fe_values.cc

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// ------------------------------------------------------------------------
//
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2021 - 2025 by the deal.II authors
//
// This file is part of the deal.II library.
//
// Part of the source code is dual licensed under Apache-2.0 WITH
// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
// governing the source code and code contributions can be found in
// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
//
// ------------------------------------------------------------------------
 
#include <deal.II/base/exceptions.h>
#include <deal.II/base/numbers.h>
 
#include <deal.II/lac/block_vector.h>
#include <deal.II/lac/la_parallel_block_vector.h>
#include <deal.II/lac/la_parallel_vector.h>
#include <deal.II/lac/petsc_block_vector.h>
#include <deal.II/lac/petsc_vector.h>
#include <deal.II/lac/trilinos_epetra_vector.h>
#include <deal.II/lac/trilinos_parallel_block_vector.h>
#include <deal.II/lac/trilinos_tpetra_block_vector.h>
#include <deal.II/lac/trilinos_tpetra_vector.h>
#include <deal.II/lac/trilinos_vector.h>
#include <deal.II/lac/vector.h>
 
#include <deal.II/non_matching/fe_values.h>
 
DEAL_II_NAMESPACE_OPEN
 
namespace NonMatching
{
  RegionUpdateFlags::RegionUpdateFlags()
    : inside(update_default)
    , outside(update_default)
    , surface(update_default)
  {}
 
 
 
  template <int dim>
  template <typename Number>
  FEValues<dim>::FEValues(const hp::FECollection<dim> &fe_collection,
                          const Quadrature<1>         &quadrature,
                          const RegionUpdateFlags      region_update_flags,
                          const MeshClassifier<dim>   &mesh_classifier,
                          const DoFHandler<dim>       &dof_handler,
                          const ReadVector<Number>    &level_set,
                          const AdditionalData        &additional_data)
    : mapping_collection(&::hp::StaticMappingQ1<dim>::mapping_collection)
    , fe_collection(&fe_collection)
    , q_collection_1D(quadrature)
    , region_update_flags(region_update_flags)
    , mesh_classifier(&mesh_classifier)
    , quadrature_generator(q_collection_1D,
                           dof_handler,
                           level_set,
                           additional_data)
  {
    // Tensor products of each quadrature in q_collection_1d. Used on the
    // non-intersected cells.
    hp::QCollection<dim> q_collection;
    for (const auto &quadrature : q_collection_1D)
      q_collection.push_back(Quadrature<dim>(quadrature));
 
    initialize(q_collection);
  }
 
 
 
  template <int dim>
  template <typename Number>
  FEValues<dim>::FEValues(const hp::MappingCollection<dim> &mapping_collection,
                          const hp::FECollection<dim>      &fe_collection,
                          const hp::QCollection<dim>       &q_collection,
                          const hp::QCollection<1>         &q_collection_1D,
                          const RegionUpdateFlags           region_update_flags,
                          const MeshClassifier<dim>        &mesh_classifier,
                          const DoFHandler<dim>            &dof_handler,
                          const ReadVector<Number>         &level_set,
                          const AdditionalData             &additional_data)
    : mapping_collection(&mapping_collection)
    , fe_collection(&fe_collection)
    , q_collection_1D(q_collection_1D)
    , region_update_flags(region_update_flags)
    , mesh_classifier(&mesh_classifier)
    , quadrature_generator(q_collection_1D,
                           dof_handler,
                           level_set,
                           additional_data)
  {
    initialize(q_collection);
  }
 
 
 
  template <int dim>
  void
  FEValues<dim>::initialize(const hp::QCollection<dim> &q_collection)
  {
    current_cell_location = LocationToLevelSet::unassigned;
    active_fe_index       = numbers::invalid_unsigned_int;
 
    Assert(fe_collection->size() > 0,
           ExcMessage("Incoming hp::FECollection can not be empty."));
    Assert(mapping_collection->size() == fe_collection->size() ||
             mapping_collection->size() == 1,
           ExcMessage("Size of hp::MappingCollection must be "
                      "the same as hp::FECollection or 1."));
    Assert(q_collection.size() == fe_collection->size() ||
             q_collection.size() == 1,
           ExcMessage("Size of hp::QCollection<dim> must be the "
                      "same as hp::FECollection or 1."));
    Assert(q_collection_1D.size() == fe_collection->size() ||
             q_collection_1D.size() == 1,
           ExcMessage("Size of hp::QCollection<1> must be the "
                      "same as hp::FECollection or 1."));
 
