transformedindexbasis.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 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_FUNCTIONS_FUNCTIONSPACEBASES_TRANSFORMEDINDEXBASIS_HH
#define DUNE_FUNCTIONS_FUNCTIONSPACEBASES_TRANSFORMEDINDEXBASIS_HH
 
#include <tuple>
#include <utility>
 
#include <dune/common/hybridutilities.hh>
#include <dune/common/reservedvector.hh>
#include <dune/common/typeutilities.hh>
#include <dune/common/hybridutilities.hh>
 
#include <dune/functions/common/staticforloop.hh>
#include <dune/functions/common/type_traits.hh>
#include <dune/functions/common/utility.hh>
#include <dune/functions/functionspacebases/basistags.hh>
#include <dune/functions/functionspacebases/nodes.hh>
#include <dune/functions/functionspacebases/concepts.hh>
#include <dune/functions/functionspacebases/defaultglobalbasis.hh>
 
 
namespace Dune {
namespace Functions {
namespace Experimental {
 
// *****************************************************************************
// *****************************************************************************

template<class RPB, class T>
class TransformedIndexPreBasis
{
  using Transformation = T;
 
  using This = TransformedIndexPreBasis<RPB, T>;
 
public:
 
  using RawPreBasis = RPB;

  using GridView = typename RawPreBasis::GridView;

  using size_type = std::size_t;

  using Node = typename RawPreBasis::Node;
 
  static constexpr size_type maxMultiIndexSize = Transformation::maxIndexSize;
  static constexpr size_type minMultiIndexSize = Transformation::minIndexSize;
  static constexpr size_type multiIndexBufferSize = std::max(RawPreBasis::multiIndexBufferSize, maxMultiIndexSize);

  template<class RPB_R, class T_R>
  TransformedIndexPreBasis(RPB_R&& rawPreBasis, T_R&& transformation) :
    rawPreBasis_(std::forward<RPB_R>(rawPreBasis)),
    transformation_(std::forward<T_R>(transformation))
  {}

  void initializeIndices()
  {
    rawPreBasis_.initializeIndices();
  }

  const GridView& gridView() const
  {
    return rawPreBasis_.gridView();
  }

  void update(const GridView& gv)
  {
    rawPreBasis_.update(gv);
  }

  Node makeNode() const
  {
    return rawPreBasis_.makeNode();
  }

  size_type size() const
  {
    return size(Dune::ReservedVector<size_type, multiIndexBufferSize>{});
  }

  template<class SizePrefix>
  size_type size(const SizePrefix& prefix) const
  {
    return transformation_.size(prefix, rawPreBasis_);
  }

  auto containerDescriptor() const
  {
    return transformation_.containerDescriptor(rawPreBasis_);
  }

  size_type dimension() const
  {
    return transformation_.dimension(rawPreBasis_);
  }

  size_type maxNodeSize() const
  {
    return rawPreBasis_.maxNodeSize();
  }
 
  const RawPreBasis& rawPreBasis() const
  {
    return rawPreBasis_;
  }
 
  RawPreBasis& rawPreBasis()
  {
    return rawPreBasis_;
  }
 
  template<class MultiIndex>
  void transformIndex(MultiIndex& multiIndex) const
  {
    transformation_.transformIndex(multiIndex, rawPreBasis_);
  }
 
  template<typename It>
  It indices(const Node& node, It it) const
  {
    rawPreBasis().indices(node, it);
    for(std::size_t i=0; i<node.size(); ++i)
    {
      transformIndex(*it);
      ++it;
    }
    return it;
  }
 
protected:
  RawPreBasis rawPreBasis_;
  Transformation transformation_;
};
 
template<class RPB, class T>
TransformedIndexPreBasis(RPB&&, T&&) -> TransformedIndexPreBasis<std::decay_t<RPB>, std::decay_t<T>>;
 
