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StraightLineStepperTests.cpp
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1 // This file is part of the Acts project.
2 //
3 // Copyright (C) 2020 CERN for the benefit of the Acts project
4 //
5 // This Source Code Form is subject to the terms of the Mozilla Public
6 // License, v. 2.0. If a copy of the MPL was not distributed with this
7 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 
9 #include <boost/test/unit_test.hpp>
10 
11 #include "Acts/EventData/NeutralParameters.hpp"
12 #include "Acts/EventData/TrackParameters.hpp"
13 #include "Acts/Propagator/StraightLineStepper.hpp"
14 #include "Acts/Tests/CommonHelpers/FloatComparisons.hpp"
15 
16 namespace tt = boost::test_tools;
17 
18 namespace Acts {
19 namespace Test {
20 
21 using Covariance = BoundSymMatrix;
22 using Jacobian = BoundMatrix;
23 
25 struct PropState {
27  PropState(StraightLineStepper::State sState) : stepping(sState) {}
29  StraightLineStepper::State stepping;
31  struct {
32  double mass = 42.;
33  } options;
34 };
35 
37 BOOST_AUTO_TEST_CASE(straight_line_stepper_state_test) {
38  // Set up some variables
39  GeometryContext tgContext = GeometryContext();
40  MagneticFieldContext mfContext = MagneticFieldContext();
41  NavigationDirection ndir = backward;
42  double stepSize = 123.;
43  double tolerance = 234.;
44 
45  Vector3D pos(1., 2., 3.);
46  Vector3D mom(4., 5., 6.);
47  double time = 7.;
48  double charge = -1.;
49 
50  // Test charged parameters without covariance matrix
51  CurvilinearParameters cp(std::nullopt, pos, mom, charge, time);
52  StraightLineStepper::State slsState(tgContext, mfContext, cp, ndir, stepSize,
53  tolerance);
54 
55  // Test the result & compare with the input/test for reasonable members
56  BOOST_TEST(slsState.jacToGlobal == BoundToFreeMatrix::Zero());
57  BOOST_TEST(slsState.jacTransport == FreeMatrix::Identity());
58  BOOST_TEST(slsState.derivative == FreeVector::Zero());
59  BOOST_TEST(!slsState.covTransport);
60  BOOST_TEST(slsState.cov == Covariance::Zero());
61  BOOST_TEST(slsState.pos == pos);
62  BOOST_TEST(slsState.dir == mom.normalized());
63  BOOST_TEST(slsState.p == mom.norm());
64  BOOST_TEST(slsState.q == charge);
65  BOOST_TEST(slsState.t == time);
66  BOOST_TEST(slsState.navDir == ndir);
67  BOOST_TEST(slsState.pathAccumulated == 0.);
68  BOOST_TEST(slsState.stepSize == ndir * stepSize);
69  BOOST_TEST(slsState.previousStepSize == 0.);
70  BOOST_TEST(slsState.tolerance == tolerance);
71 
72  // Test without charge and covariance matrix
73  NeutralCurvilinearParameters ncp(std::nullopt, pos, mom, time);
74  slsState = StraightLineStepper::State(tgContext, mfContext, ncp, ndir,
75  stepSize, tolerance);
76  BOOST_TEST(slsState.q == 0.);
77 
78  // Test with covariance matrix
79  Covariance cov = 8. * Covariance::Identity();
80  ncp = NeutralCurvilinearParameters(cov, pos, mom, time);
81  slsState = StraightLineStepper::State(tgContext, mfContext, ncp, ndir,
82  stepSize, tolerance);
83  BOOST_TEST(slsState.jacToGlobal != BoundToFreeMatrix::Zero());
84  BOOST_TEST(slsState.covTransport);
85  BOOST_TEST(slsState.cov == cov);
86 }
87 
90 BOOST_AUTO_TEST_CASE(straight_line_stepper_test) {
91  // Set up some variables for the state
92  GeometryContext tgContext = GeometryContext();
93  MagneticFieldContext mfContext = MagneticFieldContext();
