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b661165c | 1 | // Author: Anders Vestbo <mailto:vestbo@fi.uib.no> |
2 | //*-- Copyright © ASV | |
3 | ||
108615fc | 4 | #include <math.h> |
5 | ||
6 | #include "AliL3Logging.h" | |
7 | #include "AliL3ConfMapFit.h" | |
8 | #include "AliL3Vertex.h" | |
9 | #include "AliL3ConfMapTrack.h" | |
10 | #include "AliL3ConfMapPoint.h" | |
11 | ||
b661165c | 12 | //_____________________________________________________________ |
108615fc | 13 | // AliL3ConfMapFit |
14 | // | |
15 | // Fit class for conformal mapping tracking | |
16 | ||
17 | ClassImp(AliL3ConfMapFit) | |
18 | ||
19 | Double_t AliL3ConfMapFit::pi=3.14159265358979323846; | |
20 | ||
21 | AliL3ConfMapFit::AliL3ConfMapFit(AliL3ConfMapTrack *track,AliL3Vertex *vertex) | |
22 | { | |
23 | //constructor | |
24 | fTrack = track; | |
25 | fVertex = vertex; | |
26 | BFACT = 0.0029980; | |
27 | bField = 0.2; | |
28 | ||
29 | } | |
30 | ||
31 | Int_t AliL3ConfMapFit::FitHelix() | |
32 | { | |
33 | if(FitCircle()) | |
34 | { | |
35 | LOG(AliL3Log::kError,"AliL3ConfMapFit::FitHelix","TrackFit")<<AliL3Log::kDec<< | |
36 | "Problems during circle fit"<<ENDLOG; | |
37 | return 1; | |
38 | } | |
39 | if(FitLine()) | |
40 | { | |
41 | LOG(AliL3Log::kError,"AliL3ConfMapFit::FitHelix","TrackFit")<<AliL3Log::kDec<< | |
42 | "Problems during line fit"<<ENDLOG; | |
43 | return 1; | |
44 | } | |
45 | return 0; | |
46 | } | |
47 | ||
48 | Int_t AliL3ConfMapFit::FitCircle() | |
49 | { | |
50 | //----------------------------------------------------------------- | |
51 | //Fits circle parameters using algorithm | |
52 | //described by ChErnov and Oskov in Computer Physics | |
53 | //Communications. | |
54 | // | |
55 | //Written in FORTRAN by Jawluen Tang, Physics department , UT-Austin | |
56 | //Moved to C by Pablo Yepes | |
57 | //Moved to AliROOT by ASV. | |
58 | //------------------------------------------------------------------ | |
59 | ||
60 | Double_t wsum = 0.0 ; | |
61 | Double_t xav = 0.0 ; | |
62 | Double_t yav = 0.0 ; | |
63 | ||
64 | Int_t num_of_hits = fTrack->GetNumberOfPoints(); | |
65 | // | |
66 | // Loop over hits calculating average | |
67 | Int_t co=0; | |
68 | ||
69 | for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit()) | |
70 | { | |
71 | co++; | |
72 | AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->currentHit; | |
73 | cHit->SetXYWeight( 1./ (Double_t)(cHit->GetXerr()*cHit->GetXerr() + cHit->GetYerr()*cHit->GetYerr()) ); | |
74 | wsum += cHit->GetXYWeight() ; | |
75 | xav += cHit->GetXYWeight() * cHit->GetX() ; | |
76 | yav += cHit->GetXYWeight() * cHit->GetY() ; | |
77 | } | |
78 | if(co!=num_of_hits) | |
79 | LOG(AliL3Log::kError,"AliL3ConfMapFit::FitCircle","TrackFit")<<AliL3Log::kDec<< | |
80 | "Mismatch of hits. Counter: "<<co<<" nHits: "<<num_of_hits<<ENDLOG; | |
81 | if (fTrack->ComesFromMainVertex() == true) | |
82 | { | |
83 | wsum += fVertex->GetXYWeight() ; | |
84 | xav += fVertex->GetX() ; | |
85 | yav += fVertex->GetY() ; | |
