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 //_____________________________________________________________________________
37 AliTRDseed::AliTRDseed()
58 // Default constructor
61 for (Int_t i = 0; i < knTimebins; i++) {
62 fX[i] = 0; // x position
63 fY[i] = 0; // y position
64 fZ[i] = 0; // z position
65 fIndexes[i] = 0; // Indexes
66 fClusters[i] = 0x0; // Clusters
67 fUsable[i] = 0; // Indication - usable cluster
70 for (Int_t i = 0; i < 2; i++) {
71 fYref[i] = 0; // Reference y
72 fZref[i] = 0; // Reference z
73 fYfit[i] = 0; // Y fit position +derivation
74 fYfitR[i] = 0; // Y fit position +derivation
75 fZfit[i] = 0; // Z fit position
76 fZfitR[i] = 0; // Z fit position
77 fLabels[i] = 0; // Labels
82 //_____________________________________________________________________________
83 AliTRDseed::AliTRDseed(const AliTRDseed &s)
86 ,fPadLength(s.fPadLength)
107 for (Int_t i = 0; i < knTimebins; i++) {
108 fX[i] = s.fX[i]; // x position
109 fY[i] = s.fY[i]; // y position
110 fZ[i] = s.fZ[i]; // z position
111 fIndexes[i] = s.fIndexes[i]; // Indexes
112 fClusters[i] = s.fClusters[i]; // Clusters
113 fUsable[i] = s.fUsable[i]; // Indication - usable cluster
116 for (Int_t i = 0; i < 2; i++) {
117 fYref[i] = s.fYref[i]; // Reference y
118 fZref[i] = s.fZref[i]; // Reference z
119 fYfit[i] = s.fYfit[i]; // Y fit position +derivation
120 fYfitR[i] = s.fYfitR[i]; // Y fit position +derivation
121 fZfit[i] = s.fZfit[i]; // Z fit position
122 fZfitR[i] = s.fZfitR[i]; // Z fit position
123 fLabels[i] = s.fLabels[i]; // Labels
128 //_____________________________________________________________________________
129 void AliTRDseed::Copy(TObject &o) const
135 AliTRDseed &seed = (AliTRDseed &)o;
137 seed.fPadLength = fPadLength;
139 seed.fSigmaY = fSigmaY;
140 seed.fSigmaY2 = fSigmaY2;
141 seed.fMeanz = fMeanz;
142 seed.fZProb = fZProb;
145 seed.fNUsed = fNUsed;
147 seed.fNChange = fNChange;
148 seed.fMPads = fMPads;
152 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
221 AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
222 Int_t nTimeBins = cal->GetNumberOfTimeBins();
228 for (Int_t i = 0; i < nTimeBins+1; i++) {
229 if (!fClusters[i]) continue;
230 for (Int_t ilab = 0; ilab < 3; ilab++) {
231 if (fClusters[i]->GetLabel(ilab) >= 0) {
232 labels[nlab] = fClusters[i]->GetLabel(ilab);
238 Int_t nlab2 = AliTRDtracker::Freq(nlab,labels,out,kTRUE);
247 //_____________________________________________________________________________
248 void AliTRDseed::UseClusters()
254 AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
255 Int_t nTimeBins = cal->GetNumberOfTimeBins();
257 for (Int_t i = 0; i < nTimeBins+1; i++) {
258 if (!fClusters[i]) continue;
259 if (!(fClusters[i]->IsUsed())) fClusters[i]->Use();
264 //_____________________________________________________________________________
265 void AliTRDseed::Update()
271 const Float_t kRatio = 0.8;
272 const Int_t kClmin = 5;
273 const Float_t kmaxtan = 2;
275 AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
276 Int_t nTimeBins = cal->GetNumberOfTimeBins();
278 if (TMath::Abs(fYref[1]) > kmaxtan){
279 //printf("Exit: Abs(fYref[1]) = %3.3f, kmaxtan = %3.3f\n", TMath::Abs(fYref[1]), kmaxtan);
280 return; // Track inclined too much
283 Float_t sigmaexp = 0.05 + TMath::Abs(fYref[1] * 0.25); // Expected r.m.s in y direction
284 Float_t ycrosscor = fPadLength * fTilt * 0.5; // Y correction for crossing
295 // Buffering: Leave it constant fot Performance issues
296 Int_t zints[knTimebins]; // Histograming of the z coordinate
297 // Get 1 and second max probable coodinates in z
298 Int_t zouts[2*knTimebins];
299 Float_t allowedz[knTimebins]; // Allowed z for given time bin
300 Float_t yres[knTimebins]; // Residuals from reference
301 Float_t anglecor = fTilt * fZref[1]; // Correction to the angle
306 for (Int_t i = 0; i < nTimeBins; i++) {
