3 // Author: Anders Vestbo <mailto:vestbo@fi.uib.no>
4 //*-- Copyright © ASV
6 #include "AliL3StandardIncludes.h"
9 #include "AliL3Logging.h"
10 #include "AliL3Fitter.h"
11 #include "AliL3Vertex.h"
12 #include "AliL3Track.h"
13 #include "AliL3SpacePointData.h"
14 #include "AliL3MemHandler.h"
15 #include "AliL3Transform.h"
16 //_____________________________________________________________
23 AliL3Fitter::AliL3Fitter(AliL3Vertex *vertex)
28 fVertexConstraint=kTRUE;
31 void AliL3Fitter::LoadClusters(Char_t *path)
34 AliL3MemHandler *clusterfile[36][6];
35 for(Int_t s=0; s<=35; s++)
37 for(Int_t p=0; p<6; p++)
39 clusterfile[s][p] = new AliL3MemHandler();
40 sprintf(fname,"%spoints_%d_%d.raw",path,s,p);
41 if(!clusterfile[s][p]->SetBinaryInput(fname))
43 delete clusterfile[s][p];
44 clusterfile[s][p] = 0;
47 fClusters[s][p] = (AliL3SpacePointData*)clusterfile[s][p]->Allocate();
48 clusterfile[s][p]->Binary2Memory(fNcl[s][p],fClusters[s][p]);
49 clusterfile[s][p]->CloseBinaryInput();
54 Int_t AliL3Fitter::FitHelix(AliL3Track *track)
59 LOG(AliL3Log::kError,"AliL3Fitter::FitHelix","TrackFit")<<AliL3Log::kDec<<
60 "Problems during circle fit"<<ENDLOG;
65 LOG(AliL3Log::kError,"AliL3Fitter::FitHelix","TrackFit")<<AliL3Log::kDec<<
66 "Problems during line fit"<<ENDLOG;
72 Int_t AliL3Fitter::FitCircle()
74 //-----------------------------------------------------------------
75 //Fits circle parameters using algorithm
76 //described by ChErnov and Oskov in Computer Physics
79 //Written in FORTRAN by Jawluen Tang, Physics department , UT-Austin
80 //Moved to C by Pablo Yepes
81 //Moved to AliROOT by ASV.
82 //------------------------------------------------------------------
89 // Loop over hits calculating average
91 Double_t fXYWeight[(fTrack->GetNHits())];
92 UInt_t *hitnum = fTrack->GetHitNumbers();
93 for(Int_t i=0; i<fTrack->GetNHits(); i++)
95 UInt_t id = hitnum[i];
96 Int_t slice = (id>>25) & 0x7f;
97 Int_t patch = (id>>22) & 0x7;
98 UInt_t pos = id&0x3fffff;
100 AliL3SpacePointData *points = fClusters[slice][patch];
101 fXYWeight[i] = 1./ (Double_t)(points[pos].fXYErr*points[pos].fXYErr + points[pos].fXYErr*points[pos].fXYErr);
102 wsum += fXYWeight[i];
103 xav += fXYWeight[i]*points[pos].fX;
104 yav += fXYWeight[i]*points[pos].fY;
107 if (fVertexConstraint == kTRUE)
109 wsum += fVertex->GetXYWeight() ;
110 xav += fVertex->GetX() ;
111 yav += fVertex->GetY() ;
117 // CALCULATE <X**2>, <XY>, AND <Y**2> WITH <X> = 0, & <Y> = 0
119 Double_t xxav = 0.0 ;
120 Double_t xyav = 0.0 ;
121 Double_t yyav = 0.0 ;
124 for(Int_t i=0; i<fTrack->GetNHits(); i++)
126 UInt_t id = hitnum[i];
127 Int_t slice = (id>>25) & 0x7f;
128 Int_t patch = (id>>22) & 0x7;
129 UInt_t pos = id&0x3fffff;
130 AliL3SpacePointData *points = fClusters[slice][patch];
131 xi = points[pos].fX -xav;
132 yi = points[pos].fY - yav ;
133 xxav += xi * xi * fXYWeight[i];
134 xyav += xi * yi * fXYWeight[i];
135 yyav += yi * yi * fXYWeight[i];
138 if (fVertexConstraint == kTRUE)
140 xi = fVertex->GetX() - xav ;
141 yi = fVertex->GetY() - yav ;