    // For each element in fe_collection, create ::FEValues objects to use
    // on the non-intersected cells.
    fe_values_inside_full_quadrature.resize(fe_collection->size());
    fe_values_outside_full_quadrature.resize(fe_collection->size());
    for (unsigned int fe_index = 0; fe_index < fe_collection->size();
         ++fe_index)
      {
        const unsigned int mapping_index =
          mapping_collection->size() > 1 ? fe_index : 0;
        const unsigned int q_index = q_collection.size() > 1 ? fe_index : 0;
 
        fe_values_inside_full_quadrature[fe_index].emplace(
          (*mapping_collection)[mapping_index],
          (*fe_collection)[fe_index],
          q_collection[q_index],
          region_update_flags.inside);
        fe_values_outside_full_quadrature[fe_index].emplace(
          (*mapping_collection)[mapping_index],
          (*fe_collection)[fe_index],
          q_collection[q_index],
          region_update_flags.outside);
      }
  }
 
 
 
  template <int dim>
  template <bool level_dof_access>
  void
  FEValues<dim>::reinit(
    const TriaIterator<DoFCellAccessor<dim, dim, level_dof_access>> &cell,
    const unsigned int                                               q_index,
    const unsigned int mapping_index)
  {
    this->reinit_internal(cell,
                          q_index,
                          mapping_index,
                          cell->active_fe_index());
  }
 
 
 
  template <int dim>
  void
  FEValues<dim>::reinit(const TriaIterator<CellAccessor<dim, dim>> &cell,
                        const unsigned int                          q_index,
                        const unsigned int mapping_index,
                        const unsigned int fe_index)
  {
    this->reinit_internal(cell, q_index, mapping_index, fe_index);
  }
 
 
 
  template <int dim>
  template <typename CellIteratorType>
  void
  FEValues<dim>::reinit_internal(const CellIteratorType &cell,
                                 const unsigned int      q_index_in,
                                 const unsigned int      mapping_index_in,
                                 const unsigned int      fe_index_in)
  {
    current_cell_location = mesh_classifier->location_to_level_set(cell);
 
    if (fe_index_in == numbers::invalid_unsigned_int)
      this->active_fe_index = 0;
    else
      this->active_fe_index = fe_index_in;
 
    unsigned int mapping_index = mapping_index_in;
    unsigned int q_index       = q_index_in;
    unsigned int q_index_1D    = q_index_in;
 
    if (mapping_index == numbers::invalid_unsigned_int)
      {
        if (mapping_collection->size() > 1)
          mapping_index = active_fe_index;
        else
          mapping_index = 0;
      }
 
    if (q_index == numbers::invalid_unsigned_int)
      {
        if (fe_values_inside_full_quadrature.size() > 1)
          q_index = active_fe_index;
        else
          q_index = 0;
      }
 
    if (q_index_1D == numbers::invalid_unsigned_int)
      {
        if (q_collection_1D.size() > 1)
          q_index_1D = active_fe_index;
        else
          q_index_1D = 0;
      }
 
    // These objects were created with a quadrature based on the previous cell
    // and are thus no longer valid.
    fe_values_inside.reset();
    fe_values_surface.reset();
    fe_values_outside.reset();
 
    switch (current_cell_location)
      {
        case LocationToLevelSet::inside:
          {
            Assert((active_fe_index == mapping_index) ||
                     ((mapping_collection->size() == 1) &&
                      (mapping_index == 0)),
                   ExcNotImplemented());
            Assert(active_fe_index == q_index, ExcNotImplemented());
 
            fe_values_inside_full_quadrature.at(q_index)->reinit(cell);
            break;
          }
        case LocationToLevelSet::outside:
          {
            Assert((active_fe_index == mapping_index) ||
                     ((mapping_collection->size() == 1) &&
                      (mapping_index == 0)),
                   ExcNotImplemented());
            Assert(active_fe_index == q_index, ExcNotImplemented());
 
            fe_values_outside_full_quadrature.at(q_index)->reinit(cell);
            break;
          }
        case LocationToLevelSet::intersected:
          {
            quadrature_generator.set_1D_quadrature(q_index_1D);
            quadrature_generator.generate(cell);
 
            const Quadrature<dim> &inside_quadrature =
              quadrature_generator.get_inside_quadrature();
            const Quadrature<dim> &outside_quadrature =
              quadrature_generator.get_outside_quadrature();
            const ImmersedSurfaceQuadrature<dim> &surface_quadrature =
              quadrature_generator.get_surface_quadrature();
 
