commented define _ClusterTopology_ - to be used only for the special productions
[u/mrichter/AliRoot.git] / ITS / AliITSTPArrayFit.cxx
CommitLineData
6be22b3f 1/**************************************************************************
2 * Copyright(c) 2009-2011, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
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 **************************************************************************/
15/* $Id$ */
16///////////////////////////////////////////////////////////////////////////////////////////////
17// //
18// The line is defined by equations (1) //
19// a0*z+a1*x-a0*a1=0 and //
20// b0*z+b1*y-b0*b1=0 //
21// where x,y,z are NOT the lab axes but z is the lab axis along which the track //
22// has the largest lever arm and x,y are the remaining 2 axis in //
23// the order of fgkAxisID[z][0], fgkAxisID[z][1] //
24// The parameters are fParams[kA0,kB0,kA1,kB1] and the axis chosen as the independent //
25// var. is fParAxis (i.e. if fParAxis==kZ, then a0=ax,b0=bx, a1=ay,b1=by) //
26// //
27// //
28// The helix is defined by the equations (2) //
29// X(t) = (dr+R)*cos(phi0) - (R+sum{dRi})*cos(t+phi0) + sum{dRi*cos(phi0+ti)} //
30// Y(t) = (dr+R)*sin(phi0) - (R+sum{dRi})*sin(t+phi0) + sum{dRi*sin(phi0+ti)} //
31// Z(t) = dz - (R+sum{dRi})*t*tg(dip) + sum{dRi*ti}*tg(dip) //
32// where dRi is the change of the radius due to the ELoss at parameter ti //
33// //
34// Author: ruben.shahoyan@cern.ch //
35// //
36///////////////////////////////////////////////////////////////////////////////////////////////
37
38#include "AliITSTPArrayFit.h"
39#include "AliExternalTrackParam.h"
40#include "AliSymMatrix.h"
41#include "AliLog.h"
42#include "AliParamSolver.h"
43#include "AliGeomManager.h"
44#include "AliITSgeomTGeo.h"
45#include "AliTracker.h"
46#include <TRandom.h>
ef24eb3b 47#include <TArrayD.h>
6be22b3f 48
49ClassImp(AliITSTPArrayFit)
50
51const Int_t AliITSTPArrayFit::fgkAxisID[3][3] = {
52 {AliITSTPArrayFit::kY,AliITSTPArrayFit::kZ,AliITSTPArrayFit::kX},
53 {AliITSTPArrayFit::kZ,AliITSTPArrayFit::kX,AliITSTPArrayFit::kY},
54 {AliITSTPArrayFit::kX,AliITSTPArrayFit::kY,AliITSTPArrayFit::kZ} };
55
56const Int_t AliITSTPArrayFit::fgkAxisCID[3][6] = {
57 {AliITSTPArrayFit::kYY,AliITSTPArrayFit::kYZ,AliITSTPArrayFit::kXY,
58 AliITSTPArrayFit::kZZ,AliITSTPArrayFit::kXZ,AliITSTPArrayFit::kXX},
59 //
60 {AliITSTPArrayFit::kZZ,AliITSTPArrayFit::kXZ,AliITSTPArrayFit::kYZ,
61 AliITSTPArrayFit::kXX,AliITSTPArrayFit::kYX,AliITSTPArrayFit::kYY},
62 //
63 {AliITSTPArrayFit::kXX,AliITSTPArrayFit::kXY,AliITSTPArrayFit::kXZ,
64 AliITSTPArrayFit::kYY,AliITSTPArrayFit::kYZ,AliITSTPArrayFit::kZZ}
65};
66//
67
68const Double_t AliITSTPArrayFit::fgkAlmostZero = 1E-55;
69const Double_t AliITSTPArrayFit::fgkCQConv = 0.299792458e-3;// R = PT/Bz/fgkCQConv with GeV,kGauss,cm
70const Double_t AliITSTPArrayFit::fgkZSpanITS[AliITSTPArrayFit::kMaxLrITS] = {
71 36. ,14.1,14.1, 38., 22.2,29.7, 51. ,43.1,48.9};
72
73const Double_t AliITSTPArrayFit::fgkRLayITS[AliITSTPArrayFit::kMaxLrITS] = {
74 2.94, 3.9,7.6, 11.04, 15.0,23.9, 29.44 ,38.0,43.0};
75
76const Int_t AliITSTPArrayFit::fgkPassivLrITS[3] =
77 {AliITSTPArrayFit::kLrBeamPime,AliITSTPArrayFit::kLrShield1,AliITSTPArrayFit::kLrShield2};
78
79const Int_t AliITSTPArrayFit::fgkActiveLrITS[6] =
80 {AliITSTPArrayFit::kLrSPD1,AliITSTPArrayFit::kLrSPD2,
81 AliITSTPArrayFit::kLrSDD1,AliITSTPArrayFit::kLrSDD2,
82 AliITSTPArrayFit::kLrSSD1,AliITSTPArrayFit::kLrSSD2};
83
84Double_t AliITSTPArrayFit::fgRhoLITS[AliITSTPArrayFit::kMaxLrITS] = {
85 1.48e-01, 2.48e-01,2.57e-01, 1.34e-01, 3.34e-01,3.50e-01, 2.22e-01, 2.38e-01,2.25e-01};
86
87//____________________________________________________
88AliITSTPArrayFit::AliITSTPArrayFit() :
24391cd5 89 fkPoints(0),fParSol(0),fBz(0),fCharge(0),fPntFirst(-1),
6be22b3f 90 fPntLast(-1),fNPBooked(0),fParAxis(-1),fCovI(0),fChi2NDF(0),
ef24eb3b 91 fMaxIter(20),fIter(0),fEps(1e-6),fMass(0),fSwitch2Line(kFALSE),fMaxRforHelix(6.e5),
1d06ac63 92 fkAxID(0),fkAxCID(0),fCurT(0),
6be22b3f 93 fFirstPosT(0),fNElsPnt(0),fElsId(0),fElsDR(0)
94{
95 // default constructor
96 for (int i=kMaxParam;i--;) fParams[i] = 0;
97 for (int i=kMaxParamSq;i--;) fParamsCov[i] = 0;
98 SetMass();
99}
100
101//____________________________________________________
102AliITSTPArrayFit::AliITSTPArrayFit(Int_t np) :
24391cd5 103 fkPoints(0),fParSol(0),fBz(0),fCharge(0),fPntFirst(-1),
6be22b3f 104 fPntLast(-1),fNPBooked(np),fParAxis(-1),fCovI(0),fChi2NDF(0),
ef24eb3b 105 fMaxIter(20),fIter(0),fEps(1e-6),fMass(0),fSwitch2Line(kFALSE),fMaxRforHelix(6.e5),
1d06ac63 106 fkAxID(0),fkAxCID(0),fCurT(0),fFirstPosT(0),fNElsPnt(0),fElsId(0),fElsDR(0)
6be22b3f 107{
108 // constructor with booking of np points
109 for (int i=kMaxParam;i--;) fParams[i] = 0;
110 for (int i=kMaxParamSq;i--;) fParamsCov[i] = 0;
111 InitAux();
112 SetEps();
113 SetMass();
114 SetMaxIterations();
115}
116
117//____________________________________________________
118AliITSTPArrayFit::AliITSTPArrayFit(const AliITSTPArrayFit &src) :
24391cd5 119 TObject(src),fkPoints(src.fkPoints),fParSol(0),fBz(src.fBz),
6be22b3f 120 fCharge(src.fCharge),fPntFirst(src.fPntFirst),fPntLast(src.fPntLast),fNPBooked(src.fNPBooked),
121 fParAxis(src.fParAxis),fCovI(0),fChi2NDF(0),fMaxIter(20),fIter(0),fEps(0),fMass(src.fMass),
1d06ac63 122 fSwitch2Line(src.fSwitch2Line),fMaxRforHelix(src.fMaxRforHelix),fkAxID(0),fkAxCID(0),fCurT(0),
123 fFirstPosT(0),fNElsPnt(0),fElsId(0),fElsDR(0)
6be22b3f 124{
125 // copy constructor
126 InitAux();
8102b2c9 127 memcpy(fCovI,src.fCovI,fNPBooked*kNCov*sizeof(Double_t));
6be22b3f 128 for (int i=kMaxParam;i--;) fParams[i] = src.fParams[i];
129 for (int i=kMaxParamSq;i--;) fParamsCov[i] = src.fParamsCov[i];
130 memcpy(fCurT,src.fCurT,fNPBooked*sizeof(Double_t));
131 SetEps(src.fEps);
132 SetMaxIterations(src.fMaxIter);
133 //
134}
135
136//____________________________________________________
137AliITSTPArrayFit &AliITSTPArrayFit::operator =(const AliITSTPArrayFit& src)
138{
139 // assignment operator
140 if (this==&src) return *this;
141 ((TObject*)this)->operator=(src);
24391cd5 142 fkPoints = src.fkPoints;
6be22b3f 143 if (!fParSol) fParSol = new AliParamSolver(*src.fParSol);
144 else *fParSol = *src.fParSol;
145 fBz = src.fBz;
146 fCharge = src.fCharge;
147 fNPBooked = src.fNPBooked;
148 fPntFirst = src.fPntFirst;
149 fPntLast = src.fPntLast;
150 InitAux();
8102b2c9 151 memcpy(fCovI,src.fCovI,fNPBooked*kNCov*sizeof(Double_t));
6be22b3f 152 for (int i=kMaxParam;i--;) fParams[i] = src.fParams[i];
153 for (int i=kMaxParamSq;i--;) fParamsCov[i] = src.fParamsCov[i];
154 SetParAxis(src.fParAxis);
155 fNElsPnt = src.fNElsPnt;
156 fFirstPosT = src.fFirstPosT;
157 memcpy(fCurT ,src.fCurT ,fNPBooked*sizeof(Double_t));
158 memcpy(fElsId ,src.fElsId ,fNPBooked*sizeof(Int_t));
159 memcpy(fElsDR ,src.fElsDR ,fNPBooked*sizeof(Double_t));
160 memcpy(fCurT ,src.fCurT ,fNPBooked*sizeof(Double_t));
161 SetEps(src.fEps);
162 SetMaxIterations(src.fMaxIter);
163 //
164 return *this;
165 //
166}
167
168//____________________________________________________
169AliITSTPArrayFit::~AliITSTPArrayFit()
170{
171 // destructor
172 delete fParSol;
173 delete[] fCovI;
174 delete[] fCurT;
175 delete[] fElsId;
176 delete[] fElsDR;
177}
178
179//____________________________________________________
180void AliITSTPArrayFit::Reset()
181{
182 // reset to process new track
183 if (fParSol) fParSol->Clear();
24391cd5 184 fkPoints=0;
6be22b3f 185 fNElsPnt = 0;
186 fFirstPosT = 0;
187 // fBz = 0;
188 fCharge = 0;
189 fIter = 0;
190 fPntFirst=fPntLast=-1;
191 SetParAxis(-1);
1d06ac63 192 fSwitch2Line = kFALSE;
6be22b3f 193 ResetBit(kFitDoneBit|kCovInvBit);
194}
195
196//____________________________________________________
197void AliITSTPArrayFit::AttachPoints(const AliTrackPointArray* points, Int_t pfirst,Int_t plast)
198{
199 // create from piece of AliTrackPointArray
200 Reset();
24391cd5 201 fkPoints = points;
6be22b3f 202 int np = points->GetNPoints();
203 if (fNPBooked<np) {
204 fNPBooked = np;
205 InitAux();
206 }
207 fPntFirst = pfirst<0 ? 0 : pfirst;
208 fPntLast = plast<fPntFirst ? np-1 : plast;
209 //
210 for (int i=kMaxParam;i--;) fParams[i] = 0;
211 for (int i=kMaxParamSq;i--;) fParamsCov[i] = 0;
212 //
213 InvertPointsCovMat();
8102b2c9 214 ResetCovIScale();
6be22b3f 215 //
216}
217
218//____________________________________________________
219Bool_t AliITSTPArrayFit::SetFirstLast(Int_t pfirst,Int_t plast)
220{
221 // set first and last point to fit
24391cd5 222 const AliTrackPointArray* pnts = fkPoints;
6be22b3f 223 if (!pnts) {AliError("TrackPointArray is not attached yet"); return kFALSE;}
224 AttachPoints(pnts,pfirst,plast);
225 return kTRUE;
226 //
227}
228
229//____________________________________________________
230Bool_t AliITSTPArrayFit::InvertPointsCovMat()
231{
232 // invert the cov.matrices of the points
233 for (int i=fPntFirst;i<=fPntLast;i++) {
234 //
24391cd5 235 float *cov = (float*)fkPoints->GetCov() + i*6; // pointer on cov.matrix
6be22b3f 236 //
237 Double_t t0 = cov[kYY]*cov[kZZ] - cov[kYZ]*cov[kYZ];
238 Double_t t1 = cov[kXY]*cov[kZZ] - cov[kXZ]*cov[kYZ];
239 Double_t t2 = cov[kXY]*cov[kYZ] - cov[kXZ]*cov[kYY];
240 Double_t det = cov[kXX]*t0 - cov[kXY]*t1 + cov[kXZ]*t2;
66214d86 241 if (IsZero(det,1e-18)) { // one of errors is 0, fix this
