field_fe.hh

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/*!
 *
 * Copyright (C) 2015 Technical University of Liberec.  All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 3 as published by the
 * Free Software Foundation. (http://www.gnu.org/licenses/gpl-3.0.en.html)
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * 
 * @file    field_fe.hh
 * @brief   
 */

#ifndef FIELD_FE_HH_
#define FIELD_FE_HH_

#include "petscmat.h"
#include "system/system.hh"
#include "system/index_types.hh"
#include "fields/field_algo_base.hh"
#include "fields/fe_value_handler.hh"
#include "la/vector_mpi.hh"
#include "mesh/mesh.h"
#include "mesh/point.hh"
#include "mesh/bih_tree.hh"
#include "mesh/range_wrapper.hh"
#include "io/element_data_cache.hh"
#include "io/msh_basereader.hh"
#include "fem/fe_p.hh"
#include "fem/fe_system.hh"
#include "fem/dofhandler.hh"
#include "fem/finite_element.hh"
#include "fem/dh_cell_accessor.hh"
#include "input/factory.hh"

#include <memory>



/**
 * Class representing fields given by finite element approximation.
 *
 */
template <int spacedim, class Value>
class FieldFE : public FieldAlgorithmBase<spacedim, Value>
{
public:
    typedef typename FieldAlgorithmBase<spacedim, Value>::Point Point;
    typedef FieldAlgorithmBase<spacedim, Value> FactoryBaseType;

    /**
     * Possible interpolations of input data.
     */
    enum DataInterpolation
    {
        identic_msh,    //!< identical mesh
        equivalent_msh, //!< equivalent mesh (default value)
        gauss_p0,       //!< P0 interpolation (with the use of Gaussian distribution)
        interp_p0       //!< P0 interpolation (with the use of calculation of intersections)
    };

    static const unsigned int undef_uint = -1;

    /**
     * Default constructor, optionally we need number of components @p n_comp in the case of Vector valued fields.
     */
    FieldFE(unsigned int n_comp=0);

    /**
     * Return Record for initialization of FieldFE that is derived from Abstract
     */
    static const Input::Type::Record & get_input_type();

    /**
     * Return Input selection for discretization type (determines the section of VTK file).
     */
    static const Input::Type::Selection & get_disc_selection_input_type();

    /**
     * Return Input selection that allow to set interpolation of input data.
     */
    static const Input::Type::Selection & get_interp_selection_input_type();

    /**
     * Setter for the finite element data.
     * @param dh              Dof handler.
     * @param dof_values      Vector of dof values, optional (create own vector according to dofhandler).
     * @param block_index     Index of block (in FESystem) or '-1' for FieldFE under simple DOF handler.
     * @return                Data vector of dof values.
     */
    VectorMPI set_fe_data(std::shared_ptr<DOFHandlerMultiDim> dh, VectorMPI dof_values = VectorMPI::sequential(0),
            unsigned int block_index = FieldFE<spacedim, Value>::undef_uint);

    /**
     * Returns one value in one given point. ResultType can be used to avoid some costly calculation if the result is trivial.
     */
    virtual typename Value::return_type const &value(const Point &p, const ElementAccessor<spacedim> &elm);

    /**
     * Returns std::vector of scalar values in several points at once.
     */
    virtual void value_list (const Armor::array &point_list, const ElementAccessor<spacedim> &elm,
                       std::vector<typename Value::return_type>  &value_list);

    /**
     * Overload @p FieldAlgorithmBase::cache_update
     */
    void cache_update(FieldValueCache<typename Value::element_type> &data_cache,
            ElementCacheMap &cache_map, unsigned int region_patch_idx) override;

    /**
     * Overload @p FieldAlgorithmBase::cache_reinit
     *
     * Reinit fe_values_ data member.
     */
    void cache_reinit(const ElementCacheMap &cache_map) override;

    /**
     * Initialization from the input interface.
     */
    virtual void init_from_input(const Input::Record &rec, const struct FieldAlgoBaseInitData& init_data);


    /**
     * Update time and possibly update data from GMSH file.
     */
    bool set_time(const TimeStep &time) override;


    /**
     * Set target mesh.
     */
    void set_mesh(const Mesh *mesh, bool boundary_domain) override;


    /**
     * Copy data vector to given output ElementDataCache
     */
    void native_data_to_cache(ElementDataCache<double> &output_data_cache);


    /**
     * Return size of vector of data stored in Field
     */
    unsigned int data_size() const;

    inline std::shared_ptr<DOFHandlerMultiDim> get_dofhandler() const {
        return dh_;
    }

    inline VectorMPI& vec() {
        return data_vec_;
    }

    /// Call begin scatter functions (local to ghost) on data vector
    void local_to_ghost_data_scatter_begin();

    /// Call end scatter functions (local to ghost) on data vector
    void local_to_ghost_data_scatter_end();

    /// Destructor.
    virtual ~FieldFE();

private:
    /**
     * Helper class holds specific data of field evaluation.
     */
    class FEItem {
    public:
        unsigned int comp_index_;
        unsigned int range_begin_;
        unsigned int range_end_;
    };

    /// Create DofHandler object
    void make_dof_handler(const Mesh *mesh);

    /// Interpolate data (use Gaussian distribution) over all elements of target mesh.
    void interpolate_gauss(ElementDataCache<double>::ComponentDataPtr data_vec);

    /// Interpolate data (use intersection library) over all elements of target mesh.
    void interpolate_intersection(ElementDataCache<double>::ComponentDataPtr data_vec);

    /// Calculate native data over all elements of target mesh.
    void calculate_native_values(ElementDataCache<double>::ComponentDataPtr data_cache);

    /// Calculate data of identict_mesh interpolation on input data over all elements of target mesh.
    void calculate_identic_values(ElementDataCache<double>::ComponentDataPtr data_cache);

