3 // Author: Anders Vestbo <mailto:vestbo@fi.uib.no>
4 //*-- Copyright © ASV
9 #include "AliL3Logging.h"
10 #include "AliL3Fitter.h"
11 #include "AliL3Vertex.h"
12 #include "AliL3Track.h"
13 #include "AliL3SpacePointData.h"
14 #include "AliL3MemHandler.h"
16 //_____________________________________________________________
23 AliL3Fitter::AliL3Fitter(AliL3Vertex *vertex)
29 fVertexConstraint=kTRUE;
32 void AliL3Fitter::LoadClusters(Char_t *path)
35 AliL3MemHandler *clusterfile[36][6];
36 for(Int_t s=0; s<=35; s++)
38 for(Int_t p=0; p<6; p++)
40 clusterfile[s][p] = new AliL3MemHandler();
41 sprintf(fname,"%spoints_%d_%d.raw",path,s,p);
42 if(!clusterfile[s][p]->SetBinaryInput(fname))
44 delete clusterfile[s][p];
45 clusterfile[s][p] = 0;
48 fClusters[s][p] = (AliL3SpacePointData*)clusterfile[s][p]->Allocate();
49 clusterfile[s][p]->Binary2Memory(fNcl[s][p],fClusters[s][p]);
50 clusterfile[s][p]->CloseBinaryInput();
55 Int_t AliL3Fitter::FitHelix(AliL3Track *track)
60 LOG(AliL3Log::kError,"AliL3Fitter::FitHelix","TrackFit")<<AliL3Log::kDec<<
61 "Problems during circle fit"<<ENDLOG;
66 LOG(AliL3Log::kError,"AliL3Fitter::FitHelix","TrackFit")<<AliL3Log::kDec<<
67 "Problems during line fit"<<ENDLOG;
73 Int_t AliL3Fitter::FitCircle()
75 //-----------------------------------------------------------------
76 //Fits circle parameters using algorithm
77 //described by ChErnov and Oskov in Computer Physics
80 //Written in FORTRAN by Jawluen Tang, Physics department , UT-Austin
81 //Moved to C by Pablo Yepes
82 //Moved to AliROOT by ASV.
83 //------------------------------------------------------------------
90 // Loop over hits calculating average
92 Double_t fXYWeight[(fTrack->GetNHits())];
93 UInt_t *hitnum = fTrack->GetHitNumbers();
94 for(Int_t i=0; i<fTrack->GetNHits(); i++)
96 UInt_t id = hitnum[i];
97 Int_t slice = (id>>25) & 0x7f;
98 Int_t patch = (id>>22) & 0x7;
99 UInt_t pos = id&0x3fffff;
101 AliL3SpacePointData *points = fClusters[slice][patch];
102 fXYWeight[i] = 1./ (Double_t)(points[pos].fXYErr*points[pos].fXYErr + points[pos].fXYErr*points[pos].fXYErr);
103 wsum += fXYWeight[i];
104 xav += fXYWeight[i]*points[pos].fX;
105 yav += fXYWeight[i]*points[pos].fY;
108 if (fVertexConstraint == kTRUE)
110 wsum += fVertex->GetXYWeight() ;
111 xav += fVertex->GetX() ;
112 yav += fVertex->GetY() ;
118 // CALCULATE <X**2>, <XY>, AND <Y**2> WITH <X> = 0, & <Y> = 0
120 Double_t xxav = 0.0 ;
121 Double_t xyav = 0.0 ;
122 Double_t yyav = 0.0 ;
125 for(Int_t i=0; i<fTrack->GetNHits(); i++)
127 UInt_t id = hitnum[i];
128 Int_t slice = (id>>25) & 0x7f;
129 Int_t patch = (id>>22) & 0x7;
130 UInt_t pos = id&0x3fffff;
131 AliL3SpacePointData *points = fClusters[slice][patch];
132 xi = points[pos].fX -xav;
133 yi = points[pos].fY - yav ;
134 xxav += xi * xi * fXYWeight[i];
135 xyav += xi * yi * fXYWeight[i];
136 yyav += yi * yi * fXYWeight[i];
139 if (fVertexConstraint == kTRUE)
141 xi = fVertex->GetX() - xav ;
142 yi = fVertex->GetY() - yav ;
143 xxav += xi * xi * fVertex->GetXYWeight() ;
144 xyav += xi * yi * fVertex->GetXYWeight() ;
145 yyav += yi * yi * fVertex->GetXYWeight() ;
151 //--> ROTATE COORDINATES SO THAT <XY> = 0
153 //--> SIGN(C**2 - S**2) = SIGN(XXAV - YYAV) >
154 //--> & > ==> NEW : (XXAV-YYAV) > 0
155 //--> SIGN(S) = SIGN(XYAV) >
157 Double_t a = fabs( xxav - yyav ) ;
158 Double_t b = 4.0 * xyav * xyav ;
160 Double_t asqpb = a * a + b ;
161 Double_t rasqpb = sqrt ( asqpb) ;
163 Double_t splus = 1.0 + a / rasqpb ;
164 Double_t sminus = b / (asqpb * splus) ;
166 splus = sqrt (0.5 * splus ) ;
167 sminus = sqrt (0.5 * sminus) ;
169 //-> FIRST REQUIRE : SIGN(C**2 - S**2) = SIGN(XXAV - YYAV)
171 Double_t sinrot, cosrot ;
172 if ( xxav <= yyav ) {
181 //-> REQUIRE : SIGN(S) = SIGN(XYAV) * SIGN(C) (ASSUMING SIGN(C) > 0)
183 if ( xyav < 0.0 ) sinrot = - sinrot ;
185 //--> WE NOW HAVE THE SMALLEST ANGLE THAT GUARANTEES <X**2> > <Y**2>
186 //--> TO GET THE SIGN OF THE CHARGE RIGHT, THE NEW X-AXIS MUST POINT
187 //--> OUTWARD FROM THE ORGIN. WE ARE FREE TO CHANGE SIGNS OF BOTH
188 //--> COSROT AND SINROT SIMULTANEOUSLY TO ACCOMPLISH THIS.