            // Even if a cell is formally intersected the number of created
            // quadrature points can be 0. Avoid creating an FEValues object
            // if that is the case.
            if (inside_quadrature.size() > 0)
              {
                fe_values_inside.emplace((*mapping_collection)[mapping_index],
                                         (*fe_collection)[active_fe_index],
                                         inside_quadrature,
                                         region_update_flags.inside);
 
                fe_values_inside->reinit(cell);
              }
 
            if (outside_quadrature.size() > 0)
              {
                fe_values_outside.emplace((*mapping_collection)[mapping_index],
                                          (*fe_collection)[active_fe_index],
                                          outside_quadrature,
                                          region_update_flags.outside);
 
                fe_values_outside->reinit(cell);
              }
 
            if (surface_quadrature.size() > 0)
              {
                fe_values_surface.emplace((*mapping_collection)[mapping_index],
                                          (*fe_collection)[active_fe_index],
                                          surface_quadrature,
                                          region_update_flags.surface);
                fe_values_surface->reinit(cell);
              }
 
            break;
          }
        default:
          {
            DEAL_II_ASSERT_UNREACHABLE();
            break;
          }
      }
  }
 
 
 
  template <int dim>
  const std::optional<::FEValues<dim>> &
  FEValues<dim>::get_inside_fe_values() const
  {
    if (current_cell_location == LocationToLevelSet::inside)
      return fe_values_inside_full_quadrature.at(active_fe_index);
    else
      return fe_values_inside;
  }
 
 
 
  template <int dim>
  const std::optional<::FEValues<dim>> &
  FEValues<dim>::get_outside_fe_values() const
  {
    if (current_cell_location == LocationToLevelSet::outside)
      return fe_values_outside_full_quadrature.at(active_fe_index);
    else
      return fe_values_outside;
  }
 
 
 
  template <int dim>
  const std::optional<FEImmersedSurfaceValues<dim>> &
  FEValues<dim>::get_surface_fe_values() const
  {
    return fe_values_surface;
  }
 
 
 
  template <int dim>
  template <typename Number>
  FEInterfaceValues<dim>::FEInterfaceValues(
    const hp::FECollection<dim> &fe_collection,
    const Quadrature<1>         &quadrature,
    const RegionUpdateFlags      region_update_flags,
    const MeshClassifier<dim>   &mesh_classifier,
    const DoFHandler<dim>       &dof_handler,
    const ReadVector<Number>    &level_set,
    const AdditionalData        &additional_data)
    : mapping_collection(&::hp::StaticMappingQ1<dim>::mapping_collection)
    , fe_collection(&fe_collection)
    , q_collection_1D(quadrature)
    , region_update_flags(region_update_flags)
    , mesh_classifier(&mesh_classifier)
    , face_quadrature_generator(q_collection_1D,
                                dof_handler,
                                level_set,
                                additional_data)
  {
    // Tensor products of each quadrature in q_collection_1d. Used on the
    // non-intersected cells.
    hp::QCollection<dim - 1> q_collection;
    for (const auto &quadrature : q_collection_1D)
      q_collection.push_back(quadrature);
 
    initialize(q_collection);
  }
 
 
 
  template <int dim>
  template <typename Number>
  FEInterfaceValues<dim>::FEInterfaceValues(
    const hp::MappingCollection<dim> &mapping_collection,
    const hp::FECollection<dim>      &fe_collection,
    const hp::QCollection<dim - 1>   &q_collection,
    const hp::QCollection<1>         &q_collection_1D,
    const RegionUpdateFlags           region_update_flags,
    const MeshClassifier<dim>        &mesh_classifier,
    const DoFHandler<dim>            &dof_handler,
    const ReadVector<Number>         &level_set,
    const AdditionalData             &additional_data)
    : mapping_collection(&mapping_collection)
    , fe_collection(&fe_collection)
    , q_collection_1D(q_collection_1D)
    , region_update_flags(region_update_flags)
    , mesh_classifier(&mesh_classifier)
    , face_quadrature_generator(q_collection_1D,
                                dof_handler,
                                level_set,
                                additional_data)
  {
    initialize(q_collection);
  }
 
 
 
  template <int dim>
  void
  FEInterfaceValues<dim>::initialize(
    const hp::QCollection<dim - 1> &q_collection)
  {
    current_face_location = LocationToLevelSet::unassigned;
 