94  NavigationDirection ndir = backward;
95  double stepSize = 123.;
96  double tolerance = 234.;
97 
98  // Construct the parameters
99  Vector3D pos(1., 2., 3.);
100  Vector3D mom(4., 5., 6.);
101  double time = 7.;
102  double charge = -1.;
103  Covariance cov = 8. * Covariance::Identity();
104  CurvilinearParameters cp(cov, pos, mom, charge, time);
105 
106  // Build the state and the stepper
107  StraightLineStepper::State slsState(tgContext, mfContext, cp, ndir, stepSize,
108  tolerance);
109  StraightLineStepper sls;
110 
111  // Test the getters
112  BOOST_TEST(sls.position(slsState) == slsState.pos);
113  BOOST_TEST(sls.direction(slsState) == slsState.dir);
114  BOOST_TEST(sls.momentum(slsState) == slsState.p);
115  BOOST_TEST(sls.charge(slsState) == slsState.q);
116  BOOST_TEST(sls.time(slsState) == slsState.t);
117 
118  //~ BOOST_TEST(sls.overstepLimit(slsState) == tolerance);
119 
120  // Step size modifies
121  const std::string originalStepSize = slsState.stepSize.toString();
122 
123  sls.setStepSize(slsState, 1337.);
124  BOOST_TEST(slsState.previousStepSize == ndir * stepSize);
125  BOOST_TEST(slsState.stepSize == 1337.);
126 
127  sls.releaseStepSize(slsState);
128  BOOST_TEST(slsState.stepSize == -123.);
129  BOOST_TEST(sls.outputStepSize(slsState) == originalStepSize);
130 
131  // Test the curvilinear state construction
132  auto curvState = sls.curvilinearState(slsState);
133  auto curvPars = std::get<0>(curvState);
134  CHECK_CLOSE_ABS(curvPars.position(), cp.position(), 1e-6);
135  CHECK_CLOSE_ABS(curvPars.momentum(), cp.momentum(), 1e-6);
136  CHECK_CLOSE_ABS(curvPars.charge(), cp.charge(), 1e-6);
137  CHECK_CLOSE_ABS(curvPars.time(), cp.time(), 1e-6);
138  BOOST_TEST(curvPars.covariance().has_value());
139  BOOST_TEST(*curvPars.covariance() != cov);
140  CHECK_CLOSE_COVARIANCE(std::get<1>(curvState),
141  BoundMatrix(BoundMatrix::Identity()), 1e-6);
142  CHECK_CLOSE_ABS(std::get<2>(curvState), 0., 1e-6);
143 
144  // Test the update method
145  Vector3D newPos(2., 4., 8.);
146  Vector3D newMom(3., 9., 27.);
147  double newTime(321.);
148  sls.update(slsState, newPos, newMom.normalized(), newMom.norm(), newTime);
149  BOOST_TEST(slsState.pos == newPos);
150  BOOST_TEST(slsState.dir == newMom.normalized());
151  BOOST_TEST(slsState.p == newMom.norm());
152  BOOST_TEST(slsState.q == charge);
153  BOOST_TEST(slsState.t == newTime);
154 
155  // The covariance transport
156  slsState.cov = cov;
157  sls.covarianceTransport(slsState);
158  BOOST_TEST(slsState.cov != cov);
159  BOOST_TEST(slsState.jacToGlobal != BoundToFreeMatrix::Zero());
160  BOOST_TEST(slsState.jacTransport == FreeMatrix::Identity());
161  BOOST_TEST(slsState.derivative == FreeVector::Zero());
162 
163  // Perform a step without and with covariance transport
164  slsState.cov = cov;
165  PropState ps(slsState);
166 
167  ps.stepping.covTransport = false;
168  double h = sls.step(ps).value();
169  BOOST_TEST(ps.stepping.stepSize == ndir * stepSize);
170  BOOST_TEST(ps.stepping.stepSize == h);
171  CHECK_CLOSE_COVARIANCE(ps.stepping.cov, cov, 1e-6);
172  BOOST_TEST(ps.stepping.pos.norm() > newPos.norm());
173  BOOST_TEST(ps.stepping.dir == newMom.normalized());
174  BOOST_TEST(ps.stepping.p == newMom.norm());
175  BOOST_TEST(ps.stepping.q == charge);
176  BOOST_TEST(ps.stepping.t < newTime);
