1 /*
2 * ZPlaneEloss_Test.java
3 *
4 * Created on September 10, 2007, 11:05 AM
5 *
6 * $Id: ZPlaneEloss_Test.java,v 1.1.1.1 2010/04/08 20:38:00 jeremy Exp $
7 */
8
9 package org.lcsim.recon.tracking.trfzp;
10
11 import junit.framework.TestCase;
12 import org.lcsim.recon.tracking.trfbase.ETrack;
13 import org.lcsim.recon.tracking.trfbase.PropDir;
14 import org.lcsim.recon.tracking.trfbase.Surface;
15 import org.lcsim.recon.tracking.trfbase.TrackError;
16 import org.lcsim.recon.tracking.trfbase.TrackVector;
17 import org.lcsim.recon.tracking.trfeloss.DeDx;
18 import org.lcsim.recon.tracking.trfeloss.DeDxFixed;
19
20
21 import static java.lang.Math.abs;
22 import static java.lang.Math.sqrt;
23 /**
24 *
25 * @author Norman Graf
26 */
27 public class ZPlaneEloss_Test extends TestCase
28 {
29 private boolean debug;
30 /** Creates a new instance of ZPlaneEloss_Test */
31 public void testZPlaneEloss()
32 {
33 String component = "ZPlaneEloss";
34 String ok_prefix = component + " (I): ";
35 String error_prefix = component + " test (E): ";
36
37 if(debug) System.out.println( ok_prefix
38 + "---------- Testing component " + component
39 + ". ----------" );
40
41 //********************************************************************
42 TrackVector trv = new TrackVector();
43 trv.set(0,1.0);
44 trv.set(1, 1.0);
45 trv.set(2, 0.1);
46 trv.set(3, 0.2);
47 trv.set(4, 0.0);
48
49 double density = 1.0; // g/cm^3
50 double thickness = 1.0; // cm
51
52 DeDx dedx = new DeDxFixed(density);
53 ZPlaneEloss passIt = new ZPlaneEloss(thickness, dedx);
54
55 TrackError initialError = new TrackError();
56
57 Surface srf = new SurfZPlane( 20.0 );
58
59 ETrack tmpTrack = new ETrack( srf, trv, initialError );
60
61 tmpTrack.setError( initialError );
62
63 TrackVector initialVector = tmpTrack.vector();
64 passIt.interact_dir( tmpTrack, PropDir.FORWARD );
65
66 TrackError finalError = tmpTrack.error();
67 TrackVector finalVector = tmpTrack.vector();
68
69 double particleMass = 0.13957;
70 double ptmax = 10000.; // GeV
71
72 double pinv = abs(trv.get(4));
73
74 // make sure pinv is greater than a threshold (1/ptmax)
75 // in this case assume q = 1, otherwise q = q/pt/abs(q/pt)
76
77 int sign = 1;
78 if(pinv < 1./ptmax)
79 pinv = 1./ptmax;
80 else
81 sign = (int) (trv.get(4)/abs(trv.get(4)));
82
83 double initialEnergy = sqrt(1./pinv/pinv + particleMass*particleMass);
84 double finalEnergy = initialEnergy;
85
86 double d = thickness * sqrt(1. + trv.get(2)*trv.get(2) + trv.get(3)*trv.get(3));
87
88 dedx.loseEnergy(finalEnergy, d);
89 double sigmaEnergy = dedx.sigmaEnergy(initialEnergy, d);
90
91 if(finalEnergy<particleMass) finalEnergy=initialEnergy;
92
93 // now evaluate the final q/p and error(4,4)
94 double finalQoverP = sign/sqrt(finalEnergy*finalEnergy - particleMass*particleMass);
95 double finalEr = sigmaEnergy*trv.get(4)*trv.get(4);
96 finalEr *= finalEr;
97
98 assertTrue(abs(finalVector.get(4)-finalQoverP)<0.00001);
99 assertTrue(abs(finalError.get(4,4)-finalEr)<0.00001);
100
101 }
102
103 }