242 double norm[3];
243 TGeoHMatrix hcov;
244 TGeoRotation hrot,hrotI;
245 GetNormal(norm,cov);
246 double phi = TMath::ATan2(norm[1],norm[0]);
247 hrot.SetAngles(-phi*TMath::RadToDeg(),0.,0.);
248 hrotI.SetAngles(phi*TMath::RadToDeg(),0.,0.);
249 //
250 Double_t hcovel[9];
251 hcovel[0] = cov[kXX];
252 hcovel[1] = cov[kXY];
253 hcovel[2] = cov[kXZ];
254 hcovel[3] = cov[kXY];
255 hcovel[4] = cov[kYY];
256 hcovel[5] = cov[kYZ];
257 hcovel[6] = cov[kXZ];
258 hcovel[7] = cov[kYZ];
259 hcovel[8] = cov[kZZ];
260 hcov.SetRotation(hcovel);
261 //
262 Double_t *hcovscl = hcov.GetRotationMatrix();
263 // printf(">> %+e %+e %+e\n %+e %+e %+e\n %+e %+e %+e\n\n",hcovscl[0],hcovscl[1],hcovscl[2],hcovscl[3],hcovscl[4],hcovscl[5],hcovscl[6],hcovscl[7],hcovscl[8]);
264 // printf("Rot by %+.e (%+.e %+.e %+.e)\n",phi, norm[0],norm[1],norm[2]);
265 hcov.Multiply(&hrotI);
266 hcov.MultiplyLeft(&hrot);
267 // printf("|| %+e %+e %+e\n %+e %+e %+e\n %+e %+e %+e\n\n",hcovscl[0],hcovscl[1],hcovscl[2],hcovscl[3],hcovscl[4],hcovscl[5],hcovscl[6],hcovscl[7],hcovscl[8]);
268 if (hcovscl[0]<1e-8) hcovscl[0] = 1e-8;
269 if (hcovscl[4]<1e-8) hcovscl[4] = 1e-8;
270 if (hcovscl[8]<1e-8) hcovscl[8] = 1e-8;
271 // printf("** %+e %+e %+e\n %+e %+e %+e\n %+e %+e %+e\n\n",hcovscl[0],hcovscl[1],hcovscl[2],hcovscl[3],hcovscl[4],hcovscl[5],hcovscl[6],hcovscl[7],hcovscl[8]);
272 hcov.Multiply(&hrot);
273 hcov.MultiplyLeft(&hrotI);
274 // printf("^^ %+e %+e %+e\n %+e %+e %+e\n %+e %+e %+e\n\n",hcovscl[0],hcovscl[1],hcovscl[2],hcovscl[3],hcovscl[4],hcovscl[5],hcovscl[6],hcovscl[7],hcovscl[8]);
275 cov[kXX] = hcovscl[0];
276 cov[kXY] = hcovscl[1];
277 cov[kXZ] = hcovscl[2];
278 cov[kYY] = hcovscl[4];
279 cov[kYZ] = hcovscl[5];
280 cov[kZZ] = hcovscl[8];
281 }
282 t0 = cov[kYY]*cov[kZZ] - cov[kYZ]*cov[kYZ];
283 t1 = cov[kXY]*cov[kZZ] - cov[kXZ]*cov[kYZ];
284 t2 = cov[kXY]*cov[kYZ] - cov[kXZ]*cov[kYY];
285 det = cov[kXX]*t0 - cov[kXY]*t1 + cov[kXZ]*t2;
286 //
abd7ef79 287 AliDebug(2,Form("%+.4e %+.4e %+.4e -> %+.4e",t0,t1,t2,det));
66214d86 288 if (IsZero(det,fgkAlmostZero)) {
6be22b3f 289 AliInfo(Form("Cov.Matrix for point %d is singular",i));
290 return kFALSE;
291 }
292 //
293 Double_t *covI = GetCovI(i);
294 covI[kXX] = t0/det;
295 covI[kXY] = -t1/det;
296 covI[kXZ] = t2/det;
297 covI[kYY] = (cov[kXX]*cov[kZZ] - cov[kXZ]*cov[kXZ])/det;
298 covI[kYZ] = (cov[kXY]*cov[kXZ] - cov[kXX]*cov[kYZ])/det;
299 covI[kZZ] = (cov[kXX]*cov[kYY] - cov[kXY]*cov[kXY])/det;
300 //
301 }
302 SetCovInv();
303 return kTRUE;
304}
305
306//____________________________________________________
307void AliITSTPArrayFit::InitAux()
308{
309 // init auxiliary space
310 if (fCovI) delete[] fCovI;
311 if (fCurT) delete[] fCurT;
312 //
8102b2c9 313 fCovI = new Double_t[kNCov*fNPBooked];
6be22b3f 314 fCurT = new Double_t[fNPBooked+kMaxLrITS];
315 fElsId = new Int_t[fNPBooked+kMaxLrITS];
316 fElsDR = new Double_t[fNPBooked+kMaxLrITS];
317 memset(fElsDR,0,(fNPBooked+kMaxLrITS)*sizeof(Double_t));
8102b2c9 318 memset(fCovI,0,fNPBooked*kNCov*sizeof(Double_t));
319 ResetCovIScale();
6be22b3f 320 //
321}
322
323//____________________________________________________
324Bool_t AliITSTPArrayFit::FitLineCrude()
325{
326 // perform linear fit w/o accounting the errors
327 // fit is done in the parameterization
328 // x = res[0] + res[1]*z
329 // y = res[2] + res[3]*z
330 // where x,y,z are NOT the lab axes but z is the lab axis along which the track
331 // has the largest lever arm and x,y are the remaining 2 axis in
332 // the order of fgkAxisID[z][0], fgkAxisID[z][1]
333 //
334 int np = fPntLast - fPntFirst + 1;
335 if (np<2) {
336 AliError("At least 2 points are needed for straight line fit");
337 return kFALSE;
338 }
339 //
340 if (fParAxis<0) SetParAxis(ChoseParAxis());
341 Double_t sZ=0,sZZ=0,sY=0,sYZ=0,sX=0,sXZ=0,det=0;
342 //
24391cd5 343 const float *coord[3] = {fkPoints->GetX(),fkPoints->GetY(),fkPoints->GetZ()};
6be22b3f 344 const Float_t *varZ = coord[ fParAxis ];
345 const Float_t *varX = coord[ fkAxID[kX] ];
346 const Float_t *varY = coord[ fkAxID[kY] ];
347 //
348 for (int i=fPntFirst;i<=fPntLast;i++) {
349 sZ += varZ[i];
350 sZZ += varZ[i]*varZ[i];
351 //
352 sX += varX[i];
353 sXZ += varX[i]*varZ[i];
354 //
355 sY += varY[i];
356 sYZ += varY[i]*varZ[i];
357 }
358 det = sZZ*np-sZ*sZ;
359 if (TMath::Abs(det)<fgkAlmostZero) return kFALSE;
360 fParams[0] = (sX*sZZ-sZ*sXZ)/det;
361 fParams[1] = (sXZ*np-sZ*sX)/det;
362 //
363 fParams[2] = (sY*sZZ-sZ*sYZ)/det;
364 fParams[3] = (sYZ*np-sZ*sY)/det;
365 //
366 return kTRUE;
367 //
368}
369
370//____________________________________________________
371void AliITSTPArrayFit::SetParAxis(Int_t ax)
372{
373 // select the axis which will be used as a parameter for the line: longest baseline
374 if (ax>kZ) {
375 AliInfo(Form("Wrong axis choice: %d",ax));
376 fParAxis = -1;
377 }
378 fParAxis = ax;
379 if (ax>=0) {
380 fkAxID = fgkAxisID[ax];
381 fkAxCID = fgkAxisCID[ax];
382 }
383 else {
384 fkAxID = fkAxCID = 0;
385 }
386 //
387}
388
389//____________________________________________________
390Int_t AliITSTPArrayFit::ChoseParAxis() const
391{
392 // select the variable with largest base as a parameter
393 Double_t cmn[3]={1.e9,1.e9,1.e9},cmx[3]={-1.e9,-1.e9,-1.e9};
394 //
24391cd5 395 const float *coord[3] = {fkPoints->GetX(),fkPoints->GetY(),fkPoints->GetZ()};
6be22b3f 396 for (int i=fPntFirst;i<=fPntLast;i++) {
397 for (int j=3;j--;) {
398 Double_t val = coord[j][i];
399 if (cmn[j]>val) cmn[j] = val;
400 if (cmx[j]<val) cmx[j] = val;
401 }
402 }
403 //
404 int axis = kZ;
405 if (cmx[axis]-cmn[axis] < cmx[kX]-cmn[kX]) axis = kX;
406 if (cmx[axis]-cmn[axis] < cmx[kY]-cmn[kY]) axis = kY;
407 return axis;
408 //
409}
410
411//____________________________________________________
8102b2c9 412Double_t AliITSTPArrayFit::GetPosition(Double_t *xyzPCA, const Double_t *xyz, const Double_t *covI, Double_t sclCovI) const
6be22b3f 413{
414 // calculate the position of the track at PCA to xyz
8102b2c9 415 Double_t t = GetParPCA(xyz,covI,sclCovI);
6be22b3f 416 GetPosition(xyzPCA,t);
417 return t;
418}
419
420//____________________________________________________
ef24eb3b 421Double_t AliITSTPArrayFit::GetPosition(Double_t *xyzPCA, const AliTrackPoint *pntCovInv, Bool_t useErr) const
6be22b3f 422{
423 // calculate the position of the track at PCA to pntCovInv
424 // NOTE: the covariance matrix of the point must be inverted
ef24eb3b 425 double t;
426 double xyz[3] = {pntCovInv->GetX(),pntCovInv->GetY(),pntCovInv->GetZ()};
427 if (useErr) {
428 Double_t covI[6];;
429 for (int i=6;i--;) covI[i] = pntCovInv->GetCov()[i];
430 t = GetParPCA(xyz,covI);
431 }
432 else t = GetParPCA(xyz);
6be22b3f 433 GetPosition(xyzPCA,t);
434 return t;
435}
436
437//____________________________________________________
ef24eb3b 438void AliITSTPArrayFit::GetResiduals(Double_t *resPCA, const AliTrackPoint *pntCovInv, Bool_t useErr) const
6be22b3f 439{
440 // calculate the residuals of the track at PCA to pntCovInv
441 // NOTE: the covariance matrix of the point must be inverted
ef24eb3b 442 GetPosition(resPCA,pntCovInv,useErr);
6be22b3f 443 resPCA[0] -= pntCovInv->GetX();
444 resPCA[1] -= pntCovInv->GetY();
445 resPCA[2] -= pntCovInv->GetZ();
446}
447
448//____________________________________________________
8102b2c9 449void AliITSTPArrayFit::GetResiduals(Double_t *resPCA, const Double_t *xyz, const Double_t *covI, Double_t sclCovI) const
6be22b3f 450{
451 // calculate the residuals of the track at PCA to xyz
8102b2c9 452 GetPosition(resPCA,xyz,covI,sclCovI);
6be22b3f 453 resPCA[kX] -= xyz[kX];
454 resPCA[kY] -= xyz[kY];
455 resPCA[kZ] -= xyz[kZ];
456}
457
458//____________________________________________________
8102b2c9 459Double_t AliITSTPArrayFit::GetParPCALine(const Double_t *xyz, const Double_t *covI/*, Double_t sclCovI*/) const
6be22b3f 460{
461 // get parameter for the point with least weighted distance to the point
462 //
463 Double_t rhs,denom;
464 Double_t dx = fParams[kA0]-xyz[ fkAxID[kX] ];
465 Double_t dy = fParams[kA1]-xyz[ fkAxID[kY] ];
466 Double_t dz = -xyz[ fkAxID[kZ] ];
467 //
468 if (covI) {
469 Double_t tx = fParams[kB0]*covI[ fkAxCID[kXX] ] + fParams[kB1]*covI[ fkAxCID[kXY] ] + covI[ fkAxCID[kXZ] ];
470 Double_t ty = fParams[kB0]*covI[ fkAxCID[kXY] ] + fParams[kB1]*covI[ fkAxCID[kYY] ] + covI[ fkAxCID[kYZ] ];
471 Double_t tz = fParams[kB0]*covI[ fkAxCID[kXZ] ] + fParams[kB1]*covI[ fkAxCID[kYZ] ] + covI[ fkAxCID[kZZ] ];
472 rhs = tx*dx + ty*dy + tz*dz;
473 denom = -(fParams[kB0]*(covI[ fkAxCID[kXZ] ] + tx) + fParams[kB1]*(covI[ fkAxCID[kYZ] ] + ty) + covI[ fkAxCID[kZZ] ]);
474 }
475 else {
476 rhs = fParams[kB0]*dx + fParams[kB1]*dy + dz;
477 denom = -(fParams[kB0]*fParams[kB0] + fParams[kB1]*fParams[kB1] + 1);
478 }
479 //
480 return rhs/denom;
481 //
482}
483
484//____________________________________________________
8102b2c9 485void AliITSTPArrayFit::GetDResDPosLine(Double_t *dXYZdP, /*const Double_t *xyz,*/ const Double_t *covI/*,Double_t sclCovI*/) const
6be22b3f 486{
487 // calculate detivative of the PCA residuals vs point position and fill in user provide
488 // array in the format {dXdXp,dY/dXp,dZdXp, ... dXdZp,dYdZp,dZdZp}
489 //
490 Double_t dTdP[3];
8102b2c9 491 GetDtDPosLine(dTdP, /*xyz,*/ covI/*,sclCovI*/); // derivative of the t-param over point position
6be22b3f 492 //
493 for (int i=3;i--;) {
