiSq2(chi2);
618 return 0 ;
619 }
620
621 //Compute the best fitted parameters A,B
622 Double_t tanl,z0,dtanl,dz0;
623
624 tanl = (Double_t)((sum * ssz - ss * sz ) / det );
625 z0 = (Double_t)((sz * sss - ssz * ss ) / det );
626
627 fTrack->SetTgl(tanl);
628 fTrack->SetZ0(z0);
629
630 //calculate chi-square
631 chi2 = 0.;
632 Double_t r1 ;
633
634 for(Int_t i=0; i<fTrack->GetNHits(); i++)
635 {
636 UInt_t id = hitnum[i];
a371a266 637 Int_t slice = AliHLTTPCSpacePointData::GetSlice(id);
638 Int_t patch = AliHLTTPCSpacePointData::GetPatch(id);
639 UInt_t pos = AliHLTTPCSpacePointData::GetNumber(id);
a6c02c85 640 AliHLTTPCSpacePointData *points = fClusters[slice][patch];
641 r1 = points[pos].fZ - tanl * fS[i] - z0 ;
642 chi2 += (Double_t) ( (Double_t)(fZWeight[i]) * (r1 * r1) );
643 }
644
645 //fTrack->SetChiSq2(chi2);
646 //
647 //calculate estimated variance
648 //varsq=chi/(double(n)-2.)
649 //calculate covariance matrix
650 //siga=sqrt(varsq*sxx/det)
651 //sigb=sqrt(varsq*sum/det)
652 //
653 dtanl = (Double_t) ( sum / det );
654 dz0 = (Double_t) ( sss / det );
655
656 fTrack->SetTglerr(dtanl);
657 fTrack->SetZ0err(dz0);
658 delete [] fZWeight;
659 delete [] fS;
660 return 0 ;
661}