feat: Multiwire builder (#2275)

This PR introduces the builder for a Multi Layer Wire Structure using an internal and external builder. It also introduces a multilayer updator for grid-based indexed surfaces that is used inside the inner builder and a unit test that checks the surface candidates collected along a projected path as shown in the attached pictures.
![GridXYMultiWire](https://github.com/acts-project/acts/assets/63058524/bf724080-7c00-4cf5-8957-0257b80aeda1)

![grid](https://github.com/acts-project/acts/assets/63058524/57c35292-e75f-40b5-8e1a-cf32649e1f3d)

Core/include/Acts/Detector/MultiWireStructureBuilder.hpp

@@ -0,0 +1,76 @@
+// This file is part of the Acts project.
+//
+// Copyright (C) 2022-2023 CERN for the benefit of the Acts project
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+#include "Acts/Detector/LayerStructureBuilder.hpp"
+#include "Acts/Detector/ProtoBinning.hpp"
+#include "Acts/Detector/interface/IDetectorComponentBuilder.hpp"
+#include "Acts/Detector/interface/IExternalStructureBuilder.hpp"
+#include "Acts/Detector/interface/IInternalStructureBuilder.hpp"
+#include "Acts/Geometry/GeometryContext.hpp"
+#include "Acts/Surfaces/Surface.hpp"
+#include "Acts/Utilities/Logger.hpp"
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+namespace Acts {
+namespace Experimental {
+
+class MultiWireStructureBuilder {
+ public:
+  /// @brief Configuration struct for the MultiWireStructure Builder
+
+  struct Config {
+    /// The name of the detector volume component
+    std::string name = "";
+
+    /// The surfaces of the Multi Wire
+    std::vector<std::shared_ptr<Acts::Surface>> mlSurfaces = {};
+
+    /// The bounds of the multi-wire volume
+    std::vector<ActsScalar> mlBounds = {};
+
+    // The binning of the multi wire structure
+    std::vector<ProtoBinning> mlBinning = {};
+
+    /// A tolerance config
+    float toleranceOverlap = 10.;
+  };
+
+  /// Constructor
+  /// @param config The configure of the MultiWireStructureBuilder
+  /// @param logger logging instance for screen output
+
+  MultiWireStructureBuilder(
+      const Config& config,
+      std::unique_ptr<const Acts::Logger> logger = Acts::getDefaultLogger(
+          "MultiWireStructureBuilder", Acts::Logging::VERBOSE));
+
+  ~MultiWireStructureBuilder() = default;
+
+  /// Construct the detector component
+
+  /// @param gctx The Geometry Context of the current geometry
+  /// @return a detector component object with the detector volume of the multilayer
+
+  Acts::Experimental::DetectorComponent construct(
+      const Acts::GeometryContext& gctx);
+
+ private:
+  Config mCfg;
+
+  const Acts::Logger& logger() const { return *mLogger; }
+
+  std::unique_ptr<const Acts::Logger> mLogger;
+};
+
+}  // namespace Experimental
+}  // namespace Acts

Core/include/Acts/Detector/detail/IndexedSurfacesGenerator.hpp

@@ -75,12 +75,8 @@ struct IndexedSurfacesGenerator {
       bvArray[ibv] = bv;
     }
 
-    // The indexed surfaces delegate
-    // IndexedSurfacesImpl<GridType> indexedSurfaces(std::move(grid), bvArray,
-    // transform);
     indexed_updator<GridType> indexedSurfaces(std::move(grid), bvArray,
                                               transform);
-
     // Fill the bin indices
     IndexedGridFiller filler{binExpansion};
     filler.oLogger = oLogger->cloneWithSuffix("_filler");

