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Warning, file /acts/Core/include/Acts/Surfaces/PointSurface.hpp was not indexed or was modified since last indexation (in which case cross-reference links may be missing, inaccurate or erroneous).
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/Definitions/TrackParametrization.hpp" 0015 #include "Acts/Geometry/GeometryContext.hpp" 0016 #include "Acts/Geometry/Polyhedron.hpp" 0017 #include "Acts/Surfaces/BoundaryTolerance.hpp" 0018 #include "Acts/Surfaces/PointBounds.hpp" 0019 #include "Acts/Surfaces/Surface.hpp" 0020 #include "Acts/Surfaces/SurfaceConcept.hpp" 0021 #include "Acts/Utilities/AxisDefinitions.hpp" 0022 #include "Acts/Utilities/Result.hpp" 0023 0024 #include <iosfwd> 0025 #include <memory> 0026 #include <string> 0027 0028 namespace Acts { 0029 0030 class PointBounds; 0031 class SurfaceBounds; 0032 0033 /// @class PointSurface 0034 /// 0035 /// Surface describing the point of closest approach (PCA) of a track to a 0036 /// single fixed 3D point (the surface center). It is the point-analogue of the 0037 /// LineSurface (which represents the PCA to a line / Perigee). 0038 /// 0039 /// Geometrically, a PointSurface behaves like a curvilinear plane anchored at 0040 /// the fixed center: a plane through the center whose normal always equals the 0041 /// track momentum direction. The track's crossing of that plane is therefore 0042 /// the PCA to the point. Consequently there is no parallel-line degeneracy: a 0043 /// unique intersection always exists. 0044 /// 0045 /// The local coordinates are Cartesian (x, y) in the measurement plane 0046 /// perpendicular to the track direction. Cartesian (not polar r-phi) is used on 0047 /// purpose, because at the point itself (r = 0) the azimuth phi is degenerate. 0048 /// 0049 /// The measurement frame is oriented from the track direction like the 0050 /// CurvilinearSurface: the third axis is the track direction, the first axis is 0051 /// built from global Z (with a fall-back to global X when the direction is 0052 /// (anti-)parallel to Z). 0053 /// 0054 /// @note A point has no intrinsic orientation, so only translation (center) 0055 /// alignment is supported; rotational alignment derivatives are zero. 0056 class PointSurface : public Surface { 0057 friend class Surface; 0058 0059 protected: 0060 /// Constructor from a global position (unbounded point surface) 0061 /// 0062 /// @param center position of the point in the global frame 0063 explicit PointSurface(const Vector3& center); 0064 0065 /// Constructor from a global position and a maximum distance 0066 /// 0067 /// @param center position of the point in the global frame 0068 /// @param maxDistance maximum distance from the point (radius of the 0069 /// PointBounds disc in the measurement plane) 0070 PointSurface(const Vector3& center, double maxDistance); 0071 0072 /// Constructor from a Transform3 and optional PointBounds 0073 /// 0074 /// @param transform the transform whose translation positions the point 0075 /// @param pbounds the bounds describing the maximum distance, may be nullptr 0076 /// for an unbounded point surface 0077 explicit PointSurface(const Transform3& transform, 0078 std::shared_ptr<const PointBounds> pbounds = nullptr); 0079 0080 /// Copy constructor - with shift 0081 /// 0082 /// @param gctx The current geometry context object, e.g. alignment 0083 /// @param other is the source surface 0084 /// @param shift is the additional transform applied after copying 0085 PointSurface(const GeometryContext& gctx, const PointSurface& other, 0086 const Transform3& shift); 0087 0088 public: 0089 /// Copy constructor 0090 /// 0091 /// @param other The source surface for copying 0092 PointSurface(const PointSurface& other) noexcept = default; 0093 0094 /// Assignment operator 0095 /// 0096 /// @param other is the source surface for copying 0097 /// @return Reference to this PointSurface after assignment 0098 PointSurface& operator=(const PointSurface& other) noexcept = default; 0099 0100 /// Destructor 0101 ~PointSurface() noexcept override = default; 0102 0103 /// Return the surface type 0104 /// @return Surface type identifier for point surfaces 0105 SurfaceType type() const final { return Surface::Point; } 0106 0107 /// Return the surface normal, which for a point surface is the momentum 0108 /// direction (the measurement plane is perpendicular to the direction). 