dunefunctionsfunctionalassembler.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
 
// SPDX-FileCopyrightText: Copyright © DUNE-FUFEM Project contributors, see file AUTHORS.md
// SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception OR LGPL-3.0-or-later
 
#ifndef DUNE_FUFEM_ASSEMBERS_DUNEFUNCTIONSFUNCTIONALASSEMBLER_HH
#define DUNE_FUFEM_ASSEMBERS_DUNEFUNCTIONSFUNCTIONALASSEMBLER_HH
 
#ifndef DUNE_FUFEM_DISABLE_HEADER_DEPRECATION
#warning This header is deprecated and will be removed after 2.11. Use the global assemblers from dune/assembler/defaultglobalassembler.hh instead.
#endif
 
#include <dune/common/deprecated.hh>
#include <dune/common/std/type_traits.hh>
#include <dune/common/concept.hh>
 
#include <dune/istl/bvector.hh>
 
#include <dune/grid/common/capabilities.hh>
 
#include <dune/functions/backends/concepts.hh>
#include <dune/functions/backends/istlvectorbackend.hh>
 
#include <dune/fufem/parallel/parallelalgorithm.hh>
 
 
 
namespace Dune {
namespace Fufem {
 
 
template <class TestBasis>
class
[[deprecated("This class will be removed after 2.11. Use Dune::Assembler::Assembler together with Dune::Fufem::Forms based local assemblers instead.")]]
DuneFunctionsFunctionalAssembler
{
  using GridView = typename TestBasis::GridView;
 
  // SFINAE expression check for preprocess() method of local assembler
  template <class LocalAssembler>
  using LocalAssemblerPreprocess = decltype(std::declval<LocalAssembler>().preprocess(std::declval<typename TestBasis::LocalView>()));
 
public:
  [[deprecated("This class will be removed after 2.11. Use Dune::Assembler::Assembler together with Dune::Fufem::Forms based local assemblers instead.")]]
  DuneFunctionsFunctionalAssembler(const TestBasis& tBasis) :
      testBasis_(tBasis)
  {}
 
  template<class V>
  static decltype(auto) toVectorBackend(V& v)
  {
    if constexpr (Dune::models<Dune::Functions::Concept::VectorBackend<TestBasis>, decltype(v)>())
      return v;
    else
      return Dune::Functions::istlVectorBackend(v);
  }
 
  template <class Vector, class LocalAssembler>
  void assembleBulkEntries(Vector&& vector, LocalAssembler&& localAssembler) const
  {
    auto&& vectorBackend = toVectorBackend(vector);
 
    auto testLocalView     = testBasis_.localView();
 
    if constexpr(Dune::Std::is_detected_v<LocalAssemblerPreprocess, LocalAssembler>)
      localAssembler.preprocess(testLocalView);
 
    using Field = std::decay_t<decltype(vectorBackend[testLocalView.index(0)])>;
    using LocalVector = Dune::BlockVector<Dune::FieldVector<Field,1>>;
 
    auto localVector = LocalVector(testLocalView.maxSize());
 
    for (const auto& element : elements(testBasis_.gridView()))
    {
      testLocalView.bind(element);
 
      for (size_t i=0; i<testLocalView.tree().size(); ++i)
      {
        auto localRow = testLocalView.tree().localIndex(i);
        localVector[localRow] = 0;
      }
 
      localAssembler(element, localVector, testLocalView);
 
      // Add element stiffness matrix onto the global stiffness matrix
      for (size_t i=0; i<testLocalView.tree().size(); ++i)
      {
        auto localRow = testLocalView.tree().localIndex(i);
        auto row = testLocalView.index(localRow);
        vectorBackend[row] += localVector[localRow];
      }
    }
  }
 
  template <class Vector, class LocalAssembler, class ElementPartition>
  void assembleBulkEntries(Vector&& vector, LocalAssembler&& localAssembler, const ElementPartition& elementPartition, std::size_t threadCount) const
  {
    static_assert(Dune::Capabilities::viewThreadSafe<typename GridView::Grid>::v, "Trying to use thread parallel assembler but grid is not viewThreadSafe.");
 
    auto&& vectorBackend = toVectorBackend(vector);
 
    parallelAlgorithm(threadCount, [&, localAssembler](auto parallel) mutable {
      auto testLocalView = testBasis_.localView();
 
      if constexpr(Dune::Std::is_detected_v<LocalAssemblerPreprocess, LocalAssembler>)
        localAssembler.preprocess(testLocalView);
 
      using Field = std::decay_t<decltype(vectorBackend[testLocalView.index(0)])>;
      using LocalVector = Dune::BlockVector<Dune::FieldVector<Field,1>>;
 
      auto localVector = LocalVector(testLocalView.maxSize());
 
      parallel.coloredForEach(elementPartition, [&](const auto& element) {
        testLocalView.bind(element);
 
        for (size_t i=0; i<testLocalView.tree().size(); ++i)
        {
          auto localRow = testLocalView.tree().localIndex(i);
          localVector[localRow] = 0;
        }
 
        localAssembler(element, localVector, testLocalView);
 
        // Add element stiffness matrix onto the global stiffness matrix
        for (size_t i=0; i<testLocalView.tree().size(); ++i)
        {
          auto localRow = testLocalView.tree().localIndex(i);
          auto row = testLocalView.index(localRow);
          vectorBackend[row] += localVector[localRow];
        }
      });
    });
  }
 
 
  template <class Vector, class LocalAssembler>
  void assembleBulk(Vector&& vector, LocalAssembler&& localAssembler) const
  {
    auto&& vectorBackend = toVectorBackend(vector);
 
    vectorBackend.resize(testBasis_);
    vectorBackend = 0.0;
    assembleBulkEntries(vectorBackend, std::forward<LocalAssembler>(localAssembler));
  }
 
  template <class Vector, class LocalAssembler, class ElementPartition>
  void assembleBulk(Vector&& vector, LocalAssembler&& localAssembler, const ElementPartition& elementPartition, std::size_t threadCount) const
  {
    auto&& vectorBackend = toVectorBackend(vector);
 
    vectorBackend.resize(testBasis_);
    vectorBackend = 0.0;
    assembleBulkEntries(vectorBackend, std::forward<LocalAssembler>(localAssembler), elementPartition, threadCount);
  }
 
 
protected:
  const TestBasis& testBasis_;
};
 
 
template <class TestBasis>
[[deprecated("This function will be removed after 2.11. Use Dune::Assembler::Assembler together with Dune::Fufem::Forms based local assemblers instead.")]]
auto duneFunctionsFunctionalAssembler(const TestBasis& testBasis)
{
DUNE_NO_DEPRECATED_BEGIN
  return DuneFunctionsFunctionalAssembler<TestBasis>(testBasis);
DUNE_NO_DEPRECATED_END
}
 
 
 
} // namespace Fufem
} // namespace Dune
 
 
#endif // DUNE_FUFEM_ASSEMBERS_DUNEFUNCTIONSFUNCTIONALASSEMBLER_HH