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