308 if (!fClusters[i]) continue;
309 yres[i] = fY[i] - fYref[0] - (fYref[1] + anglecor) * fX[i]; // Residual y
310 zints[fN] = Int_t(fZ[i]);
315 //printf("Exit fN < kClmin: fN = %d\n", fN);
318 Int_t nz = AliTRDtracker::Freq(fN,zints,zouts,kFALSE);
320 if (nz <= 1) zouts[3] = 0;
321 if (zouts[1] + zouts[3] < kClmin) {
322 //printf("Exit zouts[1] = %d, zouts[3] = %d\n",zouts[1],zouts[3]);
326 // Z distance bigger than pad - length
327 if (TMath::Abs(zouts[0]-zouts[2]) > 12.0) {
331 Int_t breaktime = -1;
332 Bool_t mbefore = kFALSE;
333 Int_t cumul[knTimebins][2];
334 Int_t counts[2] = { 0, 0 };
339 // Find the break time allowing one chage on pad-rows
340 // with maximal numebr of accepted clusters
343 for (Int_t i = 0; i < nTimeBins; i++) {
344 cumul[i][0] = counts[0];
345 cumul[i][1] = counts[1];
346 if (TMath::Abs(fZ[i]-zouts[0]) < 2) counts[0]++;
347 if (TMath::Abs(fZ[i]-zouts[2]) < 2) counts[1]++;
350 for (Int_t i = 0; i < nTimeBins; i++) {
351 Int_t after = cumul[nTimeBins][0] - cumul[i][0];
352 Int_t before = cumul[i][1];
353 if (after + before > maxcount) {
354 maxcount = after + before;
358 after = cumul[nTimeBins-1][1] - cumul[i][1];
359 before = cumul[i][0];
360 if (after + before > maxcount) {
361 maxcount = after + before;
371 for (Int_t i = 0; i < nTimeBins+1; i++) {
372 if (i > breaktime) allowedz[i] = mbefore ? zouts[2] : zouts[0];
373 if (i <= breaktime) allowedz[i] = (!mbefore) ? zouts[2] : zouts[0];
376 if (((allowedz[0] > allowedz[nTimeBins]) && (fZref[1] < 0)) ||
377 ((allowedz[0] < allowedz[nTimeBins]) && (fZref[1] > 0))) {
379 // Tracklet z-direction not in correspondance with track z direction
382 for (Int_t i = 0; i < nTimeBins+1; i++) {
383 allowedz[i] = zouts[0]; // Only longest taken
389 // Cross pad -row tracklet - take the step change into account
391 for (Int_t i = 0; i < nTimeBins+1; i++) {
392 if (!fClusters[i]) continue;
393 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
394 yres[i] = fY[i] - fYref[0] - (fYref[1] + anglecor) * fX[i]; // Residual y
395 if (TMath::Abs(fZ[i] - fZProb) > 2) {
396 if (fZ[i] > fZProb) yres[i] += fTilt * fPadLength;
397 if (fZ[i] < fZProb) yres[i] -= fTilt * fPadLength;
402 Double_t yres2[knTimebins];
405 for (Int_t i = 0; i < nTimeBins+1; i++) {
406 if (!fClusters[i]) continue;
407 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
408 yres2[fN2] = yres[i];
412 //printf("Exit fN2 < kClmin: fN2 = %d\n", fN2);
416 AliMathBase::EvaluateUni(fN2,yres2,mean,sigma, Int_t(fN2*kRatio-2.));
417 if (sigma < sigmaexp * 0.8) {
435 for (Int_t i = 0; i < nTimeBins+1; i++) {
438 if (!fClusters[i]) continue;
439 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
440 if (TMath::Abs(yres[i] - mean) > 4.0 * sigma) continue;
443 fMPads += fClusters[i]->GetNPads();
444 Float_t weight = 1.0;
445 if (fClusters[i]->GetNPads() > 4) weight = 0.5;
446 if (fClusters[i]->GetNPads() > 5) weight = 0.2;
451 sumwx2 += x*x * weight;
452 sumwy += weight * yres[i];
453 sumwxy += weight * (yres[i]) * x;
454 sumwz += weight * fZ[i];
455 sumwxz += weight * fZ[i] * x;
460 //printf("Exit fN2 < kClmin(2): fN2 = %d\n",fN2);
464 fMeanz = sumwz / sumw;
465 Float_t correction = 0;
467 // Tracklet on boundary
468 if (fMeanz < fZProb) correction = ycrosscor;
469 if (fMeanz > fZProb) correction = -ycrosscor;
472 Double_t det = sumw * sumwx2 - sumwx * sumwx;
473 fYfitR[0] = (sumwx2 * sumwy - sumwx * sumwxy) / det;
474 fYfitR[1] = (sumw * sumwxy - sumwx * sumwy) / det;
477 for (Int_t i = 0; i < nTimeBins+1; i++) {
478 if (!fUsable[i]) continue;
479 Float_t delta = yres[i] - fYfitR[0] - fYfitR[1] * fX[i];
480 fSigmaY2 += delta*delta;
482 fSigmaY2 = TMath::Sqrt(fSigmaY2 / Float_t(fN2-2));
484 fZfitR[0] = (sumwx2 * sumwz - sumwx * sumwxz) / det;
485 fZfitR[1] = (sumw * sumwxz - sumwx * sumwz) / det;
486 fZfit[0] = (sumwx2 * sumwz - sumwx * sumwxz) / det;
