| [4] | 1 | // -*- C++ -*-
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| 2 | // ---------------------------------------------------------------------------
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| 3 | //
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| 4 | // This file is a part of the CLHEP - a Class Library for High Energy Physics.
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| 5 | //
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| 6 | // This is the implementation of those methods of the HepRotation class which
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| 7 | // were introduced when ZOOM PhysicsVectors was merged in, and which involve
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| 8 | // the angle/axis representation of a Rotation.
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| 9 | //
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| 10 |
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| 11 | #ifdef GNUPRAGMA
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| 12 | #pragma implementation
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| 13 | #endif
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| 14 |
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| 15 | #include "CLHEP/Vector/defs.h"
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| 16 | #include "CLHEP/Vector/Rotation.h"
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| 17 | #include "CLHEP/Units/PhysicalConstants.h"
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| 18 |
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| 19 | #include <iostream>
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| 20 | #include <cmath>
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| 21 |
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| 22 | namespace CLHEP {
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| 23 |
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| 24 | // ---------- Constructors and Assignment:
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| 25 |
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| 26 | // axis and angle
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| 27 |
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| 28 | HepRotation & HepRotation::set( const Hep3Vector & axis, double delta ) {
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| 29 |
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| 30 | register double sinDelta = sin(delta), cosDelta = cos(delta);
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| 31 | register double oneMinusCosDelta = 1.0 - cosDelta;
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| 32 |
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| 33 | Hep3Vector u = axis.unit();
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| 34 |
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| 35 | register double uX = u.getX();
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| 36 | register double uY = u.getY();
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| 37 | register double uZ = u.getZ();
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| 38 |
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| 39 | rxx = oneMinusCosDelta * uX * uX + cosDelta;
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| 40 | rxy = oneMinusCosDelta * uX * uY - sinDelta * uZ;
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| 41 | rxz = oneMinusCosDelta * uX * uZ + sinDelta * uY;
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| 42 |
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| 43 | ryx = oneMinusCosDelta * uY * uX + sinDelta * uZ;
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| 44 | ryy = oneMinusCosDelta * uY * uY + cosDelta;
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| 45 | ryz = oneMinusCosDelta * uY * uZ - sinDelta * uX;
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| 46 |
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| 47 | rzx = oneMinusCosDelta * uZ * uX - sinDelta * uY;
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| 48 | rzy = oneMinusCosDelta * uZ * uY + sinDelta * uX;
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| 49 | rzz = oneMinusCosDelta * uZ * uZ + cosDelta;
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| 50 |
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| 51 | return *this;
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| 52 |
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| 53 | } // HepRotation::set(axis, delta)
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| 54 |
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| 55 | HepRotation::HepRotation ( const Hep3Vector & axis, double delta )
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| 56 | {
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| 57 | set( axis, delta );
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| 58 | }
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| 59 | HepRotation & HepRotation::set( const HepAxisAngle & ax ) {
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| 60 | return set ( ax.axis(), ax.delta() );
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| 61 | }
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| 62 | HepRotation::HepRotation ( const HepAxisAngle & ax )
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| 63 | {
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| 64 | set ( ax.axis(), ax.delta() );
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| 65 | }
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| 66 |
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| 67 | |
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| 68 |
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| 69 |
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| 70 | double HepRotation::delta() const {
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| 71 |
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| 72 | double cosdelta = (rxx + ryy + rzz - 1.0) / 2.0;
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| 73 | if (cosdelta > 1.0) {
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| 74 | return 0;
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| 75 | } else if (cosdelta < -1.0) {
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| 76 | return CLHEP::pi;
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| 77 | } else {
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| 78 | return acos( cosdelta ); // Already safe due to the cosdelta > 1 check
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| 79 | }
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| 80 |
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| 81 | } // delta()
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| 82 |
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| 83 | Hep3Vector HepRotation::axis () const {
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| 84 |
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| 85 | // Determine 2*sin(delta) times the u components (I call this uX, uY, Uz)
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| 86 | // Normalization is not needed; it will be done when returning the 3-Vector
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| 87 |
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| 88 | double Uz = ryx - rxy;
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| 89 | double Uy = rxz - rzx;
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| 90 | double Ux = rzy - ryz;
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| 91 |
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| 92 | if ( (Uz==0) && (Uy==0) && (Ux==0) ) {
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| 93 | if ( rzz>0 ) {
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| 94 | return Hep3Vector(0,0,1);
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| 95 | } else if ( ryy>0 ) {
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| 96 | return Hep3Vector(0,1,0);
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| 97 | } else {
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| 98 | return Hep3Vector(1,0,0);
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| 99 | }
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| 100 | } else {
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| 101 | return Hep3Vector( Ux, Uy, Uz ).unit();
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| 102 | }
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| 103 |
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| 104 | } // axis()
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| 105 |
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| 106 | HepAxisAngle HepRotation::axisAngle() const {
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| 107 |
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| 108 | return HepAxisAngle (axis(), delta());
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| 109 |
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| 110 | } // axisAngle()
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| 111 |
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| 112 |
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| 113 | void HepRotation::setAxis (const Hep3Vector & axis) {
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| 114 | set ( axis, delta() );
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| 115 | }
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| 116 |
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| 117 | void HepRotation::setDelta (double delta) {
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| 118 | set ( axis(), delta );
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| 119 | }
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| 120 |
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| 121 | } // namespace CLHEP
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