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 ///////////////////////////////////////////////////////////////////////////////
20 // The seed of a local TRD track //
22 ///////////////////////////////////////////////////////////////////////////////
25 #include "TLinearFitter.h"
27 #include "AliMathBase.h"
29 #include "AliTRDseed.h"
30 #include "AliTRDcalibDB.h"
31 #include "AliTRDcluster.h"
32 #include "AliTRDtracker.h"
36 Int_t AliTRDseed::fgTimeBins = 0;
38 //_____________________________________________________________________________
39 AliTRDseed::AliTRDseed()
60 // Default constructor
63 for (Int_t i = 0; i < knTimebins; i++) {
64 fX[i] = 0; // x position
65 fY[i] = 0; // y position
66 fZ[i] = 0; // z position
67 fIndexes[i] = 0; // Indexes
68 fClusters[i] = 0x0; // Clusters
69 fUsable[i] = 0; // Indication - usable cluster
72 for (Int_t i = 0; i < 2; i++) {
73 fYref[i] = 0; // Reference y
74 fZref[i] = 0; // Reference z
75 fYfit[i] = 0; // Y fit position +derivation
76 fYfitR[i] = 0; // Y fit position +derivation
77 fZfit[i] = 0; // Z fit position
78 fZfitR[i] = 0; // Z fit position
79 fLabels[i] = 0; // Labels
84 //_____________________________________________________________________________
85 AliTRDseed::AliTRDseed(const AliTRDseed &s)
88 ,fPadLength(s.fPadLength)
109 for (Int_t i = 0; i < knTimebins; i++) {
110 fX[i] = s.fX[i]; // x position
111 fY[i] = s.fY[i]; // y position
112 fZ[i] = s.fZ[i]; // z position
113 fIndexes[i] = s.fIndexes[i]; // Indexes
114 fClusters[i] = s.fClusters[i]; // Clusters
115 fUsable[i] = s.fUsable[i]; // Indication - usable cluster
118 for (Int_t i = 0; i < 2; i++) {
119 fYref[i] = s.fYref[i]; // Reference y
120 fZref[i] = s.fZref[i]; // Reference z
121 fYfit[i] = s.fYfit[i]; // Y fit position +derivation
122 fYfitR[i] = s.fYfitR[i]; // Y fit position +derivation
123 fZfit[i] = s.fZfit[i]; // Z fit position
124 fZfitR[i] = s.fZfitR[i]; // Z fit position
125 fLabels[i] = s.fLabels[i]; // Labels
130 //_____________________________________________________________________________
131 void AliTRDseed::Copy(TObject &o) const
133 //printf("AliTRDseed::Copy()\n");
135 AliTRDseed &seed = (AliTRDseed &)o;
138 seed.fPadLength = fPadLength;
140 seed.fSigmaY = fSigmaY;
141 seed.fSigmaY2 = fSigmaY2;
142 seed.fMeanz = fMeanz;
143 seed.fZProb = fZProb;
146 seed.fNUsed = fNUsed;
148 seed.fNChange = fNChange;
149 seed.fMPads = fMPads;
153 seed.fChi2Z = fChi2Z;
154 for (Int_t i = 0; i < knTimebins; i++) {
158 seed.fIndexes[i] = fIndexes[i];
159 seed.fClusters[i] = fClusters[i];
160 seed.fUsable[i] = fUsable[i];
