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67427ff7 | 1 | /** |
2 | * \class AliFmHelix | |
3 | * \author Thomas Ullrich, Sep 26 1997 | |
4 | * | |
5 | * Parametrization of a helix. Can also cope with straight tracks, i.e. | |
6 | * with zero curvature. This represents only the mathematical model of | |
7 | * a helix. See the SCL user guide for more. | |
8 | */ | |
9 | /*************************************************************************** | |
10 | * | |
11 | * $Id$ | |
12 | * | |
13 | * Author: Thomas Ullrich, Sep 1997 | |
14 | *************************************************************************** | |
15 | * | |
16 | * Description: Parametrization of a helix | |
17 | * | |
18 | *************************************************************************** | |
19 | * | |
20 | * $Log$ | |
0215f606 | 21 | * Revision 1.1.1.1 2007/04/25 15:38:41 panos |
22 | * Importing the HBT code dir | |
23 | * | |
67427ff7 | 24 | * Revision 1.1.1.1 2007/03/07 10:14:49 mchojnacki |
25 | * First version on CVS | |
26 | * | |
27 | * Revision 1.11 2005/10/13 22:23:27 genevb | |
28 | * NoSolution is public | |
29 | * | |
30 | * Revision 1.10 2005/07/06 18:49:56 fisyak | |
31 | * Replace AliFmHelixD, AliFmLorentzVectorD,AliFmLorentzVectorF,AliFmMatrixD,AliFmMatrixF,AliFmPhysicalHelixD,AliFmThreeVectorD,AliFmThreeVectorF by templated version | |
32 | * | |
33 | * Revision 1.9 2004/12/02 02:51:16 ullrich | |
34 | * Added option to pathLenghth() and distance() to search for | |
35 | * DCA only within one period. Default stays as it was. | |
36 | * | |
37 | * Revision 1.8 2003/10/30 20:06:46 perev | |
38 | * Check of quality added | |
39 | * | |
40 | * Revision 1.7 2002/06/21 17:49:25 genevb | |
41 | * Some minor speed improvements | |
42 | * | |
43 | * Revision 1.6 2002/04/24 02:41:55 ullrich | |
44 | * Restored old format. | |
45 | * | |
46 | **************************************************************************/ | |
47 | ||
48 | #ifndef ST_HELIX_HH | |
49 | #define ST_HELIX_HH | |
50 | ||
51 | #include <math.h> | |
52 | #include <utility> | |
53 | #include <algorithm> | |
54 | #include "AliFmThreeVector.h" | |
55 | #if !defined(ST_NO_NAMESPACES) | |
56 | using std::pair; | |
57 | using std::swap; | |
58 | using std::max; | |
59 | #endif | |
60 | ||
61 | #ifdef WIN32 | |
62 | #include "gcc2vs.h" | |
63 | #endif | |
64 | ||
65 | class AliFmHelix { | |
66 | public: | |
67 | /// curvature, dip angle, phase, origin, h | |
68 | AliFmHelix(double c, double dip, double phase, | |
0215f606 | 69 | const AliFmThreeVector<double>& o, int h=-1); |
67427ff7 | 70 | |
71 | virtual ~AliFmHelix(); | |
72 | // AliFmHelix(const AliFmHelix&); // use default | |
73 | // AliFmHelix& operator=(const AliFmHelix&); // use default | |
74 | ||
75 | double dipAngle() const; | |
76 | double curvature() const; /// 1/R in xy-plane | |
77 | double phase() const; /// aziumth in xy-plane measured from ring center | |
78 | double xcenter() const; /// x-center of circle in xy-plane | |
79 | double ycenter() const; /// y-center of circle in xy-plane | |
80 | int h() const; /// -sign(q*B); | |
81 | ||
82 | const AliFmThreeVector<double>& origin() const; /// starting point | |
83 | ||
84 | void setParameters(double c, double dip, double phase, const AliFmThreeVector<double>& o, int h); | |
85 | ||
86 | double x(double s) const; | |
87 | double y(double s) const; | |
88 | double z(double s) const; | |
89 | ||
90 | AliFmThreeVector<double> at(double s) const; | |
91 | ||
92 | /// returns period length of helix | |
93 | double period() const; | |
94 | ||
95 | /// path length at given r (cylindrical r) | |
96 | pair<double, double> pathLength(double r) const; | |
97 | ||
98 | /// path length at given r (cylindrical r, cylinder axis at x,y) | |
99 | pair<double, double> pathLength(double r, double x, double y, bool scanPeriods = true); | |
100 | ||
101 | /// path length at distance of closest approach to a given point | |
102 | double pathLength(const AliFmThreeVector<double>& p, bool scanPeriods = true) const; | |
103 | ||
104 | /// path length at intersection with plane | |
105 | double pathLength(const AliFmThreeVector<double>& r, | |
