| Geant4 Cross Reference |
1 // -*- C++ -*-
2 // ---------------------------------------------------------------------------
3 //
4 // This file is a part of the CLHEP - a Class Library for High Energy Physics.
5 //
6 // This is the implementation of that part of the HepLorentzRotation class
7 // which is concerned with setting or constructing the transformation based
8 // on 4 supplied columns or rows.
9
10 #include "CLHEP/Vector/LorentzRotation.h"
11 #include "CLHEP/Vector/LorentzVector.h"
12
13 #include <cmath>
14 #include <iostream>
15
16 namespace CLHEP {
17
18 // ---------- Constructors and Assignment:
19
20 HepLorentzRotation & HepLorentzRotation::set (const HepLorentzVector & ccol1,
21 const HepLorentzVector & ccol2,
22 const HepLorentzVector & ccol3,
23 const HepLorentzVector & ccol4) {
24 // First, test that the four cols do represent something close to a
25 // true LT:
26
27 ZMpvMetric_t savedMetric = HepLorentzVector::setMetric (TimePositive);
28
29 if ( ccol4.getT() < 0 ) {
30 std::cerr << "HepLorentzRotation::set() - "
31 << "column 4 supplied to define transformation has negative T component"
32 << std::endl;
33 *this = HepLorentzRotation();
34 return *this;
35 }
36 /*
37 double u1u1 = ccol1.dot(ccol1);
38 double f11 = std::fabs(u1u1 + 1.0);
39 if ( f11 > Hep4RotationInterface::tolerance ) {
40 std::cerr << "HepLorentzRotation::set() - "
41 << "column 1 supplied for HepLorentzRotation has w*w != -1" << std::endl;
42 }
43 double u2u2 = ccol2.dot(ccol2);
44 double f22 = std::fabs(u2u2 + 1.0);
45 if ( f22 > Hep4RotationInterface::tolerance ) {
46 std::cerr << "HepLorentzRotation::set() - "
47 << "column 2 supplied for HepLorentzRotation has w*w != -1" << std::endl;
48 }
49 double u3u3 = ccol3.dot(ccol3);
50 double f33 = std::fabs(u3u3 + 1.0);
51 if ( f33 > Hep4RotationInterface::tolerance ) {
52 std::cerr << "HepLorentzRotation::set() - "
53 << "column 3 supplied for HepLorentzRotation has w*w != -1" << std::endl;
54 }
55 double u4u4 = ccol4.dot(ccol4);
56 double f44 = std::fabs(u4u4 - 1.0);
57 if ( f44 > Hep4RotationInterface::tolerance ) {
58 std::cerr << "HepLorentzRotation::set() - "
59 << "column 4 supplied for HepLorentzRotation has w*w != +1" << std::endl;
60 }
61
62 double u1u2 = ccol1.dot(ccol2);
63 double f12 = std::fabs(u1u2);
64 if ( f12 > Hep4RotationInterface::tolerance ) {
65 std::cerr << "HepLorentzRotation::set() - "
66 << "columns 1 and 2 supplied for HepLorentzRotation have non-zero dot" << std::endl;
67 }
68 double u1u3 = ccol1.dot(ccol3);
69 double f13 = std::fabs(u1u3);
70
71 if ( f13 > Hep4RotationInterface::tolerance ) {
72 std::cerr << "HepLorentzRotation::set() - "
73 << "columns 1 and 3 supplied for HepLorentzRotation have non-zero dot" << std::endl;
74 }
75 double u1u4 = ccol1.dot(ccol4);
76 double f14 = std::fabs(u1u4);
77 if ( f14 > Hep4RotationInterface::tolerance ) {
78 std::cerr << "HepLorentzRotation::set() - "
79 << "columns 1 and 4 supplied for HepLorentzRotation have non-zero dot" << std::endl;
80 }
81 double u2u3 = ccol2.dot(ccol3);
82 double f23 = std::fabs(u2u3);
83 if ( f23 > Hep4RotationInterface::tolerance ) {
84 std::cerr << "HepLorentzRotation::set() - "
85 << "columns 2 and 3 supplied for HepLorentzRotation have non-zero dot" << std::endl;
86 }
87 double u2u4 = ccol2.dot(ccol4);
88 double f24 = std::fabs(u2u4);
89 if ( f24 > Hep4RotationInterface::tolerance ) {
90 std::cerr << "HepLorentzRotation::set() - "
91 << "columns 2 and 4 supplied for HepLorentzRotation have non-zero dot" << std::endl;
92 }
93 double u3u4 = ccol3.dot(ccol4);
94 double f34 = std::fabs(u3u4);
95 if ( f34 > Hep4RotationInterface::tolerance ) {
96 std::cerr << "HepLorentzRotation::set() - "
97 << "columns 3 and 4 supplied for HepLorentzRotation have non-zero dot" << std::endl;
98 }
99 */
100 // Our strategy will be to order the cols, then do gram-schmidt on them
101 // (that is, remove the components of col d that make it non-orthogonal to
102 // col c, normalize that, then remove the components of b that make it
103 // non-orthogonal to d and to c, normalize that, etc.