494 int var = fkAxID[i];
495 Double_t *curd = dXYZdP + var*3; // d/dCoord_i
496 curd[ fkAxID[kX] ] = fParams[kB0]*dTdP[var];
497 curd[ fkAxID[kY] ] = fParams[kB1]*dTdP[var];
498 curd[ fkAxID[kZ] ] = dTdP[var];
499 curd[ var ]-= 1.;
500 }
501 //
502}
503
504//____________________________________________________
8102b2c9 505void AliITSTPArrayFit::GetDResDParamsLine(Double_t *dXYZdP, const Double_t *xyz, const Double_t *covI/*,Double_t sclCovI*/) const
6be22b3f 506{
507 // calculate detivative of the PCA residuals vs line parameters and fill in user provide
508 // array in the format {dXdP0,dYdP0,dZdP0, ... dXdPn,dYdPn,dZdPn}
509 //
510 Double_t dTdP[4];
8102b2c9 511 Double_t t = GetDtDParamsLine(dTdP, xyz, covI /*,sclCovI*/); // derivative of the t-param over line params
6be22b3f 512 //
513 Double_t *curd = dXYZdP + kA0*3; // d/dA0
514 curd[ fkAxID[kX] ] = fParams[kB0]*dTdP[kA0] + 1.;
515 curd[ fkAxID[kY] ] = fParams[kB1]*dTdP[kA0];
516 curd[ fkAxID[kZ] ] = dTdP[kA0];
517 //
518 curd = dXYZdP + kB0*3; // d/dB0
519 curd[ fkAxID[kX] ] = fParams[kB0]*dTdP[kB0] + t;
520 curd[ fkAxID[kY] ] = fParams[kB1]*dTdP[kB0];
521 curd[ fkAxID[kZ] ] = dTdP[kB0];
522 //
523 curd = dXYZdP + kA1*3; // d/dA1
524 curd[ fkAxID[kX] ] = fParams[kB0]*dTdP[kA1];
525 curd[ fkAxID[kY] ] = fParams[kB1]*dTdP[kA1] + 1.;
526 curd[ fkAxID[kZ] ] = dTdP[kA1];
527 //
528 curd = dXYZdP + kB1*3; // d/dB1
529 curd[ fkAxID[kX] ] = fParams[kB0]*dTdP[kB1];
530 curd[ fkAxID[kY] ] = fParams[kB1]*dTdP[kB1] + t;
531 curd[ fkAxID[kZ] ] = dTdP[kB1];
532 //
533}
534
535//____________________________________________________
536Double_t AliITSTPArrayFit::GetDtDParamsLine(Double_t *dtparam,const Double_t *xyz, const Double_t *covI) const
537{
538 // get t-param detivative over the parameters for the point with least weighted distance to the point
539 //
540 Double_t rhs,denom;
541 Double_t dx = fParams[kA0]-xyz[ fkAxID[kX] ];
542 Double_t dy = fParams[kA1]-xyz[ fkAxID[kY] ];
543 Double_t dz = -xyz[ fkAxID[kZ] ];
544 Double_t rhsDA0,rhsDA1,rhsDB0,rhsDB1,denDB0,denDB1;
545 //
546 if (covI) {
547 Double_t tx = fParams[kB0]*covI[ fkAxCID[kXX] ] + fParams[kB1]*covI[ fkAxCID[kXY] ] + covI[ fkAxCID[kXZ] ];
548 Double_t ty = fParams[kB0]*covI[ fkAxCID[kXY] ] + fParams[kB1]*covI[ fkAxCID[kYY] ] + covI[ fkAxCID[kYZ] ];
549 Double_t tz = fParams[kB0]*covI[ fkAxCID[kXZ] ] + fParams[kB1]*covI[ fkAxCID[kYZ] ] + covI[ fkAxCID[kZZ] ];
550 rhs = tx*dx + ty*dy + tz*dz;
551 denom = -(fParams[kB0]*(covI[ fkAxCID[kXZ] ] + tx) + fParams[kB1]*(covI[ fkAxCID[kYZ] ] + ty) + covI[ fkAxCID[kZZ] ]);
552 //
553 rhsDA0 = tx;
554 rhsDA1 = ty;
555 rhsDB0 = covI[ fkAxCID[kXX] ]*dx + covI[ fkAxCID[kXY] ]*dy + covI[ fkAxCID[kXZ] ]*dz;
556 rhsDB1 = covI[ fkAxCID[kXY] ]*dx + covI[ fkAxCID[kYY] ]*dy + covI[ fkAxCID[kYZ] ]*dz;
557 //
558 denDB0 = -(tx + tx);
559 denDB1 = -(ty + ty);
560 }
561 else {
562 rhs = fParams[kB0]*dx + fParams[kB1]*dy + dz;
563 denom = -(fParams[kB0]*fParams[kB0] + fParams[kB1]*fParams[kB1] + 1);
564 //
565 rhsDA0 = fParams[kB0];
566 rhsDB0 = dx;
567 rhsDA1 = fParams[kB1];
568 rhsDB1 = dy;
569 //
570 denDB0 = -(fParams[kB0]+fParams[kB0]);
571 denDB1 = -(fParams[kB1]+fParams[kB1]);
572 //
573 }
574 //
575 Double_t denom2 = denom*denom;
576 dtparam[kA0] = rhsDA0/denom; // denom does not depend on A0,A1
577 dtparam[kA1] = rhsDA1/denom;
578 dtparam[kB0] = rhsDB0/denom - rhs/denom2 * denDB0;
579 dtparam[kB1] = rhsDB1/denom - rhs/denom2 * denDB1;
580 //
581 return rhs/denom;
582}
583
584//____________________________________________________
585void AliITSTPArrayFit::GetDtDPosLine(Double_t *dtpos,/*const Double_t *xyz,*/ const Double_t *covI) const
586{
587 // get t-param detivative over the parameters for the point with least weighted distance to the point
588 //
589 // Double_t rhs;
590 // Double_t dx = fParams[kA0]-xyz[ fkAxID[kX] ];
591 // Double_t dy = fParams[kA1]-xyz[ fkAxID[kY] ];
592 // Double_t dz = -xyz[ fkAxID[kZ] ];
593 Double_t denom;
594 Double_t rhsDX,rhsDY,rhsDZ;
595 //
596 if (covI) {
597 Double_t tx = fParams[kB0]*covI[ fkAxCID[kXX] ] + fParams[kB1]*covI[ fkAxCID[kXY] ] + covI[ fkAxCID[kXZ] ];
598 Double_t ty = fParams[kB0]*covI[ fkAxCID[kXY] ] + fParams[kB1]*covI[ fkAxCID[kYY] ] + covI[ fkAxCID[kYZ] ];
599 Double_t tz = fParams[kB0]*covI[ fkAxCID[kXZ] ] + fParams[kB1]*covI[ fkAxCID[kYZ] ] + covI[ fkAxCID[kZZ] ];
600 // rhs = tx*dx + ty*dy + tz*dz;
601 denom = -(fParams[kB0]*(covI[ fkAxCID[kXZ] ] + tx) + fParams[kB1]*(covI[ fkAxCID[kYZ] ] + ty) + covI[ fkAxCID[kZZ] ]);
602 //
603 rhsDX = -tx;
604 rhsDY = -ty;
605 rhsDZ = -tz;
606 }
607 else {
608 // rhs = fParams[kB0]*dx + fParams[kB1]*dy + dz;
609 denom = -(fParams[kB0]*fParams[kB0] + fParams[kB1]*fParams[kB1] + 1);
610 //
611 rhsDX = -fParams[kB0];
612 rhsDY = -fParams[kB1];
613 rhsDZ = -1;
614 //
615 }
616 //
617 dtpos[ fkAxID[kX] ] = rhsDX/denom;
618 dtpos[ fkAxID[kY] ] = rhsDY/denom;
619 dtpos[ fkAxID[kZ] ] = rhsDZ/denom;
620 //
621 // return rhs/denom;
622}
623
624//____________________________________________________
625void AliITSTPArrayFit::GetDResDParamsLine(Double_t *dXYZdP, Int_t ipnt) const
626{
627 // calculate detivative of the PCA residuals vs line parameters and fill in user provide
628 // array in the format {dXdP0,dYdP0,dZdP0, ... dXdPn,dYdPn,dZdPn}
629 //
630 if (ipnt<fPntFirst || ipnt>fPntLast) {
631 AliError(Form("Attempt to access the point %d not in the fitted points [%d:%d]",ipnt,fPntFirst,fPntLast));
632 return;
633 }
634 GetDResDParamsLine(dXYZdP, GetPoint(ipnt) , IsCovIgnored() ? 0 : GetCovI(ipnt));
635}
636
637//____________________________________________________
638void AliITSTPArrayFit::GetDResDPosLine(Double_t *dXYZdP, Int_t ipnt) const
639{
640 // calculate detivative of the PCA residuals vs point position and fill in user provide
641 // array in the format {dXdXp,dY/dXp,dZdXp, ... dXdZp,dYdZp,dZdZp}
642 //
643 if (ipnt<fPntFirst || ipnt>fPntLast) {
644 AliError(Form("Attempt to access the point %d not in the fitted points [%d:%d]",ipnt,fPntFirst,fPntLast));
645 return;
646 }
8102b2c9 647 GetDResDPosLine(dXYZdP,IsCovIgnored() ? 0 : GetCovI(ipnt)/*,GetCovIScale(ipnt)*/);
6be22b3f 648}
649
650//____________________________________________________
651void AliITSTPArrayFit::GetDResDParams(Double_t *dXYZdP, Int_t ipnt)
652{
653 // calculate detivative of the PCA residuals vs track parameters and fill in user provide
654 // array in the format {dXdP0,dYdP0,dZdP0, ... dXdPn,dYdPn,dZdPn}
655 //
656 if (ipnt<fPntFirst || ipnt>fPntLast) {
657 AliError(Form("Attempt to access the point %d not in the fitted points [%d:%d]",ipnt,fPntFirst,fPntLast));
658 return;
659 }
8102b2c9 660 GetDResDParams(dXYZdP, GetPoint(ipnt) , IsCovIgnored() ? 0 : GetCovI(ipnt),GetCovIScale(ipnt));
6be22b3f 661}
662
663//____________________________________________________
664void AliITSTPArrayFit::GetDResDPos(Double_t *dXYZdP, Int_t ipnt)
665{
666 // calculate detivative of the PCA residuals vs point position and fill in user provide
667 // array in the format {dXdXp,dY/dXp,dZdXp, ... dXdZp,dYdZp,dZdZp}
668 //
669 if (ipnt<fPntFirst || ipnt>fPntLast) {
670 AliError(Form("Attempt to access the point %d not in the fitted points [%d:%d]",ipnt,fPntFirst,fPntLast));
671 return;
672 }
8102b2c9 673 GetDResDPos(dXYZdP, GetPoint(ipnt), IsCovIgnored() ? 0 : GetCovI(ipnt), GetCovIScale(ipnt));
6be22b3f 674}
675
676//____________________________________________________
8102b2c9 677void AliITSTPArrayFit::GetDResDParams(Double_t *dXYZdP, const Double_t *xyz, const Double_t *covI, Double_t sclCovI)
6be22b3f 678{
679 // get residual detivatives over the track parameters for the point with least weighted distance to the point
680 //
ef24eb3b 681 if (!IsHelix()) { // for the straight line calculate analytically
8102b2c9 682 GetDResDParamsLine(dXYZdP, xyz, covI /*,sclCovI*/);
6be22b3f 683 return;
684 }
685 //
686 // calculate derivative numerically
687 const Double_t delta = 0.01;
688 Double_t xyzVar[4][3];
689 //
690 for (int ipar = 5;ipar--;) {
691 double sav = fParams[ipar];
692 fParams[ipar] -= delta;
8102b2c9 693 GetPosition(xyzVar[0],xyz,covI,sclCovI);
6be22b3f 694 fParams[ipar] += delta/2;
8102b2c9 695 GetPosition(xyzVar[1],xyz,covI,sclCovI);
6be22b3f 696 fParams[ipar] += delta;
8102b2c9 697 GetPosition(xyzVar[2],xyz,covI,sclCovI);
6be22b3f 698 fParams[ipar] += delta/2;
8102b2c9 699 GetPosition(xyzVar[3],xyz,covI,sclCovI);
6be22b3f 700 fParams[ipar] = sav; // restore
701 //
702 double *curd = dXYZdP + 3*ipar;
703 for (int i=3;i--;) curd[i] = (8.*(xyzVar[2][i]-xyzVar[1][i]) - (xyzVar[3][i]-xyzVar[0][i]))/6./delta;
704 }
705 //
706}
707
708
709//____________________________________________________
b80c197e 710void AliITSTPArrayFit::GetDResDPos(Double_t *dXYZdP, const Double_t *xyz, const Double_t *covI,Double_t sclCovI) const
6be22b3f 711{
712 // get residuals detivative over the point position for the point with least weighted distance to the point
713 //
714
ef24eb3b 715 if (!IsHelix()) { // for the straight line calculate analytically
8102b2c9 716 GetDResDPosLine(dXYZdP, /*xyz,*/ covI /*,sclCovI*/);
6be22b3f 717 return;
718 }
719 //
720 // calculate derivative numerically
721 const Double_t delta = 0.005;
722 Double_t xyzVar[4][3];
723 Double_t xyzv[3] = {xyz[0],xyz[1],xyz[2]};
724 //
725 for (int ipar = 3;ipar--;) {
726 double sav = xyzv[ipar];
727 xyzv[ipar] -= delta;
