intersectionwriter.hh

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
//
// SPDX-FileCopyrightInfo: Copyright © DuMux Project contributors, see AUTHORS.md in root folder
// SPDX-License-Identifier: GPL-3.0-or-later
//
#ifndef DUMUX_IO_VTK_INTERSECTIONWRITER_HH
#define DUMUX_IO_VTK_INTERSECTIONWRITER_HH
 
#include <memory>
#include <string>
 
#include <dune/common/typetraits.hh>
#include <dune/grid/io/file/vtk.hh>
#include <dune/grid/io/file/vtk/basicwriter.hh>
#include <dune/grid/io/file/vtk/function.hh>
#include <dune/grid/io/file/vtk/skeletonfunction.hh>
#include <dumux/common/parameters.hh>
 
namespace Dumux::Detail {
 
template<typename GV>
class GridIntersectionIterator
: public Dune::ForwardIteratorFacade<GridIntersectionIterator<GV>,
                                     const typename GV::Intersection,
                                     const typename GV::Intersection&,
                                     typename std::iterator_traits<typename GV::template Codim<0>::Iterator>::difference_type>
{
public:
    using DerivedType = GridIntersectionIterator<GV>;
    using Intersection = typename GV::Intersection;
    using Value = const Intersection;
    using ElementIterator = typename GV::template Codim<0>::Iterator;
    using IntersectionIterator = typename GV::IntersectionIterator;
    using DifferenceType = typename std::iterator_traits<ElementIterator>::difference_type;
 
    GridIntersectionIterator(const GV& gv, bool end = false)
    : gridView_(gv), eIt_(end ? gridView_.template end<0>() : gridView_.template begin<0>())
    {
        if (eIt_ != gridView_.template end<0>())
            iIt_ = IntersectionIterator(gridView_.ibegin(*eIt_));
    }
 
    const Intersection& dereference() const
    {
        if constexpr (std::is_lvalue_reference_v<decltype(*std::declval<IntersectionIterator>())>)
            return *iIt_;
        else
        {
            // Some grids only return temporary intersection objects.
            // If this is the case, story a copy of the intersection here so that
            // its address can be safely taken later on.
            intersection_ = *iIt_;
            return intersection_;
        }
    }
 
    bool equals(const DerivedType& other) const
    {
        if (eIt_ != other.eIt_)
            return false;
 
        // this is a bit tricky, since we may not compare iIt_ if we are
        // passed-the-end
        bool mePassedTheEnd = eIt_ == gridView_.template end<0>();
        bool otherPassedTheEnd = other.eIt_ == other.gridView_.template end<0>();
 
        // both passed-the-end => consider them equal
        if(mePassedTheEnd && otherPassedTheEnd)
            return true;
 
        // one passed the end => not equal
        if(mePassedTheEnd || otherPassedTheEnd)
            return false;
 
        // none passed-the-end => do their iIt_ iterators match?
        return iIt_ == other.iIt_;
    }
 
    void increment()
    {
        ++iIt_;
        if (iIt_ == gridView_.iend(*eIt_))
        {
            iIt_ = IntersectionIterator();
            ++eIt_;
            if (eIt_ != gridView_.template end<0>())
                iIt_ = IntersectionIterator(gridView_.ibegin(*eIt_));
        }
    }
 
private:
    const GV gridView_;
    ElementIterator eIt_;
    IntersectionIterator iIt_;
    mutable Intersection intersection_;
};
 
template<class GridView>
class NonConformingIntersectionIteratorFactory
{
public:
    static constexpr auto dimCell = GridView::dimension-1;
    using Cell = typename GridView::Intersection;
    using CellIterator = GridIntersectionIterator<GridView>;
    using Corner = Dune::VTK::Corner<Cell>;
    using CornerIterator = Dune::VTK::CornerIterator<CellIterator>;
    using Point = Corner;
    using PointIterator = CornerIterator;
    using ConnectivityWriter = Dune::VTK::NonConformingConnectivityWriter<Cell>;
    using Communication = typename GridView::Communication;
 
    explicit NonConformingIntersectionIteratorFactory(const GridView& gv)
    : gridView_(gv) {}
 
    CellIterator beginCells() const
    { return CellIterator(gridView_); }
 
    CellIterator endCells() const
    { return CellIterator(gridView_, true); }
 
    CornerIterator beginCorners() const
    { return CornerIterator(beginCells(), endCells()); }
 
    CornerIterator endCorners() const
    { return CornerIterator(endCells()); }
 
    PointIterator beginPoints() const
    { return beginCorners(); }
 
    PointIterator endPoints() const
    { return endCorners(); }
 
    ConnectivityWriter makeConnectivity() const
    { return ConnectivityWriter(); }
 
    const Communication& comm() const
    { return gridView_.comm(); }
 
private:
    GridView gridView_;
};
 
template<class GridView, class Mapper, class F>
class SkeletonFunction
{
    using Intersection = typename GridView::Intersection;
public:
    using Traits = Dune::VTK::SkeletonFunctionTraits<GridView, typename GridView::ctype>;
 