86 | } | |
87 | ||
88 | xav = xav / wsum ; | |
89 | yav = yav / wsum ; | |
90 | // | |
91 | // CALCULATE <X**2>, <XY>, AND <Y**2> WITH <X> = 0, & <Y> = 0 | |
92 | // | |
93 | Double_t xxav = 0.0 ; | |
94 | Double_t xyav = 0.0 ; | |
95 | Double_t yyav = 0.0 ; | |
96 | Double_t xi, yi ; | |
97 | ||
98 | for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit()) | |
99 | { | |
100 | //AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint *)hits->At(hit_counter); | |
101 | AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->currentHit; | |
102 | xi = cHit->GetX() - xav ; | |
103 | yi = cHit->GetY() - yav ; | |
104 | xxav += xi * xi * cHit->GetXYWeight() ; | |
105 | xyav += xi * yi * cHit->GetXYWeight() ; | |
106 | yyav += yi * yi * cHit->GetXYWeight() ; | |
107 | } | |
108 | ||
109 | if (fTrack->ComesFromMainVertex() == true) | |
110 | { | |
111 | xi = fVertex->GetX() - xav ; | |
112 | yi = fVertex->GetY() - yav ; | |
113 | xxav += xi * xi * fVertex->GetXYWeight() ; | |
114 | xyav += xi * yi * fVertex->GetXYWeight() ; | |
115 | yyav += yi * yi * fVertex->GetXYWeight() ; | |
116 | } | |
117 | xxav = xxav / wsum ; | |
118 | xyav = xyav / wsum ; | |
119 | yyav = yyav / wsum ; | |
120 | // | |
121 | //--> ROTATE COORDINATES SO THAT <XY> = 0 | |
122 | // | |
123 | //--> SIGN(C**2 - S**2) = SIGN(XXAV - YYAV) > | |
124 | //--> & > ==> NEW : (XXAV-YYAV) > 0 | |
125 | //--> SIGN(S) = SIGN(XYAV) > | |
126 | ||
127 | Double_t a = fabs( xxav - yyav ) ; | |
128 | Double_t b = 4.0 * xyav * xyav ; | |
129 | ||
130 | Double_t asqpb = a * a + b ; | |
131 | Double_t rasqpb = sqrt ( asqpb) ; | |
132 | ||
133 | Double_t splus = 1.0 + a / rasqpb ; | |
134 | Double_t sminus = b / (asqpb * splus) ; | |
135 | ||
136 | splus = sqrt (0.5 * splus ) ; | |
137 | sminus = sqrt (0.5 * sminus) ; | |
138 | // | |
139 | //-> FIRST REQUIRE : SIGN(C**2 - S**2) = SIGN(XXAV - YYAV) | |
140 | // | |
141 | Double_t sinrot, cosrot ; | |
142 | if ( xxav <= yyav ) { | |
143 | cosrot = sminus ; | |
144 | sinrot = splus ; | |
145 | } | |
146 | else { | |
147 | cosrot = splus ; | |
148 | sinrot = sminus ; | |
149 | } | |
150 | // | |
151 | //-> REQUIRE : SIGN(S) = SIGN(XYAV) * SIGN(C) (ASSUMING SIGN(C) > 0) | |
152 | // | |
153 | if ( xyav < 0.0 ) sinrot = - sinrot ; | |
154 | // | |
155 | //--> WE NOW HAVE THE SMALLEST ANGLE THAT GUARANTEES <X**2> > <Y**2> | |
156 | //--> TO GET THE SIGN OF THE CHARGE RIGHT, THE NEW X-AXIS MUST POINT | |
157 | //--> OUTWARD FROM THE ORGIN. WE ARE FREE TO CHANGE SIGNS OF BOTH | |
158 | //--> COSROT AND SINROT SIMULTANEOUSLY TO ACCOMPLISH THIS. | |
159 | // | |
160 | //--> CHOOSE SIGN OF C WISELY TO BE ABLE TO GET THE SIGN OF THE CHARGE | |
161 | // | |
162 | if ( cosrot*xav+sinrot*yav < 0.0 ) { | |
163 | cosrot = -cosrot ; | |
164 | sinrot = -sinrot ; | |
165 | } | |
166 | // | |
167 | //-> NOW GET <R**2> AND RSCALE= SQRT(<R**2>) | |
168 | // | |
169 | Double_t rrav = xxav + yyav ; | |
170 | Double_t rscale = sqrt(rrav) ; | |
171 | ||
172 | xxav = 0.0 ; | |
173 | yyav = 0.0 ; | |
