getfem_projected_fem.h

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/* -*- c++ -*- (enables emacs c++ mode) */
/*===========================================================================
 
 Copyright (C) 2012-2026 Yves Renard, Konstantinos Poulios
 
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/**@file getfem_projected_fem.h
   @author Konstantinos Poulios <[email protected]>
   @date January 12, 2012.
   @brief FEM which projects a mesh_fem on a different mesh.
*/
 
 
#ifndef GETFEM_PROJECTED_FEM_H__
#define GETFEM_PROJECTED_FEM_H__
 
#include "getfem_fem.h"
#include "getfem_mesh_fem.h"
#include "getfem_mesh_im.h"
#include "bgeot_kdtree.h"
#include "bgeot_geotrans_inv.h"
 
namespace getfem {
 
  struct gausspt_projection_data {
    size_type cv; // convex of the source mesh_fem opposite to the gauss point
    short_type f; // convex face of the source mesh_fem opposite to the gauss point
    size_type iflags;     // flags & 1 : there is an element or not
                          // flags & 2 : base_val is stored
                          // flags & 4 : grad_val is stored
    base_node ptref;      // coords on reference element of mf_source element
    base_node normal;     // normal vector at the projected point on the mf_source element
    scalar_type gap;      // gap distance from the gauss point to the projected point
    base_tensor base_val; // optional storage of the base values
    base_tensor grad_val; // optional storage of the grad base values
    std::map<size_type,size_type> local_dof; // correspondence between dof of the
                                             // mf_source element and dof of the projected element.
    gausspt_projection_data() :
      cv(size_type(-1)), f(short_type(-1)), iflags(size_type(-1)) {}
  };
 
  /** FEM which interpolates the projection of a mesh_fem on a different mesh.
 
    Note that the memory cost of this method is extremely high!
  */
  class projected_fem : public virtual_fem, public context_dependencies {
 
  protected :
 
    struct elt_projection_data {
      short_type f;    // face number on the target mesh
      size_type nb_dof;
      std::map<size_type,gausspt_projection_data> gausspt;
      std::vector<size_type> inddof;
      pintegration_method pim; // for DEBUG
      elt_projection_data() : f(short_type(-1)), nb_dof(0), pim(0) {}
    };
 
    const mesh_fem &mf_source; // mf_source represents the original finite
                               // element method to be projected.
    const mesh_im &mim_target; // mesh on which mf_source is projected.
                               // Contains also the integration method.
    mesh_region rg_source;
    mesh_region rg_target;
 
    bool store_values;
    dal::bit_vector blocked_dofs;
 
    // auxiliary variables
    mutable std::map<size_type,elt_projection_data> elements;
    mutable bgeot::kdtree tree; // Tree containing the nodes of the
                                // projected mf_source dofs
    mutable std::vector<size_type> ind_dof; /* all functions using this work
                                               array should keep it filled
                                               with size_type(-1) */
    mutable bgeot::geotrans_inv_convex gic;
    mutable base_tensor taux;
    mutable fem_interpolation_context fictx;
    mutable size_type fictx_cv;
    mutable base_matrix G;
    mutable bgeot::pstored_point_tab pspt_override;
    mutable bgeot::multi_index mi2, mi3;
    mutable base_node ptref;
 
    void build_kdtree() const;
 
    bool find_a_projected_point(const base_node &pt, base_node &ptr_proj,
                                size_type &cv_proj, short_type &fc_proj) const;
 
    virtual void update_from_context(void) const;
    inline void actualize_fictx(pfem pf, size_type cv,
                                const base_node &ptr) const;
 
  public :
 
    virtual size_type nb_dof(size_type cv) const;
    virtual size_type index_of_global_dof(size_type cv, size_type i) const;
    virtual bgeot::pconvex_ref ref_convex(size_type cv) const;
    virtual const bgeot::convex<base_node> &node_convex(size_type cv) const;
    virtual bgeot::pstored_point_tab node_tab(size_type) const
    { return pspt_override; }
    void base_value(const base_node &, base_tensor &) const;
    void grad_base_value(const base_node &, base_tensor &) const;
    void hess_base_value(const base_node &, base_tensor &) const;
    void real_base_value(const fem_interpolation_context& c,
                         base_tensor &t, bool = true) const;
    void real_grad_base_value(const fem_interpolation_context& c,
                              base_tensor &t, bool = true) const;
    void real_hess_base_value(const fem_interpolation_context&,
                              base_tensor &, bool = true) const;
 
    void projection_data(const fem_interpolation_context& c,
                         base_node &normal, scalar_type &gap) const;
    void projection_data(const base_node &pt,
                         base_node &normal, scalar_type &gap) const;
 
    /** return the list of convexes of the projected mesh_fem which
     *  contain at least one gauss point (should be all convexes)! */
    dal::bit_vector projected_convexes() const;
    
    /** faces and convexes from the target region
     *  that contain at least one Gauss point that is projected by the source */
    mesh_region projected_target_region() const;    
 
    /** return the min/max/mean number of gauss points in the convexes
     *  of the projected mesh_fem */
    void gauss_pts_stats(unsigned &ming, unsigned &maxg,
                         scalar_type &meang) const;
    size_type memsize() const;
 
    projected_fem(const mesh_fem &mf_source_, const mesh_im &mim_target_,
                  size_type rg_source_, size_type rg_target_,
                  dal::bit_vector blocked_dofs_,
                  bool store_val);
    virtual ~projected_fem()
    { DAL_STORED_OBJECT_DEBUG_DESTROYED(this, "Projected fem"); }
  };
 
 
  /** create a new projected FEM.
      @param mf_source the mesh_fem that will be projected.
      @param mim_target the integration method on the final mesh (not the mesh
             of mf_source!).
      @param blocked_dofs list of dof of mf_source which won't be projected.
      @param store_val if true, the values/gradients of interpolated base
             function are cached at each gauss point (eats much memory).
  */
  pfem new_projected_fem(const mesh_fem &mf_source, const mesh_im &mim_target,
                         size_type rg_source_ = size_type(-1),
                         size_type rg_target_ = size_type(-1),
                         dal::bit_vector blocked_dofs = dal::bit_vector(),
                         bool store_val = true);
 
  /** release a projected fem */
  inline void del_projected_fem(pfem pf) { dal::del_stored_object(pf); }
 
 
}  /* end of namespace getfem.                                            */
 
#endif