1 package org.lcsim.recon.tracking.trfzp;
2
3
4 import org.lcsim.recon.tracking.trfutil.Assert;
5
6 import org.lcsim.recon.tracking.trfbase.Hit;
7 import org.lcsim.recon.tracking.trfbase.HitVector;
8 import org.lcsim.recon.tracking.trfbase.HitError;
9 import org.lcsim.recon.tracking.trfbase.HitDerivative;
10 import org.lcsim.recon.tracking.trfbase.ETrack;
11 import org.lcsim.recon.tracking.trfbase.TrackVector;
12 import org.lcsim.recon.tracking.trfbase.TrackError;
13
14 /**
15 * Describes a two dimensional (x,y) measurement on a ZPlane.
16 *<p>
17 * This is a very simple hit. It produces one prediction with fixed
18 * measurement which is simply the (x,y) of the track.
19 *
20 *@author Norman A. Graf
21 *@version 1.0
22 *
23 */
24
25 //cng changed to public for component tests
26 public class HitZPlane2 extends Hit
27 {
28
29 // Only ClusZPlane2 is allowed to construct HitZPlane2 objects.
30 // therefore package level protection
31
32 // store the derivative
33 static double values[] =
34 { 1.0, 0.0, 0.0, 0.0, 0.0,
35 0.0, 1.0, 0.0, 0.0, 0.0 };
36 static HitDerivative _deriv = new HitDerivative(2,values);
37
38 //
39
40 /**
41 *Return a String representation of the class' type name.
42 *Included for completeness with the C++ version.
43 *
44 * @return A String representation of the class' type name.
45 */
46 public static String typeName()
47 { return "HitZPlane2"; }
48
49 //
50
51 /**
52 *Return a String representation of the class' type name.
53 *Included for completeness with the C++ version.
54 *
55 * @return A String representation of the class' type name.
56 */
57 public static String staticType()
58 { return typeName(); }
59
60
61 // prediction for hm
62 private double _x;
63 private double _y;
64
65 // error matrix for hm
66 private double _dx2;
67 private double _dy2;
68 private double _dxdy;
69
70 // equality
71 // Hits are equal if they have the same parent cluster.
72
73 protected boolean equal( Hit hit)
74 {
75 Assert.assertTrue( type().equals(hit.type()) );
76 return cluster().equals(hit.cluster());
77 }
78
79 // constructor (package access for ClusZPlane2)
80 HitZPlane2(double x, double y, double dx2, double dy2, double dxdy)
81 {
82 _x = x;
83 _y = y;
84 _dx2 = dx2;
85 _dy2 = dy2;
86 _dxdy = dxdy;
87 }
88
89 //
90
91 /**
92 *Construct an instance replicating the HitZPlane2 ( copy constructor ).
93 *
94 * @param hit The Hit to replicate.
95 */
96 public HitZPlane2( HitZPlane2 hit)
97 {
98 super(hit);
99 _x = hit._x;
100 _y = hit._y;
101 _dx2 = hit._dx2;
102 _dy2 = hit._dy2;
103 _dxdy = hit._dxdy;
104 }
105
106 //
107
108 /**
109 *Return a String representation of the class' type name.
110 *Included for completeness with the C++ version.
111 *
112 * @return A String representation of the class' type name.
113 */
114 public String type()
115 { return staticType(); }
116
117 //
118
119 /**
120 *Return the dimension of an (x,y) measurement on a z plane.
121 *The value is always two.
122 *
123 * @return The dimension of this hit (2).
124 */
125 public int size()
126 { return 2; }
127
128 //
129
130 /**
131 *Return the measured hit vector.
132 *
133 * @return The HitVector for this hit.
134 */
135 public HitVector measuredVector()
136 {
137 ClusZPlane2 clu = fullCluster();
138 return new HitVector( clu.x(), clu.y() );
139 }
140
141 //
142
143 /**
144 *Return the measured hit error.
145 *
146 * @return The HitError for this hit.
147 */
148 public HitError measuredError()
149 {
150 ClusZPlane2 clu = fullCluster();
151 return new HitError(clu.dX2(),clu.dXdY(), clu.dY2() );
152 }
153
154 //
155
156 /**
157 *Return the predicted hit vector.
158 *
159 * @return The HitVector for the prediction.
160 */
161 public HitVector predictedVector()
162 {
163 return new HitVector( _x , _y );
164 }
165
166 //
167
168 /**
169 *Return the predicted hit error.
170 *
171 * @return The HitError for the prediction.
172 */
173 public HitError predictedError()
174 {
175 return new HitError( _dx2,_dxdy, _dy2 );
176 }
177
178 //
179
180 /**
181 *Return the hit derivative with respect to a track on this surface.
182 *
183 * @return The HitDerivative for a track on this surface.
184 */
185 public HitDerivative dHitdTrack()
186 {
187 return _deriv;
188 }
189
190 //
191
192 /**
193 *Return the difference between prediction and measurement.
194 *
195 * @return The HitVector for the difference between the hit prediction and measurement.
196 */
197 public HitVector differenceVector()
198 {
199
200 ClusZPlane2 clu = fullCluster();
201
202 double diff_x = _x - clu.x();
203 double diff_y = _y - clu.y();
204 return new HitVector( diff_x, diff_y );
205 }
206
207 //
208
209 /**
210 *Update the prediction (measurement and derivative do not change).
211 *
212 * @param tre The ETrack for which to predict this hit measurement.
213 */
214 public void update( ETrack tre)
215 {
216
217 TrackVector vec = tre.vector();
218
219 _x = vec.get(SurfZPlane.IX);
220 _y = vec.get(SurfZPlane.IY);
221
222 TrackError err = tre.error() ;
223
224 _dx2 = err.get(SurfZPlane.IX,SurfZPlane.IX);
225 _dxdy = err.get(SurfZPlane.IX,SurfZPlane.IY);
226 _dy2 = err.get(SurfZPlane.IY,SurfZPlane.IY);
227 }
228
229
230 /**
231 * Return the measured x position of the hit.
232 *
233 * @return The measured x position of the hit.
234 */
235 public double x()
236 { return _x; }
237
238 /**
239 * Return the measured y position of the hit.
240 *
241 * @return The measured y position of the hit.
242 */
243 public double y()
244 { return _y; }
245
246 /**
247 * Return the error matrix term for x.
248 *
249 * @return The error matrix term for x.
250 */
251 public double dX2()
252 { return _dx2; }
253
254 /**
255 * Return the error matrix term for y.
256 *
257 * @return The error matrix term for y.
258 */
259 public double dY2()
260 { return _dy2; }
261
262 /**
263 * Return the error matrix covariance term.
264 *
265 * @return The error matrix covariance term.
266 */
267 public double dXdY()
268 { return _dxdy; }
269
270 //
271
272 /**
273 *Return a ClusZPlane2 reference to the cluster.
274 *
275 * @return The hit as a ClusZPlane2 object.
276 */
277 public ClusZPlane2 fullCluster()
278 { return ( ClusZPlane2) _pclus; }
279
280
281 /**
282 *output stream
283 *
284 * @return A String representation of this instance.
285 */
286 public String toString()
287 {
288 if( _pclus != null )
289 {
290 return "HitZPlane2 from " + _pclus;
291 }
292 else
293 {
294 return "HitZPlane2 with no parent clusters";
295 }
296 }
297
298 }