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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/Alignment.hpp" 0013 #include "Acts/Definitions/Tolerance.hpp" 0014 #include "Acts/Geometry/GeometryContext.hpp" 0015 #include "Acts/Geometry/Polyhedron.hpp" 0016 #include "Acts/Surfaces/BoundaryTolerance.hpp" 0017 #include "Acts/Surfaces/CylinderBounds.hpp" 0018 #include "Acts/Surfaces/RegularSurface.hpp" 0019 #include "Acts/Surfaces/Surface.hpp" 0020 #include "Acts/Surfaces/SurfaceConcept.hpp" 0021 #include "Acts/Utilities/AxisDefinitions.hpp" 0022 #include "Acts/Utilities/Logger.hpp" 0023 #include "Acts/Utilities/Result.hpp" 0024 #include "Acts/Utilities/detail/RealQuadraticEquation.hpp" 0025 0026 #include <memory> 0027 #include <numbers> 0028 #include <string> 0029 0030 namespace Acts { 0031 class DetectorElementBase; 0032 0033 /// @class CylinderSurface 0034 /// 0035 /// Class for a CylinderSurface in the TrackingGeometry. 0036 /// It inherits from Surface. 0037 /// 0038 /// The cylinder surface has a special role in the TrackingGeometry, 0039 /// since it builds the surfaces of all TrackingVolumes at container level 0040 /// for a cylindrical tracking geometry. 0041 /// 0042 /// @image html CylinderSurface.png 0043 0044 class CylinderSurface : public RegularSurface { 0045 friend class Surface; 0046 0047 protected: 0048 /// Constructor from Transform3 and CylinderBounds 0049 /// 0050 /// @param transform The transform to position the surface 0051 /// @param radius The radius of the cylinder 0052 /// @param halfz The half length in z 0053 /// @param halfphi The half opening angle 0054 /// @param avphi The phi value from which the opening angle spans (both sides) 0055 /// @param bevelMinZ (optional) The bevel on the negative z side 0056 /// @param bevelMaxZ (optional) The bevel on the positive z sid The bevel on the positive z side 0057 CylinderSurface(const Transform3& transform, double radius, double halfz, 0058 double halfphi = std::numbers::pi, double avphi = 0., 0059 double bevelMinZ = 0., double bevelMaxZ = 0.); 0060 0061 /// Constructor from Transform3 and CylinderBounds arguments 0062 /// 0063 /// @param transform The transform to position the surface 0064 /// @param cbounds is a shared pointer to a cylindeer bounds object, 0065 /// it must exist (assert test) 0066 CylinderSurface(const Transform3& transform, 0067 std::shared_ptr<const CylinderBounds> cbounds); 0068 0069 /// Constructor from DetectorElementBase: Element proxy 0070 /// 0071 /// @param cbounds are the provided cylinder bounds (shared) 0072 /// @param detelement is the linked detector element to this surface 0073 CylinderSurface(std::shared_ptr<const CylinderBounds> cbounds, 0074 const DetectorElementBase& detelement); 0075 0076 /// Copy constructor 0077 /// 0078 /// @param other is the source cylinder for the copy 0079 CylinderSurface(const CylinderSurface& other); 0080 0081 /// Copy constructor - with shift 0082 /// 0083 /// @param gctx The current geometry context object, e.g. alignment 0084 /// @param other is the source cone surface 0085 /// @param shift is the additional transform applied after copying 0086 CylinderSurface(const GeometryContext& gctx, const CylinderSurface& other, 0087 const Transform3& shift); 0088 0089 public: 0090 /// Assignment operator 0091 /// 0092 /// @param other is the source cylinder for the copy 0093 CylinderSurface& operator=(const CylinderSurface& other); 0094 0095 /// The binning position method - is overloaded for r-type binning 0096 /// 0097 /// @param gctx The current geometry context object, e.g. alignment 0098 /// @param aDir is the axis Direction of global binning to be done 0099 /// 0100 /// @return is the global position to be used for binning 0101 Vector3 referencePosition(const GeometryContext& gctx, 0102 AxisDirection aDir) const final; 0103 0104 /// Return the measurement frame - this is needed for alignment, in particular 0105 /// The measurement frame of a cylinder is the tangential plane at a given 0106 /// position 0107 /// 0108 /// @param gctx The current geometry context object, e.g. alignment 0109 /// @param position is the position where the measurement frame is defined 0110 /// @param direction is the momentum direction vector (ignored) 0111 /// @return rotation matrix that defines the measurement frame 0112 RotationMatrix3 referenceFrame(const GeometryContext& gctx, 0113 const Vector3& position, 0114 