177  BOOST_TEST(ps.stepping.derivative == FreeVector::Zero());
178  BOOST_TEST(ps.stepping.jacTransport == FreeMatrix::Identity());
179 
180  ps.stepping.covTransport = true;
181  double h2 = sls.step(ps).value();
182  BOOST_TEST(ps.stepping.stepSize == ndir * stepSize);
183  BOOST_TEST(h2 == h);
184  CHECK_CLOSE_COVARIANCE(ps.stepping.cov, cov, 1e-6);
185  BOOST_TEST(ps.stepping.pos.norm() > newPos.norm());
186  BOOST_TEST(ps.stepping.dir == newMom.normalized());
187  BOOST_TEST(ps.stepping.p == newMom.norm());
188  BOOST_TEST(ps.stepping.q == charge);
189  BOOST_TEST(ps.stepping.t < newTime);
190  BOOST_TEST(ps.stepping.derivative != FreeVector::Zero());
191  BOOST_TEST(ps.stepping.jacTransport != FreeMatrix::Identity());
192 
194  auto plane = Surface::makeShared<PlaneSurface>(pos, mom.normalized());
195  BoundParameters bp(tgContext, cov, pos, mom, charge, time, plane);
196  slsState = StraightLineStepper::State(tgContext, mfContext, cp, ndir,
197  stepSize, tolerance);
198 
199  // Test the intersection in the context of a surface
200  auto targetSurface = Surface::makeShared<PlaneSurface>(
201  pos + ndir * 2. * mom.normalized(), mom.normalized());
202  sls.updateSurfaceStatus(slsState, *targetSurface, BoundaryCheck(false));
203  BOOST_TEST(slsState.stepSize.value(ConstrainedStep::actor), ndir * 2.);
204 
205  // Test the step size modification in the context of a surface
206  sls.updateStepSize(
207  slsState,
208  targetSurface->intersect(slsState.geoContext, slsState.pos,
209  slsState.navDir * slsState.dir, false),
210  false);
211  BOOST_TEST(slsState.stepSize == 2.);
212  slsState.stepSize = ndir * stepSize;
213  sls.updateStepSize(
214  slsState,
215  targetSurface->intersect(slsState.geoContext, slsState.pos,
216  slsState.navDir * slsState.dir, false),
217  true);
218  BOOST_TEST(slsState.stepSize == 2.);
219 
220  // Test the bound state construction
221  auto boundState = sls.boundState(slsState, *plane);
222  auto boundPars = std::get<0>(boundState);
223  CHECK_CLOSE_ABS(boundPars.position(), bp.position(), 1e-6);
224  CHECK_CLOSE_ABS(boundPars.momentum(), bp.momentum(), 1e-6);
225  CHECK_CLOSE_ABS(boundPars.charge(), bp.charge(), 1e-6);
226  CHECK_CLOSE_ABS(boundPars.time(), bp.time(), 1e-6);
227  BOOST_TEST(boundPars.covariance().has_value());
228  BOOST_TEST(*boundPars.covariance() != cov);
229  CHECK_CLOSE_COVARIANCE(std::get<1>(boundState),
230  BoundMatrix(BoundMatrix::Identity()), 1e-6);
231  CHECK_CLOSE_ABS(std::get<2>(boundState), 0., 1e-6);
232 
233  // Update in context of a surface
234  BoundParameters bpTarget(tgContext, 2. * cov, 2. * pos, 2. * mom,
235  -1. * charge, 2. * time, targetSurface);
236  sls.update(slsState, bpTarget);
237  BOOST_TEST(slsState.pos == 2. * pos);
238  BOOST_TEST(slsState.dir == mom.normalized());
239  BOOST_TEST(slsState.p == 2. * mom.norm());
240  BOOST_TEST(slsState.q == 1. * charge);
241  BOOST_TEST(slsState.t == 2. * time);
242  CHECK_CLOSE_COVARIANCE(slsState.cov, Covariance(2. * cov), 1e-6);
243 
244  // Transport the covariance in the context of a surface
245  sls.covarianceTransport(slsState, *plane);
246  BOOST_TEST(slsState.cov != cov);
247  BOOST_TEST(slsState.jacToGlobal != BoundToFreeMatrix::Zero());
248  BOOST_TEST(slsState.jacTransport == FreeMatrix::Identity());
249  BOOST_TEST(slsState.derivative == FreeVector::Zero());
250 }
251 } // namespace Test
252 } // namespace Acts