1 package org.lcsim.recon.tracking.trfcyl;
2 // Generator for ClusCylPhiZ2D objects.
3 import org.lcsim.recon.tracking.trfutil.Assert;
4
5 import org.lcsim.recon.tracking.trfbase.HitGenerator;
6 import org.lcsim.recon.tracking.trfbase.HitError;
7 import org.lcsim.recon.tracking.trfbase.Surface;
8 import org.lcsim.recon.tracking.trfbase.Cluster;
9 import org.lcsim.recon.tracking.trfbase.VTrack;
10 import org.lcsim.recon.tracking.trfbase.CrossStat;
11 /**
12 * Generates HitCylPhiZ2D hits on a cylindrical surface with a
13 * gaussian spread in the measurements correlated according to
14 * the covariance matrix.
15 *
16 *@author Norman A. Graf
17 *@version 1.0
18 *
19 */
20 public class HitCylPhiZ2DGenerator extends HitGenerator
21 {
22
23 // attributes
24
25 // the surface
26 private Surface _srf;
27
28 // Error (standard deviation) for the phi measurement.
29 private double _dphi;
30
31 // Error for the z measurement
32 private double _dz;
33
34 // The correlation term in the covariance matrix
35 private double _dphidz;
36
37 //
38
39 /**
40 *Construct an instance from a cylinder surface and the measurement uncertainty.
41 * The cylinder is cloned so user can pass subclass.
42 *
43 * @param srf The cylindrical surface.
44 * @param dphi The gaussian sigma for the phi measurement uncertainty.
45 * @param dz The gaussian sigma for the z measurement uncertainty.
46 * @param dphidz The covariance matrix for the phi an z measurements.
47 */
48 public HitCylPhiZ2DGenerator( SurfCylinder srf,
49 double dphi, double dz, double dphidz)
50 {
51 super();
52 _srf = new SurfCylinder(srf);
53 _dphi = dphi;
54 _dz = dz;
55 _dphidz = dphidz;
56 Assert.assertTrue( _dphi >= 0.0 );
57 Assert.assertTrue( _dz >= 0.0 );
58 //check the determinant as well...
59 Assert.assertTrue( _dphi*_dphi*_dz*dz - _dphidz*dphidz >= 0.0 );
60 }
61
62 //
63
64 /**
65 *Construct an instance from a cylinder surface and the measurement uncertainty.
66 * The cylinder is cloned so user can pass subclass.
67 *
68 * @param srf The cylindrical surface.
69 * @param dphi The gaussian sigma for the phi measurement uncertainty.
70 * @param dz The gaussian sigma for the z measurement uncertainty.
71 * @param dphidz The covariance matrix for the phi an z measurements.
72 * @param iseed The seed for the random number used by the HitGenerator.
73 */
74 public HitCylPhiZ2DGenerator( SurfCylinder srf,
75 double dphi, double dz, double dphidz,
76 long iseed)
77 {
78 super(iseed);
79 _srf = new SurfCylinder(srf);
80 _dphi = dphi;
81 _dz = dz;
82 _dphidz = dphidz;
83 // Check covariance matrix
84 Assert.assertTrue( _dphi >= 0.0 );
85 Assert.assertTrue( _dz >= 0.0 );
86 //check the determinant as well...
87 Assert.assertTrue( _dphi*_dphi*_dz*dz - _dphidz*dphidz >= 0.0 );
88 }
89 //
90
91 /**
92 *Construct an instance replicating the HitCylPhiZ2DGenerator ( copy constructor ).
93 *
94 * @param hgen The HitCylPhiZ2DGenerator to replicate.
95 */
96 public HitCylPhiZ2DGenerator( HitCylPhiZ2DGenerator hgen)
97 {
98 super(hgen);
99 _srf = hgen._srf;
100 _dphi = hgen._dphi;
101 _dz = hgen._dz;
102 _dphidz = hgen._dphidz;
103 Assert.assertTrue( _dphi >= 0.0 );
104 Assert.assertTrue( _dz >= 0.0 );
105
106 }
107
108 //
109
110 /**
111 *Return the surface associated with this HitCylPhiZ2DGenerator.
112 *
113 * @return The surface associated with this HitCylPhiZ2DGenerator.
114 */
115 public Surface surface()
116 { return _srf;
117 }
118
119 //
120
121 /**
122 *Generate a new cluster.
123 * Return null for failure.
124 *
125 * @param trv The VTrack for which to generate a cluster at this surface.
126 * @return The cluster for this track at this surface, null for failure.
127 */
128 public Cluster newCluster( VTrack trv )
129 {
130 return newCluster(trv, 0);
131 }
132
133
134 /**
135 *Generate a new cluster with the specified Monte Carlo track ID.
136 * Return null for failure.
137 *
138 * @param trv The VTrack for which to generate a cluster at this surface.
139 * @param mcid The MC ID to associate with this cluster.
140 * @return The cluster for this track at this surface, null for failure.
141 */
142 public Cluster newCluster( VTrack trv, int mcid )
143 {
144 Cluster clu = null;
145 // Check track has been propagated to the surface.
146 Assert.assertTrue( _srf.pureEqual( trv.surface() ) );
147 if ( ! _srf.pureEqual( trv.surface() ) ) return clu;
148
149 // Require that track is in bounds if surface is bounded.
150 CrossStat xstat = _srf.status(trv);
151 if ( (! _srf.isPure()) && (! xstat.inBounds()) ) return clu;
152
153 // Covariantly smear phi and z...
154 double ran1 = gauss();
155 double ran2 = gauss();
156 double a2 = 0;
157 if ( _dphi != 0.0 ) a2 = _dphidz/_dphi;
158 double b2 = _dz;
159 if (a2 != 0.0 ) b2 = Math.sqrt( _dz*_dz - a2*a2);
160
161 double phi = trv.vector().get(SurfCylinder.IPHI) + _dphi*ran1;
162 double z = trv.vector().get(SurfCylinder.IZ) + a2*ran1 + b2*ran2;
163
164 // construct cluster
165 double radius = _srf.parameter(SurfCylinder.RADIUS);
166 clu = new ClusCylPhiZ2D( radius, phi, _dphi, z, _dz, _dphidz, mcid );
167
168 return clu;
169
170 }
171
172
173 /**
174 *output stream
175 *
176 * @return A String representation of this instance.
177 */
178 public String toString()
179 {
180 StringBuffer sb = new StringBuffer("HitCylPhiZ2D Generator at \n" + surface());
181 sb.append("\n dphi: " + _dphi);
182 sb.append("\n dz: " + _dz);
183 sb.append("\n dhidz: " + _dphidz);
184 sb.append(super.toString());
185 return sb.toString();
186 }
187
188 }
189