EIC code displayed by LXR |
|
|
|
|||
File indexing completed on 2026-08-06 08:47:43
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 #include "Acts/Definitions/TrackParametrization.hpp" 0013 #include "Acts/Definitions/Units.hpp" 0014 #include "Acts/EventData/TransformationHelpers.hpp" 0015 #include "Acts/Geometry/GeometryContext.hpp" 0016 #include "Acts/Surfaces/Surface.hpp" 0017 #include "Acts/Utilities/Zip.hpp" 0018 0019 #include <array> 0020 #include <optional> 0021 #include <stdexcept> 0022 0023 namespace Acts { 0024 0025 /// @defgroup est_track_params Estimate track parameters from seed 0026 /// 0027 /// The implemented method is based on the conformal map transformation. It 0028 /// estimates the full free track parameters, i.e. (x, y, z, t, dx, dy, dz, q/p) 0029 /// at the bottom space point. The magnetic field (which can be along any 0030 /// direction) is also necessary for the momentum estimation. 0031 /// 0032 /// It resembles the method used in ATLAS for the track parameters estimated 0033 /// from seed, i.e. the function InDet::SiTrackMaker_xk::getAtaPlane here: 0034 /// https://acode-browser.usatlas.bnl.gov/lxr/source/athena/InnerGeometry/InDetRecTools/SiTrackMakerTool_xk/src/SiTrackMaker_xk.cxx 0035 /// 0036 /// @{ 0037 0038 /// Estimate free track parameters from three space points 0039 /// 0040 /// This is a purely spatial estimation, i.e. the time parameter will be set to 0041 /// 0. 0042 /// 0043 /// @param sp0 is the bottom space point 0044 /// @param sp1 is the middle space point 0045 /// @param sp2 is the top space point 0046 /// @param bField is the magnetic field vector 0047 /// 0048 /// @return the free parameters 0049 [[deprecated( 0050 "Use the version of estimateTrackParamsFromSeed with time information " 0051 "instead.")]] 0052 FreeVector estimateTrackParamsFromSeed(const Vector3& sp0, const Vector3& sp1, 0053 const Vector3& sp2, 0054 const Vector3& bField); 0055 0056 /// Estimate free track parameters from three space points 0057 /// 0058 /// @param sp0 is the bottom space point 0059 /// @param t0 is the time of the bottom space point 0060 /// @param sp1 is the middle space point 0061 /// @param sp2 is the top space point 0062 /// @param bField is the magnetic field vector 0063 /// 0064 /// @return the free parameters 0065 FreeVector estimateTrackParamsFromSeed(const Vector3& sp0, double t0, 0066 const Vector3& sp1, const Vector3& sp2, 0067 const Vector3& bField); 0068 0069 /// Estimate free track parameters from three space points 0070 /// 0071 /// @tparam space_point_range_t The type of space point range 0072 /// 0073 /// @param spRange is the range of space points 0074 /// @param bField is the magnetic field vector 0075 /// 0076 /// @return the free parameters 0077 template <std::ranges::range space_point_range_t> 0078 FreeVector estimateTrackParamsFromSeed(space_point_range_t spRange, 0079 const Vector3& bField) { 0080 // Check the number of provided space points 0081 if (spRange.size() != 3) { 0082 throw std::invalid_argument( 0083 "There should be exactly three space points provided."); 0084 } 0085 0086 // The global positions of the bottom, middle and space points 0087 std::array<Vector3, 3> spPositions = {Vector3::Zero(), Vector3::Zero(), 0088 Vector3::Zero()}; 0089 std::array<std::optional<double>, 3> spTimes = {std::nullopt, std::nullopt, 0090 std::nullopt}; 0091 // The first, second and third space point are assumed to be bottom, middle 0092 // and top space point, respectively 0093 for (auto [sp, spPosition, spTime] : 0094 Acts::zip(spRange, spPositions, spTimes)) { 0095 if (sp == nullptr) { 0096 throw std::invalid_argument("Empty space point found."); 0097 } 0098 spPosition = Vector3(sp->x(), sp->y(), sp->z()); 0099 spTime = sp->t(); 0100 } 0101 0102 return estimateTrackParamsFromSeed(spPositions[0], spTimes[0].value_or(0), 0103 spPositions[1], spPositions[2], bField); 0104 } 0105 0106 /// Estimate bound track parameters from three space points 0107 /// 0108 /// @param gctx is the geometry context 0109 /// @param surface is the surface of the bottom space point. The estimated bound 0110 /// track parameters will be represented at this surface. 