0109 /// 0110 /// @param gctx The current geometry context object, e.g. alignment 0111 /// @param pos is the global position (ignored) 0112 /// @param direction is the global momentum direction 0113 /// @return the normal vector (equal to @p direction) 0114 Vector3 normal(const GeometryContext& gctx, const Vector3& pos, 0115 const Vector3& direction) const final; 0116 0117 /// The binning position is the center of the point surface. 0118 /// 0119 /// @param gctx The current geometry context object, e.g. alignment 0120 /// @param aDir is the axis direction for the reference position request 0121 /// @return the center position 0122 Vector3 referencePosition(const GeometryContext& gctx, 0123 AxisDirection aDir) const final; 0124 0125 /// Return the measurement frame, built from the momentum direction like a 0126 /// curvilinear surface. Columns are (U, V, T) with T the direction. 0127 /// 0128 /// @param gctx The current geometry context object, e.g. alignment 0129 /// @param position is the global position (ignored) 0130 /// @param direction is the momentum direction used to build the frame 0131 /// @return a rotation matrix that indicates the measurement frame 0132 RotationMatrix3 referenceFrame(const GeometryContext& gctx, 0133 const Vector3& position, 0134 const Vector3& direction) const final; 0135 0136 /// Calculate the jacobian from local to global. 0137 /// 0138 /// @param gctx The current geometry context object, e.g. alignment 0139 /// @param position global 3D position 0140 /// @param direction global 3D momentum direction 0141 /// @return Jacobian from local to global 0142 BoundToFreeMatrix boundToFreeJacobian(const GeometryContext& gctx, 0143 const Vector3& position, 0144 const Vector3& direction) const final; 0145 0146 /// Calculate the derivative of path length at the point-of-closest-approach 0147 /// w.r.t. free parameters. 0148 /// 0149 /// @param gctx The current geometry context object, e.g. alignment 0150 /// @param position global 3D position 0151 /// @param direction global 3D momentum direction 0152 /// @return Derivative of path length w.r.t. free parameters 0153 FreeToPathMatrix freeToPathDerivative(const GeometryContext& gctx, 0154 const Vector3& position, 0155 const Vector3& direction) const final; 0156 0157 /// Local to global transformation 0158 /// 0159 /// @note for point surfaces the momentum direction is used in order to 0160 /// build the measurement plane 0161 /// 0162 /// @param gctx The current geometry context object, e.g. alignment 0163 /// @param lposition is the local (x, y) position to be transformed 0164 /// @param direction is the global momentum direction 0165 /// @return global position by value 0166 Vector3 localToGlobal(const GeometryContext& gctx, const Vector2& lposition, 0167 const Vector3& direction) const final; 0168 0169 /// Global to local transformation 0170 /// 0171 /// @param gctx The current geometry context object, e.g. alignment 0172 /// @param position global 3D position - considered to be on surface but not 0173 /// inside bounds (check is done) 0174 /// @param direction global 3D momentum direction 0175 /// @param tolerance the tolerance for the on-surface check 0176 /// @return A Result<Vector2> which is !ok() if @p position is not the point 0177 /// of closest approach to the point surface. 0178 Result<Vector2> globalToLocal( 0179 const GeometryContext& gctx, const Vector3& position, 0180 const Vector3& direction, 0181 double tolerance = s_onSurfaceTolerance) const final; 0182 0183 /// Calculate the straight-line intersection with the point surface, i.e. the 0184 /// point of closest approach of the track to the point. 0185 /// 0186 /// Given the track (@p position @f$ \vec m @f$, @p direction @f$ \vec e @f$, 0187 /// normalized), the PCA path length is @f$ u = (\vec c - \vec m) \cdot \vec e 0188 /// @f$ where @f$ \vec c @f$ is the point, and the intersection point is @f$ 0189 /// \vec m + u \vec e @f$. Unlike the LineSurface there is no parallel 0190 /// degeneracy. 