const Vector3& direction) const final; 0115 0116 /// Return the surface type 0117 SurfaceType type() const override; 0118 0119 /// Return method for surface normal information 0120 /// @note for a Cylinder a local position is always required for the normal 0121 /// vector 0122 /// 0123 /// @param gctx The current geometry context object, e.g. alignment 0124 /// @param lposition is the local position for which the normal vector is 0125 /// requested 0126 /// 0127 /// @return normal vector at the local position by value 0128 Vector3 normal(const GeometryContext& gctx, 0129 const Vector2& lposition) const final; 0130 0131 /// Return method for surface normal information 0132 /// @note for a Cylinder a local position is always required for the normal 0133 /// vector 0134 /// 0135 /// @param gctx The current geometry context object, e.g. alignment 0136 /// @param position is the global position for which the normal vector is 0137 /// requested 0138 /// 0139 /// @return normal vector at the global position by value 0140 Vector3 normal(const GeometryContext& gctx, 0141 const Vector3& position) const final; 0142 0143 // Use overloads from `RegularSurface` 0144 using RegularSurface::globalToLocal; 0145 using RegularSurface::localToGlobal; 0146 using RegularSurface::normal; 0147 0148 /// Return method for the rotational symmetry axis 0149 /// 0150 /// @param gctx The current geometry context object, e.g. alignment 0151 /// 0152 /// @return the z-Axis of transform 0153 virtual Vector3 rotSymmetryAxis(const GeometryContext& gctx) const; 0154 0155 /// This method returns the CylinderBounds by reference 0156 const CylinderBounds& bounds() const final; 0157 0158 /// Local to global transformation 0159 /// 0160 /// @param gctx The current geometry context object, e.g. alignment 0161 /// @param lposition is the local position to be transformed 0162 /// 0163 /// @return The global position by value 0164 Vector3 localToGlobal(const GeometryContext& gctx, 0165 const Vector2& lposition) const final; 0166 0167 /// Global to local transformation 0168 /// 0169 /// @param gctx The current geometry context object, e.g. alignment 0170 /// @param position is the global position to be transformed 0171 /// @param tolerance optional tolerance within which a point is considered 0172 /// valid on surface 0173 /// 0174 /// @return a Result<Vector2> which can be !ok() if the operation fails 0175 Result<Vector2> globalToLocal( 0176 const GeometryContext& gctx, const Vector3& position, 0177 double tolerance = s_onSurfaceTolerance) const final; 0178 0179 /// Straight line intersection schema from position/direction 0180 /// 0181 /// @param gctx The current geometry context object, e.g. alignment 0182 /// @param position The position to start from 0183 /// @param direction The direction at start 0184 /// @param boundaryTolerance the Boundary Check Tolerance 0185 /// @param tolerance the tolerance used for the intersection 0186 /// 0187 /// If possible returns both solutions for the cylinder 0188 /// 0189 /// @return SurfaceIntersection object (contains intersection & surface) 0190 SurfaceMultiIntersection intersect( 0191 const GeometryContext& gctx, const Vector3& position, 0192 const Vector3& direction, 0193 const BoundaryTolerance& boundaryTolerance = 0194 BoundaryTolerance::Infinite(), 0195 double tolerance = s_onSurfaceTolerance) const final; 0196 0197 /// Path correction due to incident of the track 0198 /// 0199 /// @param gctx The current geometry context object, e.g. alignment 0200 /// @param position is the global position as a starting point 0201 /// @param direction is the global momentum direction at the starting point 0202 /// 0203 /// @return is the correction factor due to incident 0204 double pathCorrection(const GeometryContext& gctx, const Vector3& position, 0205 const Vector3& direction) const final; 0206 0207 /// Return method for properly formatted output string 0208 std::string name() const override; 0209 0210 /// Return a Polyhedron for a cylinder 0211 /// 0212 /// This method represents the cylinder as a polyhedron with a given number 0213 /// of segments to represent a quarter of a full circle. The polyedron will 0214 /// consist of the vertices of the cylinder on both sides, and faces between 0215 /// them, both as rectangular faces and as triangular faces. 