    /// Calculate data of equivalent_mesh interpolation on input over all elements of target mesh.
    void calculate_equivalent_values(ElementDataCache<double>::ComponentDataPtr data_cache);

    /**
     * Fill data to boundary_dofs_ vector.
     *
     * TODO: Temporary solution. Fix problem with merge new DOF handler and boundary Mesh. Will be removed in future.
     */
    void fill_boundary_dofs();

    /// Initialize FEValues object of given dimension.
    template <unsigned int dim>
    Quadrature init_quad(std::shared_ptr<EvalPoints> eval_points);

    inline Armor::ArmaMat<typename Value::element_type, Value::NRows_, Value::NCols_> handle_fe_shape(unsigned int dim,
            unsigned int i_dof, unsigned int i_qp)
    {
        Armor::ArmaMat<typename Value::element_type, Value::NCols_, Value::NRows_> v;
        for (unsigned int c=0; c<Value::NRows_*Value::NCols_; ++c)
            v(c/spacedim,c%spacedim) = fe_values_[dim].shape_value_component(i_dof, i_qp, c);
        if (Value::NRows_ == Value::NCols_)
            return v;
        else
            return v.t();
    }

    template<unsigned int dim>
    void fill_fe_system_data(unsigned int block_index) {
        auto fe_system_ptr = std::dynamic_pointer_cast<FESystem<dim>>( dh_->ds()->fe()[Dim<dim>{}] );
        ASSERT_DBG(fe_system_ptr != nullptr).error("Wrong type, must be FESystem!\n");
        this->fe_item_[dim].comp_index_ = fe_system_ptr->function_space()->dof_indices()[block_index].component_offset;
        this->fe_item_[dim].range_begin_ = fe_system_ptr->fe_dofs(block_index)[0];
        this->fe_item_[dim].range_end_ = this->fe_item_[dim].range_begin_ + fe_system_ptr->fe()[block_index]->n_dofs();
    }


    template<unsigned int dim>
    void fill_fe_item() {
        this->fe_item_[dim].comp_index_ = 0;
        this->fe_item_[dim].range_begin_ = 0;
        this->fe_item_[dim].range_end_ = dh_->ds()->fe()[Dim<dim>{}]->n_dofs();
    }


    /// DOF handler object
    std::shared_ptr<DOFHandlerMultiDim> dh_;
    /// Store data of Field
    VectorMPI data_vec_;

    /// Value handler that allows get value of 0D elements.
    FEValueHandler<0, spacedim, Value> value_handler0_;
    /// Value handler that allows get value of 1D elements.
    FEValueHandler<1, spacedim, Value> value_handler1_;
    /// Value handler that allows get value of 2D elements.
    FEValueHandler<2, spacedim, Value> value_handler2_;
    /// Value handler that allows get value of 3D elements.
    FEValueHandler<3, spacedim, Value> value_handler3_;

    /// mesh reader file
    FilePath reader_file_;

    /// field name read from input
    std::string field_name_;

    /// Specify section where to find the field data in input mesh file
    OutputTime::DiscreteSpace discretization_;

    /// Specify type of FE data interpolation
    DataInterpolation interpolation_;

    /// Field flags.
    FieldFlag::Flags flags_;

    /// Default value of element if not set in mesh data file
    double default_value_;

    /// Accessor to Input::Record
    Input::Record in_rec_;

    /// Is set in set_mesh method. Value true means, that we accept only boundary element accessors in the @p value method.
    bool boundary_domain_;

    /**
     * Hold dofs of boundary elements.
     *
     * TODO: Temporary solution. Fix problem with merge new DOF handler and boundary Mesh. Will be removed in future.
     */
    std::shared_ptr< std::vector<IntIdx> > boundary_dofs_;

    /// List of FEValues objects of dimensions 0,1,2,3 used for value calculation
    std::vector<FEValues<spacedim>> fe_values_;

    /// Maps element indices between source (data) and target (computational) mesh if data interpolation is set to equivalent_msh
    std::shared_ptr<std::vector<LongIdx>> source_target_mesh_elm_map_;

    /// Holds specific data of field evaluation over all dimensions.
    std::array<FEItem, 4> fe_item_;
    MixedPtr<FiniteElement> fe_;

    /// Registrar of class to factory
    static const int registrar;
};


/** Create FieldFE from dof handler */
template <int spacedim, class Value>
std::shared_ptr<FieldFE<spacedim, Value> > create_field_fe(std::shared_ptr<DOFHandlerMultiDim> dh,
                                                           VectorMPI *vec = nullptr,
                                                           unsigned int block_index = FieldFE<spacedim, Value>::undef_uint)
{
    // Construct FieldFE
    std::shared_ptr< FieldFE<spacedim, Value> > field_ptr = std::make_shared< FieldFE<spacedim, Value> >();
    if (vec == nullptr)
        field_ptr->set_fe_data( dh, dh->create_vector(), block_index );
    else
        field_ptr->set_fe_data( dh, *vec, block_index );

    return field_ptr;
}


/** Create FieldFE with parallel VectorMPI from finite element */
template <int spacedim, class Value>
std::shared_ptr<FieldFE<spacedim, Value> > create_field_fe(Mesh & mesh, const MixedPtr<FiniteElement> &fe)
{
    // Prepare DOF handler
    std::shared_ptr<DOFHandlerMultiDim> dh_par = std::make_shared<DOFHandlerMultiDim>(mesh);
    std::shared_ptr<DiscreteSpace> ds = std::make_shared<EqualOrderDiscreteSpace>( &mesh, fe);
    dh_par->distribute_dofs(ds);

    return create_field_fe<spacedim,Value>(dh_par);
}


#endif /* FIELD_FE_HH_ */