163 for (Int_t i = 0; i < 2; i++) {
164 seed.fYref[i] = fYref[i];
165 seed.fZref[i] = fZref[i];
166 seed.fYfit[i] = fYfit[i];
167 seed.fYfitR[i] = fYfitR[i];
168 seed.fZfit[i] = fZfit[i];
169 seed.fZfitR[i] = fZfitR[i];
170 seed.fLabels[i] = fLabels[i];
177 //_____________________________________________________________________________
178 void AliTRDseed::Reset()
184 for (Int_t i = 0; i < knTimebins; i++) {
185 fX[i] = 0; // X position
186 fY[i] = 0; // Y position
187 fZ[i] = 0; // Z position
188 fIndexes[i] = 0; // Indexes
189 fClusters[i] = 0x0; // Clusters
193 for (Int_t i = 0; i < 2; i++) {
194 fYref[i] = 0; // Reference y
195 fZref[i] = 0; // Reference z
196 fYfit[i] = 0; // Y fit position +derivation
197 fYfitR[i] = 0; // Y fit position +derivation
198 fZfit[i] = 0; // Z fit position
199 fZfitR[i] = 0; // Z fit position
200 fLabels[i] = -1; // Labels
202 fSigmaY = 0; // "Robust" sigma in y
203 fSigmaY2 = 0; // "Robust" sigma in y
204 fMeanz = 0; // Mean vaue of z
205 fZProb = 0; // Max probbable z
207 fN = 0; // Number of associated clusters
208 fN2 = 0; // Number of not crossed
209 fNUsed = 0; // Number of used clusters
210 fNChange = 0; // Change z counter
214 //_____________________________________________________________________________
215 void AliTRDseed::CookLabels()
218 // Cook 2 labels for seed
225 for (Int_t i = 0; i < fgTimeBins+1; i++) {
226 if (!fClusters[i]) continue;
227 for (Int_t ilab = 0; ilab < 3; ilab++) {
228 if (fClusters[i]->GetLabel(ilab) >= 0) {
229 labels[nlab] = fClusters[i]->GetLabel(ilab);
235 Int_t nlab2 = AliTRDtracker::Freq(nlab,labels,out,kTRUE);
244 //_____________________________________________________________________________
245 void AliTRDseed::UseClusters()
251 for (Int_t i = 0; i < fgTimeBins+1; i++) {
252 if (!fClusters[i]) continue;
253 if (!(fClusters[i]->IsUsed())) fClusters[i]->Use();
258 //_____________________________________________________________________________
259 void AliTRDseed::Update()
267 // linear fit on the y direction with respect to the reference direction.
268 // The residuals for each x (x = xc - x0) are deduced from:
270 // the tilting correction is written :
271 // y = yc + h*(zc-zt) (2)
272 // yt = y0+dy/dx*x (3)
273 // zt = z0+dz/dx*x (4)
274 // from (1),(2),(3) and (4)
275 // dy = yc - y0 - (dy/dx + h*dz/dx)*x + h*(zc-z0)
276 // the last term introduces the correction on y direction due to tilting pads. There are 2 ways to account for this:
277 // 1. use tilting correction for calculating the y
278 // 2. neglect tilting correction here and account for it in the error parametrization of the tracklet.
