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"
35 Int_t AliTRDseed::fgTimeBins = 0;
36 //_____________________________________________________________________________
37 AliTRDseed::AliTRDseed()
59 // Default constructor
62 for (Int_t i = 0; i < knTimebins; i++) {
63 fX[i] = 0; // x position
64 fY[i] = 0; // y position
65 fZ[i] = 0; // z position
66 fIndexes[i] = 0; // Indexes
67 fClusters[i] = 0x0; // Clusters
68 fUsable[i] = 0; // Indication - usable cluster
71 for (Int_t i = 0; i < 2; i++) {
72 fYref[i] = 0; // Reference y
73 fZref[i] = 0; // Reference z
74 fYfit[i] = 0; // Y fit position +derivation
75 fYfitR[i] = 0; // Y fit position +derivation
76 fZfit[i] = 0; // Z fit position
77 fZfitR[i] = 0; // Z fit position
78 fLabels[i] = 0; // Labels
83 //_____________________________________________________________________________
84 AliTRDseed::AliTRDseed(const AliTRDseed &s)
86 ,fTimeBinsRange(s.fTimeBinsRange)
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;
137 seed.fTimeBinsRange = fTimeBinsRange;
139 seed.fPadLength = fPadLength;
141 seed.fSigmaY = fSigmaY;
142 seed.fSigmaY2 = fSigmaY2;
143 seed.fMeanz = fMeanz;
144 seed.fZProb = fZProb;
147 seed.fNUsed = fNUsed;
149 seed.fNChange = fNChange;
150 seed.fMPads = fMPads;
154 seed.fChi2Z = fChi2Z;
155 for (Int_t i = 0; i < knTimebins; i++) {
159 seed.fIndexes[i] = fIndexes[i];
160 seed.fClusters[i] = fClusters[i];
161 seed.fUsable[i] = fUsable[i];
164 for (Int_t i = 0; i < 2; i++) {
165 seed.fYref[i] = fYref[i];
166 seed.fZref[i] = fZref[i];
167 seed.fYfit[i] = fYfit[i];
168 seed.fYfitR[i] = fYfitR[i];
169 seed.fZfit[i] = fZfit[i];
170 seed.fZfitR[i] = fZfitR[i];
171 seed.fLabels[i] = fLabels[i];
178 //_____________________________________________________________________________
179 void AliTRDseed::Reset()
185 for (Int_t i = 0; i < knTimebins; i++) {
186 fX[i] = 0; // X position
187 fY[i] = 0; // Y position
188 fZ[i] = 0; // Z position
189 fIndexes[i] = 0; // Indexes
190 fClusters[i] = 0x0; // Clusters
194 for (Int_t i = 0; i < 2; i++) {
195 fYref[i] = 0; // Reference y
196 fZref[i] = 0; // Reference z
197 fYfit[i] = 0; // Y fit position +derivation
198 fYfitR[i] = 0; // Y fit position +derivation
199 fZfit[i] = 0; // Z fit position
200 fZfitR[i] = 0; // Z fit position
201 fLabels[i] = -1; // Labels
203 fSigmaY = 0; // "Robust" sigma in y
204 fSigmaY2 = 0; // "Robust" sigma in y
205 fMeanz = 0; // Mean vaue of z
206 fZProb = 0; // Max probbable z
208 fN = 0; // Number of associated clusters
209 fN2 = 0; // Number of not crossed
210 fNUsed = 0; // Number of used clusters
211 fNChange = 0; // Change z counter
215 //_____________________________________________________________________________
216 void AliTRDseed::CookLabels()
219 // Cook 2 labels for seed
226 for (Int_t i = 0; i < fgTimeBins+1; i++) {
227 if (!fClusters[i]) continue;
228 for (Int_t ilab = 0; ilab < 3; ilab++) {
229 if (fClusters[i]->GetLabel(ilab) >= 0) {
230 labels[nlab] = fClusters[i]->GetLabel(ilab);
236 Int_t nlab2 = AliTRDtracker::Freq(nlab,labels,out,kTRUE);