0191 /// 0192 /// @param gctx The current geometry context object, e.g. alignment 0193 /// @param position The global position as a starting point 0194 /// @param direction The global direction at the starting point 0195 /// @note expected to be normalized 0196 /// @param boundaryTolerance The boundary check directive for the estimate 0197 /// @param tolerance the tolerance used for the intersection 0198 /// @return is the intersection object 0199 MultiIntersection3D intersect( 0200 const GeometryContext& gctx, const Vector3& position, 0201 const Vector3& direction, 0202 const BoundaryTolerance& boundaryTolerance = 0203 BoundaryTolerance::Infinite(), 0204 double tolerance = s_onSurfaceTolerance) const final; 0205 0206 /// The pathCorrection is by definition 1 for point surfaces 0207 /// 0208 /// @param gctx Geometry context (ignored) 0209 /// @param position Position parameter (ignored) 0210 /// @param direction Direction parameter (ignored) 0211 /// @return Always returns 1.0 for point surfaces 0212 double pathCorrection(const GeometryContext& gctx, const Vector3& position, 0213 const Vector3& direction) const final; 0214 0215 /// This method returns the bounds of the surface by reference 0216 /// @return Reference to the surface bounds 0217 const SurfaceBounds& bounds() const final; 0218 /// This method returns the shared_ptr to the PointBounds 0219 /// @return Shared pointer to the point bounds (may be nullptr) 0220 const std::shared_ptr<const PointBounds>& boundsPtr() const; 0221 /// Overwrite the existing surface bounds with new ones 0222 /// @param newBounds Pointer to the new bounds 0223 void assignSurfaceBounds(std::shared_ptr<const PointBounds> newBounds); 0224 0225 /// Return properly formatted class name for screen output 0226 /// @return String representation of the class name 0227 std::string name() const final; 0228 0229 /// Return a Polyhedron for the surface (a non-physical marker at the center) 0230 /// 0231 /// @param gctx The current geometry context object, e.g. alignment 0232 /// @param quarterSegments is an ignored parameter 0233 /// @return A list of vertices and a face/facet description of it 0234 Polyhedron polyhedronRepresentation(const GeometryContext& gctx, 0235 unsigned int quarterSegments) const final; 0236 0237 /// Calculate the derivative of path length at the point-of-closest-approach 0238 /// w.r.t. alignment parameters of the surface. Only the center (translation) 0239 /// contributes; a point has no orientation so the rotation block is zero. 0240 /// 0241 /// @param gctx The current geometry context object, e.g. alignment 0242 /// @param position global 3D position 0243 /// @param direction global 3D momentum direction 0244 /// @return Derivative of path length w.r.t. the alignment parameters 0245 AlignmentToPathMatrix alignmentToPathDerivative( 0246 const GeometryContext& gctx, const Vector3& position, 0247 const Vector3& direction) const final; 0248 0249 /// Calculate the derivative of bound track parameters local position w.r.t. 0250 /// position in local 3D Cartesian coordinates 0251 /// 0252 /// @param gctx The current geometry context object, e.g. alignment 0253 /// @param position The position of the parameters in global 0254 /// @return Derivative of bound local position w.r.t. position in local 3D 0255 /// cartesian coordinates 0256 Matrix<2, 3> localCartesianToBoundLocalDerivative( 0257 const GeometryContext& gctx, const Vector3& position) const final; 0258 0259 protected: 0260 std::shared_ptr<const PointBounds> 0261 m_bounds; ///< bounds (shared, may be null) 0262 0263 /// @copydoc Surface::localAxes 0264 std::array<AxisDirection, 2> localAxes() const final { 0265 return {AxisDirection::AxisX, AxisDirection::AxisY}; 0266 } 0267 0268 /// Output Method for std::ostream 0269 /// 0270 /// @param gctx The current geometry context object, e.g. alignment 0271 /// @param sl is the ostream to be dumped into 0272 /// @return ostream object which was streamed into 0273 std::ostream& toStreamImpl(const GeometryContext& gctx, 0274 std::ostream& sl) const final; 0275 }; 0276 0277 static_assert(SurfaceConcept<PointSurface>, 0278 "PointSurface does not fulfill SurfaceConcept"); 0279 0280 } // namespace Acts
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