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98937d93 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, 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 | ||
16 | //----------------------------------------------------------------- | |
17 | // Implementation of the derived class for track residuals | |
18 | // based on Chi2 minimization | |
19 | // | |
20 | //----------------------------------------------------------------- | |
21 | ||
22 | #include <TMinuit.h> | |
23 | #include <TGeoMatrix.h> | |
24 | ||
25 | #include "AliAlignObj.h" | |
26 | #include "AliTrackPointArray.h" | |
27 | #include "AliTrackResidualsChi2.h" | |
28 | ||
29 | ClassImp(AliTrackResidualsChi2) | |
30 | ||
31 | //______________________________________________________________________________ | |
32 | void Fcn(Int_t &npar, Double_t *gin, Double_t &f, Double_t *par, Int_t iflag) | |
33 | { | |
34 | // This function is called by minuit | |
35 | // The corresponding member method is called | |
36 | // using SetObjectFit/GetObjectFit methods of TMinuit | |
37 | AliTrackResidualsChi2* dummy = (AliTrackResidualsChi2 *)gMinuit->GetObjectFit(); | |
38 | dummy->Chi2(npar, gin, f, par, iflag); | |
39 | } | |
40 | ||
41 | //______________________________________________________________________________ | |
42 | Bool_t AliTrackResidualsChi2::Minimize() | |
43 | { | |
44 | // Implementation of Chi2 based minimization | |
45 | // of track residuala sum | |
46 | TMinuit *gMinuit = new TMinuit(6); //initialize TMinuit | |
47 | gMinuit->SetObjectFit(this); | |
48 | gMinuit->SetFCN(Fcn); | |
49 | ||
50 | Double_t arglist[10]; | |
51 | Int_t ierflg = 0; | |
52 | ||
53 | arglist[0] = 1; | |
54 | gMinuit->mnexcm("SET ERR", arglist ,1,ierflg); | |
55 | ||
56 | // Set starting values and step sizes for parameters | |
57 | Double_t tr[3],rot[3]; | |
58 | fAlignObj->GetPars(tr,rot); | |
59 | static Double_t step[6] = {0,0,0,0,0,0}; | |
60 | gMinuit->mnparm(0, "x", tr[0], step[0], 0,0,ierflg); | |
61 | gMinuit->mnparm(1, "y", tr[1], step[1], 0,0,ierflg); | |
62 | gMinuit->mnparm(2, "z", tr[2], step[2], 0,0,ierflg); | |
63 | gMinuit->mnparm(3, "psi", rot[0], step[3], 0,0,ierflg); | |
64 | gMinuit->mnparm(4, "theta", rot[1], step[4], 0,0,ierflg); | |
65 | gMinuit->mnparm(5, "phi", rot[2], step[5], 0,0,ierflg); | |
66 | ||
67 | // Now ready for minimization step | |
68 | arglist[0] = 500; | |
69 | arglist[1] = 1.; | |
70 | gMinuit->mnexcm("MIGRAD", arglist ,2,ierflg); | |
71 | ||
72 | // Print results | |
73 | Double_t amin,edm,errdef; | |
74 | Int_t nvpar,nparx,icstat; | |
75 | gMinuit->mnstat(amin,edm,errdef,nvpar,nparx,icstat); | |
76 | gMinuit->mnprin(3,amin); | |
77 | ||
78 | return kTRUE; | |
79 | } | |
80 | ||
81 | //______________________________________________________________________________ | |
82 | void AliTrackResidualsChi2::Chi2(Int_t & /* npar */, Double_t * /* gin */, Double_t &f, Double_t *par, Int_t /* iflag */) | |
83 | { | |
84 | // Chi2 function to be minimized | |
85 | // Sums all the track residuals | |
86 | Double_t chi2 = 0; | |
87 | ||
88 | fAlignObj->SetPars(par[0],par[1],par[2],par[3],par[4],par[5]); | |
89 | TGeoHMatrix m; | |
90 | fAlignObj->GetMatrix(m); | |
91 | Double_t *rot = m.GetRotationMatrix(); | |
92 | Double_t *tr = m.GetTranslation(); | |
93 | ||
94 | AliTrackPoint p1,p2; | |
95 | Double_t dR[3]; | |
96 | Float_t xyzvol[3],xyztr[3]; | |
97 | Float_t covvol[6],covtr[6]; | |
98 | ||
99 | for (Int_t itrack = 0; itrack < fLast; itrack++) { | |
100 | if (!fVolArray[itrack] || !fTrackArray[itrack]) continue; | |
101 | for (Int_t ipoint = 0; ipoint < fVolArray[itrack]->GetNPoints(); ipoint++) { | |
102 | fVolArray[itrack]->GetPoint(p1,ipoint); | |
103 | fTrackArray[itrack]->GetPoint(p2,ipoint); | |
104 | p1.GetXYZ(xyzvol,covvol); | |
105 | p2.GetXYZ(xyztr,covtr); | |
106 | ||
107 | for (Int_t i = 0; i < 3; i++) | |
108 | dR[i] = tr[i] | |
109 | + xyzvol[0]*rot[3*i] | |
110 | + xyzvol[1]*rot[3*i+1] | |
111 | + xyzvol[2]*rot[3*i+2] | |
112 | - xyztr[i]; | |
113 | chi2 += dR[0]*dR[0]+dR[1]*dR[1]+dR[2]*dR[2]; | |
114 | } | |
115 | } | |
116 | f = chi2; | |
117 | } |