245 //_____________________________________________________________________________
246 void AliTRDseed::UseClusters()
252 for (Int_t i = 0; i < fgTimeBins+1; i++) {
253 if (!fClusters[i]) continue;
254 if (!(fClusters[i]->IsUsed())) fClusters[i]->Use();
259 //_____________________________________________________________________________
260 void AliTRDseed::Update()
267 // linear fit on the y direction
268 // dy|x = (yc|x - dz|x*tg(tilt)) - (y0 + dy/dx|x * x )
269 // dz|x = zc|x - (z0 + dz/dx|x)
271 const Float_t kRatio = 0.8;
272 const Int_t kClmin = 5;
273 const Float_t kmaxtan = 2;
276 if (TMath::Abs(fYref[1]) > kmaxtan){
277 //printf("Exit: Abs(fYref[1]) = %3.3f, kmaxtan = %3.3f\n", TMath::Abs(fYref[1]), kmaxtan);
278 return; // Track inclined too much
281 Float_t sigmaexp = 0.05 + TMath::Abs(fYref[1] * 0.25); // Expected r.m.s in y direction
282 Float_t ycrosscor = fPadLength * fTilt * 0.5; // Y correction for crossing
293 // Buffering: Leave it constant fot Performance issues
294 Int_t zints[knTimebins]; // Histograming of the z coordinate
295 // Get 1 and second max probable coodinates in z
296 Int_t zouts[2*knTimebins];
297 Float_t allowedz[knTimebins]; // Allowed z for given time bin
298 Float_t yres[knTimebins]; // Residuals from reference
299 Float_t anglecor = fTilt * fZref[1]; // Correction to the angle
304 for (Int_t i = 0; i < fTimeBinsRange; i++) {
306 if (!fClusters[i]) continue;
307 yres[i] = fY[i] - fYref[0] - (fYref[1] + anglecor) * fX[i]; // Residual y
308 zints[fN] = Int_t(fZ[i]);
313 //printf("Exit fN < kClmin: fN = %d\n", fN);
316 Int_t nz = AliTRDtracker::Freq(fN,zints,zouts,kFALSE);
318 if (nz <= 1) zouts[3] = 0;
319 if (zouts[1] + zouts[3] < kClmin) {
320 //printf("Exit zouts[1] = %d, zouts[3] = %d\n",zouts[1],zouts[3]);
324 // Z distance bigger than pad - length
325 if (TMath::Abs(zouts[0]-zouts[2]) > 12.0) {
329 Int_t breaktime = -1;
330 Bool_t mbefore = kFALSE;
331 Int_t cumul[knTimebins][2];
332 Int_t counts[2] = { 0, 0 };
337 // Find the break time allowing one chage on pad-rows
338 // with maximal numebr of accepted clusters
341 for (Int_t i = 0; i < fTimeBinsRange; i++) {
342 cumul[i][0] = counts[0];
343 cumul[i][1] = counts[1];
344 if (TMath::Abs(fZ[i]-zouts[0]) < 2) counts[0]++;
345 if (TMath::Abs(fZ[i]-zouts[2]) < 2) counts[1]++;
348 for (Int_t i = 0; i < fTimeBinsRange; i++) {
349 Int_t after = cumul[fTimeBinsRange][0] - cumul[i][0];
350 Int_t before = cumul[i][1];
351 if (after + before > maxcount) {
352 maxcount = after + before;
356 after = cumul[fTimeBinsRange-1][1] - cumul[i][1];
357 before = cumul[i][0];
358 if (after + before > maxcount) {
359 maxcount = after + before;
369 for (Int_t i = 0; i < fTimeBinsRange+1; i++) {
370 if (i > breaktime) allowedz[i] = mbefore ? zouts[2] : zouts[0];
371 if (i <= breaktime) allowedz[i] = (!mbefore) ? zouts[2] : zouts[0];
374 if (((allowedz[0] > allowedz[fTimeBinsRange]) && (fZref[1] < 0)) ||
375 ((allowedz[0] < allowedz[fTimeBinsRange]) && (fZref[1] > 0))) {
377 // Tracklet z-direction not in correspondance with track z direction
380 for (Int_t i = 0; i < fTimeBinsRange+1; i++) {