8102b2c9 728 GetPosition(xyzVar[0],xyzv,covI,sclCovI);
6be22b3f 729 xyzv[ipar] += delta/2;
8102b2c9 730 GetPosition(xyzVar[1],xyzv,covI,sclCovI);
6be22b3f 731 xyzv[ipar] += delta;
8102b2c9 732 GetPosition(xyzVar[2],xyzv,covI,sclCovI);
6be22b3f 733 xyzv[ipar] += delta/2;
8102b2c9 734 GetPosition(xyzVar[3],xyzv,covI,sclCovI);
6be22b3f 735 xyzv[ipar] = sav; // restore
736 //
737 double *curd = dXYZdP + 3*ipar;
738 for (int i=3;i--;) curd[i] = (8.*(xyzVar[2][i]-xyzVar[1][i]) - (xyzVar[3][i]-xyzVar[0][i]))/6./delta;
739 curd[ipar] -= 1.;
740 }
741 //
742}
743
744//________________________________________________________________________________________________________
8102b2c9 745Double_t AliITSTPArrayFit::GetParPCAHelix(const Double_t* xyz, const Double_t* covI,Double_t sclCovI) const
6be22b3f 746{
747 // find track parameter t (eq.2) corresponding to point of closest approach to xyz
748 //
749 Double_t phi = GetParPCACircle(xyz[kX],xyz[kY]);
750 Double_t cs = TMath::Cos(fParams[kPhi0]);
751 Double_t sn = TMath::Sin(fParams[kPhi0]);
752 Double_t xc = (fParams[kD0]+fParams[kR0])*cs;
753 Double_t yc = (fParams[kD0]+fParams[kR0])*sn;
754 Double_t dchi2,ddchi2;
755 //
756 Double_t dzD = -fParams[kR0]*fParams[kDip];
757 Double_t dphi = 0;
758 //
ef24eb3b 759 double rEps = 1e-5/TMath::Abs(fParams[kR0]); // dphi corresponding to 0.1 micron
760 if (rEps>fEps) rEps = fEps;
761 //
6be22b3f 762 int it=0;
763 do {
764 cs = TMath::Cos(phi + fParams[kPhi0]);
765 sn = TMath::Sin(phi + fParams[kPhi0]);
766 //
767 Double_t dxD = fParams[kR0]*sn;
768 Double_t dyD = -fParams[kR0]*cs;
769 Double_t dxDD = -dyD;
770 Double_t dyDD = dxD;
771 //
772 Double_t dx = xc - fParams[kR0]*cs - xyz[kX];
773 Double_t dy = yc - fParams[kR0]*sn - xyz[kY];
774 Double_t dz = fParams[kDZ] + dzD*phi- xyz[kZ];
775 //
776 if (covI) {
777 Double_t tx = dx*covI[kXX] + dy*covI[kXY] + dz*covI[kXZ];
778 Double_t ty = dx*covI[kXY] + dy*covI[kYY] + dz*covI[kYZ];
779 Double_t tz = dx*covI[kXZ] + dy*covI[kYZ] + dz*covI[kZZ];
780 //
781 Double_t ttx = dxD*covI[kXX] + dyD*covI[kXY] + dzD*covI[kXZ];
782 Double_t tty = dxD*covI[kXY] + dyD*covI[kYY] + dzD*covI[kYZ];
783 Double_t ttz = dxD*covI[kXZ] + dyD*covI[kYZ] + dzD*covI[kZZ];
784 //
785 // chi2 = dx*tx + dy*ty + dz*tz;
786 dchi2 = dxD*tx + dyD*ty + dzD*tz;
787 ddchi2 = dxDD*tx + dyDD*ty + dxD *ttx + dyD *tty + dzD *ttz;
788 //
8102b2c9 789 if (sclCovI>0) {dchi2 *= sclCovI; ddchi2 *= sclCovI;}
6be22b3f 790 }
791 else {
792 // chi2 = dx*dx + dy*dy + dz*dz;
793 dchi2 = dxD*dx + dyD*dy + dzD*dz;
794 ddchi2 = dxDD*dx + dyDD*dy + + dxD*dxD + dyD*dyD + dzD*dzD;
795 }
796 //
ef24eb3b 797 if (TMath::Abs(ddchi2)<fgkAlmostZero || TMath::Abs(dphi=dchi2/ddchi2)<rEps) break;
6be22b3f 798 phi -= dphi;
799 } while(++it<fMaxIter);
ef24eb3b 800
6be22b3f 801 //
802 return phi;
803}
804
805//________________________________________________________________________________________________________
806Double_t AliITSTPArrayFit::GetParPCACircle(Double_t x,Double_t y) const
807{
808 // find track parameter t (eq.2) corresponding to point on the circle with closest approach to x,y
809 //
810 Double_t r = fParams[kD0]+fParams[kR0];
811 Double_t t = TMath::ATan2( r*TMath::Sin(fParams[kPhi0])-y, r*TMath::Cos(fParams[kPhi0])-x ) - fParams[kPhi0];
812 if (fParams[kR0] < 0) t += TMath::Pi();
813 if (t > TMath::Pi()) t -= TMath::Pi()*2;
814 if (t <-TMath::Pi()) t += TMath::Pi()*2;
815 return t;
816}
817
818//________________________________________________________________________________________________________
819Double_t AliITSTPArrayFit::GetHelixParAtR(Double_t r) const
820{
821 // find helix parameter t (eq.2) corresponding to point on the circle of radius t
822 //
823 double gam = 1. - (r-fParams[kD0])*(r+fParams[kD0])/fParams[kR0]/(fParams[kD0]+fParams[kR0])/2.;
824 return (TMath::Abs(gam)>1) ? -1e9 : TMath::ACos(gam);
825}
826
827//________________________________________________________________________________________________________
828Double_t AliITSTPArrayFit::CalcChi2NDF() const
829{
830 // calculate fit chi2/ndf
831 Double_t chi2 = 0;
832 Double_t dr[3]; // residuals
833 //if (!IsFitDone()) return -1;
834 for (int ipnt=fPntFirst;ipnt<=fPntLast;ipnt++) {
835 GetResiduals(dr,ipnt);
836 Double_t* covI = GetCovI(ipnt);
8102b2c9 837 Double_t chi2p = dr[kX]*(dr[kX]*covI[ kXX ]+dr[kY]*covI[ kXY ]+dr[kZ]*covI[ kXZ ])
838 + dr[kY]*(dr[kX]*covI[ kXY ]+dr[kY]*covI[ kYY ]+dr[kZ]*covI[ kYZ ])
839 + dr[kZ]*(dr[kX]*covI[ kXZ ]+dr[kY]*covI[ kYZ ]+dr[kZ]*covI[ kZZ ]);
840 if (covI[kScl]>0) chi2p *= covI[kScl]; // rescaling was requested for this point's errors
841 chi2 += chi2p;
6be22b3f 842 }
843 int ndf = (fPntLast-fPntFirst+1)*3 - GetNParams();
844 chi2 /= ndf;
845 return chi2;
846}
847
848//________________________________________________________________________________________________________
849void AliITSTPArrayFit::GetResiduals(Double_t *res,Int_t ipnt) const
850{
851 // calculate residuals at point
852 if (ipnt<fPntFirst || ipnt>fPntLast) {
853 AliError(Form("Attempt to access the point %d not in the fitted points [%d:%d]",ipnt,fPntFirst,fPntLast));
854 return;
855 }
856 GetPosition(res,fCurT[ipnt]);
24391cd5 857 res[kX] -= fkPoints->GetX()[ipnt];
858 res[kY] -= fkPoints->GetY()[ipnt];
859 res[kZ] -= fkPoints->GetZ()[ipnt];
6be22b3f 860}
861
862//________________________________________________________________________________________________________
863void AliITSTPArrayFit::GetPosition(Double_t *xyz, Double_t t) const
864{
865 // calculate track position for parameter value t
ef24eb3b 866 if (IsHelix()) {
6be22b3f 867 //
868 Double_t rrho = fParams[kD0]+fParams[kR0];
869 Double_t xc = rrho*TMath::Cos(fParams[kPhi0]);
870 Double_t yc = rrho*TMath::Sin(fParams[kPhi0]);
871 Double_t r = fParams[kR0];
872 Double_t ze = 0;
873 //
874 if (IsELossON()) {
875 if (t>0) {
876 for (int i=fFirstPosT;i<fNElsPnt;i++) { // along the track direction
877 int indE = fElsId[i];
878 if ( t<fCurT[indE] ) break; // does not reach this layer on its way to t
879 xc += fElsDR[indE] * TMath::Cos(fParams[kPhi0] + fCurT[indE]);
880 yc += fElsDR[indE] * TMath::Sin(fParams[kPhi0] + fCurT[indE]);
881 ze += fElsDR[indE] * fCurT[indE];
882 r += fElsDR[indE];
883 //printf("ELoss@ %+.2e r:%+.3e got %+.3e\n",fCurT[indE],r,fElsDR[indE]);
884 }
885 } else {
886 for (int i=fFirstPosT;i--;) { // against the track direction
887 int indE = fElsId[i];
888 if ( t>=fCurT[indE] ) break; // does not reach this layer on its way to t
889 xc += fElsDR[indE] * TMath::Cos(fParams[kPhi0] + fCurT[indE]);
890 yc += fElsDR[indE] * TMath::Sin(fParams[kPhi0] + fCurT[indE]);
891 ze += fElsDR[indE] * fCurT[indE];
892 r += fElsDR[indE];
893 //printf("ELoss@ %+.2e r:%+.3e got %+.3e\n",fCurT[indE],r,fElsDR[indE]);
894 }
895 }
896 }
897 //
898 xyz[kZ] = fParams[kDZ] - fParams[kDip]*(t*r - ze);
899 //
900 t += fParams[kPhi0];
901 xyz[kX] = xc - r*TMath::Cos(t);
902 xyz[kY] = yc - r*TMath::Sin(t);
903 // printf("t: %+.3e xyz:%+.2e %+.2e %+.2e | R %+.6e -> %+.6e | sign %d\n",t-fParams[kPhi0],xyz[0],xyz[1],xyz[2],fParams[kR0],r,GetSignQB());
904 }
905 else {
906 xyz[ fkAxID[kX] ] = fParams[kA0] + fParams[kB0]*t;
907 xyz[ fkAxID[kY] ] = fParams[kA1] + fParams[kB1]*t;
908 xyz[ fParAxis ] = t;
909 }
910}
911
912//________________________________________________________________________________________________________
913void AliITSTPArrayFit::GetDirCos(Double_t *dircos, Double_t t) const
914{
915 // calculate track direction cosines for parameter value t
ef24eb3b 916 if (IsHelix()) {
6be22b3f 917 dircos[kZ] = -fParams[kDip];
918 t += fParams[kPhi0];
919 dircos[kX] = TMath::Sin(t);
920 dircos[kY] =-TMath::Cos(t);
921 double gam = TMath::Sign(1/TMath::Sqrt(dircos[kZ]*dircos[kZ]+dircos[kY]*dircos[kY]+dircos[kX]*dircos[kX]),fParams[kR0]);
922 for (int i=3;i--;) dircos[i] *= gam;
66214d86 923 if (GetSignQB()>0) for (int i=3;i--;) dircos[i] = -dircos[i]; // positive tracks move along decreasing t
6be22b3f 924 }
925 else {
926 double gam = 1/TMath::Sqrt( fParams[kB0]*fParams[kB0] + fParams[kB1]*fParams[kB1] + 1.);
927 dircos[ fkAxID[kX] ] = fParams[kB0]*gam;
928 dircos[ fkAxID[kY] ] = fParams[kB1]*gam;
929 dircos[ fParAxis ] = gam;
66214d86 930 // decide direction
931 if (IsTypeCollision()) {
932 static double xyzF[3],xyzL[3];
933 GetPosition(xyzF,fPntFirst);
934 GetPosition(xyzL,fPntLast);
935 double dif = fCurT[fPntLast] - fCurT[fPntFirst];
936 double dr = (xyzL[kX]-xyzF[kX])*(xyzL[kX]+xyzF[kX]) + (xyzL[kY]-xyzF[kY])*(xyzL[kY]+xyzF[kY]);
937 if (dr*dif<0) for (int i=3;i--;) dircos[i] = -dircos[i]; // with increasing t the tracks comes closer to origin
938 }
939 else if (dircos[kY]>0) for (int i=3;i--;) dircos[i] = -dircos[i]; // cosmic tracks have negative angle to Y axis
6be22b3f 940 }
66214d86 941 //
6be22b3f 942}
943
944//________________________________________________________________________________________________________
945Double_t AliITSTPArrayFit::GetMachinePrec()
946{
947 // estimate machine precision
948 Double_t eps=1.0,a;
949 do { a = 1. + (eps=eps/2.0); } while(a>1.);
950 return TMath::Abs(2.*eps);
951}
952
953//________________________________________________________________________________________________________
954Bool_t AliITSTPArrayFit::FitHelixCrude(Int_t extQ)
955{
956 // crude estimate of helix parameters, w/o errors and Eloss.