174 | xyav = 0.0 ; | |
175 | Double_t xrrav = 0.0 ; | |
176 | Double_t yrrav = 0.0 ; | |
177 | Double_t rrrrav = 0.0 ; | |
178 | ||
179 | Double_t xixi, yiyi, riri, wiriri, xold, yold ; | |
180 | ||
181 | //for (hit_counter=0; hit_counter<num_of_hits; hit_counter++) | |
182 | for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit()) | |
183 | { | |
184 | //AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)hits->At(hit_counter); | |
185 | AliL3ConfMapPoint* cHit = (AliL3ConfMapPoint*)fTrack->currentHit; | |
186 | ||
187 | xold = cHit->GetX() - xav ; | |
188 | yold = cHit->GetY() - yav ; | |
189 | // | |
190 | //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1 | |
191 | // | |
192 | xi = ( cosrot * xold + sinrot * yold ) / rscale ; | |
193 | yi = ( -sinrot * xold + cosrot * yold ) / rscale ; | |
194 | ||
195 | xixi = xi * xi ; | |
196 | yiyi = yi * yi ; | |
197 | riri = xixi + yiyi ; | |
198 | wiriri = cHit->GetXYWeight() * riri ; | |
199 | ||
200 | xyav += cHit->GetXYWeight() * xi * yi ; | |
201 | xxav += cHit->GetXYWeight() * xixi ; | |
202 | yyav += cHit->GetXYWeight() * yiyi ; | |
203 | ||
204 | xrrav += wiriri * xi ; | |
205 | yrrav += wiriri * yi ; | |
206 | rrrrav += wiriri * riri ; | |
207 | } | |
208 | // | |
209 | // Include vertex if required | |
210 | // | |
211 | if (fTrack->ComesFromMainVertex() == true) | |
212 | { | |
213 | xold = fVertex->GetX() - xav ; | |
214 | yold = fVertex->GetY() - yav ; | |
215 | // | |
216 | //--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1 | |
217 | // | |
218 | xi = ( cosrot * xold + sinrot * yold ) / rscale ; | |
219 | yi = ( -sinrot * xold + cosrot * yold ) / rscale ; | |
220 | ||
221 | xixi = xi * xi ; | |
222 | yiyi = yi * yi ; | |
223 | riri = xixi + yiyi ; | |
224 | wiriri = fVertex->GetXYWeight() * riri ; | |
225 | ||
226 | xyav += fVertex->GetXYWeight() * xi * yi ; | |
227 | xxav += fVertex->GetXYWeight() * xixi ; | |
228 | yyav += fVertex->GetXYWeight() * yiyi ; | |
229 | ||
230 | xrrav += wiriri * xi ; | |
231 | yrrav += wiriri * yi ; | |
232 | rrrrav += wiriri * riri ; | |
233 | } | |
234 | // | |
235 | // | |
236 | // | |
237 | //--> DIVIDE BY WSUM TO MAKE AVERAGES | |
238 | // | |
239 | xxav = xxav / wsum ; | |
240 | yyav = yyav / wsum ; | |
241 | xrrav = xrrav / wsum ; | |
242 | yrrav = yrrav / wsum ; | |
243 | rrrrav = rrrrav / wsum ; | |
244 | xyav = xyav / wsum ; | |
245 | ||
246 | Int_t const ntry = 5 ; | |
247 | // | |
248 | //--> USE THESE TO GET THE COEFFICIENTS OF THE 4-TH ORDER POLYNIMIAL | |
249 | //--> DON'T PANIC - THE THIRD ORDER TERM IS ZERO ! | |
250 | // | |
251 | Double_t xrrxrr = xrrav * xrrav ; | |
252 | Double_t yrryrr = yrrav * yrrav ; | |
253 | Double_t rrrrm1 = rrrrav - 1.0 ; | |
254 | Double_t xxyy = xxav * yyav ; | |
255 | ||
256 | Double_t c0 = rrrrm1*xxyy - xrrxrr*yyav - yrryrr*xxav ; | |
257 | Double_t c1 = - rrrrm1 + xrrxrr + yrryrr - 4.0*xxyy ; | |
258 | Double_t c2 = 4.0 + rrrrm1 - 4.0*xxyy ; | |
259 | Double_t c4 = - 4.0 ; | |
260 | // | |