280 const Float_t kRatio = 0.8;
281 const Int_t kClmin = 5;
282 const Float_t kmaxtan = 2;
285 if (TMath::Abs(fYref[1]) > kmaxtan){
286 //printf("Exit: Abs(fYref[1]) = %3.3f, kmaxtan = %3.3f\n", TMath::Abs(fYref[1]), kmaxtan);
287 return; // Track inclined too much
290 Float_t sigmaexp = 0.05 + TMath::Abs(fYref[1] * 0.25); // Expected r.m.s in y direction
291 Float_t ycrosscor = fPadLength * fTilt * 0.5; // Y correction for crossing
302 // Buffering: Leave it constant fot Performance issues
303 Int_t zints[knTimebins]; // Histograming of the z coordinate
304 // Get 1 and second max probable coodinates in z
305 Int_t zouts[2*knTimebins];
306 Float_t allowedz[knTimebins]; // Allowed z for given time bin
307 Float_t yres[knTimebins]; // Residuals from reference
308 Float_t anglecor = fTilt * fZref[1]; // Correction to the angle
313 for (Int_t i = 0; i < fgTimeBins; i++) {
315 if (!fClusters[i]) continue;
316 if(!fClusters[i]->IsInChamber()) continue;
317 yres[i] = fY[i] - fYref[0] - (fYref[1] + anglecor) * fX[i] + fTilt*(fZ[i] - fZref[0]); // Residual y
318 zints[fN] = Int_t(fZ[i]);
323 //printf("Exit fN < kClmin: fN = %d\n", fN);
326 Int_t nz = AliTRDtracker::Freq(fN, zints, zouts, kFALSE);
328 if (nz <= 1) zouts[3] = 0;
329 if (zouts[1] + zouts[3] < kClmin) {
330 //printf("Exit zouts[1] = %d, zouts[3] = %d\n",zouts[1],zouts[3]);
334 // Z distance bigger than pad - length
335 if (TMath::Abs(zouts[0]-zouts[2]) > 12.0) zouts[3] = 0;
337 Int_t breaktime = -1;
338 Bool_t mbefore = kFALSE;
339 Int_t cumul[knTimebins][2];
340 Int_t counts[2] = { 0, 0 };
345 // Find the break time allowing one chage on pad-rows
346 // with maximal number of accepted clusters
349 for (Int_t i = 0; i < fgTimeBins; i++) {
350 cumul[i][0] = counts[0];
351 cumul[i][1] = counts[1];
352 if (TMath::Abs(fZ[i]-zouts[0]) < 2) counts[0]++;
353 if (TMath::Abs(fZ[i]-zouts[2]) < 2) counts[1]++;
356 for (Int_t i = 0; i < fgTimeBins; i++) {
357 Int_t after = cumul[fgTimeBins][0] - cumul[i][0];
358 Int_t before = cumul[i][1];
359 if (after + before > maxcount) {
360 maxcount = after + before;
364 after = cumul[fgTimeBins-1][1] - cumul[i][1];
365 before = cumul[i][0];
366 if (after + before > maxcount) {
367 maxcount = after + before;
377 for (Int_t i = 0; i < fgTimeBins+1; i++) {
378 if (i > breaktime) allowedz[i] = mbefore ? zouts[2] : zouts[0];
379 if (i <= breaktime) allowedz[i] = (!mbefore) ? zouts[2] : zouts[0];
382 if (((allowedz[0] > allowedz[fgTimeBins]) && (fZref[1] < 0)) ||
383 ((allowedz[0] < allowedz[fgTimeBins]) && (fZref[1] > 0))) {
385 // Tracklet z-direction not in correspondance with track z direction
388 for (Int_t i = 0; i < fgTimeBins+1; i++) {
389 allowedz[i] = zouts[0]; // Only longest taken
395 // Cross pad -row tracklet - take the step change into account
397 for (Int_t i = 0; i < fgTimeBins+1; i++) {
398 if (!fClusters[i]) continue;
399 if(!fClusters[i]->IsInChamber()) continue;
400 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