142 xxav += xi * xi * fVertex->GetXYWeight() ;
143 xyav += xi * yi * fVertex->GetXYWeight() ;
144 yyav += yi * yi * fVertex->GetXYWeight() ;
150 //--> ROTATE COORDINATES SO THAT <XY> = 0
152 //--> SIGN(C**2 - S**2) = SIGN(XXAV - YYAV) >
153 //--> & > ==> NEW : (XXAV-YYAV) > 0
154 //--> SIGN(S) = SIGN(XYAV) >
156 Double_t a = fabs( xxav - yyav ) ;
157 Double_t b = 4.0 * xyav * xyav ;
159 Double_t asqpb = a * a + b ;
160 Double_t rasqpb = sqrt ( asqpb) ;
162 Double_t splus = 1.0 + a / rasqpb ;
163 Double_t sminus = b / (asqpb * splus) ;
165 splus = sqrt (0.5 * splus ) ;
166 sminus = sqrt (0.5 * sminus) ;
168 //-> FIRST REQUIRE : SIGN(C**2 - S**2) = SIGN(XXAV - YYAV)
170 Double_t sinrot, cosrot ;
171 if ( xxav <= yyav ) {
180 //-> REQUIRE : SIGN(S) = SIGN(XYAV) * SIGN(C) (ASSUMING SIGN(C) > 0)
182 if ( xyav < 0.0 ) sinrot = - sinrot ;
184 //--> WE NOW HAVE THE SMALLEST ANGLE THAT GUARANTEES <X**2> > <Y**2>
185 //--> TO GET THE SIGN OF THE CHARGE RIGHT, THE NEW X-AXIS MUST POINT
186 //--> OUTWARD FROM THE ORGIN. WE ARE FREE TO CHANGE SIGNS OF BOTH
187 //--> COSROT AND SINROT SIMULTANEOUSLY TO ACCOMPLISH THIS.
189 //--> CHOOSE SIGN OF C WISELY TO BE ABLE TO GET THE SIGN OF THE CHARGE
191 if ( cosrot*xav+sinrot*yav < 0.0 ) {
196 //-> NOW GET <R**2> AND RSCALE= SQRT(<R**2>)
198 Double_t rrav = xxav + yyav ;
199 Double_t rscale = sqrt(rrav) ;
204 Double_t xrrav = 0.0 ;
205 Double_t yrrav = 0.0 ;
206 Double_t rrrrav = 0.0 ;
208 Double_t xixi, yiyi, riri, wiriri, xold, yold ;
210 for(Int_t i=0; i<fTrack->GetNHits(); i++)
212 UInt_t id = hitnum[i];
213 Int_t slice = (id>>25) & 0x7f;
214 Int_t patch = (id>>22) & 0x7;
215 UInt_t pos = id&0x3fffff;
216 AliL3SpacePointData *points = fClusters[slice][patch];
218 xold = points[pos].fX - xav ;
219 yold = points[pos].fY - yav ;
221 //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
223 xi = ( cosrot * xold + sinrot * yold ) / rscale ;
224 yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
229 wiriri = fXYWeight[i] * riri ;
231 xyav += fXYWeight[i] * xi * yi ;
232 xxav += fXYWeight[i] * xixi ;
233 yyav += fXYWeight[i] * yiyi ;
235 xrrav += wiriri * xi ;
236 yrrav += wiriri * yi ;
237 rrrrav += wiriri * riri ;
240 // Include vertex if required
242 if (fVertexConstraint == kTRUE)
244 xold = fVertex->GetX() - xav ;
245 yold = fVertex->GetY() - yav ;
247 //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
249 xi = ( cosrot * xold + sinrot * yold ) / rscale ;
250 yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
255 wiriri = fVertex->GetXYWeight() * riri ;
257 xyav += fVertex->GetXYWeight() * xi * yi ;
258 xxav += fVertex->GetXYWeight() * xixi ;
259 yyav += fVertex->GetXYWeight() * yiyi ;
261 xrrav += wiriri * xi ;
262 yrrav += wiriri * yi ;
263 rrrrav += wiriri * riri ;
268 //--> DIVIDE BY WSUM TO MAKE AVERAGES
272 xrrav = xrrav / wsum ;
273 yrrav = yrrav / wsum ;
274 rrrrav = rrrrav / wsum ;
277 Int_t const ntry = 5 ;
279 //--> USE THESE TO GET THE COEFFICIENTS OF THE 4-TH ORDER POLYNIMIAL
280 //--> DON'T PANIC - THE THIRD ORDER TERM IS ZERO !