106 | const AliFmThreeVector<double>& n) const; | |
107 | ||
108 | /// path length at distance of closest approach in the xy-plane to a given point | |
109 | double pathLength(double x, double y) const; | |
110 | ||
111 | /// path lengths at dca between two helices | |
112 | pair<double, double> pathLengths(const AliFmHelix&, bool scanPeriods = true) const; | |
113 | ||
114 | /// minimal distance between point and helix | |
115 | double distance(const AliFmThreeVector<double>& p, bool scanPeriods = true) const; | |
116 | ||
117 | /// checks for valid parametrization | |
118 | bool valid(double world = 1.e+5) const {return !bad(world);} | |
119 | int bad(double world = 1.e+5) const; | |
120 | ||
121 | /// move the origin along the helix to s which becomes then s=0 | |
122 | virtual void moveOrigin(double s); | |
123 | ||
124 | static const double NoSolution; | |
125 | ||
126 | protected: | |
127 | AliFmHelix(); | |
128 | ||
129 | void setCurvature(double); /// performs also various checks | |
130 | void setPhase(double); | |
131 | void setDipAngle(double); | |
132 | ||
133 | /// value of S where distance in x-y plane is minimal | |
134 | double fudgePathLength(const AliFmThreeVector<double>&) const; | |
135 | ||
136 | protected: | |
137 | bool mSingularity; // true for straight line case (B=0) | |
138 | AliFmThreeVector<double> mOrigin; | |
139 | double mDipAngle; | |
140 | double mCurvature; | |
141 | double mPhase; | |
142 | int mH; // -sign(q*B); | |
143 | ||
144 | double mCosDipAngle; | |
145 | double mSinDipAngle; | |
146 | double mCosPhase; | |
147 | double mSinPhase; | |
148 | #ifdef __ROOT__ | |
149 | ClassDef(AliFmHelix,1) | |
150 | #endif | |
151 | }; | |
152 | ||
153 | // | |
154 | // Non-member functions | |
155 | // | |
156 | int operator== (const AliFmHelix&, const AliFmHelix&); | |
157 | int operator!= (const AliFmHelix&, const AliFmHelix&); | |
158 | ostream& operator<<(ostream&, const AliFmHelix&); | |
159 | ||
160 | // | |
161 | // Inline functions | |
162 | // | |
163 | inline int AliFmHelix::h() const {return mH;} | |
164 | ||
165 | inline double AliFmHelix::dipAngle() const {return mDipAngle;} | |
166 | ||
167 | inline double AliFmHelix::curvature() const {return mCurvature;} | |
168 | ||
169 | inline double AliFmHelix::phase() const {return mPhase;} | |
170 | ||
171 | inline double AliFmHelix::x(double s) const | |
172 | { | |
173 | if (mSingularity) | |
174 | return mOrigin.x() - s*mCosDipAngle*mSinPhase; | |
175 | else | |
176 | return mOrigin.x() + (cos(mPhase + s*mH*mCurvature*mCosDipAngle)-mCosPhase)/mCurvature; | |
177 | } | |
178 | ||
179 | inline double AliFmHelix::y(double s) const | |
180 | { | |
181 | if (mSingularity) | |
182 | return mOrigin.y() + s*mCosDipAngle*mCosPhase; | |
183 | else | |
184 | return mOrigin.y() + (sin(mPhase + s*mH*mCurvature*mCosDipAngle)-mSinPhase)/mCurvature; | |
185 | } | |
186 | ||
187 | inline double AliFmHelix::z(double s) const | |
188 | { | |
189 | return mOrigin.z() + s*mSinDipAngle; | |
190 | } | |
191 | ||
192 | inline const AliFmThreeVector<double>& AliFmHelix::origin() const {return mOrigin;} | |
193 | ||
194 | inline AliFmThreeVector<double> AliFmHelix::at(double s) const | |
195 | { | |
196 | return AliFmThreeVector<double>(x(s), y(s), z(s)); | |
197 | } | |
198 | ||
199 | inline double AliFmHelix::pathLength(double x, double y) const | |
200 | { | |
201 | return fudgePathLength(AliFmThreeVector<double>(x, y, 0)); | |
202 | } | |
203 | inline int AliFmHelix::bad(double WorldSize) const | |
204 | { | |
205 | ||
206 | int ierr; | |
207 | if (!::finite(mDipAngle )) return 11; | |
208 | if (!::finite(mCurvature )) return 12; | |
209 | ||
210 | ierr = mOrigin.bad(WorldSize); | |
211 | if (ierr) return 3+ierr*100; | |
212 | ||
213 | if (::fabs(mDipAngle) >1.58) return 21; | |
214 | double qwe = ::fabs(::fabs(mDipAngle)-M_PI/2); | |
215 | if (qwe < 1./WorldSize ) return 31; | |
216 | ||
217 | if (::fabs(mCurvature) > WorldSize) return 22; | |
218 | if (mCurvature < 0 ) return 32; | |
219 | ||
220 | if (abs(mH) != 1 ) return 24; | |
221 | ||
222 | return 0; | |
223 | } | |
224 | ||
225 | #endif |