401 yres[i] = fY[i] - fYref[0] - (fYref[1] + anglecor) * fX[i] /*+ fTilt*(fZ[i] - fZref[0])*/; // Residual y
402 if (TMath::Abs(fZ[i] - fZProb) > 2) {
403 if (fZ[i] > fZProb) yres[i] += fTilt * fPadLength;
404 if (fZ[i] < fZProb) yres[i] -= fTilt * fPadLength;
409 Double_t yres2[knTimebins];
412 for (Int_t i = 0; i < fgTimeBins+1; i++) {
413 if (!fClusters[i]) continue;
414 if(!fClusters[i]->IsInChamber()) continue;
415 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
416 yres2[fN2] = yres[i];
420 //printf("Exit fN2 < kClmin: fN2 = %d\n", fN2);
424 AliMathBase::EvaluateUni(fN2,yres2,mean,sigma, Int_t(fN2*kRatio-2.));
425 if (sigma < sigmaexp * 0.8) {
443 for (Int_t i = 0; i < fgTimeBins+1; i++) {
446 if (!fClusters[i]) continue;
447 if (!fClusters[i]->IsInChamber()) continue;
448 if (TMath::Abs(fZ[i] - allowedz[i]) > 2){fClusters[i] = 0x0; continue;}
449 if (TMath::Abs(yres[i] - mean) > 4.0 * sigma){fClusters[i] = 0x0; continue;}
452 fMPads += fClusters[i]->GetNPads();
453 Float_t weight = 1.0;
454 if (fClusters[i]->GetNPads() > 4) weight = 0.5;
455 if (fClusters[i]->GetNPads() > 5) weight = 0.2;
459 //printf("x = %7.3f dy = %7.3f fit %7.3f\n", x, yres[i], fY[i]-yres[i]);
463 sumwx2 += x*x * weight;
464 sumwy += weight * yres[i];
465 sumwxy += weight * (yres[i]) * x;
466 sumwz += weight * fZ[i];
467 sumwxz += weight * fZ[i] * x;
472 //printf("Exit fN2 < kClmin(2): fN2 = %d\n",fN2);
476 fMeanz = sumwz / sumw;
477 Float_t correction = 0;
479 // Tracklet on boundary
480 if (fMeanz < fZProb) correction = ycrosscor;
481 if (fMeanz > fZProb) correction = -ycrosscor;
484 Double_t det = sumw * sumwx2 - sumwx * sumwx;
485 fYfitR[0] = (sumwx2 * sumwy - sumwx * sumwxy) / det;
486 fYfitR[1] = (sumw * sumwxy - sumwx * sumwy) / det;
489 for (Int_t i = 0; i < fgTimeBins+1; i++) {
490 if (!fUsable[i]) continue;
491 Float_t delta = yres[i] - fYfitR[0] - fYfitR[1] * fX[i];
492 fSigmaY2 += delta*delta;
494 fSigmaY2 = TMath::Sqrt(fSigmaY2 / Float_t(fN2-2));
495 // TEMPORARY UNTIL covariance properly calculated
496 fSigmaY2 = TMath::Max(fSigmaY2, Float_t(.1));
498 fZfitR[0] = (sumwx2 * sumwz - sumwx * sumwxz) / det;
499 fZfitR[1] = (sumw * sumwxz - sumwx * sumwz) / det;
500 fZfit[0] = (sumwx2 * sumwz - sumwx * sumwxz) / det;
501 fZfit[1] = (sumw * sumwxz - sumwx * sumwz) / det;
502 fYfitR[0] += fYref[0] + correction;
503 fYfitR[1] += fYref[1];
504 fYfit[0] = fYfitR[0];
505 fYfit[1] = fYfitR[1];
507 //printf("y0 = %7.3f tgy = %7.3f z0 = %7.3f tgz = %7.3f \n", fYfitR[0], fYfitR[1], fZfitR[0], fZfitR[1]);
513 //_____________________________________________________________________________
514 void AliTRDseed::UpdateUsed()
521 for (Int_t i = 0; i < fgTimeBins; i++) {
522 if (!fClusters[i]) continue;
523 if(!fUsable[i]) continue;
524 if ((fClusters[i]->IsUsed())) fNUsed++;
529 //_____________________________________________________________________________
530 Float_t AliTRDseed::FitRiemanTilt(AliTRDseed * cseed, Bool_t terror)
533 // Fit the Rieman tilt
536 // Fitting with tilting pads - kz not fixed