190 //--> CHOOSE SIGN OF C WISELY TO BE ABLE TO GET THE SIGN OF THE CHARGE
192 if ( cosrot*xav+sinrot*yav < 0.0 ) {
197 //-> NOW GET <R**2> AND RSCALE= SQRT(<R**2>)
199 Double_t rrav = xxav + yyav ;
200 Double_t rscale = sqrt(rrav) ;
205 Double_t xrrav = 0.0 ;
206 Double_t yrrav = 0.0 ;
207 Double_t rrrrav = 0.0 ;
209 Double_t xixi, yiyi, riri, wiriri, xold, yold ;
211 for(Int_t i=0; i<fTrack->GetNHits(); i++)
213 UInt_t id = hitnum[i];
214 Int_t slice = (id>>25) & 0x7f;
215 Int_t patch = (id>>22) & 0x7;
216 UInt_t pos = id&0x3fffff;
217 AliL3SpacePointData *points = fClusters[slice][patch];
219 xold = points[pos].fX - xav ;
220 yold = points[pos].fY - yav ;
222 //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
224 xi = ( cosrot * xold + sinrot * yold ) / rscale ;
225 yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
230 wiriri = fXYWeight[i] * riri ;
232 xyav += fXYWeight[i] * xi * yi ;
233 xxav += fXYWeight[i] * xixi ;
234 yyav += fXYWeight[i] * yiyi ;
236 xrrav += wiriri * xi ;
237 yrrav += wiriri * yi ;
238 rrrrav += wiriri * riri ;
241 // Include vertex if required
243 if (fVertexConstraint == kTRUE)
245 xold = fVertex->GetX() - xav ;
246 yold = fVertex->GetY() - yav ;
248 //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
250 xi = ( cosrot * xold + sinrot * yold ) / rscale ;
251 yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
256 wiriri = fVertex->GetXYWeight() * riri ;
258 xyav += fVertex->GetXYWeight() * xi * yi ;
259 xxav += fVertex->GetXYWeight() * xixi ;
260 yyav += fVertex->GetXYWeight() * yiyi ;
262 xrrav += wiriri * xi ;
263 yrrav += wiriri * yi ;
264 rrrrav += wiriri * riri ;
269 //--> DIVIDE BY WSUM TO MAKE AVERAGES
273 xrrav = xrrav / wsum ;
274 yrrav = yrrav / wsum ;
275 rrrrav = rrrrav / wsum ;
278 Int_t const ntry = 5 ;
280 //--> USE THESE TO GET THE COEFFICIENTS OF THE 4-TH ORDER POLYNIMIAL
281 //--> DON'T PANIC - THE THIRD ORDER TERM IS ZERO !
