| Geant4 Cross Reference |
1 // -*- C++ -*- 1 // -*- C++ -*-
2 // ------------------------------------------- 2 // ---------------------------------------------------------------------------
3 // 3 //
4 // This file is a part of the CLHEP - a Class 4 // This file is a part of the CLHEP - a Class Library for High Energy Physics.
5 // 5 //
6 // This is the implementation of the subset of 6 // This is the implementation of the subset of those methods of the Hep3Vector
7 // class which originated from the ZOOM SpaceV 7 // class which originated from the ZOOM SpaceVector class *and* which involve
8 // the esoteric concepts of polar/azimuthal an 8 // the esoteric concepts of polar/azimuthal angular decomposition.
9 // 9 //
10 10
11 #include "CLHEP/Vector/ThreeVector.h" 11 #include "CLHEP/Vector/ThreeVector.h"
12 12
13 #include <cmath> 13 #include <cmath>
14 14
15 namespace CLHEP { 15 namespace CLHEP {
16 16
17 //-******************************************* 17 //-*********************************************
18 // - 6 - 18 // - 6 -
19 // Decomposition of an angle between two vecto 19 // Decomposition of an angle between two vectors
20 // 20 //
21 //-******************************************* 21 //-*********************************************
22 22
23 23
24 double Hep3Vector::polarAngle (const Hep3Vecto 24 double Hep3Vector::polarAngle (const Hep3Vector & v2) const {
25 return std::fabs(v2.getTheta() - getTheta()) 25 return std::fabs(v2.getTheta() - getTheta());
26 } /* polarAngle */ 26 } /* polarAngle */
27 27
28 double Hep3Vector::polarAngle (const Hep3Vecto 28 double Hep3Vector::polarAngle (const Hep3Vector & v2,
29 const Hep3Vector & ref) const { 29 const Hep3Vector & ref) const {
30 return std::fabs( v2.angle(ref) - angle(ref) 30 return std::fabs( v2.angle(ref) - angle(ref) );
31 } /* polarAngle (v2, ref) */ 31 } /* polarAngle (v2, ref) */
32 32
33 // double Hep3Vector::azimAngle (const Hep3Vec 33 // double Hep3Vector::azimAngle (const Hep3Vector & v2) const
34 // is now in the .icc file as deltaPhi(v2) 34 // is now in the .icc file as deltaPhi(v2)
35 35
36 double Hep3Vector::azimAngle (const Hep3Vecto 36 double Hep3Vector::azimAngle (const Hep3Vector & v2,
37 const Hep3Vector & ref) const { 37 const Hep3Vector & ref) const {
38 38
39 Hep3Vector vperp ( perpPart(ref) ); 39 Hep3Vector vperp ( perpPart(ref) );
40 if ( vperp.mag2() == 0 ) { 40 if ( vperp.mag2() == 0 ) {
41 std::cerr << "Hep3Vector::azimAngle() - " 41 std::cerr << "Hep3Vector::azimAngle() - "
42 << "Cannot find azimuthal angle with ref 42 << "Cannot find azimuthal angle with reference direction parallel to "
43 << "vector 1 -- will return zero" << std 43 << "vector 1 -- will return zero" << std::endl;
44 return 0; 44 return 0;
45 } 45 }
46 46
47 Hep3Vector v2perp ( v2.perpPart(ref) ); 47 Hep3Vector v2perp ( v2.perpPart(ref) );
48 if ( v2perp.mag2() == 0 ) { 48 if ( v2perp.mag2() == 0 ) {
49 std::cerr << "Hep3Vector::azimAngle() - " 49 std::cerr << "Hep3Vector::azimAngle() - "
50 << "Cannot find azimuthal angle with ref 50 << "Cannot find azimuthal angle with reference direction parallel to "
51 << "vector 2 -- will return zero" << std 51 << "vector 2 -- will return zero" << std::endl;
52 return 0; 52 return 0;
53 } 53 }
54 54
55 double ang = vperp.angle(v2perp); 55 double ang = vperp.angle(v2perp);
56 56
57 // Now compute the sign of the answer: that 57 // Now compute the sign of the answer: that of U*(VxV2) or
58 // the equivalent expression V*(V2xU). 58 // the equivalent expression V*(V2xU).
59 59
60 if ( dot(v2.cross(ref)) >= 0 ) { 60 if ( dot(v2.cross(ref)) >= 0 ) {
61 return ang; 61 return ang;
62 } else { 62 } else {
63 return -ang; 63 return -ang;
64 } 64 }
65 65
66 //-| Note that if V*(V2xU) is zero, we want 66 //-| Note that if V*(V2xU) is zero, we want to return 0 or PI
67 //-| depending on whether vperp is aligned o 67 //-| depending on whether vperp is aligned or antialigned with v2perp.
68 //-| The computed angle() expression does th 68 //-| The computed angle() expression does this properly.
69 69
70 } /* azimAngle (v2, ref) */ 70 } /* azimAngle (v2, ref) */
71 71
72 } // namespace CLHEP 72 } // namespace CLHEP
73 73