ef24eb3b 957 // Fast Riemann fit: Comp.Phy.Comm.131 (2000) 95
958 //
959 // if charge is not imposed (extQ==0) then it will be determined from the collision type
960 //
961 static TArrayD arrU,arrV,arrW;
962 double *parrW,*parrU,*parrV;
963 Bool_t eloss = IsELossON();
964 //
965 int np = fPntLast - fPntFirst + 1;
966 if (np<3) { AliError("At least 3 points are needed for helix fit"); return kFALSE; }
967 //
968 const float *x=fkPoints->GetX(),*y=fkPoints->GetY(),*z=fkPoints->GetZ(),*cov=fkPoints->GetCov();
969 //
de8bf740 970 if (fPntLast>=arrU.GetSize()) {
ef24eb3b 971 arrU.Set(2*fPntLast);
972 arrV.Set(2*fPntLast);
973 arrW.Set(2*fPntLast);
974 }
975 parrU = arrU.GetArray();
976 parrV = arrV.GetArray();
977 parrW = arrW.GetArray();
978 //
979 double uav=0,vav=0,wav=0,muu=0,muv=0,muw=0,mvv=0,mvw=0,mww=0;
980 int minRId = fPntFirst;
981 //
982 // get points span
983 double xmn=1e9,xmx=-1e9, ymn=1e9,ymx=-1e9;
984 for (int i=fPntFirst;i<=fPntLast;i++) {
985 parrW[i] = x[i]*x[i]+y[i]*y[i];
986 if (parrW[i]<parrW[minRId]) minRId = i; // point closest to origin
987 if (xmn>x[i]) xmn = x[i];
988 if (xmx<x[i]) xmx = x[i];
989 if (ymn>y[i]) ymn = y[i];
990 if (ymx<y[i]) ymx = y[i];
991 }
992 int minRId1 = minRId>fPntFirst ? fPntFirst:fPntFirst+1;
993 for (int i=fPntFirst;i<=fPntLast;i++) if (parrW[i]<parrW[minRId1] && i!=minRId) minRId1 = i;
994 //
995 double xshift = (xmx+xmn)/2 + 10*(ymx-ymn); // shift origin to have uniform weights
996 double yshift = (ymx+ymn)/2 - 10*(xmx-xmn);
997 // printf("X: %+e %+e Y: %+e %+e | shift: %+e %+e\n",xmn,xmx,ymn,ymx,xshift,yshift);
998 //
999 for (int i=fPntFirst;i<=fPntLast;i++) {
1000 double xs = x[i] - xshift;
1001 double ys = y[i] - yshift;
1002 double w = xs*xs + ys*ys;
1003 double scl = 1./(1.+w);
1004 int i0 = i-fPntFirst;
1005 wav += parrW[i0] = w*scl;
1006 uav += parrU[i0] = xs*scl;
1007 vav += parrV[i0] = ys*scl;
1008 }
1009 uav /= np; vav /= np; wav /= np;
1010 //
1011 for (int i=fPntFirst;i<=fPntLast;i++) {
1012 //
1013 // point next to closest
1014 int i0 = i-fPntFirst;
1015 if (parrW[i0]<parrW[minRId1-fPntFirst] && i!=minRId) minRId1 = i;
1016 double u = parrU[i0] - uav;
1017 double v = parrV[i0] - vav;
1018 double w = parrW[i0] - wav;
1019 muu += u*u;
1020 muv += u*v;
1021 muw += u*w;
1022 mvv += v*v;
1023 mvw += v*w;
1024 mww += w*w;
1025 }
1026 muu/=np; muv/=np; muw/=np; mvv/=np; mvw/=np; mww/=np;
1027 //
1028 // find eigenvalues:
1029 double trace3 = (muu + mvv + mww)/3.;
1030 double muut = muu-trace3;
1031 double mvvt = mvv-trace3;
1032 double mwwt = mww-trace3;
1033 double q = (muut*(mvvt*mwwt-mvw*mvw) - muv*(muv*mwwt-mvw*muw) + muw*(muv*mvw-mvvt*muw))/2;
1034 double p = (muut*muut+mvvt*mvvt+mwwt*mwwt+2*(muv*muv+muw*muw+mvw*mvw))/6;
1035 double dfpp = p*p*p-q*q;
1036 dfpp = dfpp>0 ? TMath::Sqrt(dfpp)/q : 0;
1037 double ph = TMath::ATan( dfpp )/3.;
1038 if (ph<0) ph += TMath::Pi()/3;
1039 p = p>0 ? TMath::Sqrt(p) : 0;
1040 const double kSqrt3 = 1.73205080;
1041 double snp = TMath::Sin(ph);
1042 double csp = TMath::Cos(ph);
1043 // double eg1 = trace3 + 2*p*csp;
1044 double eg2 = trace3 - p*(csp+kSqrt3*snp); // smallest one
1045 // double eg3 = trace3 - p*(csp-kSqrt3*snp);
1046 // eigenvector for min.eigenvalue
1047 muut = muu-eg2;
1048 mvvt = mvv-eg2;
1049 mwwt = mww-eg2;
1050 double n0 = muv*mvw-muw*mvvt;
1051 double n1 = muv*muw-mvw*muut;
1052 double n2 = muut*mvvt-muv*muv;
1053 // normalize to largest one
1054 double nrm = TMath::Abs(n0);
1055 if (nrm<TMath::Abs(n1)) nrm = TMath::Abs(n1);
1056 if (nrm<TMath::Abs(n2)) nrm = TMath::Abs(n2);
1057 n0/=nrm; n1/=nrm; n2/=nrm;
1058 //
1059 double cpar = -(uav*n0 + vav*n1 + wav*n2);
1060 double xc = -n0/(cpar+n2)/2 + xshift;
1061 double yc = -n1/(cpar+n2)/2 + yshift;
1062 double rad = TMath::Sqrt(n0*n0+n1*n1-4*cpar*(cpar+n2))/2./TMath::Abs(cpar+n2);
1063 //
1064 // printf("Rad: %+e xc: %+e yc: %+e | X0: %+e Y0: %+e | X1: %+e Y1: %+e\n",rad,xc,yc, x[minRId],y[minRId],x[minRId1],y[minRId1]);
1065
1066 // linear circle fit --------------------------------------------------- <<<
1067 //
1068 // decide sign(Q*B) and fill cicrle parameters ------------------------- >>>
1069 int sqb;
1070 if (extQ) {
1071 SetCharge(extQ);
1072 sqb = fBz<0 ? -GetCharge():GetCharge();
1073 }
1074 else {
1075 // determine the charge from the collision type and field sign
1076 // the negative Q*B will have positive Vc x dir product Z component
1077 // with Vc={-xc,-yc} : vector from circle center to the origin
1078 // and V0 - track direction vector (take {0,-1,1} for cosmics)
1079 // If Bz is not provided, assume positive Bz
1080 if ( IsTypeCosmics() ) sqb = xc>0 ? -1:1;
1081 else {
1082 // track direction vector as a - diference between the closest and the next to closest to origin points
1083 double v0X = x[minRId1] - x[minRId];
1084 double v0Y = y[minRId1] - y[minRId];
8102b2c9 1085 sqb = (yc*v0X - xc*v0Y)>0 ? -1:1;
ef24eb3b 1086 }
1087 SetCharge( fBz<0 ? -sqb : sqb);
1088 }
1089 //
1090 Double_t phi = TMath::ATan2(yc,xc);
1091 if (sqb<0) phi += TMath::Pi();
1092 if (phi > TMath::Pi()) phi -= 2.*TMath::Pi();
1093 else if (phi <-TMath::Pi()) phi += 2.*TMath::Pi();
1094 fParams[kPhi0] = phi;
1095 fParams[kR0] = sqb<0 ? -rad:rad;
1096 fParams[kD0] = xc*TMath::Cos(phi) + yc*TMath::Sin(phi) - fParams[kR0];
1097 //
1098 // decide sign(Q*B) and fill cicrle parameters ------------------------- <<<
1099 //
1100 // find z-offset and dip + the parameter t of closest approach to hits - >>>
1101 //
1102 UInt_t hitLrPos=0; // pattern of hit layers at pos
1103 UInt_t hitLrNeg=0; // and negative t's
1104
1105 Double_t ss=0,st=0,sz=0,stt=0,szt=0;
1106 for (int i=fPntFirst;i<=fPntLast;i++) {
1107 //
1108 Double_t ze2 = cov[i*6 + kZZ];
1109 Double_t t = TMath::ATan2(yc-y[i],xc-x[i]) - fParams[kPhi0]; // angle at measured z
1110 if (fParams[kR0]<0) t += TMath::Pi();
1111 if (t > TMath::Pi()) t -= TMath::Pi()*2;
1112 else if (t <-TMath::Pi()) t += TMath::Pi()*2;
1113 if (ze2<fgkAlmostZero) ze2 = 1E-8;
1114 ze2 = 1./ze2;
1115 ss += ze2;
1116 st += t*ze2;
1117 stt+= t*t*ze2;
1118 sz += z[i]*ze2;
1119 szt+= z[i]*t*ze2;
1120 //
1121 fCurT[i] = t; // parameter of the closest approach to the point
1122 // printf("%d %+e %+e %+e %+e\n",i,x[i],y[i],z[i],t);
1123 if (eloss) {
1124 double r = TMath::Sqrt(x[i]*x[i]+y[i]*y[i]);
1125 int lr;
1126 for (lr=kMaxLrITS;lr--;) if ( IsZero(r-fgkRLayITS[ lr ],1.) ) break;
1127 if (lr<kMaxLrITS) {
1128 if (t>0) hitLrPos |= (1<<lr); // set bit of the layer
1129 else hitLrNeg |= (1<<lr); // set bit of the layer
1130 }
1131 }
1132 }
1133 double det = ss*stt - st*st;
1134 if (TMath::Abs(det)<fgkAlmostZero) { // no Z dependence
1135 fParams[kDZ] = sz/ss;
1136 fParams[kDip] = 0;
1137 }
1138 else {
1139 fParams[kDZ] = (sz*stt-st*szt)/det;
1140 fParams[kDip] = -(ss*szt-st*sz)/det/fParams[kR0];
1141 }
1142 //
1143 // find z-offset and dip + the parameter t of closest approach to hits - <<<
1144 //
1145 // fill info needed to account for ELoss ------------------------------- >>>
1146 if (eloss) {
1147 fNElsPnt = fPntLast - fPntFirst + 1;
1148 //
1149 // to account for the energy loss in the passive volumes, calculate the relevant t-parameters
1150 double* tcur = fCurT + fPntFirst;
1151 double* ecur = fElsDR+ fPntFirst;
1152 //
1153 for (int ilp=3;ilp--;) {
1154 int id = fgkPassivLrITS[ilp];
1155 double tp = GetHelixParAtR( fgkRLayITS[ id ] );
1156 if (tp<0) continue; // does not hit this radius
1157 //
1158 tcur[fNElsPnt] = GetSignQB()>0 ? -tp : tp;
1159 ecur[fNElsPnt] = fgRhoLITS[ id ];
1160 fNElsPnt++;
1161 // printf("Passive on lr %d %+e\n",ilp,tcur[fNElsPnt-1]);
1162 //
1163 if (IsTypeCosmics() && !IsZero(tp)) { // 2 crossings for cosmics
1164 tcur[fNElsPnt] = -tcur[fNElsPnt-1];
1165 ecur[fNElsPnt] = ecur[fNElsPnt-1];
1166 fNElsPnt++;
1167 //printf("Passive* on lr %d %+e\n",ilp,-tcur[fNElsPnt-1]);
1168 }
1169 //
1170 }
1171 // check if some active layers did not miss the hit, treat them as passive
1172 for (int ilp=6;ilp--;) {
1173 int id = fgkActiveLrITS[ilp];
1174 double tp = GetHelixParAtR( fgkRLayITS[ id ] );
1175 if (tp<0) continue; // does not hit this radius
1176 //
1177 if ( (GetSignQB()>0||IsTypeCosmics()) && !(hitLrNeg & (1<<id)) ) {
1178 tcur[fNElsPnt] = -tp;
1179 ecur[fNElsPnt] = fgRhoLITS[ id ];
1180 fNElsPnt++;
1181 //printf("Missed on lr %d %+e\n",ilp,-tp);
1182 }
1183 //
1184 if ( (GetSignQB()<0||IsTypeCosmics()) && !(hitLrPos & (1<<id)) ) {
1185 tcur[fNElsPnt] = tp;
1186 ecur[fNElsPnt] = fgRhoLITS[ id ];
1187 fNElsPnt++;
1188 //printf("Missed* on lr %d %e\n",ilp,tp);
1189 }
1190 }
1191 //
1192 TMath::Sort(fNElsPnt,fCurT+fPntFirst,fElsId,kFALSE); // index e-loss points in increasing order
1193 // find the position of smallest positive t-param
1194 for (fFirstPosT=0;fFirstPosT<fNElsPnt;fFirstPosT++) if (fCurT[ fElsId[ fFirstPosT ] ]>0) break;
1195 //
1196 Double_t cdip = 1./TMath::Sqrt(1.+fParams[kDip]*fParams[kDip]);
1197 Double_t ptot = TMath::Abs(fParams[kR0]*fgkCQConv*fBz/cdip); // momentum and energy
1198 Double_t etot = TMath::Sqrt(ptot*ptot + fMass*fMass); // in the point of closest approach to beam
1199 Double_t normS[3];
1200 //
1201 // Positive t-params: along the track direction for negative track, against for positive
15be6f41 1202 // Double_t pcur = ptot, ecurr = etot;
ef24eb3b 1203 for (int ip=fFirstPosT;ip<fNElsPnt;ip++) {
1204 int tID = fElsId[ip];
1205 Double_t t = fCurT[ tID ];
1206 //
1207 if (tID>fPntLast) { // this is not a hit layer but passive layer
1208 double php = TMath::ATan2(yc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t),
1209 xc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t));
1210 normS[0] = -TMath::Cos(php); // normal to the cylinder at intersection point
1211 normS[1] = -TMath::Sin(php);
1212 normS[2] = 0;
1213 }
1214 else GetNormal(normS,fkPoints->GetCov()+tID*6); // vector normal to hit module
1215 fElsDR[tID] = GetDRofELoss(t,cdip,fElsDR[tID],normS,ptot,etot);
1216 }
1217 //
1218 // negaive t-params: against the track direction for negative track, along for positive
15be6f41 1219 // pcur = ptot;
1220 // ecurr = etot;
ef24eb3b 1221 for (int ip=fFirstPosT;ip--;) {
1222 int tID = fElsId[ip];
1223 Double_t t = fCurT[ tID ];
1224 //
1225 if (tID>fPntLast) { // this is not a hit layer but passive layer
1226 double php = TMath::ATan2(yc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t),
1227 xc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t));
1228 normS[0] = -TMath::Cos(php); // normal to the cylinder at intersection point
1229 normS[1] = -TMath::Sin(php);
1230 normS[2] = 0;
1231 }
1232 else GetNormal(normS,fkPoints->GetCov()+tID*6); // vector normal to hit module
1233 //
1234 fElsDR[tID] = GetDRofELoss(t,cdip,fElsDR[tID],normS,ptot,etot);
1235 }
1236 }
1237 // fill info needed to account for ELoss ------------------------------- <<<
1238 //
1239 return kTRUE;
1240}
1241
1242/*
1243//________________________________________________________________________________________________________
1244Bool_t AliITSTPArrayFit::FitHelixCrude(Int_t extQ)
1245{
1246 // crude estimate of helix parameters, w/o errors and Eloss.
