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MaterialSlabTests.cpp
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1 // This file is part of the Acts project.
2 //
3 // Copyright (C) 2017-2018 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/Material/MaterialSlab.hpp"
12 #include "Acts/Tests/CommonHelpers/FloatComparisons.hpp"
13 
14 #include <limits>
15 #include <vector>
16 
17 static constexpr auto eps = 2 * std::numeric_limits<float>::epsilon();
18 
19 BOOST_AUTO_TEST_SUITE(material_properties)
20 
21 BOOST_AUTO_TEST_CASE(construct_simple) {
23  Acts::MaterialSlab fromMaterial(
24  Acts::Material::fromMolarDensity(1., 2., 3., 4., 5.), 6.);
25 
26  CHECK_CLOSE_REL(fromMaterial.thickness(), 6., eps);
27  CHECK_CLOSE_REL(fromMaterial.thicknessInX0(), 6., eps);
28  CHECK_CLOSE_REL(fromMaterial.thicknessInL0(), 3., eps);
29 }
30 
31 BOOST_AUTO_TEST_CASE(construct_compound) {
32  using Acts::Material;
33  using Acts::MaterialSlab;
34 
35  MaterialSlab a(Material::fromMolarDensity(1., 2., 3., 4., 5.), 1.);
36  MaterialSlab b(Material::fromMolarDensity(2., 4., 6., 8., 10.), 2.);
37  MaterialSlab c(Material::fromMolarDensity(4., 8., 12., 16., 20.), 3.);
38  std::vector<MaterialSlab> components = {a, b, c};
39  MaterialSlab abc(components);
40 
41  // consistency checks
42  CHECK_CLOSE_REL(abc.thickness() / abc.material().X0(), abc.thicknessInX0(),
43  eps);
44  CHECK_CLOSE_REL(abc.thickness() / abc.material().L0(), abc.thicknessInL0(),
45  eps);
46 
47  // absolute and relative thicknesses are additive
48  CHECK_CLOSE_REL(abc.thickness(),
49  a.thickness() + b.thickness() + c.thickness(), eps);
50  CHECK_CLOSE_REL(abc.thicknessInX0(),
51  a.thicknessInX0() + b.thicknessInX0() + c.thicknessInX0(),
52  eps);
53  CHECK_CLOSE_REL(abc.thicknessInL0(),
54  a.thicknessInL0() + b.thicknessInL0() + c.thicknessInL0(),
55  eps);
56  // The density scales with the thickness
57  CHECK_CLOSE_REL(abc.material().massDensity(),
58  (a.thickness() * a.material().massDensity() +
59  b.thickness() * b.material().massDensity() +
60  c.thickness() * c.material().massDensity()) /
61  (a.thickness() + b.thickness() + c.thickness()),
62  eps);
63 }
64 
65 BOOST_AUTO_TEST_CASE(scale_thickness) {
66  const auto material = Acts::Material::fromMassDensity(1., 2., 3., 4., 5.);
67  const Acts::MaterialSlab mat(material, 0.1);
68  const Acts::MaterialSlab halfMat(material, 0.05);
69  Acts::MaterialSlab halfScaled = mat;
70  halfScaled.scaleThickness(0.5);
71 
72  BOOST_CHECK_NE(mat, halfMat);
73  BOOST_CHECK_EQUAL(halfMat, halfScaled);
74  CHECK_CLOSE_REL(mat.thicknessInX0(), 2 * halfMat.thicknessInX0(), eps);
75  CHECK_CLOSE_REL(mat.thicknessInL0(), 2 * halfMat.thicknessInL0(), eps);
76  CHECK_CLOSE_REL(mat.thickness() * mat.material().massDensity(),
77  2. * halfMat.thickness() * halfMat.material().massDensity(),
78  eps);
79 }
80 
81 BOOST_AUTO_TEST_SUITE_END()