Acts/Definitions/Tolerance.hpp

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 #pragma once
0010
0011 #include "Acts/Definitions/Algebra.hpp"
0012
0013 #include <limits>
0014
0015 namespace Acts {
0016
0017 /// Tolerance for being numerical equal for geometry building
0018 static constexpr double s_epsilon = 3 * std::numeric_limits<double>::epsilon();
0019
0020 /// Tolerance for being on Surface
0021 ///
0022 /// @note This is intentionally given w/o an explicit unit to avoid having
0023 ///       to include the units header unnecessarily. With the native length
0024 ///       unit of mm this corresponds to 0.1um.
0025 static constexpr double s_onSurfaceTolerance = 1e-4;
0026
0027 /// Tolerance in radians for a phi sector to count as the full azimuth
0028 ///
0029 /// @note Geometry descriptions state phi edges with about ten significant
0030 ///       digits, so a full sector can miss its nominal value by ~1e-9. Even
0031 ///       at a metre radius that is a nanometre of arc, while the narrowest
0032 ///       real sectors are milliradians wide.
0033 static constexpr double s_fullAzimuthTolerance = 1e-9;
0034
0035 /// Tolerance for not being within curvilinear projection
0036 /// this allows using the same curvilinear frame to eta = 6,
0037 /// validity tested with IntegrationTests/PropagationTest
0038 static constexpr double s_curvilinearProjTolerance = 0.999995;
0039
0040 }  // namespace Acts