DOFVectorBase.hpp

#pragma once

#include <cmath>
#include <utility>

#include <dune/common/typetraits.hh>
#include <dune/functions/functionspacebases/sizeinfo.hh>

#include <amdis/DataTransfer.hpp>
#include <amdis/GridTransferManager.hpp>
#include <amdis/OperatorList.hpp>
#include <amdis/common/FlatVector.hpp>
#include <amdis/common/Math.hpp>
#include <amdis/common/TypeTraits.hpp>
#include <amdis/linearalgebra/DOFVectorInterface.hpp>
#include <amdis/typetree/MultiIndex.hpp>
#include <amdis/typetree/TreePath.hpp>

namespace AMDiS
{
  /// The container that stores a data-vector and a corresponding basis, should be
  /// derived from \ref DOFVectorBase.
  template <class GlobalBasis, class ValueType = double>
  class DOFVector;

  /// \brief Create a DOFVector from a basis.
  /**
   * This generator function accepts the basis as reference, temporary, or
   * shared_ptr. Internally the reference is wrapped into a non-destroying
   * shared_ptr and the temporary is moved into a new shared_ptr.
   *
   * The DataTransferOperation controls what is done during grid changes with the
   * DOFVector. The default is interpolation of the data to the new grid. See
   * \ref DataTransferOperation for more options.
   **/
  template <class ValueType = double, class GlobalBasis>
  DOFVector<Underlying_t<GlobalBasis>, ValueType>
  makeDOFVector(GlobalBasis&& basis, DataTransferOperation op = DataTransferOperation::INTERPOLATE)
  {
    return {FWD(basis), op};
  }


  /// \brief The basic container that stores a base vector and a corresponding basis
  /**
   * Basis implementation of DOFVector, i.e. a vector storing all the
   * assembled Operators indexed with DOF indices. The vector data is associated
   * to a global basis.
   *
   * \tparam GB  Basis of the vector
   * \tparam Backend  A linear algebra backend implementing the storage and operations.
   **/
  template <class GB, class Backend>
  class DOFVectorBase
      : public DOFVectorInterface
  {
    using Self = DOFVectorBase;

  public:
    /// The type of the functionspace basis associated to this vector
    using GlobalBasis = GB;
    using LocalView = typename GB::LocalView;

    using Element = typename LocalView::Element;
    using Geometry = typename Element::Geometry;

    /// The index/size - type
    using size_type  = typename GB::size_type;

    /// The type of the elements of the DOFVector
    using value_type = typename Backend::value_type;

    /// The type of the data vector used in the backend
    using BaseVector = typename Backend::BaseVector;

    /// The type of the vector filled on an element with local contributions
    using ElementVector = FlatVector<value_type>;

    /// Defines an interface to transfer the data during grid adaption
    using DataTransfer = DataTransferInterface<Self>;

    /// A creator for a concrete data transfer object, depending on \ref DataTransferOperation
    using DataTransferFactory = AMDiS::DataTransferFactory<Self>;

  public:
    /// Constructor. Stores the shared_ptr of the basis and creates a new DataTransfer.
    DOFVectorBase(std::shared_ptr<GlobalBasis> basis, DataTransferOperation op)
      : basis_(std::move(basis))
      , dataTransfer_(DataTransferFactory::create(op, basis_))
    {
      compress();
      attachToGridTransfer();
      operators_.init(*basis_);
    }

    /// Constructor. Wraps the reference into a non-destroying shared_ptr or moves
    /// the basis into a new shared_ptr.
    template <class GB_>
    DOFVectorBase(GB_&& basis, DataTransferOperation op)
      : DOFVectorBase(Dune::wrap_or_move(FWD(basis)), op)
    {}

    /// Copy constructor
    DOFVectorBase(Self const& that)
      : basis_(that.basis_)
      , backend_(that.backend_)
      , elementVector_(that.elementVector_)
      , operators_(that.operators_)
      , dataTransfer_(that.dataTransfer_)
    {
      attachToGridTransfer();
    }

    /// Move constructor
    DOFVectorBase(Self&& that)
      : basis_(std::move(that.basis_))
      , backend_(std::move(that.backend_))
      , elementVector_(std::move(that.elementVector_))
      , operators_(std::move(that.operators_))
      , dataTransfer_(std::move(that.dataTransfer_))
    {
      attachToGridTransfer();
    }

    /// Destructor
    ~DOFVectorBase() override
    {
      detachFromGridTransfer();
    }

    /// Copy assignment operator
    Self& operator=(Self const& that)
    {
      detachFromGridTransfer();
      basis_ = that.basis_;
      backend_.resize(that.size());
      backend_ = that.backend_;
      dataTransfer_ = that.dataTransfer_;
      attachToGridTransfer();
      return *this;
    }