282 Double_t xrrxrr = xrrav * xrrav ;
283 Double_t yrryrr = yrrav * yrrav ;
284 Double_t rrrrm1 = rrrrav - 1.0 ;
285 Double_t xxyy = xxav * yyav ;
287 Double_t c0 = rrrrm1*xxyy - xrrxrr*yyav - yrryrr*xxav ;
288 Double_t c1 = - rrrrm1 + xrrxrr + yrryrr - 4.0*xxyy ;
289 Double_t c2 = 4.0 + rrrrm1 - 4.0*xxyy ;
290 Double_t c4 = - 4.0 ;
292 //--> COEFFICIENTS OF THE DERIVATIVE - USED IN NEWTON-RAPHSON ITERATIONS
294 Double_t c2d = 2.0 * c2 ;
295 Double_t c4d = 4.0 * c4 ;
297 //--> 0'TH VALUE OF LAMDA - LINEAR INTERPOLATION BETWEEN P(0) & P(YYAV)
299 // LAMDA = YYAV * C0 / (C0 + YRRSQ * (XXAV-YYAV))
300 Double_t lamda = 0.0 ;
301 Double_t dlamda = 0.0 ;
303 Double_t chiscl = wsum * rscale * rscale ;
304 Double_t dlamax = 0.001 / chiscl ;
307 for ( int itry = 1 ; itry <= ntry ; itry++ ) {
308 p = c0 + lamda * (c1 + lamda * (c2 + lamda * lamda * c4 )) ;
309 pd = (c1 + lamda * (c2d + lamda * lamda * c4d)) ;
311 lamda = lamda + dlamda ;
312 if (fabs(dlamda)< dlamax) break ;
315 Double_t chi2 = (Double_t)(chiscl * lamda) ;
317 //fTrack->SetChiSq1(chi2);
318 // Double_t dchisq = chiscl * dlamda ;
320 //--> NOW CALCULATE THE MATRIX ELEMENTS FOR ALPHA, BETA & KAPPA
322 Double_t h11 = xxav - lamda ;
323 Double_t h14 = xrrav ;
324 Double_t h22 = yyav - lamda ;
325 Double_t h24 = yrrav ;
326 Double_t h34 = 1.0 + 2.0*lamda ;
327 if ( h11 == 0.0 || h22 == 0.0 ){
328 LOG(AliL3Log::kError,"AliL3Fitter::FitCircle","TrackFit")<<AliL3Log::kDec<<
329 "Problems fitting circle"<<ENDLOG;
332 Double_t rootsq = (h14*h14)/(h11*h11) + 4.0*h34 ;
334 Double_t ratio, kappa, beta ;
335 if ( fabs(h22) > fabs(h24) ) {
337 rootsq = ratio * ratio + rootsq ;
338 kappa = 1.0 / sqrt(rootsq) ;
339 beta = - ratio * kappa ;
343 rootsq = 1.0 + ratio * ratio * rootsq ;
344 beta = 1.0 / sqrt(rootsq) ;
345 if ( h24 > 0 ) beta = - beta ;
346 kappa = -ratio * beta ;
348 Double_t alpha = - (h14/h11) * kappa ;
350 //--> transform these into the lab coordinate system
351 //--> first get kappa and back to real dimensions
353 Double_t kappa1 = kappa / rscale ;
354 Double_t dbro = 0.5 / kappa1 ;
356 //--> next rotate alpha and beta and scale
358 Double_t alphar = (cosrot * alpha - sinrot * beta)* dbro ;
359 Double_t betar = (sinrot * alpha + cosrot * beta)* dbro ;
361 //--> then translate by (xav,yav)
363 Double_t acent = (double)(xav - alphar) ;
364 Double_t bcent = (double)(yav - betar ) ;