487 fZfit[1] = (sumw * sumwxz - sumwx * sumwz) / det;
488 fYfitR[0] += fYref[0] + correction;
489 fYfitR[1] += fYref[1];
490 fYfit[0] = fYfitR[0];
491 fYfit[1] = fYfitR[1];
497 //_____________________________________________________________________________
498 void AliTRDseed::UpdateUsed()
504 AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
505 Int_t nTimeBins = cal->GetNumberOfTimeBins();
508 for (Int_t i = 0; i < nTimeBins; i++) {
512 if ((fClusters[i]->IsUsed())) {
519 //_____________________________________________________________________________
520 Float_t AliTRDseed::FitRiemanTilt(AliTRDseed * cseed, Bool_t terror)
523 // Fit the Rieman tilt
526 // Fitting with tilting pads - kz not fixed
527 TLinearFitter fitterT2(4,"hyp4");
528 fitterT2.StoreData(kTRUE);
530 AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
531 Int_t nTimeBins = cal->GetNumberOfTimeBins();
533 Float_t xref2 = (cseed[2].fX0 + cseed[3].fX0) * 0.5; // Reference x0 for z
536 fitterT2.ClearPoints();
538 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
540 if (!cseed[iLayer].IsOK()) continue;
541 Double_t tilt = cseed[iLayer].fTilt;
543 for (Int_t itime = 0; itime < nTimeBins+1; itime++) {
545 if (!cseed[iLayer].fUsable[itime]) continue;
546 // x relative to the midle chamber
547 Double_t x = cseed[iLayer].fX[itime] + cseed[iLayer].fX0 - xref2;
548 Double_t y = cseed[iLayer].fY[itime];
549 Double_t z = cseed[iLayer].fZ[itime];
555 Double_t x2 = cseed[iLayer].fX[itime] + cseed[iLayer].fX0; // Global x
556 Double_t t = 1.0 / (x2*x2 + y*y);
558 uvt[0] = 2.0 * x2 * uvt[1];
559 uvt[2] = 2.0 * tilt * uvt[1];
560 uvt[3] = 2.0 * tilt *uvt[1] * x;
561 uvt[4] = 2.0 * (y + tilt * z) * uvt[1];
563 Double_t error = 2.0 * uvt[1];
565 error *= cseed[iLayer].fSigmaY;
568 error *= 0.2; //Default error
570 fitterT2.AddPoint(uvt,uvt[4],error);
578 Double_t rpolz0 = fitterT2.GetParameter(3);
579 Double_t rpolz1 = fitterT2.GetParameter(4);
582 // Linear fitter - not possible to make boundaries
583 // non accept non possible z and dzdx combination
585 Bool_t acceptablez = kTRUE;
586 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
587 if (!cseed[iLayer].IsOK()) continue;
588 Double_t zT2 = rpolz0 + rpolz1 * (cseed[iLayer].fX0 - xref2);
589 if (TMath::Abs(cseed[iLayer].fZProb - zT2) > cseed[iLayer].fPadLength * 0.5 + 1.0) acceptablez = kFALSE;
592 Double_t zmf = cseed[2].fZref[0] + cseed[2].fZref[1] * (xref2 - cseed[2].fX0);
593 Double_t dzmf = (cseed[2].fZref[1] + cseed[3].fZref[1]) * 0.5;
594 fitterT2.FixParameter(3,zmf);
595 fitterT2.FixParameter(4,dzmf);
597 fitterT2.ReleaseParameter(3);
598 fitterT2.ReleaseParameter(4);
599 rpolz0 = fitterT2.GetParameter(3);
600 rpolz1 = fitterT2.GetParameter(4);
603 Double_t chi2TR = fitterT2.GetChisquare() / Float_t(npointsT);
605 params[0] = fitterT2.GetParameter(0);
606 params[1] = fitterT2.GetParameter(1);
607 params[2] = fitterT2.GetParameter(2);
608 Double_t curvature = 1.0 + params[1] * params[1] - params[2] * params[0];
611 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
612 Double_t x = cseed[iLayer].fX0;
619 Double_t res2 = (x * params[0] + params[1]);
621 res2 = 1.0 - params[2]*params[0] + params[1]*params[1] - res2;
623 res2 = TMath::Sqrt(res2);
624 y = (1.0 - res2) / params[0];
628 Double_t x0 = -params[1] / params[0];
629 if (-params[2]*params[0] + params[1]*params[1] + 1 > 0) {
630 Double_t rm1 = params[0] / TMath::Sqrt(-params[2]*params[0] + params[1]*params[1] + 1);
631 if (1.0/(rm1*rm1) - (x-x0) * (x-x0) > 0.0) {
632 Double_t res = (x - x0) / TMath::Sqrt(1.0 / (rm1*rm1) - (x-x0)*(x-x0));
633 if (params[0] < 0) res *= -1.0;
637 z = rpolz0 + rpolz1 * (x - xref2);
639 cseed[iLayer].fYref[0] = y;
640 cseed[iLayer].fYref[1] = dy;
641 cseed[iLayer].fZref[0] = z;
642 cseed[iLayer].fZref[1] = dz;
643 cseed[iLayer].fC = curvature;