261 | //--> COEFFICIENTS OF THE DERIVATIVE - USED IN NEWTON-RAPHSON ITERATIONS | |
262 | // | |
263 | Double_t c2d = 2.0 * c2 ; | |
264 | Double_t c4d = 4.0 * c4 ; | |
265 | // | |
266 | //--> 0'TH VALUE OF LAMDA - LINEAR INTERPOLATION BETWEEN P(0) & P(YYAV) | |
267 | // | |
268 | // LAMDA = YYAV * C0 / (C0 + YRRSQ * (XXAV-YYAV)) | |
269 | Double_t lamda = 0.0 ; | |
270 | Double_t dlamda = 0.0 ; | |
271 | // | |
272 | Double_t chiscl = wsum * rscale * rscale ; | |
273 | Double_t dlamax = 0.001 / chiscl ; | |
274 | ||
275 | Double_t p, pd ; | |
276 | for ( int itry = 1 ; itry <= ntry ; itry++ ) { | |
277 | p = c0 + lamda * (c1 + lamda * (c2 + lamda * lamda * c4 )) ; | |
278 | pd = (c1 + lamda * (c2d + lamda * lamda * c4d)) ; | |
279 | dlamda = -p / pd ; | |
280 | lamda = lamda + dlamda ; | |
281 | if (fabs(dlamda)< dlamax) break ; | |
282 | } | |
283 | ||
284 | Double_t chi2 = (Double_t)(chiscl * lamda) ; | |
285 | ||
286 | fTrack->SetChiSq1(chi2); | |
287 | // Double_t dchisq = chiscl * dlamda ; | |
288 | // | |
289 | //--> NOW CALCULATE THE MATRIX ELEMENTS FOR ALPHA, BETA & KAPPA | |
290 | // | |
291 | Double_t h11 = xxav - lamda ; | |
292 | Double_t h14 = xrrav ; | |
293 | Double_t h22 = yyav - lamda ; | |
294 | Double_t h24 = yrrav ; | |
295 | Double_t h34 = 1.0 + 2.0*lamda ; | |
296 | if ( h11 == 0.0 || h22 == 0.0 ){ | |
297 | LOG(AliL3Log::kError,"AliL3ConfMapFit::FitCircle","TrackFit")<<AliL3Log::kDec<< | |
298 | "Problems fitting circle"<<ENDLOG; | |
299 | return 1 ; | |
300 | } | |
301 | Double_t rootsq = (h14*h14)/(h11*h11) + 4.0*h34 ; | |
302 | ||
303 | Double_t ratio, kappa, beta ; | |
304 | if ( fabs(h22) > fabs(h24) ) { | |
305 | ratio = h24 / h22 ; | |
306 | rootsq = ratio * ratio + rootsq ; | |
307 | kappa = 1.0 / sqrt(rootsq) ; | |
308 | beta = - ratio * kappa ; | |
309 | } | |
310 | else { | |
311 | ratio = h22 / h24 ; | |
312 | rootsq = 1.0 + ratio * ratio * rootsq ; | |
313 | beta = 1.0 / sqrt(rootsq) ; | |
314 | if ( h24 > 0 ) beta = - beta ; | |
315 | kappa = -ratio * beta ; | |
316 | } | |
317 | Double_t alpha = - (h14/h11) * kappa ; | |
318 | // | |
319 | //--> transform these into the lab coordinate system | |
320 | //--> first get kappa and back to real dimensions | |
321 | // | |
322 | Double_t kappa1 = kappa / rscale ; | |
323 | Double_t dbro = 0.5 / kappa1 ; | |
324 | // | |
325 | //--> next rotate alpha and beta and scale | |
326 | // | |
327 | Double_t alphar = (cosrot * alpha - sinrot * beta)* dbro ; | |
328 | Double_t betar = (sinrot * alpha + cosrot * beta)* dbro ; | |
329 | // | |
330 | //--> then translate by (xav,yav) | |
331 | // | |
332 | Double_t acent = (double)(xav - alphar) ; | |
333 | Double_t bcent = (double)(yav - betar ) ; | |
334 | Double_t radius = (double)dbro ; | |
335 | // | |
336 | // Get charge | |
337 | // | |
5dd30052 | 338 | Int_t q = ( ( yrrav < 0 ) ? 1 : -1 ) ; |
108615fc | 339 | |
340 | fTrack->SetCharge(q); | |
341 | ||
342 | // | |
343 | // Get other track parameters | |
344 | // | |
345 | Double_t x0, y0,phi0,r0,psi,pt ; | |