    SkeletonFunction(const GridView& gv, const Mapper& mapper, const F& field)
    : gv_(gv)
    , mapper_(mapper)
    , field_(field)
    , components_(1)
    {
        if constexpr (std::is_invocable_v<F, Intersection, int>)
        {
            if constexpr (Dune::IsIndexable<std::decay_t<decltype(field(std::declval<Intersection>(), 0))>>{})
            {
                if constexpr (Dune::IsIndexable<std::decay_t<decltype(field(std::declval<Intersection>(), 0)[0])>>{})
                    DUNE_THROW(Dune::InvalidStateException, "Invalid field type");
                else
                {
                    const auto& is = *(intersections(gv, *(elements(gv).begin())).begin());
                    components_ = field(is, mapper_(is, gv_)).size();
                }
            }
        }
        else if constexpr (Dune::IsIndexable<std::decay_t<decltype(field[0])>>{})
        {
            assert(field.size() == gv.size(1));
            if constexpr (Dune::IsIndexable<std::decay_t<decltype(field[0][0])>>{})
              DUNE_THROW(Dune::InvalidStateException, "Invalid field type");
            else
              components_ = field[0].size();
        }
    }
 
    unsigned dimRange() const { return components_; }
 
    void evaluate(const typename Traits::Cell& intersection,
                  const typename Traits::Domain& xl,
                  typename Traits::Range& result) const
    {
        assert(intersection.conforming());
        result.resize(components_);
        const auto idx = mapper_(intersection, gv_);
 
        auto accessEntry = [&](auto i)
        {
            if constexpr (std::is_invocable_v<F, Intersection, int>)
            {
                if constexpr (Dune::IsIndexable<std::decay_t<decltype(field_(intersection, idx))>>{})
                    return field_(intersection, idx)[i];
                else
                    return field_(intersection, idx);
            }
            else
            {
                if constexpr (Dune::IsIndexable<std::decay_t<decltype(std::declval<F>()[0])>>{})
                    return field_[idx][i];
                else
                    return field_[idx];
            }
        };
 
        for (int i = 0; i < components_; ++i)
            result[i] = accessEntry(i);
    }
 
private:
    GridView gv_;
    const Mapper& mapper_;
 
    // If F is callable we store a copy of it, otherwise we assume that F is a container
    // stored somewhere else, thus we only keep a reference here
    std::conditional_t<std::is_invocable_v<F,Intersection, int>, const F, const F&> field_;
 
    std::size_t components_;
};
 
} // end namespace Dumux::Detail
 
namespace Dumux {
template<class GridView>
class ConformingIntersectionWriter
: public Detail::NonConformingIntersectionIteratorFactory<GridView>
, public Dune::VTK::BasicWriter<Detail::NonConformingIntersectionIteratorFactory<GridView>>
{
    using Factory = Detail::NonConformingIntersectionIteratorFactory<GridView>;
    using Base = Dune::VTK::BasicWriter<Factory>;
 
public:
    ConformingIntersectionWriter(const GridView& gridView, const std::string& paramGroup = "")
    : Factory(gridView), Base(static_cast<const Factory&>(*this)), gridView_(gridView)
    {
        static bool addProcessRank = getParamFromGroup<bool>(paramGroup, "Vtk.AddProcessRank");
        if (addProcessRank)
        {
            auto getRank = [rank = gridView_.comm().rank()](const auto& is, const auto idx)
            { return rank; };
 
            auto mapper = getStandardMapper();
            using SF = Detail::SkeletonFunction<GridView, decltype(mapper), decltype(getRank)>;
            auto fun = std::make_shared<SF>(gridView_, mapper, getRank);
            addCellData(fun, "processRank");
        }
    }
 
    using Base::addCellData;
 
    static auto getStandardMapper()
    {
        return [](const auto& is, const GridView& gridView){ return gridView.indexSet().subIndex(is.inside(), is.indexInInside(), 1); };
    }
 
    template<class F, class Mapper = decltype(getStandardMapper())>
    auto makeSkeletonFunction(const F& f, const Mapper& mapper = getStandardMapper()) const
    {
        return std::make_shared<Detail::SkeletonFunction<GridView, decltype(mapper), decltype(f)>>(gridView_, mapper, f);
    }
 
    template<class Func>
    void addCellData(const std::shared_ptr<Func>& p, const std::string& name)
    {
      addCellData(std::shared_ptr<typename Base::FunctionWriter>
                  (new Dune::VTK::SkeletonFunctionWriter<Func>(p, name)));
    }
 
    template<class Func>
    void addCellData(Func* p, const std::string& name)
    {
        addCellData(std::shared_ptr<Func>(p), name);
    }
 
    template<class F>
    void addField(const F& field, const std::string& name)
    {
        auto mapper = getStandardMapper();
        addCellData(makeSkeletonFunction(field, mapper), name);
    }
 
    using Base::addPointData;
 
    template<class Func>
    void addPointData(const std::shared_ptr<Func>& p, const std::string& name)
    {
        addPointData(std::shared_ptr<typename Base::FunctionWriter>
                     (new Dune::VTK::SkeletonFunctionWriter<Func>(p, name)));
    }
 
    template<class Func>
    void addPointData(Func* p, const std::string& name)
    {
        addPointData(std::shared_ptr<Func>(p), name);
    }
 
    std::string write(const std::string& name, Dune::VTK::OutputType outputType = Dune::VTK::OutputType::ascii)
    {
        return Base::write(name, outputType);
    }
 
private:
    GridView gridView_;
};
 
} // end namespace Dumux
 
#endif