0111 /// @param sp0 is the bottom space point 0112 /// @param t0 is the time of the bottom space point 0113 /// @param sp1 is the middle space point 0114 /// @param sp2 is the top space point 0115 /// @param bField is the magnetic field vector 0116 /// 0117 /// @return bound parameters 0118 Result<BoundVector> estimateTrackParamsFromSeed( 0119 const GeometryContext& gctx, const Surface& surface, const Vector3& sp0, 0120 double t0, const Vector3& sp1, const Vector3& sp2, const Vector3& bField); 0121 0122 /// Estimate bound track parameters from three space points 0123 /// 0124 /// @tparam space_point_range_t The type of space point range 0125 /// 0126 /// @param gctx is the geometry context 0127 /// @param spRange is the range of space points 0128 /// @param surface is the surface of the bottom space point. The estimated bound 0129 /// track parameters will be represented at this surface. 0130 /// @param bField is the magnetic field vector 0131 /// 0132 /// @return bound parameters 0133 template <std::ranges::range space_point_range_t> 0134 Result<BoundVector> estimateTrackParamsFromSeed(const GeometryContext& gctx, 0135 space_point_range_t spRange, 0136 const Surface& surface, 0137 const Vector3& bField) { 0138 const FreeVector freeParams = estimateTrackParamsFromSeed(spRange, bField); 0139 return transformFreeToBoundParameters(freeParams, surface, gctx); 0140 } 0141 0142 /// Configuration for the estimation of the covariance matrix of the track 0143 /// parameters with `estimateTrackParamCovariance`. 0144 struct EstimateTrackParamCovarianceConfig { 0145 /// The initial sigmas for the track parameters 0146 BoundVector initialSigmas = {1. * UnitConstants::mm, 0147 1. * UnitConstants::mm, 0148 1. * UnitConstants::degree, 0149 1. * UnitConstants::degree, 0150 1. * UnitConstants::e / UnitConstants::GeV, 0151 1. * UnitConstants::ns}; 0152 0153 /// The initial sigma for the q/pt 0154 /// @note The resulting q/p sigma is added to the one in `initialSigmas` 0155 double initialSigmaQoverPt = 0. * UnitConstants::e / UnitConstants::GeV; 0156 0157 /// The initial relative uncertainty sigma(pt)/pt 0158 /// @note The resulting q/p sigma is added to the one in `initialSigmas` 0159 double initialSigmaPtRel = 0.1; 0160 0161 /// The inflation factors for the variances of the track parameters 0162 BoundVector initialVarInflation = {1., 1., 1., 1., 1., 1.}; 0163 /// The inflation factor for time uncertainty if the time parameter was not 0164 /// estimated 0165 double noTimeVarInflation = 100.; 0166 }; 0167 0168 /// Estimate the covariance matrix of the given track parameters based on the 0169 /// provided configuration. The assumption is that we can model the uncertainty 0170 /// of the track parameters as a diagonal matrix with the provided initial 0171 /// sigmas. The inflation factors are used to inflate the initial variances 0172 /// based on the provided configuration. The uncertainty of q/p is estimated 0173 /// based on the relative uncertainty of the q/pt and the theta uncertainty. 0174 /// 0175 /// @param config is the configuration for the estimation 0176 /// @param params is the track parameters 0177 /// @param hasTime is true if the track parameters have time 0178 /// 0179 /// @return the covariance matrix of the track parameters 0180 BoundMatrix estimateTrackParamCovariance( 0181 const EstimateTrackParamCovarianceConfig& config, const BoundVector& params, 0182 bool hasTime); 0183 0184 /// @} 0185 0186 } // namespace Acts
| [ Source navigation ] | [ Diff markup ] | [ Identifier search ] | [ general search ] |
|
This page was automatically generated by the 2.3.7 LXR engine. The LXR team |
|