| 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 #ifdef GNUPRAGMA
>> 12 #pragma implementation
>> 13 #endif
>> 14
11 #include "CLHEP/Vector/ThreeVector.h" 15 #include "CLHEP/Vector/ThreeVector.h"
12 16
13 #include <cmath> 17 #include <cmath>
14 18
15 namespace CLHEP { 19 namespace CLHEP {
16 20
17 //-******************************************* 21 //-*********************************************
18 // - 6 - 22 // - 6 -
19 // Decomposition of an angle between two vecto 23 // Decomposition of an angle between two vectors
20 // 24 //
21 //-******************************************* 25 //-*********************************************
22 26
23 27
24 double Hep3Vector::polarAngle (const Hep3Vecto 28 double Hep3Vector::polarAngle (const Hep3Vector & v2) const {
25 return std::fabs(v2.getTheta() - getTheta()) 29 return std::fabs(v2.getTheta() - getTheta());
26 } /* polarAngle */ 30 } /* polarAngle */
27 31
28 double Hep3Vector::polarAngle (const Hep3Vecto 32 double Hep3Vector::polarAngle (const Hep3Vector & v2,
29 const Hep3Vector & ref) const { 33 const Hep3Vector & ref) const {
30 return std::fabs( v2.angle(ref) - angle(ref) 34 return std::fabs( v2.angle(ref) - angle(ref) );
31 } /* polarAngle (v2, ref) */ 35 } /* polarAngle (v2, ref) */
32 36
33 // double Hep3Vector::azimAngle (const Hep3Vec 37 // double Hep3Vector::azimAngle (const Hep3Vector & v2) const
34 // is now in the .icc file as deltaPhi(v2) 38 // is now in the .icc file as deltaPhi(v2)
35 39
36 double Hep3Vector::azimAngle (const Hep3Vecto 40 double Hep3Vector::azimAngle (const Hep3Vector & v2,
37 const Hep3Vector & ref) const { 41 const Hep3Vector & ref) const {
38 42
39 Hep3Vector vperp ( perpPart(ref) ); 43 Hep3Vector vperp ( perpPart(ref) );
40 if ( vperp.mag2() == 0 ) { 44 if ( vperp.mag2() == 0 ) {
41 std::cerr << "Hep3Vector::azimAngle() - " 45 std::cerr << "Hep3Vector::azimAngle() - "
42 << "Cannot find azimuthal angle with ref 46 << "Cannot find azimuthal angle with reference direction parallel to "
43 << "vector 1 -- will return zero" << std 47 << "vector 1 -- will return zero" << std::endl;
44 return 0; 48 return 0;
45 } 49 }
46 50
47 Hep3Vector v2perp ( v2.perpPart(ref) ); 51 Hep3Vector v2perp ( v2.perpPart(ref) );
48 if ( v2perp.mag2() == 0 ) { 52 if ( v2perp.mag2() == 0 ) {
49 std::cerr << "Hep3Vector::azimAngle() - " 53 std::cerr << "Hep3Vector::azimAngle() - "
50 << "Cannot find azimuthal angle with ref 54 << "Cannot find azimuthal angle with reference direction parallel to "
51 << "vector 2 -- will return zero" << std 55 << "vector 2 -- will return zero" << std::endl;
52 return 0; 56 return 0;
53 } 57 }
54 58
55 double ang = vperp.angle(v2perp); 59 double ang = vperp.angle(v2perp);
56 60
57 // Now compute the sign of the answer: that 61 // Now compute the sign of the answer: that of U*(VxV2) or
58 // the equivalent expression V*(V2xU). 62 // the equivalent expression V*(V2xU).
59 63
60 if ( dot(v2.cross(ref)) >= 0 ) { 64 if ( dot(v2.cross(ref)) >= 0 ) {
61 return ang; 65 return ang;
62 } else { 66 } else {
63 return -ang; 67 return -ang;
64 } 68 }
65 69
66 //-| Note that if V*(V2xU) is zero, we want 70 //-| Note that if V*(V2xU) is zero, we want to return 0 or PI
67 //-| depending on whether vperp is aligned o 71 //-| depending on whether vperp is aligned or antialigned with v2perp.
68 //-| The computed angle() expression does th 72 //-| The computed angle() expression does this properly.
69 73
70 } /* azimAngle (v2, ref) */ 74 } /* azimAngle (v2, ref) */
71 75
72 } // namespace CLHEP 76 } // namespace CLHEP
73 77