6be22b3f 1247 // 1st fit the circle (R,xc,yc) by minimizing
1248 // chi2 = sum{ (bx*xi + by*yi + xi^2+yi^2 + rho)^2 } vs bx,by,rho
1249 // with bx = -2*xc, by = -2*yc , rho = xc^2+yc^2 - R2
1250 //
1251 // if charge is not imposed (extQ==0) then it will be determined from the collision type
1252 //
1253 Bool_t eloss = IsELossON();
1254 //
1255 int np = fPntLast - fPntFirst + 1;
1d06ac63 1256 if (np<3) { AliError("At least 3 points are needed for helix fit"); return kFALSE; }
6be22b3f 1257 //
24391cd5 1258 const float *x=fkPoints->GetX(),*y=fkPoints->GetY(),*z=fkPoints->GetZ(),*cov=fkPoints->GetCov();
6be22b3f 1259 //
1260 // linear circle fit --------------------------------------------------- >>>
1261 Double_t sxx=0,sxy=0,syy=0,sx=0,sy=0,rhs0=0,rhs1=0,rhs2=0,minR=1E9;
1262 int minRId = 0;
1263 for (int i=fPntFirst;i<=fPntLast;i++) {
1264 Double_t xx = x[i]*x[i];
1265 Double_t yy = y[i]*y[i];
1266 Double_t xy = x[i]*y[i];
1267 Double_t xxyy = xx + yy;
1268 //
1269 sxx += xx;
1270 sxy += xy;
1271 syy += yy;
1272 sx += x[i];
1273 sy += y[i];
1274 //
1275 rhs0 -= xxyy*x[i];
1276 rhs1 -= xxyy*y[i];
1277 rhs2 -= xxyy;
1278 //
1279 // remember Id of the point closest to origin, to determine the charge
1280 if (xxyy<minR) { minR = xxyy; minRId = i; }
1281 //
1282 if (eloss) { // find layer id
24391cd5 1283 int lrid,volid = fkPoints->GetVolumeID()[i];
1284 if (volid>0) lrid = fgkActiveLrITS[AliGeomManager::VolUIDToLayer(fkPoints->GetVolumeID()[i])-1];
6be22b3f 1285 else { // missing layer info, find from radius
1286 double r = TMath::Sqrt(xxyy);
1287 for (lrid=kMaxLrITS;lrid--;) if ( IsZero(r-fgkRLayITS[ lrid ],1.) ) break;
1288 }
1289 fElsDR[i] = (lrid>=0 && lrid<kMaxLrITS) ? fgRhoLITS[ lrid ] : 0; // eloss for normal track
1290 }
1291 //
1292 }
1293 //
1294 Double_t mn00 = syy*np-sy*sy;
1295 Double_t mn01 = sxy*np-sy*sx;
1296 Double_t mn02 = sxy*sy-syy*sx;
1297 Double_t det = sxx*mn00 - sxy*mn01 + sx*mn02;
1298 if (TMath::Abs(det)<fgkAlmostZero) return kFALSE;
1299 //
1300 Double_t mn11 = sxx*np-sx*sx;
1301 Double_t mn12 = sxx*sy-sxy*sx;
1302 Double_t mn22 = sxx*syy-sxy*sxy;
1303 //
1304 Double_t mi00 = mn00/det;
1305 Double_t mi01 = -mn01/det;
1306 Double_t mi02 = mn02/det;
1307 Double_t mi11 = mn11/det;
1308 Double_t mi12 = -mn12/det;
1309 Double_t mi22 = mn22/det;
1310 //
1311 Double_t xc = -(rhs0*mi00 + rhs1*mi01 + rhs2*mi02)/2;
1312 Double_t yc = -(rhs0*mi01 + rhs1*mi11 + rhs2*mi12)/2;
1313 Double_t rho2 = (rhs0*mi02 + rhs1*mi12 + rhs2*mi22);
ef24eb3b 1314
1315 //
1316 // check
1317 double bx = -2*xc;
1318 double by = -2*yc;
1319 double sm0=0,sm1=0;
1320 for (int i=fPntFirst;i<=fPntLast;i++) {
1321 double dst = bx*x[i]+by*y[i]+x[i]*x[i]+y[i]*y[i]+rho2;
1322 sm0 += dst;
1323 sm1 += dst*dst;
1324 printf("Point %d: %+e %+e %+e\n",i,dst,sm0,sm1);
1325 }
1326
6be22b3f 1327 //
1d06ac63 1328 Double_t rad = xc*xc + yc*yc - rho2;
6be22b3f 1329 rad = (rad>fgkAlmostZero) ? (TMath::Sqrt(rad)):fgkAlmostZero;
1330 //
1331 // printf("Rad: %+e xc: %+e yc: %+e\n",rad,xc,yc);
1d06ac63 1332
6be22b3f 1333 // linear circle fit --------------------------------------------------- <<<
1334 //
1335 // decide sign(Q*B) and fill cicrle parameters ------------------------- >>>
1336 int sqb;
1337 if (extQ) {
1338 SetCharge(extQ);
1339 sqb = fBz<0 ? -GetCharge():GetCharge();
1340 }
1341 else {
1342 // determine the charge from the collision type and field sign
1343 // the negative Q*B will have positive Vc x V0 product Z component
1344 // with Vc={-xc,-yc} : vector from circle center to the origin
1345 // and V0 - track direction vector (take {0,-1,1} for cosmics)
1346 // If Bz is not provided, assume positive Bz
1347 sqb = ( IsTypeCosmics() ? xc:(yc*x[minRId]-xc*y[minRId]) ) > 0 ? -1:1;
1348 SetCharge( fBz<0 ? -sqb : sqb);
1349 }
1350 //
6be22b3f 1351 Double_t phi = TMath::ATan2(yc,xc);
1352 if (sqb<0) phi += TMath::Pi();
1353 if (phi > TMath::Pi()) phi -= 2.*TMath::Pi();
1354 else if (phi <-TMath::Pi()) phi += 2.*TMath::Pi();
1355 fParams[kPhi0] = phi;
1356 fParams[kR0] = sqb<0 ? -rad:rad;
1d06ac63 1357 fParams[kD0] = xc*TMath::Cos(phi) + yc*TMath::Sin(phi) - fParams[kR0];
6be22b3f 1358 //
1359 // decide sign(Q*B) and fill cicrle parameters ------------------------- <<<
1360 //
1361 // find z-offset and dip + the parameter t of closest approach to hits - >>>
1362 //
1363 UInt_t hitLrPos=0; // pattern of hit layers at pos
1364 UInt_t hitLrNeg=0; // and negative t's
1365
1366 Double_t ss=0,st=0,sz=0,stt=0,szt=0;
1367 for (int i=fPntFirst;i<=fPntLast;i++) {
1368 //
1369 Double_t ze2 = cov[i*6 + kZZ];
1370 Double_t t = TMath::ATan2(yc-y[i],xc-x[i]) - fParams[kPhi0]; // angle at measured z
1371 if (fParams[kR0]<0) t += TMath::Pi();
1372 if (t > TMath::Pi()) t -= TMath::Pi()*2;
1373 else if (t <-TMath::Pi()) t += TMath::Pi()*2;
1374 if (ze2<fgkAlmostZero) ze2 = 1E-8;
1375 ze2 = 1./ze2;
1376 ss += ze2;
1377 st += t*ze2;
1378 stt+= t*t*ze2;
1379 sz += z[i]*ze2;
1380 szt+= z[i]*t*ze2;
1381 //
1382 fCurT[i] = t; // parameter of the closest approach to the point
1383 // printf("%d %+e %+e %+e %+e\n",i,x[i],y[i],z[i],t);
1384 if (eloss) {
1385 double r = TMath::Sqrt(x[i]*x[i]+y[i]*y[i]);
1386 int lr;
1387 for (lr=kMaxLrITS;lr--;) if ( IsZero(r-fgkRLayITS[ lr ],1.) ) break;
1388 if (lr<kMaxLrITS) {
1389 if (t>0) hitLrPos |= (1<<lr); // set bit of the layer
1390 else hitLrNeg |= (1<<lr); // set bit of the layer
1391 }
1392 }
1393 }
1394 det = ss*stt - st*st;
1395 if (TMath::Abs(det)<fgkAlmostZero) { // no Z dependence
1396 fParams[kDZ] = sz/ss;
1397 fParams[kDip] = 0;
1398 }
1399 else {
1400 fParams[kDZ] = (sz*stt-st*szt)/det;
1401 fParams[kDip] = -(ss*szt-st*sz)/det/fParams[kR0];
1402 }
1403 //
1404 // find z-offset and dip + the parameter t of closest approach to hits - <<<
1405 //
1406 // fill info needed to account for ELoss ------------------------------- >>>
1407 if (eloss) {
1408 fNElsPnt = fPntLast - fPntFirst + 1;
1409 //
1410 // to account for the energy loss in the passive volumes, calculate the relevant t-parameters
1411 double* tcur = fCurT + fPntFirst;
1412 double* ecur = fElsDR+ fPntFirst;
1413 //
1414 for (int ilp=3;ilp--;) {
1415 int id = fgkPassivLrITS[ilp];
1416 double tp = GetHelixParAtR( fgkRLayITS[ id ] );
1417 if (tp<0) continue; // does not hit this radius
1418 //
1419 tcur[fNElsPnt] = GetSignQB()>0 ? -tp : tp;
1420 ecur[fNElsPnt] = fgRhoLITS[ id ];
1421 fNElsPnt++;
1422 // printf("Passive on lr %d %+e\n",ilp,tcur[fNElsPnt-1]);
1423 //
1424 if (IsTypeCosmics() && !IsZero(tp)) { // 2 crossings for cosmics
1425 tcur[fNElsPnt] = -tcur[fNElsPnt-1];
1426 ecur[fNElsPnt] = ecur[fNElsPnt-1];
1427 fNElsPnt++;
1428 //printf("Passive* on lr %d %+e\n",ilp,-tcur[fNElsPnt-1]);
1429 }
1430 //
1431 }
1432 // check if some active layers did not miss the hit, treat them as passive
1433 for (int ilp=6;ilp--;) {
1434 int id = fgkActiveLrITS[ilp];
1435 double tp = GetHelixParAtR( fgkRLayITS[ id ] );
1436 if (tp<0) continue; // does not hit this radius
1437 //
1438 if ( (GetSignQB()>0||IsTypeCosmics()) && !(hitLrNeg & (1<<id)) ) {
1439 tcur[fNElsPnt] = -tp;
1440 ecur[fNElsPnt] = fgRhoLITS[ id ];
1441 fNElsPnt++;
1442 //printf("Missed on lr %d %+e\n",ilp,-tp);
1443 }
1444 //
1445 if ( (GetSignQB()<0||IsTypeCosmics()) && !(hitLrPos & (1<<id)) ) {
1446 tcur[fNElsPnt] = tp;
1447 ecur[fNElsPnt] = fgRhoLITS[ id ];
1448 fNElsPnt++;
1449 //printf("Missed* on lr %d %e\n",ilp,tp);
1450 }
1451 }
1452 //
1453 TMath::Sort(fNElsPnt,fCurT+fPntFirst,fElsId,kFALSE); // index e-loss points in increasing order
1454 // find the position of smallest positive t-param
1455 for (fFirstPosT=0;fFirstPosT<fNElsPnt;fFirstPosT++) if (fCurT[ fElsId[ fFirstPosT ] ]>0) break;
1456 //
1457 Double_t cdip = 1./TMath::Sqrt(1.+fParams[kDip]*fParams[kDip]);
1458 Double_t ptot = TMath::Abs(fParams[kR0]*fgkCQConv*fBz/cdip); // momentum and energy
1459 Double_t etot = TMath::Sqrt(ptot*ptot + fMass*fMass); // in the point of closest approach to beam
1460 Double_t normS[3];
1461 //
1462 // Positive t-params: along the track direction for negative track, against for positive
1463 Double_t pcur = ptot, ecurr = etot;
1464 for (int ip=fFirstPosT;ip<fNElsPnt;ip++) {
1465 int tID = fElsId[ip];
1466 Double_t t = fCurT[ tID ];
1467 //
1468 if (tID>fPntLast) { // this is not a hit layer but passive layer
1469 double php = TMath::ATan2(yc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t),
1470 xc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t));
1471 normS[0] = -TMath::Cos(php); // normal to the cylinder at intersection point
1472 normS[1] = -TMath::Sin(php);
1473 normS[2] = 0;
1474 }
24391cd5 1475 else GetNormal(normS,fkPoints->GetCov()+tID*6); // vector normal to hit module
6be22b3f 1476 fElsDR[tID] = GetDRofELoss(t,cdip,fElsDR[tID],normS,ptot,etot);
1477 }
1478 //
1479 // negaive t-params: against the track direction for negative track, along for positive
1480 pcur = ptot;
1481 ecurr = etot;
1482 for (int ip=fFirstPosT;ip--;) {
1483 int tID = fElsId[ip];
1484 Double_t t = fCurT[ tID ];
1485 //
1486 if (tID>fPntLast) { // this is not a hit layer but passive layer
1487 double php = TMath::ATan2(yc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t),
1488 xc-fParams[kR0]*TMath::Cos(fParams[kPhi0]+t));
1489 normS[0] = -TMath::Cos(php); // normal to the cylinder at intersection point
1490 normS[1] = -TMath::Sin(php);
1491 normS[2] = 0;
1492 }
24391cd5 1493 else GetNormal(normS,fkPoints->GetCov()+tID*6); // vector normal to hit module
6be22b3f 1494 //
1495 fElsDR[tID] = GetDRofELoss(t,cdip,fElsDR[tID],normS,ptot,etot);
1496 }
1497 }
1498 // fill info needed to account for ELoss ------------------------------- <<<
1499 //
1500 return kTRUE;
1501}
ef24eb3b 1502*/
6be22b3f 1503//____________________________________________________
1504Double_t AliITSTPArrayFit::FitHelix(Int_t extQ, Double_t extPT,Double_t extPTerr)
1505{
1506 // fit by helix accounting for the errors of all coordinates (and energy loss if requested)
