cpu/propagator/line_stepper.cpp

0001 // This file is part of the ACTS project.
0002 //
0003 // Copyright (C) 2016 CERN for the benefit of the ACTS project
0004 //
0005 // This Source Code Form is subject to the terms of the Mozilla Public
0006 // License, v. 2.0. If a copy of the MPL was not distributed with this
0007 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
0008
0009 // detray include(s)
0010 #include "detray/propagator/line_stepper.hpp"
0011
0012 #include "detray/definitions/units.hpp"
0013 #include "detray/tracks/tracks.hpp"
0014
0015 // Detray test include(s)
0016 #include "detray/test/framework/types.hpp"
0017
0018 // google-test include(s)
0019 #include <gtest/gtest.h>
0020
0021 using namespace detray;
0022
0023 using test_algebra = test::algebra;
0024 using scalar = test::scalar;
0025 using vector3 = test::vector3;
0026 using point3 = test::point3;
0027 using transform3 = test::transform3;
0028
0029 namespace {
0030
0031 constexpr scalar tol{1e-3f};
0032 constexpr scalar step_size{1.f * unit<scalar>::mm};
0033 constexpr stepping::config step_cfg{};
0034
0035 }  // namespace
0036
0037 // This tests the base functionality of the line stepper
0038 GTEST_TEST(detray_propagator, line_stepper) {
0039   using namespace step;
0040
0041   // Line stepper with and without constrained stepping
0042   using line_stepper_t = line_stepper<test_algebra>;
0043   using cline_stepper_t = line_stepper<test_algebra, constrained_step<scalar>>;
0044
0045   point3 pos{0.f, 0.f, 0.f};
0046   vector3 mom{1.f, 1.f, 0.f};
0047   free_track_parameters<test_algebra> track(pos, 0.f, mom, -1.f);
0048   free_track_parameters<test_algebra> c_track(pos, 0.f, mom, -1.f);
0049
0050   line_stepper_t l_stepper;
0051   cline_stepper_t cl_stepper;
0052
0053   line_stepper_t::state l_state{track};
0054   cline_stepper_t::state cl_state{c_track};
0055
0056   // Test the setting of step constraints
0057   cl_state.template set_constraint<constraint::e_accuracy>(10.f *
0058                                                            unit<scalar>::mm);
0059   cl_state.template set_constraint<constraint::e_actor>(2.f * unit<scalar>::mm);
0060   cl_state.template set_constraint<constraint::e_aborter>(5.f *
0061                                                           unit<scalar>::mm);
0062   cl_state.template set_constraint<constraint::e_user>(0.5f * unit<scalar>::mm);
0063   ASSERT_NEAR(cl_state.constraints().template size<>(), 0.5f * unit<scalar>::mm,
0064               tol);
0065
0066   // Release all except 'actor', then set 'user' again
0067   cl_state.template release_step<constraint::e_accuracy>();
0068   cl_state.template release_step<constraint::e_aborter>();
0069   cl_state.template release_step<constraint::e_user>();
0070   ASSERT_NEAR(cl_state.constraints().template size<>(), 2.f * unit<scalar>::mm,
0071               tol);
0072
0073   cl_state.template set_constraint<constraint::e_user>(0.5f * unit<scalar>::mm);
0074   ASSERT_NEAR(cl_state.constraints().template size<>(), 0.5f * unit<scalar>::mm,
0075               tol);
0076
0077   // Run a few steps
0078   ASSERT_TRUE(l_stepper.step(step_size, l_state, step_cfg));
0079   // Step constraint to half step size
0080   ASSERT_TRUE(cl_stepper.step(step_size, cl_state, step_cfg));
0081   ASSERT_TRUE(cl_stepper.step(step_size, cl_state, step_cfg));
0082
0083   track = l_state();
0084   ASSERT_NEAR(track.pos()[0], constant<scalar>::inv_sqrt2, tol);
0085   ASSERT_NEAR(track.pos()[1], constant<scalar>::inv_sqrt2, tol);
0086   ASSERT_NEAR(track.pos()[2], 0.f, tol);
0087
0088   c_track = cl_state();
0089   ASSERT_NEAR(c_track.pos()[0], constant<scalar>::inv_sqrt2, tol);
0090   ASSERT_NEAR(c_track.pos()[1], constant<scalar>::inv_sqrt2, tol);
0091   ASSERT_NEAR(c_track.pos()[2], 0.f, tol);
0092
0093   ASSERT_TRUE(l_stepper.step(step_size, l_state, step_cfg));
0094
0095   track = l_state();
0096   ASSERT_NEAR(track.pos()[0], constant<scalar>::sqrt2, tol);
0097   ASSERT_NEAR(track.pos()[1], constant<scalar>::sqrt2, tol);
0098   ASSERT_NEAR(track.pos()[2], 0.f, tol);
0099 }