104
105 // Because col4, the time col, is most likely to be computed directly, we
106 // will start from there and work left-ward.
107
108 HepLorentzVector a, b, c, d;
109 bool isLorentzTransformation = true;
110 double norm;
111
112 d = ccol4;
113 norm = d.dot(d);
114 if (norm <= 0.0) {
115 isLorentzTransformation = false;
116 if (norm == 0.0) {
117 d = T_HAT4; // Moot, but let's keep going...
118 norm = 1.0;
119 }
120 }
121 d /= norm;
122
123 c = ccol3 - ccol3.dot(d) * d;
124 norm = -c.dot(c);
125 if (norm <= 0.0) {
126 isLorentzTransformation = false;
127 if (norm == 0.0) {
128 c = Z_HAT4; // Moot
129 norm = 1.0;
130 }
131 }
132 c /= norm;
133
134 b = ccol2 + ccol2.dot(c) * c - ccol2.dot(d) * d;
135 norm = -b.dot(b);
136 if (norm <= 0.0) {
137 isLorentzTransformation = false;
138 if (norm == 0.0) {
139 b = Y_HAT4; // Moot
140 norm = 1.0;
141 }
142 }
143 b /= norm;
144
145 a = ccol1 + ccol1.dot(b) * b + ccol1.dot(c) * c - ccol1.dot(d) * d;
146 norm = -a.dot(a);
147 if (norm <= 0.0) {
148 isLorentzTransformation = false;
149 if (norm == 0.0) {
150 a = X_HAT4; // Moot
151 norm = 1.0;
152 }
153 }
154 a /= norm;
155
156 if ( !isLorentzTransformation ) {
157 std::cerr << "HepLorentzRotation::set() - "
158 << "cols 1-4 supplied to define transformation form either \n"
159 << " a boosted reflection or a tachyonic transformation -- \n"
160 << " transformation will be set to Identity " << std::endl;
161
162 *this = HepLorentzRotation();
163 }
164
165 if ( isLorentzTransformation ) {
166 mxx = a.x(); myx = a.y(); mzx = a.z(); mtx = a.t();
167 mxy = b.x(); myy = b.y(); mzy = b.z(); mty = b.t();
168 mxz = c.x(); myz = c.y(); mzz = c.z(); mtz = c.t();
169 mxt = d.x(); myt = d.y(); mzt = d.z(); mtt = d.t();
170 }
171
172 HepLorentzVector::setMetric (savedMetric);
173 return *this;
174
175 } // set ( col1, col2, col3, col4 )
176
177 HepLorentzRotation & HepLorentzRotation::setRows
178 (const HepLorentzVector & rrow1,
179 const HepLorentzVector & rrow2,
180 const HepLorentzVector & rrow3,
181 const HepLorentzVector & rrow4) {
182 // Set based on using those rows as columns:
183 set (rrow1, rrow2, rrow3, rrow4);
184 // Now transpose in place:
185 double q1, q2, q3;
186 q1 = mxy; q2 = mxz; q3 = mxt;
187 mxy = myx; mxz = mzx; mxt = mtx;
188 myx = q1; mzx = q2; mtx = q3;
189 q1 = myz; q2 = myt; q3 = mzt;
190 myz = mzy; myt = mty; mzt = mtz;
191 mzy = q1; mty = q2; mtz = q3;
192 return *this;
193 } // LorentzTransformation::setRows(row1 ... row4)
194
195 HepLorentzRotation::HepLorentzRotation ( const HepLorentzVector & ccol1,
196 const HepLorentzVector & ccol2,
197 const HepLorentzVector & ccol3,
198 const HepLorentzVector & ccol4 )
199 {
200 set ( ccol1, ccol2, ccol3, ccol4 );
201 }
202
203 } // namespace CLHEP
204
205