Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <array>
       7             : #include <cstddef>
       8             : 
       9             : #include "DataStructures/ApplyMatrices.hpp"
      10             : #include "DataStructures/DataVector.hpp"
      11             : #include "DataStructures/Index.hpp"
      12             : #include "DataStructures/Matrix.hpp"  // IWYU pragma: keep
      13             : #include "DataStructures/Variables.hpp"
      14             : #include "Utilities/Gsl.hpp"
      15             : 
      16             : // IWYU pragma: no_forward_declare Variables
      17             : 
      18             : /// \cond
      19             : template <size_t Dim>
      20             : class Mesh;
      21             : namespace PUP {
      22             : class er;
      23             : }  // namespace PUP
      24             : /// \endcond
      25             : 
      26             : namespace intrp {
      27             : 
      28             : /// \ingroup NumericalAlgorithmsGroup
      29             : /// \brief Interpolate data from a Mesh onto a regular grid of points.
      30             : ///
      31             : /// The target points must lie on a tensor-product grid that is aligned with the
      32             : /// source Mesh. In any direction where the source and target points share an
      33             : /// identical Mesh (i.e., where the underlying 1-dimensional meshes share the
      34             : /// same extent, basis, and quadrature), the code is optimized to avoid
      35             : /// performing identity interpolations.
      36             : ///
      37             : /// Note, however, that in each dimension of the target grid, the points can
      38             : /// be freely distributed; in particular, the grid points need not be the
      39             : /// collocation points corresponding to a particular basis and quadrature. Note
      40             : /// also that the target grid need not overlap the source grid. In this case,
      41             : /// polynomial extrapolation is performed, with order set by the order of the
      42             : /// basis in the source grid. The extrapolation will be correct but may suffer
      43             : /// from reduced accuracy, especially for higher-order polynomials.
      44             : template <size_t Dim>
      45           1 : class RegularGrid {
      46             :  public:
      47             :   /// \brief An interpolator between two regular grids.
      48             :   ///
      49             :   /// When the optional third argument is NOT passed, creates an interpolator
      50             :   /// between two regular meshes.
      51             :   ///
      52             :   /// The optional third argument allows the caller to override the distribution
      53             :   /// of grid points in any dimension(s) of the target grid. Each non-empty
      54             :   /// element of `override_target_mesh_with_1d_logical_coords` gives the logical
      55             :   /// coordinates which will override the default coordinates of `target_mesh`.
      56           1 :   RegularGrid(const Mesh<Dim>& source_mesh, const Mesh<Dim>& target_mesh,
      57             :               const std::array<DataVector, Dim>&
      58             :                   override_target_mesh_with_1d_logical_coords = {});
      59             : 
      60           0 :   RegularGrid();
      61             : 
      62             :   // NOLINTNEXTLINE(google-runtime-references)
      63           0 :   void pup(PUP::er& p);
      64             : 
      65             :   /// @{
      66             :   /// \brief Interpolate a Variables onto the target points.
      67             :   template <typename TagsList>
      68           1 :   void interpolate(gsl::not_null<Variables<TagsList>*> result,
      69             :                    const Variables<TagsList>& vars) const;
      70             :   template <typename TagsList>
      71           1 :   Variables<TagsList> interpolate(const Variables<TagsList>& vars) const;
      72             :   /// @}
      73             : 
      74             :   /// @{
      75             :   /// \brief Interpolate a DataVector onto the target points.
      76             :   ///
      77             :   /// \note When interpolating multiple tensors, the Variables interface is more
      78             :   /// efficient. However, this DataVector interface is useful for applications
      79             :   /// where only some components of a Tensor or Variables need to be
      80             :   /// interpolated.
      81           1 :   void interpolate(gsl::not_null<DataVector*> result,
      82             :                    const DataVector& input) const;
      83           1 :   DataVector interpolate(const DataVector& input) const;
      84             :   /// @}
      85             : 
      86             :   /// \brief Return the internally-stored matrices that interpolate from the
      87             :   /// source grid to the target grid.
      88             :   ///
      89             :   /// Each matrix interpolates in one logical direction, and can be empty if the
      90             :   /// interpolation in that direction is the identity (i.e., if the source
      91             :   /// and target grids have the same logical coordinates in this direction).
      92           1 :   const std::array<Matrix, Dim>& interpolation_matrices() const;
      93             : 
      94             :  private:
      95             :   template <size_t LocalDim>
      96             :   // NOLINTNEXTLINE(readability-redundant-declaration)
      97           0 :   friend bool operator==(const RegularGrid<LocalDim>& lhs,
      98             :                          const RegularGrid<LocalDim>& rhs);
      99             : 
     100           0 :   size_t number_of_target_points_{};
     101           0 :   Index<Dim> source_extents_;
     102           0 :   std::array<Matrix, Dim> interpolation_matrices_;
     103             : };
     104             : 
     105             : template <size_t Dim>
     106             : template <typename TagsList>
     107           0 : void RegularGrid<Dim>::interpolate(
     108             :     const gsl::not_null<Variables<TagsList>*> result,
     109             :     const Variables<TagsList>& vars) const {
     110             :   if (result->number_of_grid_points() != number_of_target_points_) {
     111             :     result->initialize(number_of_target_points_);
     112             :   }
     113             :   apply_matrices(result, interpolation_matrices_, vars, source_extents_);
     114             : }
     115             : 
     116             : template <size_t Dim>
     117             : template <typename TagsList>
     118             : Variables<TagsList> RegularGrid<Dim>::interpolate(
     119             :     const Variables<TagsList>& vars) const {
     120             :   Variables<TagsList> result;
     121             :   interpolate(make_not_null(&result), vars);
     122             :   return result;
     123             : }
     124             : 
     125             : template <size_t Dim>
     126           0 : bool operator!=(const RegularGrid<Dim>& lhs, const RegularGrid<Dim>& rhs);
     127             : 
     128             : }  // namespace intrp