    /// Move assignment
    Self& operator=(Self&& that) = default;

    /// Sets each DOFVector to the scalar \p value.
    template <class Number,
      REQUIRES(Dune::IsNumber<Number>::value)>
    Self& operator=(Number value)
    {
      backend_.set(value);
      return *this;
    }

    /// Return the basis \ref basis_ associated to the vector
    std::shared_ptr<GlobalBasis const> basis() const
    {
      return basis_;
    }

    /// Return the data-vector
    BaseVector const& vector() const
    {
      return backend_.vector();
    }

    /// Return the data-vector
    BaseVector& vector()
    {
      return backend_.vector();
    }

    /// Return the size of the \ref basis
    size_type size() const
    {
      return basis_->dimension();
    }

    /// Resize the \ref vector to the size of the \ref basis
    void resize(Dune::Functions::SizeInfo<GB> const& s)
    {
      backend_.resize(size_type(s));
    }

    /// Resize the \ref vector to the size of the \ref basis and set to zero
    void compress() override
    {
      if (size_type(backend_.size()) != size()) {
        backend_.resize(size());
        backend_.set(0);
      }
    }

    /// Access the entry \p idx of the \ref vector with read-access.
    template <class Index>
    auto const& operator[](Index idx) const
    {
      size_type i = flatMultiIndex(idx);
      return backend_[i];
    }

    /// Access the entry \p idx of the \ref vector with write-access.
    template <class Index>
    auto& operator[](Index idx)
    {
      size_type i = flatMultiIndex(idx);
      return backend_[i];
    }

    /// Prepare the DOFVector for insertion of values, finish the insertion with
    /// \ref finish().
    void init(bool asmVector);

    /// Finish the insertion of values, see \ref init()
    void finish(bool asmVector);

    /// Insert a block of values into the matrix (add to existing values)
    void insert(LocalView const& localView, ElementVector const& elementVector);

    /// Associate a local operator with this DOFVector
    template <class ContextTag, class Expr, class TreePath = RootTreePath>
    void addOperator(ContextTag contextTag, Expr const& expr, TreePath path = {});

    /// Assemble the vector operators on the bound element.
    void assemble(LocalView const& localView);

    /// Assemble all vector operators added by \ref addOperator().
    void assemble();

    /// Write DOFVector to file
    void backup(std::string const& filename);

    /// Read backup data from file
    void restore(std::string const& filename);

    /// Return the associated DataTransfer object
    std::shared_ptr<DataTransfer const> dataTransfer() const
    {
      return dataTransfer_;
    }

    /// Return the associated DataTransfer object
    std::shared_ptr<DataTransfer> dataTransfer()
    {
      return dataTransfer_;
    }

    /// Create a new DataTransfer object based on the operation type
    void setDataTransfer(DataTransferOperation op)
    {
      dataTransfer_ = DataTransferFactory::create(op, this->basis());
    }

    /// Assign the DataTransfer object
    void setDataTransfer(std::shared_ptr<DataTransfer> const& dataTransfer)
    {
      dataTransfer_ = dataTransfer;
    }

    /// Implementation of \ref DOFVectorInterface::preAdapt
    /// Redirects to a \ref DataTransfer object.
    void preAdapt(bool mightCoarsen) override
    {
      dataTransfer_->preAdapt(*this, mightCoarsen);
    }

    /// Implementation of \ref DOFVectorInterface::postAdapt
    /// Redirects to a \ref DataTransfer object.
    void postAdapt(bool refined) override
    {
      dataTransfer_->postAdapt(*this, refined);
    }

  private:
    // register this DOFVector and its basis to the DataTransfer
    void attachToGridTransfer()
    {
      GridTransferManager::attach(basis_->gridView().grid(), *this);
      GridTransferManager::attach(basis_->gridView().grid(), *basis_);
    }

    // deregister this DOFVector and its basis from the DataTransfer
    void detachFromGridTransfer()
    {
      GridTransferManager::detach(basis_->gridView().grid(), *basis_);
      GridTransferManager::detach(basis_->gridView().grid(), *this);
    }

  private:
    /// The finite element space / basis associated with the data vector
    std::shared_ptr<GlobalBasis> basis_;

    /// Data backend
    Backend backend_;

    /// Dense vector to store coefficients during \ref assemble()
    ElementVector elementVector_;

    /// List of operators associated to nodes, filled in \ref addOperator().
    VectorOperators<GlobalBasis,ElementVector> operators_;

    /// Data interpolation when the grid changes, set by default
    /// to \ref DataTransferOperation::INTERPOLATE.
    std::shared_ptr<DataTransfer> dataTransfer_;
  };

} // end namespace AMDiS

#include "DOFVectorBase.inc.hpp"