Core/include/Acts/Navigation/MultiLayerSurfacesUpdator.hpp

@@ -0,0 +1,143 @@
+// This file is part of the Acts project.
+//
+// Copyright (C) 2022 CERN for the benefit of the Acts project
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+#include "Acts/Detector/DetectorVolume.hpp"
+#include "Acts/Navigation/NavigationDelegates.hpp"
+#include "Acts/Navigation/NavigationStateFillers.hpp"
+#include "Acts/Navigation/NavigationStateUpdators.hpp"
+#include "Acts/Utilities/VectorHelpers.hpp"
+
+#include <array>
+#include <memory>
+
+namespace Acts {
+namespace Experimental {
+
+template <typename grid_t, typename path_generator>
+class MultiLayerSurfacesUpdatorImpl : public INavigationDelegate {
+ public:
+  /// Broadcast the grid type
+  using grid_type = grid_t;
+
+  /// The grid where the indices are stored
+  grid_type grid;
+
+  /// These are the cast parameters - copied from constructor
+  std::array<BinningValue, grid_type::DIM> casts{};
+
+  /// A transform to be applied to the position
+  Transform3 transform = Transform3::Identity();
+
+  /// The path generator
+  path_generator pgenerator;
+
+  /// @brief  Constructor for a grid based surface attacher
+  ///@param igrid the grid that is moved into this attacher
+  /// @param icasts is the cast values array
+  /// @param itr a transform applied to the global position
+  MultiLayerSurfacesUpdatorImpl(
+      grid_type&& igrid, const std::array<BinningValue, grid_type::DIM>& icasts,
+      const Transform3& itr = Transform3::Identity())
+      : grid(std::move(igrid)), casts(icasts), transform(itr) {}
+
+  MultiLayerSurfacesUpdatorImpl() = delete;
+
+  void update(const GeometryContext& gctx, NavigationState& nState) const {
+    auto step = std::sqrt(std::pow(grid.binWidth()[0], 2) +
+                          std::pow(grid.binWidth()[1], 2));
+    auto path = pgenerator(nState.position, nState.direction, step,
+                           grid.numLocalBins()[1]);
+
+    std::vector<const Acts::Surface*> surfCandidates = {};
+
+    for (const auto& p : path) {
+      const auto& entry = grid.atPosition(castPosition(p));
+      const auto extracted =
+          IndexedSurfacesExtractor::extract(gctx, nState, entry);
+      surfCandidates.insert(surfCandidates.end(), extracted.begin(),
+                            extracted.end());
+    }
+
+    resolveDuplicates(gctx, surfCandidates);
+    SurfacesFiller::fill(nState, surfCandidates);
+  }
+
+  /// Cast into a lookup position
+  ///
+  /// @param position is the position of the update call
+  std::array<ActsScalar, grid_type::DIM> castPosition(
+      const Vector3& position) const {
+    // Transform into local 3D frame
+    Vector3 tposition = transform * position;
+
+    std::array<ActsScalar, grid_type::DIM> casted{};
+    fillCasts(tposition, casted,
+              std::make_integer_sequence<std::size_t, grid_type::DIM>{});
+    return casted;
+  }
+
+  /// Resolve duplicate on surface candidates
+  ///
+  /// @param gctx The geometry context of the current geometry
+  /// @param surfaces is the surface candidates to check and resolve for duplicates
+  void resolveDuplicates(const GeometryContext& gctx,
+                         std::vector<const Acts::Surface*>& surfaces) const {
+    // sorting the surfaces according to their radial distance
+    std::sort(surfaces.begin(), surfaces.end(),
+              [&gctx](const auto& surf1, const auto& surf2) {
+                if (surf1->center(gctx).x() != surf2->center(gctx).x()) {
+                  return surf1->center(gctx).x() < surf2->center(gctx).x();
+                }
+                if (surf1->center(gctx).y() != surf2->center(gctx).y()) {
+                  return surf1->center(gctx).y() < surf2->center(gctx).y();
+                }
+                return surf1->center(gctx).z() < surf2->center(gctx).z();
+              });
+
+    // Remove the duplicates
+    surfaces.erase(std::unique(surfaces.begin(), surfaces.end()),
+                   surfaces.end());
+  }
+
+ private:
+  /// Unroll the cast loop
+  /// @param position is the position of the update call
+  /// @param a is the array to be filled
+  template <typename Array, std::size_t... idx>
+  void fillCasts(const Vector3& position, Array& a,
+                 std::index_sequence<idx...> /*indices*/) const {
+    ((a[idx] = VectorHelpers::cast(position, casts[idx])), ...);
+  }
+};
+
+struct PathGridSurfacesGenerator {
+  std::vector<Vector3> operator()(Vector3 startPosition,
+                                  const Vector3& direction, ActsScalar stepSize,
+                                  std::size_t numberOfSteps) const {
+    std::vector<Vector3> pathCoordinates = {};
+    pathCoordinates.reserve(numberOfSteps);
+
+    auto tposition = std::move(startPosition);
+    auto stepSizeY = stepSize * sin(Acts::VectorHelpers::phi(direction));
+    auto stepSizeX = stepSize * cos(Acts::VectorHelpers::phi(direction));
+
+    for (std::size_t i = 0; i < numberOfSteps; i++) {
+      pathCoordinates.push_back(tposition);
+      tposition.y() = tposition.y() + stepSizeY;
+      tposition.x() = tposition.x() + stepSizeX;
+    }
+
+    return pathCoordinates;
+  }
+};
+
+}  // namespace Experimental
+
+}  // namespace Acts

Core/include/Acts/Navigation/SurfaceCandidatesUpdators.hpp

@@ -13,6 +13,7 @@
 #include "Acts/Detector/DetectorVolume.hpp"
 #include "Acts/Detector/Portal.hpp"
 #include "Acts/Geometry/GeometryContext.hpp"
+#include "Acts/Navigation/MultiLayerSurfacesUpdator.hpp"
 #include "Acts/Navigation/NavigationState.hpp"
 #include "Acts/Navigation/NavigationStateFillers.hpp"
 #include "Acts/Navigation/NavigationStateUpdators.hpp"
@@ -45,9 +46,8 @@ inline static void updateCandidates(const GeometryContext& gctx,
         (c.surface != nullptr) ? (*c.surface) : (c.portal->surface());
 
     // Get the intersection @todo make a templated intersector
-    // TODO surface tolerance
-    auto sIntersection = sRep.intersect(gctx, position, direction,
-                                        c.boundaryCheck, s_onSurfaceTolerance);
+    auto sIntersection =
+        sRep.intersect(gctx, position, direction, c.boundaryCheck);
     // Re-order and swap if necessary
     if (sIntersection.intersection.pathLength + s_onSurfaceTolerance <
             nState.overstepTolerance and
@@ -192,6 +192,13 @@ template <typename grid_type>
 using IndexedSurfacesImpl =
     IndexedUpdatorImpl<grid_type, IndexedSurfacesExtractor, SurfacesFiller>;
 
+/// @brief  An indexed multi layer surface implementation access
+///
+/// @tparam grid_type is the grid type used for this indexed lookup
+template <typename grid_type>
+using MultiLayerSurfacesImpl =
+    MultiLayerSurfacesUpdatorImpl<grid_type, PathGridSurfacesGenerator>;
+
 /// @brief An indexed surface implementation with portal access
 ///
 ///@tparam inexed_updator is the updator for the indexed surfaces

Core/src/Detector/CMakeLists.txt

@@ -15,4 +15,7 @@ target_sources(
     PortalGenerators.cpp
     ProtoDetector.cpp
     VolumeStructureBuilder.cpp
+    MultiWireStructureBuilder.cpp
+
+
 )