 
} // end namespace Experimental
 
 
namespace BasisFactory {
namespace Experimental {

template<class RawPreBasisFactory, class Transformation>
auto transformIndices(
    RawPreBasisFactory&& preBasisFactory,
    Transformation&& transformation)
{
  return [
    preBasisFactory=std::forward<RawPreBasisFactory>(preBasisFactory),
    transformation =std::forward<Transformation>(transformation)
  ](const auto& gridView) {
    return Dune::Functions::Experimental::TransformedIndexPreBasis(preBasisFactory(gridView), std::move(transformation));
  };
}
 
 

template<class IndexTransformation, class SizeImplementation, class ContainerDescriptorImplementation, std::size_t minIS, std::size_t maxIS>
class GenericIndexingTransformation
{
public:
 
  static constexpr std::size_t minIndexSize = minIS;
  static constexpr std::size_t maxIndexSize = maxIS;
 
  template<class IT_R, class SI_R, class CD_R>
  GenericIndexingTransformation(IT_R&& indexTransformation, SI_R&& sizeImplementation, CD_R&& containerDescriptorImplementation) :
    indexTransformation_(std::forward<IT_R>(indexTransformation)),
    sizeImplementation_(std::forward<SI_R>(sizeImplementation)),
    containerDescriptorImplementation_(std::forward<CD_R>(containerDescriptorImplementation))
  {}
 
  template<class MultiIndex, class PreBasis>
  void transformIndex(MultiIndex& multiIndex, const PreBasis& preBasis) const
  {
    indexTransformation_(multiIndex, preBasis);
  }
 
  template<class Prefix, class PreBasis>
  auto size(const Prefix& prefix, const PreBasis& preBasis) const
  {
    return sizeImplementation_(prefix, preBasis);
  }
 
  template<class PreBasis>
  auto dimension(const PreBasis& preBasis) const
  {
    return preBasis.dimension();
  }
 
  template<class PreBasis>
  auto containerDescriptor(const PreBasis& preBasis) const
  {
    return containerDescriptorImplementation_(preBasis);
  }
 
private:
  IndexTransformation indexTransformation_;
  SizeImplementation sizeImplementation_;
  ContainerDescriptorImplementation containerDescriptorImplementation_;
};
 
 

template<class IndexTransformation, class SizeImplementation, class ContainerDescriptorImplementation, std::size_t minIndexSize, std::size_t maxIndexSize>
auto indexTransformation(IndexTransformation&& indexTransformation,
                         SizeImplementation&& sizeImplementation,
                         ContainerDescriptorImplementation&& containerDescriptorImplementation,
                         Dune::index_constant<minIndexSize>,
                         Dune::index_constant<maxIndexSize>)
{
  return GenericIndexingTransformation<
    std::decay_t<IndexTransformation>,
    std::decay_t<SizeImplementation>,
    std::decay_t<ContainerDescriptorImplementation>,
    minIndexSize, maxIndexSize>(
        std::forward<IndexTransformation>(indexTransformation),
        std::forward<SizeImplementation>(sizeImplementation),
        std::forward<ContainerDescriptorImplementation>(containerDescriptorImplementation));
}

template<class IndexTransformation, class SizeImplementation,
         std::size_t minIndexSize, std::size_t maxIndexSize>
auto indexTransformation(IndexTransformation&& indexTrafo,
                         SizeImplementation&& sizeImpl,
                         Dune::index_constant<minIndexSize> minSize,
                         Dune::index_constant<maxIndexSize> maxSize)
{
  return indexTransformation(indexTrafo, sizeImpl,
    [](auto&&) { return Dune::Functions::ContainerDescriptors::Unknown{}; },
    minSize, maxSize);
}
 
} // end namespace Experimental
} // end namespace BasisFactory
} // end namespace Functions
} // end namespace Dune
 
 
#endif // DUNE_FUNCTIONS_FUNCTIONSPACEBASES_TRANSFORMEDINDEXBASIS_HH