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87eecb52 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-2003, 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 | // A straight line is coded as a point (3 Double_t) and // | |
18 | // 3 direction cosines // | |
19 | // // | |
20 | /////////////////////////////////////////////////////////////////// | |
21 | #include <Riostream.h> | |
22 | #include <TMath.h> | |
23 | #include <TObject.h> | |
24 | #include <TObjArray.h> | |
25 | #include <TTree.h> | |
26 | #include <TClonesArray.h> | |
27 | #include "AliITSStrLine.h" | |
28 | ||
29 | ClassImp(AliITSStrLine) | |
30 | ||
31 | //________________________________________________________ | |
32 | AliITSStrLine::AliITSStrLine() { | |
33 | // Default constructor | |
34 | for(Int_t i=0;i<3;i++) { | |
35 | fP0[i] = 0.; | |
36 | fCd[i] = 0.; | |
37 | } | |
38 | fTpar = 0.; | |
39 | SetDebug(); | |
40 | } | |
41 | ||
42 | //________________________________________________________ | |
43 | AliITSStrLine::AliITSStrLine(Double_t *point, Double_t *cd) { | |
44 | // Standard constructor | |
45 | Double_t norm = 0.; | |
46 | for(Int_t i=0;i<3;i++)norm+=cd[i]*cd[i]; | |
47 | if(norm) { | |
48 | norm = TMath::Sqrt(norm); | |
49 | for(Int_t i=0;i<3;i++) cd[i]/=norm; | |
50 | } | |
51 | else { | |
52 | Error("AliITSStrLine","Null direction cosines!!!"); | |
53 | } | |
54 | SetP0(point); | |
55 | SetCd(cd); | |
56 | fTpar = 0.; | |
57 | SetDebug(); | |
58 | } | |
59 | ||
60 | //________________________________________________________ | |
61 | AliITSStrLine::~AliITSStrLine() { | |
62 | // destructor | |
63 | } | |
64 | ||
65 | //________________________________________________________ | |
66 | void AliITSStrLine::PrintStatus() const { | |
67 | // Print current status | |
68 | cout <<"=======================================================\n"; | |
69 | cout <<"Direction cosines: "; | |
70 | for(Int_t i=0;i<3;i++)cout <<fCd[i]<<"; "; | |
71 | cout <<endl; | |
72 | cout <<"Known point: "; | |
73 | for(Int_t i=0;i<3;i++)cout <<fP0[i]<<"; "; | |
74 | cout <<endl; | |
75 | cout <<"Current value for the parameter: "<<fTpar<<endl; | |
76 | cout <<" Debug flag: "<<fDebug<<endl; | |
77 | } | |
78 | ||
79 | //________________________________________________________ | |
80 | Int_t AliITSStrLine::Crossrphi(AliITSStrLine *line){ | |
81 | // Cross 2 lines in the X-Y plane | |
82 | Double_t p2[3]; | |
83 | Double_t cd2[3]; | |
84 | line->GetP0(p2); | |
85 | line->GetCd(cd2); | |
86 | Double_t a=fCd[0]; | |
87 | Double_t b=-cd2[0]; | |
88 | Double_t c=p2[0]-fP0[0]; | |
89 | Double_t d=fCd[1]; | |
90 | Double_t e=-cd2[1]; | |
91 | Double_t f=p2[1]-fP0[1]; | |
92 | Double_t deno = a*e-b*d; | |
93 | Int_t retcode = 0; | |
94 | if(deno != 0.) { | |
95 | fTpar = (c*e-b*f)/deno; | |
96 | } | |
97 | else { | |
98 | retcode = -1; | |
99 | } | |
100 | return retcode; | |
101 | } | |
102 | ||
103 | //________________________________________________________ | |
104 | Int_t AliITSStrLine::Cross(AliITSStrLine *line, Double_t *point){ | |
105 | // Looks for the crossing point estimated starting from the | |
106 | // DCA segment | |
107 | Double_t p2[3]; | |
108 | Double_t cd2[3]; | |
109 | line->GetP0(p2); | |
110 | line->GetCd(cd2); | |
111 | Int_t i; | |
112 | Double_t k1 = 0; | |
113 | for(i=0;i<3;i++)k1+=(fP0[i]-p2[i])*fCd[i]; | |
114 | Double_t k2 = 0; | |
115 | for(i=0;i<3;i++)k2+=(fP0[i]-p2[i])*cd2[i]; | |
116 | Double_t a11 = 0; | |
117 | for(i=0;i<3;i++)a11+=fCd[i]*cd2[i]; | |
118 | Double_t a22 = -a11; | |
119 | Double_t a21 = 0; | |
120 | for(i=0;i<3;i++)a21+=cd2[i]*cd2[i]; | |
121 | Double_t a12 = 0; | |
122 | for(i=0;i<3;i++)a12-=fCd[i]*fCd[i]; | |
123 | Double_t deno = a11*a22-a21*a12; | |
124 | if(deno == 0.) return -1; | |
125 | fTpar = (a11*k2-a21*k1) / deno; | |
126 | Double_t par2 = (k1*a22-k2*a12) / deno; | |
127 | line->SetPar(par2); | |
128 | Double_t point1[3]; | |
129 | Double_t point2[3]; | |
130 | GetCurrentPoint(point1); | |
131 | line->GetCurrentPoint(point2); | |
132 | for(i=0;i<3;i++)point[i]=(point1[i]+point2[i])/2.; | |
133 | return 0; | |
134 | } | |
135 | //________________________________________________________ | |
136 | void AliITSStrLine::GetCurrentPoint(Double_t *point){ | |
137 | // Fills the array point with the current value on the line | |
138 | for(Int_t i=0;i<3;i++)point[i]=fP0[i]+fCd[i]*fTpar; | |
139 | } |