    Assert(fe_collection->size() > 0,
           ExcMessage("Incoming hp::FECollection can not be empty."));
    Assert(
      mapping_collection->size() == fe_collection->size() ||
        mapping_collection->size() == 1,
      ExcMessage(
        "Size of hp::MappingCollection must be the same as hp::FECollection or 1."));
    Assert(
      q_collection.size() == fe_collection->size() || q_collection.size() == 1,
      ExcMessage(
        "Size of hp::QCollection<dim> must be the same as hp::FECollection or 1."));
    Assert(
      q_collection_1D.size() == fe_collection->size() ||
        q_collection_1D.size() == 1,
      ExcMessage(
        "Size of hp::QCollection<1> must be the same as hp::FECollection or 1."));
 
    fe_values_inside_full_quadrature.emplace(*mapping_collection,
                                             *fe_collection,
                                             q_collection,
                                             region_update_flags.inside);
    fe_values_outside_full_quadrature.emplace(*mapping_collection,
                                              *fe_collection,
                                              q_collection,
                                              region_update_flags.outside);
  }
 
 
 
  template <int dim>
  template <typename CellAccessorType>
  void
  FEInterfaceValues<dim>::do_reinit(
    const TriaIterator<CellAccessorType>          &cell,
    const unsigned int                             face_no,
    const unsigned int                             q_index_in,
    const unsigned int                             active_fe_index_in,
    const std::function<void(::FEInterfaceValues<dim> &,
                             const unsigned int)> &call_reinit)
  {
    current_face_location =
      mesh_classifier->location_to_level_set(cell, face_no);
 
    // These objects were created with a quadrature based on the previous cell
    // and are thus no longer valid.
    fe_values_inside.reset();
    fe_values_outside.reset();
 
    switch (current_face_location)
      {
        case LocationToLevelSet::inside:
          {
            call_reinit(*fe_values_inside_full_quadrature, q_index_in);
            break;
          }
        case LocationToLevelSet::outside:
          {
            call_reinit(*fe_values_outside_full_quadrature, q_index_in);
            break;
          }
        case LocationToLevelSet::intersected:
          {
            unsigned int q_index = q_index_in;
 
            if (q_index == numbers::invalid_unsigned_int)
              {
                unsigned int active_fe_index = active_fe_index_in;
 
                if (active_fe_index == numbers::invalid_unsigned_int)
                  {
                    if constexpr (std::is_same_v<
                                    DoFCellAccessor<dim, dim, true>,
                                    CellAccessorType> ||
                                  std::is_same_v<
                                    DoFCellAccessor<dim, dim, false>,
                                    CellAccessorType>)
                      active_fe_index = cell->active_fe_index();
                    else
                      active_fe_index = 0;
                  }
 
                if (q_collection_1D.size() > 1)
                  q_index = active_fe_index;
                else
                  q_index = 0;
              }
 
            AssertIndexRange(q_index, q_collection_1D.size());
 
            face_quadrature_generator.set_1D_quadrature(q_index);
            face_quadrature_generator.generate(cell, face_no);
 
            const Quadrature<dim - 1> &inside_quadrature =
              face_quadrature_generator.get_inside_quadrature();
            const Quadrature<dim - 1> &outside_quadrature =
              face_quadrature_generator.get_outside_quadrature();
 
            // Even if a cell is formally intersected the number of created
            // quadrature points can be 0. Avoid creating an FEInterfaceValues
            // object if that is the case.
            if (inside_quadrature.size() > 0)
              {
                fe_values_inside.emplace(*mapping_collection,
                                         *fe_collection,
                                         hp::QCollection<dim - 1>(
                                           inside_quadrature),
                                         region_update_flags.inside);
 
                call_reinit(*fe_values_inside, /*q_index=*/0);
              }
 
            if (outside_quadrature.size() > 0)
              {
                fe_values_outside.emplace(*mapping_collection,
                                          *fe_collection,
                                          hp::QCollection<dim - 1>(
                                            outside_quadrature),
                                          region_update_flags.outside);
 
                call_reinit(*fe_values_outside, /*q_index=*/0);
              }
            break;
          }
        default:
          {
            DEAL_II_ASSERT_UNREACHABLE();
            break;
          }
      }
  }
 
 
 
  template <int dim>
  const std::optional<::FEInterfaceValues<dim>> &
  FEInterfaceValues<dim>::get_inside_fe_values() const
  {
    if (current_face_location == LocationToLevelSet::inside)
      return fe_values_inside_full_quadrature;
    else
      return fe_values_inside;
  }
 
 
 
  template <int dim>
  const std::optional<::FEInterfaceValues<dim>> &
  FEInterfaceValues<dim>::get_outside_fe_values() const
  {
    if (current_face_location == LocationToLevelSet::outside)
      return fe_values_outside_full_quadrature;
    else
      return fe_values_outside;
  }
 
 
#include "non_matching/fe_values.inst"
 
} // namespace NonMatching
DEAL_II_NAMESPACE_CLOSE