365 Double_t radius = (double)dbro ;
369 Int_t q = ( ( yrrav < 0 ) ? 1 : -1 ) ;
371 fTrack->SetCharge(q);
374 // Get other track parameters
376 Double_t x0, y0,phi0,r0,psi,pt ;
377 if ( fVertexConstraint == kTRUE)
379 //flag = 1 ; // primary track flag
380 x0 = fVertex->GetX() ;
381 y0 = fVertex->GetY() ;
382 phi0 = fVertex->GetPhi() ;
383 r0 = fVertex->GetR() ;
384 fTrack->SetPhi0(phi0);
389 Int_t lastid=fTrack->GetNHits()-1;
390 UInt_t id = hitnum[lastid];
391 Int_t slice = (id>>25) & 0x7f;
392 Int_t patch = (id>>22) & 0x7;
393 UInt_t pos = id&0x3fffff;
394 AliL3SpacePointData *points = fClusters[slice][patch];
396 //flag = 0 ; // primary track flag
399 phi0 = atan2(points[pos].fY,points[pos].fX);
400 if ( phi0 < 0 ) phi0 += 2*AliL3Transform::Pi();
401 r0 = sqrt ( points[pos].fX * points[pos].fX + points[pos].fY*points[pos].fY);
402 fTrack->SetPhi0(phi0);
406 psi = (Double_t)atan2(bcent-y0,acent-x0) ;
407 psi = psi + q * 0.5F * AliL3Transform::Pi() ;
408 if ( psi < 0 ) psi = psi + 2*AliL3Transform::Pi();
410 pt = (Double_t)(AliL3Transform::GetBFact() * AliL3Transform::GetBField() * radius ) ;
413 fTrack->SetFirstPoint(x0,y0,0);
415 // Get errors from fast fit
417 //if ( getPara()->getErrors ) getErrorsCircleFit ( acent, bcent, radius ) ;
423 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
424 // Fit Line in s-z plane
425 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
426 Int_t AliL3Fitter::FitLine ( )
437 //find sum , sums ,sumz, sumss
440 Double_t radius = (Double_t)(fTrack->GetPt() / ( AliL3Transform::GetBFact() * AliL3Transform::GetBField() ) ) ;
442 //TObjArray *hits = fTrack->GetHits();
443 //Int_t num_of_hits = fTrack->GetNumberOfPoints();
445 Double_t fS[(fTrack->GetNHits())];
446 UInt_t *hitnum = fTrack->GetHitNumbers();
447 if (fVertexConstraint==kTRUE)
449 UInt_t id = hitnum[0];
450 Int_t slice = (id>>25) & 0x7f;
451 Int_t patch = (id>>22) & 0x7;
452 UInt_t pos = id&0x3fffff;
453 AliL3SpacePointData *points = fClusters[slice][patch];
455 dx = points[pos].fX - fVertex->GetX();
456 dy = points[pos].fY - fVertex->GetY() ;
460 UInt_t id = hitnum[0];
461 Int_t slice = (id>>25) & 0x7f;
462 Int_t patch = (id>>22) & 0x7;
463 UInt_t posf = id&0x3fffff;
464 AliL3SpacePointData *pointsf = fClusters[slice][patch];
465 id = hitnum[(fTrack->GetNHits()-1)];
466 slice = (id>>25) & 0x7f;
467 patch = (id>>22) & 0x7;