381 allowedz[i] = zouts[0]; // Only longest taken
387 // Cross pad -row tracklet - take the step change into account
389 for (Int_t i = 0; i < fTimeBinsRange+1; i++) {
390 if (!fClusters[i]) continue;
391 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
392 yres[i] = fY[i] - fYref[0] - (fYref[1] + anglecor) * fX[i]; // Residual y
393 if (TMath::Abs(fZ[i] - fZProb) > 2) {
394 if (fZ[i] > fZProb) yres[i] += fTilt * fPadLength;
395 if (fZ[i] < fZProb) yres[i] -= fTilt * fPadLength;
400 Double_t yres2[knTimebins];
403 for (Int_t i = 0; i < fTimeBinsRange+1; i++) {
404 if (!fClusters[i]) continue;
405 if (TMath::Abs(fZ[i] - allowedz[i]) > 2) continue;
406 yres2[fN2] = yres[i];
410 //printf("Exit fN2 < kClmin: fN2 = %d\n", fN2);
414 AliMathBase::EvaluateUni(fN2,yres2,mean,sigma, Int_t(fN2*kRatio-2.));
415 if (sigma < sigmaexp * 0.8) {
433 for (Int_t i = 0; i < fTimeBinsRange+1; i++) {
436 if (!fClusters[i]) continue;
437 if (TMath::Abs(fZ[i] - allowedz[i]) > 2){fClusters[i] = 0x0; continue;}
438 if (TMath::Abs(yres[i] - mean) > 4.0 * sigma){fClusters[i] = 0x0; continue;}
441 fMPads += fClusters[i]->GetNPads();
442 Float_t weight = 1.0;
443 if (fClusters[i]->GetNPads() > 4) weight = 0.5;
444 if (fClusters[i]->GetNPads() > 5) weight = 0.2;
448 //printf("x = %7.3f dy = %7.3f fit %7.3f\n", x, yres[i], fY[i]-yres[i]);
452 sumwx2 += x*x * weight;
453 sumwy += weight * yres[i];
454 sumwxy += weight * (yres[i]) * x;
455 sumwz += weight * fZ[i];
456 sumwxz += weight * fZ[i] * x;
461 //printf("Exit fN2 < kClmin(2): fN2 = %d\n",fN2);
465 fMeanz = sumwz / sumw;
466 Float_t correction = 0;
468 // Tracklet on boundary
469 if (fMeanz < fZProb) correction = ycrosscor;
470 if (fMeanz > fZProb) correction = -ycrosscor;
473 Double_t det = sumw * sumwx2 - sumwx * sumwx;
474 fYfitR[0] = (sumwx2 * sumwy - sumwx * sumwxy) / det;
475 fYfitR[1] = (sumw * sumwxy - sumwx * sumwy) / det;
478 for (Int_t i = 0; i < fTimeBinsRange+1; i++) {
479 if (!fUsable[i]) continue;
480 Float_t delta = yres[i] - fYfitR[0] - fYfitR[1] * fX[i];
481 fSigmaY2 += delta*delta;
483 fSigmaY2 = TMath::Sqrt(fSigmaY2 / Float_t(fN2-2));
484 // TEMPORARY UNTIL covariance properly calculated
485 fSigmaY2 = TMath::Max(fSigmaY2, Float_t(.1));
487 fZfitR[0] = (sumwx2 * sumwz - sumwx * sumwxz) / det;
488 fZfitR[1] = (sumw * sumwxz - sumwx * sumwz) / det;
489 fZfit[0] = (sumwx2 * sumwz - sumwx * sumwxz) / det;
490 fZfit[1] = (sumw * sumwxz - sumwx * sumwz) / det;
491 fYfitR[0] += fYref[0] + correction;
492 fYfitR[1] += fYref[1];
493 fYfit[0] = fYfitR[0];
494 fYfit[1] = fYfitR[1];
496 //printf("y0 = %7.3f tgy = %7.3f z0 = %7.3f tgz = %7.3f \n", fYfitR[0], fYfitR[1], fZfitR[0], fZfitR[1]);
502 //_____________________________________________________________________________
503 void AliTRDseed::UpdateUsed()
510 for (Int_t i = 0; i < fgTimeBins; i++) {
511 if (!fClusters[i]) continue;
512 if(!fUsable[i]) continue;
513 if ((fClusters[i]->IsUsed())) fNUsed++;
518 //_____________________________________________________________________________
519 Float_t AliTRDseed::FitRiemanTilt(AliTRDseed * cseed, Bool_t terror)