283 Double_t xrrxrr = xrrav * xrrav ;
284 Double_t yrryrr = yrrav * yrrav ;
285 Double_t rrrrm1 = rrrrav - 1.0 ;
286 Double_t xxyy = xxav * yyav ;
288 Double_t c0 = rrrrm1*xxyy - xrrxrr*yyav - yrryrr*xxav ;
289 Double_t c1 = - rrrrm1 + xrrxrr + yrryrr - 4.0*xxyy ;
290 Double_t c2 = 4.0 + rrrrm1 - 4.0*xxyy ;
291 Double_t c4 = - 4.0 ;
293 //--> COEFFICIENTS OF THE DERIVATIVE - USED IN NEWTON-RAPHSON ITERATIONS
295 Double_t c2d = 2.0 * c2 ;
296 Double_t c4d = 4.0 * c4 ;
298 //--> 0'TH VALUE OF LAMDA - LINEAR INTERPOLATION BETWEEN P(0) & P(YYAV)
300 // LAMDA = YYAV * C0 / (C0 + YRRSQ * (XXAV-YYAV))
301 Double_t lamda = 0.0 ;
302 Double_t dlamda = 0.0 ;
304 Double_t chiscl = wsum * rscale * rscale ;
305 Double_t dlamax = 0.001 / chiscl ;
308 for ( int itry = 1 ; itry <= ntry ; itry++ ) {
309 p = c0 + lamda * (c1 + lamda * (c2 + lamda * lamda * c4 )) ;
310 pd = (c1 + lamda * (c2d + lamda * lamda * c4d)) ;
312 lamda = lamda + dlamda ;
313 if (fabs(dlamda)< dlamax) break ;
316 Double_t chi2 = (Double_t)(chiscl * lamda) ;
318 //fTrack->SetChiSq1(chi2);
319 // Double_t dchisq = chiscl * dlamda ;
321 //--> NOW CALCULATE THE MATRIX ELEMENTS FOR ALPHA, BETA & KAPPA
323 Double_t h11 = xxav - lamda ;
324 Double_t h14 = xrrav ;
325 Double_t h22 = yyav - lamda ;
326 Double_t h24 = yrrav ;
327 Double_t h34 = 1.0 + 2.0*lamda ;
328 if ( h11 == 0.0 || h22 == 0.0 ){
329 LOG(AliL3Log::kError,"AliL3Fitter::FitCircle","TrackFit")<<AliL3Log::kDec<<
330 "Problems fitting circle"<<ENDLOG;
333 Double_t rootsq = (h14*h14)/(h11*h11) + 4.0*h34 ;
335 Double_t ratio, kappa, beta ;
336 if ( fabs(h22) > fabs(h24) ) {
338 rootsq = ratio * ratio + rootsq ;
339 kappa = 1.0 / sqrt(rootsq) ;
340 beta = - ratio * kappa ;
344 rootsq = 1.0 + ratio * ratio * rootsq ;
345 beta = 1.0 / sqrt(rootsq) ;
346 if ( h24 > 0 ) beta = - beta ;
347 kappa = -ratio * beta ;
349 Double_t alpha = - (h14/h11) * kappa ;
351 //--> transform these into the lab coordinate system
352 //--> first get kappa and back to real dimensions
354 Double_t kappa1 = kappa / rscale ;
355 Double_t dbro = 0.5 / kappa1 ;
357 //--> next rotate alpha and beta and scale
359 Double_t alphar = (cosrot * alpha - sinrot * beta)* dbro ;
360 Double_t betar = (sinrot * alpha + cosrot * beta)* dbro ;
362 //--> then translate by (xav,yav)
364 Double_t acent = (double)(xav - alphar) ;
365 Double_t bcent = (double)(yav - betar ) ;
366 Double_t radius = (double)dbro ;
370 Int_t q = ( ( yrrav < 0 ) ? 1 : -1 ) ;
372 fTrack->SetCharge(q);
375 // Get other track parameters
377 Double_t x0, y0,phi0,r0,psi,pt ;
378 if ( fVertexConstraint == kTRUE)
380 //flag = 1 ; // primary track flag
381 x0 = fVertex->GetX() ;
382 y0 = fVertex->GetY() ;
383 phi0 = fVertex->GetPhi() ;
384 r0 = fVertex->GetR() ;
385 fTrack->SetPhi0(phi0);
390 Int_t lastid=fTrack->GetNHits()-1;
391 UInt_t id = hitnum[lastid];
392 Int_t slice = (id>>25) & 0x7f;
393 Int_t patch = (id>>22) & 0x7;
394 UInt_t pos = id&0x3fffff;
395 AliL3SpacePointData *points = fClusters[slice][patch];
397 //flag = 0 ; // primary track flag
400 phi0 = atan2(points[pos].fY,points[pos].fX);
401 if ( phi0 < 0 ) phi0 += 2*Pi;
402 r0 = sqrt ( points[pos].fX * points[pos].fX + points[pos].fY*points[pos].fY);
403 fTrack->SetPhi0(phi0);
407 psi = (Double_t)atan2(bcent-y0,acent-x0) ;
408 psi = psi + q * 0.5F * Pi ;
409 if ( psi < 0 ) psi = psi + 2*Pi;
411 pt = (Double_t)(BFACT * BField * radius ) ;
414 fTrack->SetFirstPoint(x0,y0,0);
416 // Get errors from fast fit