346 | if ( fTrack->ComesFromMainVertex() == true ) | |
347 | { | |
348 | //flag = 1 ; // primary track flag | |
349 | x0 = fVertex->GetX() ; | |
350 | y0 = fVertex->GetY() ; | |
351 | phi0 = fVertex->GetPhi() ; | |
352 | r0 = fVertex->GetR() ; | |
353 | fTrack->SetPhi0(phi0); | |
354 | fTrack->SetR0(r0); | |
355 | } | |
356 | else | |
357 | { | |
358 | //AliL3ConfMapPoint *lHit = (AliL3ConfMapPoint*)hits->Last(); | |
359 | AliL3ConfMapPoint *lHit = (AliL3ConfMapPoint*)fTrack->lastHit; | |
360 | //flag = 0 ; // primary track flag | |
361 | x0 = lHit->GetX() ; | |
362 | y0 = lHit->GetY() ; | |
363 | phi0 = atan2(lHit->GetY(),lHit->GetX()); | |
364 | if ( phi0 < 0 ) phi0 += 2*pi; | |
365 | r0 = sqrt ( lHit->GetX() * lHit->GetX() + lHit->GetY() * lHit->GetY() ) ; | |
366 | fTrack->SetPhi0(phi0); | |
367 | fTrack->SetR0(r0); | |
368 | } | |
369 | // | |
370 | psi = (Double_t)atan2(bcent-y0,acent-x0) ; | |
371 | psi = psi + q * 0.5F * pi ; | |
372 | if ( psi < 0 ) psi = psi + 2*pi; | |
373 | ||
374 | pt = (Double_t)(BFACT * bField * radius ) ; | |
375 | fTrack->SetPsi(psi); | |
376 | fTrack->SetPt(pt); | |
377 | ||
378 | // | |
379 | // Get errors from fast fit | |
380 | // | |
381 | //if ( getPara()->getErrors ) getErrorsCircleFit ( acent, bcent, radius ) ; | |
382 | // | |
383 | return 0 ; | |
384 | ||
385 | } | |
386 | ||
387 | //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
388 | // Fit Line in s-z plane | |
389 | //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
390 | Int_t AliL3ConfMapFit::FitLine ( ) | |
391 | { | |
392 | // | |
393 | //Initialization | |
394 | // | |
395 | Double_t sum = 0.F ; | |
396 | Double_t ss = 0.F ; | |
397 | Double_t sz = 0.F ; | |
398 | Double_t sss = 0.F ; | |
399 | Double_t ssz = 0.F ; | |
400 | // | |
401 | //find sum , sums ,sumz, sumss | |
402 | // | |
403 | Double_t dx, dy ; | |
404 | Double_t radius = (Double_t)(fTrack->GetPt() / ( BFACT * bField ) ) ; | |
405 | ||
406 | //TObjArray *hits = fTrack->GetHits(); | |
407 | //Int_t num_of_hits = fTrack->GetNumberOfPoints(); | |
408 | ||
409 | if ( fTrack->ComesFromMainVertex() == true ) | |
410 | { | |
411 | dx = ((AliL3ConfMapPoint*)fTrack->firstHit)->GetX() - fVertex->GetX(); | |
412 | dy = ((AliL3ConfMapPoint*)fTrack->firstHit)->GetY() - fVertex->GetY() ; | |
413 | } | |
414 | else | |
415 | { | |
416 | dx = ((AliL3ConfMapPoint *)fTrack->firstHit)->GetX() - ((AliL3ConfMapPoint *)fTrack->lastHit)->GetX() ; | |
417 | dy = ((AliL3ConfMapPoint *)fTrack->firstHit)->GetY() - ((AliL3ConfMapPoint *)fTrack->lastHit)->GetY() ; | |
418 | //dx = ((AliL3ConfMapPoint *)hits->First())->GetX() - ((AliL3ConfMapPoint *)hits->Last())->GetX() ; | |
419 | //dy = ((AliL3ConfMapPoint *)hits->First())->GetY() - ((AliL3ConfMapPoint *)hits->Last())->GetY() ; | |
420 | } | |
421 | ||
422 | Double_t localPsi = 0.5F * sqrt ( dx*dx + dy*dy ) / radius ; | |
423 | Double_t total_s ; | |
424 | ||
425 | if ( fabs(localPsi) < 1. ) | |
426 | { | |
427 | total_s = 2.0 * radius * asin ( localPsi ) ; | |