522 // Fit the Rieman tilt
525 // Fitting with tilting pads - kz not fixed
526 TLinearFitter fitterT2(4,"hyp4");
527 fitterT2.StoreData(kTRUE);
529 Float_t xref2 = (cseed[2].fX0 + cseed[3].fX0) * 0.5; // Reference x0 for z
532 fitterT2.ClearPoints();
534 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
536 if (!cseed[iLayer].IsOK()) continue;
537 Double_t tilt = cseed[iLayer].fTilt;
539 for (Int_t itime = 0; itime < fgTimeBins+1; itime++) {
541 if (!cseed[iLayer].fUsable[itime]) continue;
542 // x relative to the midle chamber
543 Double_t x = cseed[iLayer].fX[itime] + cseed[iLayer].fX0 - xref2;
544 Double_t y = cseed[iLayer].fY[itime];
545 Double_t z = cseed[iLayer].fZ[itime];
551 Double_t x2 = cseed[iLayer].fX[itime] + cseed[iLayer].fX0; // Global x
552 Double_t t = 1.0 / (x2*x2 + y*y);
554 uvt[0] = 2.0 * x2 * uvt[1];
555 uvt[2] = 2.0 * tilt * uvt[1];
556 uvt[3] = 2.0 * tilt *uvt[1] * x;
557 uvt[4] = 2.0 * (y + tilt * z) * uvt[1];
559 Double_t error = 2.0 * uvt[1];
561 error *= cseed[iLayer].fSigmaY;
564 error *= 0.2; //Default error
566 fitterT2.AddPoint(uvt,uvt[4],error);
574 Double_t rpolz0 = fitterT2.GetParameter(3);
575 Double_t rpolz1 = fitterT2.GetParameter(4);
578 // Linear fitter - not possible to make boundaries
579 // non accept non possible z and dzdx combination
581 Bool_t acceptablez = kTRUE;
582 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
583 if (!cseed[iLayer].IsOK()) continue;
584 Double_t zT2 = rpolz0 + rpolz1 * (cseed[iLayer].fX0 - xref2);
585 if (TMath::Abs(cseed[iLayer].fZProb - zT2) > cseed[iLayer].fPadLength * 0.5 + 1.0) acceptablez = kFALSE;
588 Double_t zmf = cseed[2].fZref[0] + cseed[2].fZref[1] * (xref2 - cseed[2].fX0);
589 Double_t dzmf = (cseed[2].fZref[1] + cseed[3].fZref[1]) * 0.5;
590 fitterT2.FixParameter(3,zmf);
591 fitterT2.FixParameter(4,dzmf);
593 fitterT2.ReleaseParameter(3);
594 fitterT2.ReleaseParameter(4);
595 rpolz0 = fitterT2.GetParameter(3);
596 rpolz1 = fitterT2.GetParameter(4);
599 Double_t chi2TR = fitterT2.GetChisquare() / Float_t(npointsT);
601 params[0] = fitterT2.GetParameter(0);
602 params[1] = fitterT2.GetParameter(1);
603 params[2] = fitterT2.GetParameter(2);
604 Double_t curvature = 1.0 + params[1] * params[1] - params[2] * params[0];
607 for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
608 Double_t x = cseed[iLayer].fX0;
615 Double_t res2 = (x * params[0] + params[1]);
617 res2 = 1.0 - params[2]*params[0] + params[1]*params[1] - res2;
619 res2 = TMath::Sqrt(res2);
620 y = (1.0 - res2) / params[0];
624 Double_t x0 = -params[1] / params[0];
625 if (-params[2]*params[0] + params[1]*params[1] + 1 > 0) {
626 Double_t rm1 = params[0] / TMath::Sqrt(-params[2]*params[0] + params[1]*params[1] + 1);
627 if (1.0/(rm1*rm1) - (x-x0) * (x-x0) > 0.0) {
628 Double_t res = (x - x0) / TMath::Sqrt(1.0 / (rm1*rm1) - (x-x0)*(x-x0));
629 if (params[0] < 0) res *= -1.0;
633 z = rpolz0 + rpolz1 * (x - xref2);
635 cseed[iLayer].fYref[0] = y;
636 cseed[iLayer].fYref[1] = dy;
637 cseed[iLayer].fZref[0] = z;
638 cseed[iLayer].fZref[1] = dz;
639 cseed[iLayer].fC = curvature;