418 //if ( getPara()->getErrors ) getErrorsCircleFit ( acent, bcent, radius ) ;
424 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
425 // Fit Line in s-z plane
426 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
427 Int_t AliL3Fitter::FitLine ( )
438 //find sum , sums ,sumz, sumss
441 Double_t radius = (Double_t)(fTrack->GetPt() / ( BFACT * BField ) ) ;
443 //TObjArray *hits = fTrack->GetHits();
444 //Int_t num_of_hits = fTrack->GetNumberOfPoints();
446 Double_t fS[(fTrack->GetNHits())];
447 UInt_t *hitnum = fTrack->GetHitNumbers();
448 if (fVertexConstraint==kTRUE)
450 UInt_t id = hitnum[0];
451 Int_t slice = (id>>25) & 0x7f;
452 Int_t patch = (id>>22) & 0x7;
453 UInt_t pos = id&0x3fffff;
454 AliL3SpacePointData *points = fClusters[slice][patch];
456 dx = points[pos].fX - fVertex->GetX();
457 dy = points[pos].fY - fVertex->GetY() ;
461 UInt_t id = hitnum[0];
462 Int_t slice = (id>>25) & 0x7f;
463 Int_t patch = (id>>22) & 0x7;
464 UInt_t posf = id&0x3fffff;
465 AliL3SpacePointData *pointsf = fClusters[slice][patch];
466 id = hitnum[(fTrack->GetNHits()-1)];
467 slice = (id>>25) & 0x7f;
468 patch = (id>>22) & 0x7;
469 UInt_t posl = id&0x3fffff;
470 AliL3SpacePointData *pointsl = fClusters[slice][patch];
471 dx = pointsf[posf].fX - pointsl[posl].fX;
472 dy = pointsf[posf].fY - pointsl[posl].fY;
476 Double_t localPsi = 0.5F * sqrt ( dx*dx + dy*dy ) / radius ;
479 if ( fabs(localPsi) < 1. )
481 total_s = 2.0 * radius * asin ( localPsi ) ;
485 total_s = 2.0 * radius * Pi ;
490 for(Int_t i=0; i<fTrack->GetNHits(); i++)
492 UInt_t id = hitnum[i];
493 Int_t slice = (id>>25) & 0x7f;
494 Int_t patch = (id>>22) & 0x7;
495 UInt_t pos = id&0x3fffff;
496 AliL3SpacePointData *points = fClusters[slice][patch];
501 slice = (id>>25) & 0x7f;
502 patch = (id>>22) & 0x7;
503 UInt_t lastpos = id&0x3fffff;
504 AliL3SpacePointData *lastpoints = fClusters[slice][patch];
505 dx = points[pos].fX -lastpoints[lastpos].fX;
506 dy = points[pos].fY -lastpoints[lastpos].fY;
507 dpsi = 0.5 * (Double_t)sqrt ( dx*dx + dy*dy ) / radius ;
508 fTrack->SetPsierr(dpsi);
509 s = fS[i-1] - 2.0 * radius * (Double_t)asin ( dpsi ) ;
515 sum += 1/(points[pos].fZErr*points[pos].fZErr);
516 ss += 1/(points[pos].fZErr*points[pos].fZErr) * fS[i];
517 sz += 1/(points[pos].fZErr*points[pos].fZErr)*points[pos].fZ;
518 sss += 1/(points[pos].fZErr*points[pos].fZErr)* fS[i] * fS[i];
519 ssz += 1/(points[pos].fZErr*points[pos].fZErr) * fS[i] * points[pos].fZ;
524 Double_t chi2,det = sum * sss - ss * ss;
525 if ( fabs(det) < 1e-20)
528 //fTrack->SetChiSq2(chi2);
532 //Compute the best fitted parameters A,B
533 Double_t tanl,z0,dtanl,dz0;
535 tanl = (Double_t)((sum * ssz - ss * sz ) / det );
536 z0 = (Double_t)((sz * sss - ssz * ss ) / det );
538 fTrack->SetTgl(tanl);
541 // calculate chi-square
546 for(Int_t i=0; i<fTrack->GetNHits(); i++)
548 UInt_t id = hitnum[i];
549 Int_t slice = (id>>25) & 0x7f;
550 Int_t patch = (id>>22) & 0x7;
551 UInt_t pos = id&0x3fffff;
552 AliL3SpacePointData *points = fClusters[slice][patch];
553 r1 = points[pos].fZ - tanl * fS[i] - z0 ;
554 chi2 += (Double_t) ( (Double_t)(1/(points[pos].fZErr*points[pos].fZErr)) * (r1 * r1) );
557 //fTrack->SetChiSq2(chi2);
559 // calculate estimated variance
560 // varsq=chi/(double(n)-2.)
561 // calculate covariance matrix
562 // siga=sqrt(varsq*sxx/det)
563 // sigb=sqrt(varsq*sum/det)
565 dtanl = (Double_t) ( sum / det );
566 dz0 = (Double_t) ( sss / det );
568 fTrack->SetTglerr(dtanl);
569 fTrack->SetZ0err(dz0);