428 | } | |
429 | else | |
430 | { | |
431 | total_s = 2.0 * radius * pi ; | |
432 | } | |
433 | ||
434 | AliL3ConfMapPoint *previousHit = NULL; | |
435 | ||
436 | // FtfBaseHit *previousHit = 0 ; | |
437 | ||
438 | //for ( startLoop() ; done() ; nextHit() ) { | |
439 | Double_t dpsi,s; | |
440 | ||
441 | // for(hit_counter=0; hit_counter<num_of_hits; hit_counter++) | |
442 | for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit()) | |
443 | { | |
444 | // AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)hits->At(hit_counter); | |
445 | AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->currentHit; | |
446 | // if ( currentHit != firstHit ) | |
447 | if(cHit != fTrack->firstHit)// hits->First()) | |
448 | { | |
449 | dx = cHit->GetX() - previousHit->GetX() ; | |
450 | dy = cHit->GetY() - previousHit->GetY() ; | |
451 | dpsi = 0.5 * (Double_t)sqrt ( dx*dx + dy*dy ) / radius ; | |
452 | fTrack->SetPsierr(dpsi); | |
453 | s = previousHit->GetS() - 2.0 * radius * (Double_t)asin ( dpsi ) ; | |
454 | cHit->SetS(s); | |
455 | } | |
456 | else | |
457 | cHit->SetS(total_s); | |
458 | // cHit->s = total_s ; | |
459 | ||
460 | sum += cHit->GetZWeight() ; | |
461 | ss += cHit->GetZWeight() * cHit->GetS() ; | |
462 | sz += cHit->GetZWeight() * cHit->GetZ() ; | |
463 | sss += cHit->GetZWeight() * cHit->GetS() * cHit->GetS() ; | |
464 | ssz += cHit->GetZWeight() * cHit->GetS() * cHit->GetZ() ; | |
465 | previousHit = cHit ; | |
466 | } | |
467 | ||
468 | Double_t chi2,det = sum * sss - ss * ss; | |
469 | if ( fabs(det) < 1e-20) | |
470 | { | |
471 | chi2 = 99999.F ; | |
472 | fTrack->SetChiSq2(chi2); | |
473 | return 0 ; | |
474 | } | |
475 | ||
476 | //Compute the best fitted parameters A,B | |
477 | Double_t tanl,z0,dtanl,dz0; | |
478 | ||
479 | tanl = (Double_t)((sum * ssz - ss * sz ) / det ); | |
480 | z0 = (Double_t)((sz * sss - ssz * ss ) / det ); | |
481 | ||
482 | fTrack->SetTgl(tanl); | |
483 | fTrack->SetZ0(z0); | |
484 | ||
485 | // calculate chi-square | |
486 | ||
487 | chi2 = 0.; | |
488 | Double_t r1 ; | |
489 | ||
490 | //for(hit_counter=0; hit_counter<num_of_hits; hit_counter++) | |
491 | for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit()) | |
492 | { | |
493 | //AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)hits->At(hit_counter); | |
494 | AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->currentHit; | |
495 | r1 = cHit->GetZ() - tanl * cHit->GetS() - z0 ; | |
496 | chi2 += (Double_t) ( (Double_t)cHit->GetZWeight() * (r1 * r1) ); | |
497 | } | |
498 | fTrack->SetChiSq2(chi2); | |
499 | // | |
500 | // calculate estimated variance | |
501 | // varsq=chi/(double(n)-2.) | |
502 | // calculate covariance matrix | |
503 | // siga=sqrt(varsq*sxx/det) | |
504 | // sigb=sqrt(varsq*sum/det) | |
505 | // | |
506 | dtanl = (Double_t) ( sum / det ); | |
507 | dz0 = (Double_t) ( sss / det ); | |
508 | ||
509 | fTrack->SetTglerr(dtanl); | |
510 | fTrack->SetZ0err(dz0); | |
511 | ||
512 | return 0 ; | |
513 | } |