1507 //
1508 // If extQ is non-0, its sign is imposed as a charge of the track
1509 // If extPT>0 and extPTerr>=0, constrain to measured tr.momentum PT
1510 // with corresponding error (err=0 -> rel.err=1e-6)
1511 //
1512 double chiprev=1e99;
1513 //const Double_t kMaxTEffect = 1E-6;
1514 Double_t dXYZdGlo[3*5],dXYZdLoc[3],xyzRes[3];
1515 //
1516 SetFitDone(kFALSE);
1517 fChi2NDF = -1;
1518 //
1519 if (!FitHelixCrude(extQ)) return -1; // get initial estimate, ignoring the errors
1520 //
1d06ac63 1521 if (TMath::Abs(fParams[kR0])>fMaxRforHelix && extPT<=0) {
1522 fSwitch2Line = kTRUE;
1523 return FitLine();
1524 }
1525 //
1526 //
6be22b3f 1527 if (!IsCovInv()) InvertPointsCovMat(); // prepare inverted errors
1528 if (!fParSol) fParSol = new AliParamSolver(5);
1529 fParSol->SetNGlobal(5);
1530 //
1531 // printf("-1 | %+.2e %+.2e %+.2e %+.2e %+.2e | chi2: %+.4e\n",fParams[0],fParams[1],fParams[2],fParams[3],fParams[4],CalcChi2NDF());
1532 int iter = 0;
1533 fChi2NDF = 1e99;
1534 Bool_t converged = kFALSE;
1535 while(iter<fMaxIter) {
1536 chiprev = fChi2NDF;
1537 fParSol->Clear();
1538 for (int ip=fPntFirst;ip<=fPntLast;ip++) {
1539 //
1540 GetResiduals(xyzRes, ip); // current residuals at point ip
1541 Double_t rrho = fParams[kR0]+fParams[kD0];
1542 Double_t cs0 = TMath::Cos(fParams[kPhi0]);
1543 Double_t sn0 = TMath::Sin(fParams[kPhi0]);
1544 Double_t cst = TMath::Cos(fCurT[ip]+fParams[kPhi0]);
1545 Double_t snt = TMath::Sin(fCurT[ip]+fParams[kPhi0]);
1546 //
1547 int offs = kD0; // dXYZ/dD0
1548 dXYZdGlo[offs + kX] = cs0;
1549 dXYZdGlo[offs + kY] = sn0;
1550 dXYZdGlo[offs + kZ] = 0;
1551 //
1552 offs = kPhi0*3; // dXYZ/dPhi0
1d06ac63 1553 dXYZdGlo[offs + kX] = -rrho*sn0 + fParams[kR0]*snt;
1554 dXYZdGlo[offs + kY] = rrho*cs0 - fParams[kR0]*cst;
6be22b3f 1555 dXYZdGlo[offs + kZ] = 0;
1556 //
1557 offs = kR0*3; // dXYZ/dR0
ef24eb3b 1558 if (TMath::Abs(fParams[kR0])<0.9*fMaxRforHelix) {
1559 dXYZdGlo[offs + kX] = cs0 - cst;
1560 dXYZdGlo[offs + kY] = sn0 - snt;
1561 dXYZdGlo[offs + kZ] = -fParams[kDip]*fCurT[ip];
1562 }
1563 else {
1564 dXYZdGlo[offs + kX] = dXYZdGlo[offs + kY] = dXYZdGlo[offs + kZ] = 0;
1565 fParSol->AddConstraint(kR0,0,1.e2);
1566 }
6be22b3f 1567 //
1568 offs = kDZ*3; // dXYZ/dDZ
1569 dXYZdGlo[offs + kX] = 0;
1570 dXYZdGlo[offs + kY] = 0;
1571 dXYZdGlo[offs + kZ] = 1.;
1572 //
1573 offs = kDip*3; // dXYZ/dDip
1574 dXYZdGlo[offs + kX] = 0;
1575 dXYZdGlo[offs + kY] = 0;
1576 dXYZdGlo[offs + kZ] = -fParams[kR0]*fCurT[ip];
1577 //
ef24eb3b 1578 // /*
6be22b3f 1579 dXYZdLoc[kX] = fParams[kR0]*snt;
1580 dXYZdLoc[kY] = -fParams[kR0]*cst;
1581 dXYZdLoc[kZ] = -fParams[kR0]*fParams[kDip];
ef24eb3b 1582 // */
1583 // dXYZdLoc[0] = dXYZdLoc[1] = dXYZdLoc[2] = 0;
6be22b3f 1584 //
8102b2c9 1585 fParSol->AddEquation(dXYZdGlo,dXYZdLoc,xyzRes,GetCovI(ip),GetCovIScale(ip));
6be22b3f 1586 }
1587 //
1588 if (extPT>0) { // add constraint on pt
1589 if (extPTerr<fgkAlmostZero) extPTerr = 1e-6*extPT;
1590 Double_t cf = fBz*GetCharge()*fgkCQConv;
1591 Double_t err2i = extPTerr/cf;
1592 err2i = 1./err2i/err2i;
1593 // printf("Constrain R to %+e\n",extPT/cf);
1594 fParSol->AddConstraint(kR0,-extPT/cf+fParams[kR0],err2i);
1595 }
1596 if (!fParSol->Solve()) { AliError("Failed to fit helix"); return -1; }
1597 Double_t *deltaG = fParSol->GetGlobals();
ef0526f3 1598 // Double_t *deltaT = fParSol->GetLocals();
6be22b3f 1599 for (int ipar=5;ipar--;) fParams[ipar] -= deltaG[ipar];
ef24eb3b 1600 //
1601 if (TMath::Abs(fParams[kR0])>0.9*fMaxRforHelix) fParams[kR0] = TMath::Sign(0.9*fMaxRforHelix,fParams[kR0]);
1602 //
1d06ac63 1603 for (int ip=fPntFirst;ip<=fPntLast;ip++) {
1604 fCurT[ip] = CalcParPCA(ip);
1605 // printf("iter%d : delta%2d : expl: %+e | %+e | R=%+e p0=%+e\n",iter,ip,deltaT[ip-fPntFirst], fCurT[ip],fParams[kR0],fParams[kPhi0]);
1606 // fCurT[ip] -= deltaT[ip-fPntFirst];
1607 }
6be22b3f 1608 iter++;
1609 //
1610 fChi2NDF = CalcChi2NDF();
ef24eb3b 1611 // printf("%2d | %+.2e %+.2e %+.2e %+.2e %+.2e | chi2: %+.4e %+.4e\n",iter,deltaG[0],deltaG[1],deltaG[2],deltaG[3],deltaG[4],fChi2NDF,fChi2NDF-chiprev);
1612 // printf("->> %+.2e %+.2e %+.2e %+.2e %+.2e | Chi2: %+.6e %+.6e\n",fParams[0],fParams[1],fParams[2],fParams[3],fParams[4],fChi2NDF,fChi2NDF-chiprev);
6be22b3f 1613 double difchi2 = chiprev - fChi2NDF;
1614 if ( difchi2<fEps && TMath::Abs(difchi2)<1e-4) {converged = kTRUE; break;}
1615 // if (errT*TMath::Abs(fParams[kR0])<kMaxTEffect && errP<fEps) {converged = kTRUE; break;}
1616 }
1617 //
1618 if (!converged) {
1619 AliDebug(2,Form("Max number of %d iteration reached, Current chi2:%.3e, chi2 change %+.3e",iter,
1620 fChi2NDF,chiprev-fChi2NDF));
1621 for (int ip=fPntFirst;ip<=fPntLast;ip++)
24391cd5 1622 AliDebug(2,Form("P%2d| %+.3e %+.3e %+.3e\n",ip,fkPoints->GetX()[ip],fkPoints->GetY()[ip],fkPoints->GetZ()[ip]));
6be22b3f 1623
1624 }
1625 fIter = iter;
1626 SetCharge( fParams[kR0]>0 ? (fBz<0?-1:1):(fBz>0?-1:1) );
1627 SetFitDone();
1628 // printf("F1>> %+.7e %+.7e %+.7e %+.7e %.7e\n",fParams[0],fParams[1],fParams[2],fParams[3],fParams[4]);
1629 //
1630 return fChi2NDF;
1631}
1632
1633//____________________________________________________
1634Double_t AliITSTPArrayFit::FitLine()
1635{
1636 // fit by helix accounting for the errors of all coordinates (and energy loss if requested)
1637 //
1638 double chiprev=1e99;
1639 // const Double_t kMaxTEffect = 1.e-6;
1640 Double_t dXYZdGlo[3*4],dXYZdLoc[3],xyzRes[3];
1641 SetFitDone(kFALSE);
1642 fChi2NDF = -1;
1643 //
1644 if (fParAxis<0) SetParAxis(ChoseParAxis());
1645 //
24391cd5 1646 const float *xyzp[3]={fkPoints->GetX(),fkPoints->GetY(),fkPoints->GetZ()};
6be22b3f 1647 if (!IsCovInv()) InvertPointsCovMat();
1648 if (!FitLineCrude()) return -1; // get initial estimate, ignoring the errors
1649 //
1650 if (!fParSol) fParSol = new AliParamSolver(5);
1651 fParSol->SetNGlobal(4);
1652 // initial set of parameters
1653 for (int ip=fPntFirst;ip<=fPntLast;ip++) fCurT[ip] = xyzp[fParAxis][ip]; // use measured param-coordinate
1654 //
1655 int iter = 0;
1656 Bool_t converged = kFALSE;
1657 fChi2NDF = 1e99;
1658 while(iter<fMaxIter) {
1659 chiprev = fChi2NDF;
1660 fParSol->Clear();
1661 for (int ip=fPntFirst;ip<=fPntLast;ip++) {
1662 //
1663 int offs;
1664 GetResiduals(xyzRes, ip); // current residuals at point ip
1665 //
1666 offs = kA0*3; // dXYZ/dA0
1667 dXYZdGlo[offs + fkAxID[kX]] = 1;
1668 dXYZdGlo[offs + fkAxID[kY]] = 0;
1669 dXYZdGlo[offs + fParAxis ] = 0;
1670 //
1671 offs = kB0*3; // dXYZ/dB0
1672 dXYZdGlo[offs + fkAxID[kX]] = fCurT[ip];
1673 dXYZdGlo[offs + fkAxID[kY]] = 0;
1674 dXYZdGlo[offs + fParAxis ] = 0;
1675 //
1676 offs = kA1*3; // dXYZ/dA1
1677 dXYZdGlo[offs + fkAxID[kX]] = 0;
1678 dXYZdGlo[offs + fkAxID[kY]] = 1;
1679 dXYZdGlo[offs + fParAxis ] = 0;
1680 //
1681 offs = kB1*3; // dXYZ/dB1
1682 dXYZdGlo[offs + fkAxID[kX]] = 0;
1683 dXYZdGlo[offs + fkAxID[kY]] = fCurT[ip];
1684 dXYZdGlo[offs + fParAxis ] = 0;
1685 //
1686 dXYZdLoc[ fkAxID[kX] ] = fParams[kB0]; // dX/dt
1687 dXYZdLoc[ fkAxID[kY] ] = fParams[kB1]; // dY/dt
1688 dXYZdLoc[ fParAxis ] = 1;
1689 //
8102b2c9 1690 fParSol->AddEquation(dXYZdGlo,dXYZdLoc,xyzRes,GetCovI(ip),GetCovIScale(ip));
6be22b3f 1691 }
1692 //
1693 if (!fParSol->Solve()) { AliError("Failed to fit line"); return -1; }
1694 Double_t *deltaG = fParSol->GetGlobals();
1695 Double_t *deltaT = fParSol->GetLocals();
1696 for (int ipar=4;ipar--;) fParams[ipar] -= deltaG[ipar];
1697 for (int ip=fPntFirst;ip<=fPntLast;ip++) fCurT[ip] -= deltaT[ip-fPntFirst];
1698 iter++;
1699 fChi2NDF = CalcChi2NDF();
1700 // printf("%d %+e %+e | %+.2e %+.2e %+.2e %+.2e | chi2: %+.4e %+.4e\n",iter,errP,errT, deltaG[0],deltaG[1],deltaG[2],deltaG[3],fChi2NDF,fChi2NDF-chiprev);
1701 // printf("->> %+.2e %+.2e %+.2e %+.2e %+.2e | Chi2: %+.6e %+.6e\n",fParams[0],fParams[1],fParams[2],fParams[3],fParams[4],fChi2NDF,fChi2NDF-chiprev);
1702 double difchi2 = chiprev - fChi2NDF;
1703 if ( difchi2<fEps && TMath::Abs(difchi2)<1e-4) {converged = kTRUE; break;}
1704 chiprev = fChi2NDF;
1705 // if (errT<kMaxTEffect && errP<fEps) {converged = kTRUE; break;}
1706 }
1707 //
1708 if (!converged) {
1709 AliDebug(2,Form("Max number of %d iteration reached, Current chi2:%.3e, chi2 change %+.3e",iter,
1710 fChi2NDF,chiprev-fChi2NDF));
1711 for (int ip=fPntFirst;ip<=fPntLast;ip++)
24391cd5 1712 AliDebug(2,Form("P%2d| %+.3e %+.3e %+.3e\n",ip,fkPoints->GetX()[ip],fkPoints->GetY()[ip],fkPoints->GetZ()[ip]));
6be22b3f 1713 }
1714 fIter = iter;
1715 SetFitDone();
1716 //printf("F1>> %+.2e %+.2e %+.2e %+.2e\n",fParams[0],fParams[1],fParams[2],fParams[3]);
1717 return fChi2NDF;
1718 //
1719}
1720
1721//____________________________________________________
1722void AliITSTPArrayFit::GetNormal(Double_t *norm, const Float_t *covMat)
1723{
1724 // obtain the lab normal vector to the sensor from the covariance matrix
1725 // in such a way that when the local frame of the sensor coincides with
1726 // the lab frame, the vector {0,1,0} is obtained
1727 Double_t tgxy = TMath::Tan(0.5*TMath::ATan2(2.*covMat[kXY],covMat[kYY]-covMat[kXX]));
1728 Double_t tgyz = TMath::Tan(0.5*TMath::ATan2(2.*covMat[kYZ],covMat[kZZ]-covMat[kYY]));
1729 norm[kY] = 1./TMath::Sqrt(1 + tgxy*tgxy + tgyz*tgyz);
1730 norm[kX] = norm[kY]*tgxy;
1731 norm[kZ] = norm[kY]*tgyz;
1732 //
1733}
1734
1735//____________________________________________________
1736Double_t AliITSTPArrayFit::GetDRofELoss(Double_t t,Double_t cdip,Double_t rhoL,const Double_t *normS,
1737 Double_t &p,Double_t &e) const
1738{
1739 // Calculate energy loss of the particle at given t-param on the layer with rhoL (thickness*density) with
1740 // normal vector normS in the lab. The particle before eloss has energy "e" and momentum "p"
1741 // cdip = cosine of the dip angle = 1/sqrt(1+tgL^2)
1742 // Return the change DR of the radius due to the ELoss
1743 //
1744 // NOTE: with B>0 the negative particles propagate along increasing t-param and positive
1745 // particles - against.