468 UInt_t posl = id&0x3fffff;
469 AliL3SpacePointData *pointsl = fClusters[slice][patch];
470 dx = pointsf[posf].fX - pointsl[posl].fX;
471 dy = pointsf[posf].fY - pointsl[posl].fY;
475 Double_t localPsi = 0.5F * sqrt ( dx*dx + dy*dy ) / radius ;
478 if ( fabs(localPsi) < 1. )
480 total_s = 2.0 * radius * asin ( localPsi ) ;
484 total_s = 2.0 * radius * AliL3Transform::Pi() ;
489 for(Int_t i=0; i<fTrack->GetNHits(); i++)
491 UInt_t id = hitnum[i];
492 Int_t slice = (id>>25) & 0x7f;
493 Int_t patch = (id>>22) & 0x7;
494 UInt_t pos = id&0x3fffff;
495 AliL3SpacePointData *points = fClusters[slice][patch];
500 slice = (id>>25) & 0x7f;
501 patch = (id>>22) & 0x7;
502 UInt_t lastpos = id&0x3fffff;
503 AliL3SpacePointData *lastpoints = fClusters[slice][patch];
504 dx = points[pos].fX -lastpoints[lastpos].fX;
505 dy = points[pos].fY -lastpoints[lastpos].fY;
506 dpsi = 0.5 * (Double_t)sqrt ( dx*dx + dy*dy ) / radius ;
507 fTrack->SetPsierr(dpsi);
508 s = fS[i-1] - 2.0 * radius * (Double_t)asin ( dpsi ) ;
514 sum += 1/(points[pos].fZErr*points[pos].fZErr);
515 ss += 1/(points[pos].fZErr*points[pos].fZErr) * fS[i];
516 sz += 1/(points[pos].fZErr*points[pos].fZErr)*points[pos].fZ;
517 sss += 1/(points[pos].fZErr*points[pos].fZErr)* fS[i] * fS[i];
518 ssz += 1/(points[pos].fZErr*points[pos].fZErr) * fS[i] * points[pos].fZ;
523 Double_t chi2,det = sum * sss - ss * ss;
524 if ( fabs(det) < 1e-20)
527 //fTrack->SetChiSq2(chi2);
531 //Compute the best fitted parameters A,B
532 Double_t tanl,z0,dtanl,dz0;
534 tanl = (Double_t)((sum * ssz - ss * sz ) / det );
535 z0 = (Double_t)((sz * sss - ssz * ss ) / det );
537 fTrack->SetTgl(tanl);
540 // calculate chi-square
545 for(Int_t i=0; i<fTrack->GetNHits(); i++)
547 UInt_t id = hitnum[i];
548 Int_t slice = (id>>25) & 0x7f;
549 Int_t patch = (id>>22) & 0x7;
550 UInt_t pos = id&0x3fffff;
551 AliL3SpacePointData *points = fClusters[slice][patch];
552 r1 = points[pos].fZ - tanl * fS[i] - z0 ;
553 chi2 += (Double_t) ( (Double_t)(1/(points[pos].fZErr*points[pos].fZErr)) * (r1 * r1) );
556 //fTrack->SetChiSq2(chi2);
558 // calculate estimated variance
559 // varsq=chi/(double(n)-2.)
560 // calculate covariance matrix
561 // siga=sqrt(varsq*sxx/det)
562 // sigb=sqrt(varsq*sum/det)
564 dtanl = (Double_t) ( sum / det );
565 dz0 = (Double_t) ( sss / det );
567 fTrack->SetTglerr(dtanl);
568 fTrack->SetZ0err(dz0);