537 TLinearFitter fitterT2(4,"hyp4");
538 fitterT2.StoreData(kTRUE);
540 Float_t xref2 = (cseed[2].fX0 + cseed[3].fX0) * 0.5; // Reference x0 for z
543 fitterT2.ClearPoints();
545 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
547 if (!cseed[iLayer].IsOK()) continue;
548 Double_t tilt = cseed[iLayer].fTilt;
550 for (Int_t itime = 0; itime < fgTimeBins+1; itime++) {
552 if (!cseed[iLayer].fUsable[itime]) continue;
553 // x relative to the midle chamber
554 Double_t x = cseed[iLayer].fX[itime] + cseed[iLayer].fX0 - xref2;
555 Double_t y = cseed[iLayer].fY[itime];
556 Double_t z = cseed[iLayer].fZ[itime];
562 Double_t x2 = cseed[iLayer].fX[itime] + cseed[iLayer].fX0; // Global x
563 Double_t t = 1.0 / (x2*x2 + y*y);
565 uvt[0] = 2.0 * x2 * uvt[1];
566 uvt[2] = 2.0 * tilt * uvt[1];
567 uvt[3] = 2.0 * tilt *uvt[1] * x;
568 uvt[4] = 2.0 * (y + tilt * z) * uvt[1];
570 Double_t error = 2.0 * uvt[1];
572 error *= cseed[iLayer].fSigmaY;
575 error *= 0.2; //Default error
577 fitterT2.AddPoint(uvt,uvt[4],error);
585 Double_t rpolz0 = fitterT2.GetParameter(3);
586 Double_t rpolz1 = fitterT2.GetParameter(4);
589 // Linear fitter - not possible to make boundaries
590 // non accept non possible z and dzdx combination
592 Bool_t acceptablez = kTRUE;
593 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
594 if (!cseed[iLayer].IsOK()) continue;
595 Double_t zT2 = rpolz0 + rpolz1 * (cseed[iLayer].fX0 - xref2);
596 if (TMath::Abs(cseed[iLayer].fZProb - zT2) > cseed[iLayer].fPadLength * 0.5 + 1.0) acceptablez = kFALSE;
599 Double_t zmf = cseed[2].fZref[0] + cseed[2].fZref[1] * (xref2 - cseed[2].fX0);
600 Double_t dzmf = (cseed[2].fZref[1] + cseed[3].fZref[1]) * 0.5;
601 fitterT2.FixParameter(3,zmf);
602 fitterT2.FixParameter(4,dzmf);
604 fitterT2.ReleaseParameter(3);
605 fitterT2.ReleaseParameter(4);
606 rpolz0 = fitterT2.GetParameter(3);
607 rpolz1 = fitterT2.GetParameter(4);
610 Double_t chi2TR = fitterT2.GetChisquare() / Float_t(npointsT);
612 params[0] = fitterT2.GetParameter(0);
613 params[1] = fitterT2.GetParameter(1);
614 params[2] = fitterT2.GetParameter(2);
615 Double_t curvature = 1.0 + params[1] * params[1] - params[2] * params[0];
618 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
619 Double_t x = cseed[iLayer].fX0;
626 Double_t res2 = (x * params[0] + params[1]);
628 res2 = 1.0 - params[2]*params[0] + params[1]*params[1] - res2;
630 res2 = TMath::Sqrt(res2);
631 y = (1.0 - res2) / params[0];
635 Double_t x0 = -params[1] / params[0];
636 if (-params[2]*params[0] + params[1]*params[1] + 1 > 0) {
637 Double_t rm1 = params[0] / TMath::Sqrt(-params[2]*params[0] + params[1]*params[1] + 1);
638 if (1.0/(rm1*rm1) - (x-x0) * (x-x0) > 0.0) {
639 Double_t res = (x - x0) / TMath::Sqrt(1.0 / (rm1*rm1) - (x-x0)*(x-x0));
640 if (params[0] < 0) res *= -1.0;
644 z = rpolz0 + rpolz1 * (x - xref2);
646 cseed[iLayer].fYref[0] = y;
647 cseed[iLayer].fYref[1] = dy;
648 cseed[iLayer].fZref[0] = z;
649 cseed[iLayer].fZref[1] = dz;
650 cseed[iLayer].fC = curvature;