1746 // t-param = 0 corresponds to the point of closest approach of the track to the beam.
1747 // Since the fitted helix parameters of the track are defined in this PCA point, when the correction
1748 // is applied upstream of the PCS, the energy must be increased (DR>0) rather than decreased (DR<0)
1749 //
1750 Double_t dirTr[3];
1751 dirTr[0] = -TMath::Sin(fParams[kPhi0]+t);
1752 dirTr[1] = TMath::Cos(fParams[kPhi0]+t);
1753 dirTr[2] = fParams[kDip];
1754 // cosine of the impact angle
1755 Double_t cosImp = cdip*TMath::Abs(dirTr[0]*normS[0]+dirTr[1]*normS[1]+dirTr[2]*normS[2]);
1756 //
1757 if (cosImp<0.3) cosImp = 0.3; //?
1758 Double_t dE = AliExternalTrackParam::BetheBlochSolid(p/fMass)*rhoL/cosImp;
1759 Double_t dP = e/p*dE;
1760 //
1761 if (t*GetSignQB() < 0) {
1762 dP = -dP;
1763 dE = -dE;
1764 }
1765 //
1766 if (p+dP<0) {
1767 AliInfo(Form("Estimated PLoss %.3f is larger than particle momentum %.3f. Skipping",dP,p));
1768 return 0;
1769 }
1770 //
1771 p += dP;
1772 e += dE;
1773 //
1774 return fCharge*dP*cdip/fBz/fgkCQConv;
1775}
1776
1777//_____________________________________________________________
1778Double_t AliITSTPArrayFit::GetLineOffset(Int_t axis) const
1779{
1780 // return intercept of the parameterization coord = intercept + slope*t for given axis
1781 if (fParAxis<0) return -1E6; // no line fit
1782 if (axis==fParAxis) return 0;
1783 if (fParAxis==kX) return fParams[axis==kY ? kA0 : kA1 ];
1784 if (fParAxis==kY) return fParams[axis==kZ ? kA0 : kA1 ];
1785 return fParams[axis==kX ? kA0 : kA1 ];
1786}
1787
1788//_____________________________________________________________
1789Double_t AliITSTPArrayFit::GetLineSlope(Int_t axis) const
1790{
1791 // return intercept of the parameterization coord = intercept + slope*t for given axis
1792 if (fParAxis<0) return -1E6; // no line fit
1793 if (axis==fParAxis) return 1.;
1794 if (fParAxis==kX) return fParams[axis==kY ? kB0 : kB1 ];
1795 if (fParAxis==kY) return fParams[axis==kZ ? kB0 : kB1 ];
1796 return fParams[axis==kX ? kB0 : kB1 ];
1797}
1798
1799//_____________________________________________________________
1800void AliITSTPArrayFit::Print(Option_t *) const
1801{
24391cd5 1802 // print results of the fit
1803 //
6be22b3f 1804 const char kCxyz[] = "XYZ";
24391cd5 1805 if (!fkPoints) return;
6be22b3f 1806 //
1807 printf("Track of %3d points in Bz=%+.1f |Fit ",fPntLast-fPntFirst+1,fBz);
1808 if ( IsFitDone() ) {
ef24eb3b 1809 if (IsHelix())
6be22b3f 1810 printf("Helix: Chi2: %5.1f | %+.2e %+.2e %+.2e %+.2e %+.2e\n",
1811 fChi2NDF,fParams[kD0],fParams[kPhi0],fParams[kR0],fParams[kDZ],fParams[kDip]);
1812 else
1813 printf("Line%c: Chi2: %5.1f | %+.2e %+.2e %+.2e %+.2e\n",
1814 kCxyz[fParAxis],fChi2NDF,fParams[kA0],fParams[kB0],fParams[kA1],fParams[kB1]);
1815 }
1816 else printf("N/A\n");
1817}
1818
1819
1820
1821
1822//____________________________________________________
1823void AliITSTPArrayFit::BuildMaterialLUT(Int_t ntri)
1824{
1825 // Fill a look-up table with mean material a la AliITSTrackerMI
1826 //
1827 if (!AliGeomManager::GetGeometry()) AliFatal("Geometry is not loaded");
1828 //
1829 // detector layer to check: dX,dZ,Ymin,Ymax
1830 const double kLayr[9][4] = {{0. ,60. , 2.80,3.00}, // beam pipe
1831 {1.28,7.07,-0.20,0.22}, // SPD1
1832 {1.28,7.07,-0.20,0.22}, // SPD2
1833 {0. ,76.0, 10.4,11.8}, // Shield1
1834 {7.02,7.53,-1.00,4.50}, // SDD1
1835 {7.02,7.53,-1.00,4.50}, // SDD2
1836 {0. ,102., 29.0,30.0}, // Shield2
1837 {7.50,4.20,-0.15,4.50}, // SSD1
1838 {7.50,4.20,-0.15,4.50}}; // SSD2
1839 //
1840 //
1841 // build <dens*L> for detectors (track hitting the sensor in normal direction)
1842 double pg1[3],pg2[3],res[7];
1843 //
1844 int sID = 0;
1845 int actLrID = 0;
1846 for (int lr=0;lr<9;lr++) {
1847 //
1848 Bool_t active = kFALSE;
1849 const double* tpars = kLayr[lr];
1850 //
1851 if (IsZero(tpars[0])) { // passive layer
1852 active = kFALSE;
1853 AliInfo(Form("Probing passive layer (total layer #%d)",lr));
1854 }
1855 else {
1856 active = kTRUE;
1857 sID += AliGeomManager::LayerSize(++actLrID);
1858 AliInfo(Form("Probing sensors of active layer #%d (total layers #%d)",actLrID,lr));
1859 }
1860 double shift = TMath::Abs(tpars[2]-tpars[3])*1E-4;
1861 double rhol = 0;
1862 for (int i=ntri;i--;) {
1863 //
1864 if (active) {
10d14322 1865 int ssID = sID -1 - (int)(AliGeomManager::LayerSize(actLrID)*gRandom->Rndm());
6be22b3f 1866 pg1[0] = pg2[0] = (gRandom->Rndm()-0.5)*tpars[0] + shift; // local X
1867 pg2[0] -= 2*shift;
1868 pg1[1] = tpars[2];
1869 pg2[1] = tpars[3];
1870 pg1[2] = pg2[2] = (gRandom->Rndm()-0.5)*tpars[1] + shift; // local Z
1871 pg2[2] -= 2*shift;
1872 AliITSgeomTGeo::LocalToGlobal(ssID,pg1,pg1);
1873 AliITSgeomTGeo::LocalToGlobal(ssID,pg2,pg2);
1874 }
1875 else {
1876 double ang = gRandom->Rndm()*TMath::Pi()*2;
1877 pg1[0] = tpars[2]*TMath::Cos(ang)+shift;
1878 pg2[0] = tpars[3]*TMath::Cos(ang)-shift;
1879 pg1[1] = tpars[2]*TMath::Sin(ang);
1880 pg2[1] = tpars[3]*TMath::Sin(ang);
1881 pg1[2] = pg2[2] = (gRandom->Rndm()-0.5)*tpars[1]+shift; // local Z
1882 pg2[2] -= 2*shift;
1883 }
1884
1885 //
1886 AliTracker::MeanMaterialBudget(pg1,pg2,res);
1887 rhol += res[0]*res[4]; // rho*L
1888 }
1889 fgRhoLITS[lr] = rhol/ntri;
1890 AliInfo(Form("Obtained <rho*L> = %e\n",fgRhoLITS[lr]));
1891 }
1892 //
1893 return;
1894}
1895
6be22b3f 1896//____________________________________________________
1897Double_t AliITSTPArrayFit::GetPCA2PlaneInfo(Double_t *xyz, Double_t *dir, Int_t axis, Double_t axval) const
1898{
1899 // calculate the PCA to plane normal ti axis and crossing it at axval
1900 // fill the position and direction cosines at this point
1901 //
1902 double xyzp[3] = {0,0,0}; // create fake point
1903 xyzp[axis] = axval;
1904 double covI[6] = {1e-4,0,0,1e-4,0,1e-4}; // fake cov.matrix loose in all directions
1905 covI[4*axis - axis*(axis+1)/2] = 1e8; // except axis
1906 //
1907 double t = GetPosition(xyz, xyzp, covI); // got pca
1908 //
1909 if (dir) GetDirCos(dir,t);
1910 return t;
1911}
1912
66214d86 1913//____________________________________________________
1914void AliITSTPArrayFit::GetT0Info(Double_t* xyz, Double_t *dir) const
1915{
1916 // get direction cosines for t = 0;
1917 GetPosition(xyz, 0);
1918 if (dir) GetDirCos(dir,0);
1919}
1920
1921//____________________________________________________
1922Bool_t AliITSTPArrayFit::CalcErrorMatrix()
1923{
1924 // compute covariance matrix in lenear approximation of residuals on parameters
1925 static AliSymMatrix cv(5);
1926 static Double_t dres[5][3];
1927 cv.Reset();
ef24eb3b 1928 int npar = IsHelix() ? 5:4;
66214d86 1929 //
1930 for (int ip=fPntFirst;ip<=fPntLast;ip++) {
1931 GetDResDParams(&dres[0][0],ip);
1932 Double_t* covI = GetCovI(ip);
1933 for (int i=npar;i--;)
8102b2c9 1934 for (int j=i+1;j--;) {
1935 double cvadd = dres[i][kX]*(dres[j][kX]*covI[ kXX ] + dres[j][kY]*covI[ kXY ] + dres[j][kZ]*covI[ kXZ ])
1936 + dres[i][kY]*(dres[j][kX]*covI[ kXY ] + dres[j][kY]*covI[ kYY ] + dres[j][kZ]*covI[ kYZ ])
1937 + dres[i][kZ]*(dres[j][kX]*covI[ kXZ ] + dres[j][kY]*covI[ kYZ ] + dres[j][kZ]*covI[ kZZ ]);
1938 if (covI[kScl]>0) cvadd *= covI[kScl];
1939 cv(i,j) += cvadd;
1940 }
66214d86 1941 }
1942 cv.SetSizeUsed(npar);
1943 if (cv.InvertChol()) {
ef24eb3b 1944 //cv.Print("l");
66214d86 1945 int cnt = 0;
1946 for (int i=npar;i--;) for (int j=i+1;j--;)fParamsCov[cnt++] = cv(i,j);
1947 return kTRUE;
1948 }
1949 //
1950 return kFALSE;
1951}
1d06ac63 1952
1953//____________________________________________________
1954Double_t AliITSTPArrayFit::CalcParPCA(Int_t ipnt) const
1955{
1956 // get parameter for the point with least weighted distance to the point
1957 const double *xyz = GetPoint(ipnt);
1958 const double *covI = GetCovI(ipnt);
8102b2c9 1959 if (IsHelix()) return GetParPCAHelix(xyz,covI,covI[kScl]);
1960 else return GetParPCALine(xyz,covI/*,covI[kScl]*/);
1d06ac63 1961}
24391cd5 1962
ef24eb3b 1963//____________________________________________________
1964Double_t AliITSTPArrayFit::GetPt() const
1965{
1966 return IsFieldON()&&IsHelix() ? TMath::Abs(fParams[kR0]*fBz*fgkCQConv) : -1;
1967}
1968
1969//____________________________________________________
1970Double_t AliITSTPArrayFit::GetP() const
1971{
1972 if (!IsFieldON()) return -1;
1973 Double_t cdip = 1./TMath::Sqrt(1.+fParams[kDip]*fParams[kDip]);
1974 return TMath::Abs(fParams[kR0]*fgkCQConv*fBz/cdip); // momentum
1975}
24391cd5 1976