0216 /// 0217 /// @param gctx The current geometry context object, e.g. alignment 0218 /// @param quarterSegments The number of segments to approximate a quarter of the 0219 /// full circle; it's chosen to be 1, only the extrema points (-pi, -0.5pi, 0220 /// 0., 0.5pi) are inserted to capture the correct extent in the x-y plane 0221 /// 0222 /// @return A list of vertices and a face/facett description of it 0223 Polyhedron polyhedronRepresentation( 0224 const GeometryContext& gctx, 0225 unsigned int quarterSegments = 2u) const override; 0226 0227 /// Calculate the derivative of path length at the geometry constraint or 0228 /// point-of-closest-approach w.r.t. alignment parameters of the surface (i.e. 0229 /// local frame origin in global 3D Cartesian coordinates and its rotation 0230 /// represented with extrinsic Euler angles) 0231 /// 0232 /// @param gctx The current geometry context object, e.g. alignment 0233 /// @param position global 3D position 0234 /// @param direction global 3D momentum direction 0235 /// 0236 /// @return Derivative of path length w.r.t. the alignment parameters 0237 AlignmentToPathMatrix alignmentToPathDerivative( 0238 const GeometryContext& gctx, const Vector3& position, 0239 const Vector3& direction) const final; 0240 0241 /// Calculate the derivative of bound track parameters local position w.r.t. 0242 /// position in local 3D Cartesian coordinates 0243 /// 0244 /// @param gctx The current geometry context object, e.g. alignment 0245 /// @param position The position of the parameters in global 0246 /// 0247 /// @return Derivative of bound local position w.r.t. position in local 3D 0248 /// cartesian coordinates 0249 ActsMatrix<2, 3> localCartesianToBoundLocalDerivative( 0250 const GeometryContext& gctx, const Vector3& position) const final; 0251 0252 /// Merge two cylinder surfaces into a single one. 0253 /// @image html Cylinder_Merging.svg 0254 /// @note The surfaces need to be *compatible*, i.e. have cylinder bounds 0255 /// that align, and have the same radius 0256 /// @param other The other cylinder surface to merge with 0257 /// @param direction The axis direction: either @c AxisZ or @c AxisRPhi 0258 /// @param externalRotation If true, any phi rotation is done in the transform 0259 /// @param logger The logger to use 0260 /// @return The merged cylinder surface and a boolean indicating if surfaces are reversed 0261 /// @note The returned boolean is `false` if `this` is *left* or 0262 /// *counter-clockwise* of @p other, and `true` if not. 0263 std::pair<std::shared_ptr<CylinderSurface>, bool> mergedWith( 0264 const CylinderSurface& other, AxisDirection direction, 0265 bool externalRotation, const Logger& logger = getDummyLogger()) const; 0266 0267 protected: 0268 std::shared_ptr<const CylinderBounds> m_bounds; //!< bounds (shared) 0269 0270 private: 0271 /// Implementation of the intersection solver 0272 /// 0273 /// <b>mathematical motivation:</b> 0274 /// 0275 /// The cylinder is given by : 0276 /// - cylinder center: ccenter (C) 0277 /// - the direction of the cylinder axis: cdirection (DZ) 0278 /// - the radius r 0279 /// The line is given by : 0280 /// - a reference position : lposition (L0) 0281 /// - the line direction: ldirection (DL) 0282 /// the parametric form for the line is then : L(t) = L0 + t * DL 0283 /// 0284 /// Any point P on infinite cylinder if : 0285 /// ((P - C) x DZ)^2 = r^2 * DZ^2 0286 /// We know that DZ is a unit vector: 0287 /// DZ^2 == 1 0288 /// When expanded with the line equation, this is : 0289 /// ((L0 - C) x DZ + t * (DL x DZ))^2 = r^2 * DZ^2 0290 /// which is a quadratic equation in the form (X + t * Y)^2 = d, where : 0291 /// X = (L0 - C) x DZ 0292 /// Y = DL x DZ 0293 /// d = r^2 * (DZ)^2 0294 /// Now, expand the equation : 0295 /// t^2 * (Y . Y) + t * (2 * (X . Y)) + (X . X) - d = 0 0296 /// => second order equation in the form : a*t^2 + b*t + c = 0 where 0297 /// a = (Y . Y) 0298 /// b = 2 * (X . Y) 0299 /// c = (X . X) - d 0300 /// finally solve the second order equation : a*t^2 + b*t + c = 0 0301 /// reinsertion into the line equation. 0302 /// 0303 /// @return the quadratic equation 0304 detail::RealQuadraticEquation intersectionSolver( 0305 const Transform3& transform, const Vector3& position, 0306 const Vector3& direction) const; 0307 }; 0308 0309 static_assert(RegularSurfaceConcept<CylinderSurface>, 0310 "CylinderSurface does not fulfill RegularSurfaceConcept"); 0311 0312 } // namespace Acts
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