Masse_DG_base.cpp

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#include <Masse_DG_base.h>
#include <Domaine_Cl_DG.h>
#include <Domaine_DG.h>
#include <Equation_base.h>
#include <Milieu_base.h>
#include <BasisFunction.h>
 
Implemente_base(Masse_DG_base, "Masse_DG_base", Solveur_Masse_base);
Sortie& Masse_DG_base::printOn(Sortie& s) const { return s << que_suis_je() << " " << le_nom(); }
Entree& Masse_DG_base::readOn(Entree& s) { return s; }
 
void Masse_DG_base::associer_domaine_dis_base(const Domaine_dis_base& le_dom_dis_base)
{
  le_dom_dg_ = ref_cast(Domaine_DG, le_dom_dis_base);
}
 
void Masse_DG_base::associer_domaine_cl_dis_base(const Domaine_Cl_dis_base& le_dom_Cl_dis_base)
{
  le_dom_Cl_dg_ = ref_cast(Domaine_Cl_DG, le_dom_Cl_dis_base);
}
 
/**
 * @brief Multiplies the mass coefficient vector element-wise by an optional temporal field.
 *
 * @details If a temporal coefficient has been registered (has_coefficient_temporel_ == true),
 * the field named name_of_coefficient_temporel_ is retrieved from the equation and its
 * values are applied to coef via tab_multiply_any_shape(). Three field types are handled:
 *  - Champ_Inc_base: uses the first part of the field's values (ConstDoubleTab_parts[0]).
 *  - Champ_Fonc_base: uses the field's values directly.
 *  - Champ_Don_base: evaluates the field at the unknown's node coordinates.
 * If no temporal coefficient is registered, coef is left unchanged.
 *
 * @param coef The coefficient vector to scale in-place (typically initialized to 1).
 */
void Masse_DG_base::appliquer_coef(DoubleVect& coef) const
{
  if (has_coefficient_temporel_)
    {
      OBS_PTR(Champ_base) ref_coeff;
      ref_coeff = equation().get_champ(name_of_coefficient_temporel_);
 
      DoubleTab values;
      if (sub_type(Champ_Inc_base,ref_coeff.valeur()))
        {
          const Champ_Inc_base& coeff = ref_cast(Champ_Inc_base,ref_coeff.valeur());
          ConstDoubleTab_parts val_parts(coeff.valeurs());
          values.ref(val_parts[0]);
 
        }
      else if (sub_type(Champ_Fonc_base,ref_coeff.valeur()))
        {
          const Champ_Fonc_base& coeff = ref_cast(Champ_Fonc_base,ref_coeff.valeur());
          values.ref(coeff.valeurs());
 
        }
      else if (sub_type(Champ_Don_base,ref_coeff.valeur()))
        {
          DoubleTab nodes;
          equation().inconnue().remplir_coord_noeuds(nodes);
          ref_coeff->valeur_aux(nodes,values);
        }
      tab_multiply_any_shape(coef, values, VECT_REAL_ITEMS);
    }
}
 
/**
 * @brief Builds the sparsity pattern of the mass matrix block.
 *
 * @details The pattern depends on whether the basis is orthonormalized:
 *  - **Orthonormal basis**: purely diagonal — one non-zero per DOF
 *    (indice(k,0) == indice(k,1) for every k).
 *  - **Non-orthonormal basis**: full local block — every pair (i,j) within
 *    the same element and same spatial component is coupled.
 *
 * The number of spatial components (dim) is set to Objet_U::dimension for
 * velocity unknowns and 1 for all other fields (scalar).
 *
 * @param matrices  Map of matrix name → Matrice_Morse pointer to be sized.
 * @param semi_impl Unused here; kept for interface compatibility.
 */
void Masse_DG_base::dimensionner_blocs(matrices_t matrices, const tabs_t& semi_impl) const
{
  const Nom& nom_inco = equation().inconnue().le_nom();
  if (!matrices.count(nom_inco.getString())) return; //nothing to do
 
  int order = Option_DG::Get_order_for(nom_inco);
  int dim = nom_inco.debute_par("vitesse") ? Objet_U::dimension : 1;
 
  const BasisFunction& bfunc = le_dom_dg_->get_basisFunction(order);
  const int nb_bfunc = bfunc.nb_bfunc();
 
  Matrice_Morse& mat = *matrices.at(nom_inco.getString());
  const int nb_elem_tot = le_dom_dg_->nb_elem_tot();
 
  int size_indices = le_dom_dg_->gram_schmidt() ? nb_elem_tot*dim*nb_bfunc : nb_elem_tot*dim*nb_bfunc*nb_bfunc;
 
  IntTab indice(size_indices, 2);
  int current_indice = 0;
  if (le_dom_dg_->gram_schmidt())
    {
      for (int e = 0; e < nb_elem_tot; e++)
        {
          for (int d = 0; d<dim; d++)
            {
              for (int i = 0; i < nb_bfunc; i++ )
                {
                  indice(current_indice+i, 0) = current_indice+i;
                  indice(current_indice+i, 1) = current_indice+i;
                }
              current_indice+=nb_bfunc;
            }
        }
    }
  else
    {
      int index = 0;
      for (int e = 0; e < nb_elem_tot; e++)
        {
          for (int d = 0; d<dim; d++)
            {
              for (int i = 0; i < nb_bfunc; i++ )
                for (int j = 0; j < nb_bfunc; j++ )
                  {
                    indice(index, 0) = current_indice+i;
                    indice(index, 1) = current_indice+j;
                    index++;
                  }
              current_indice+=nb_bfunc;
            }
        }
    }
  mat.dimensionner(indice);
}
 
/**
 * @brief Assembles the mass matrix contribution (M/dt) into the matrix and right-hand side.
 *
 * @details Computes and accumulates the term (M/dt) * u into the global system,
 * where M is the L2 mass matrix and dt is the time step. The assembly strategy
 * depends on whether the basis is orthonormalized:
 *
 *  - **Orthonormal basis** (gram_schmidt == true):
 *    The mass matrix is diagonal with entries coef[e] * volume[e]. For each DOF:
 *      mat(dof, dof) += coef[e] * volume[e] / dt
 *      secmem(e, dof) += coef[e] * volume[e] * (u^n - delta * u^{n+1}) / dt
 *    where delta = resoudre_en_increments (1 if solving for the increment, 0 otherwise).
 *
 *  - **Non-orthonormal basis, order 0**: reduces to a single scalar per element
 *    (one DOF), equivalent to the cell-average finite volume mass term.
 *
 *  - **Non-orthonormal basis, order > 0**: the full local mass matrix M_ij is
 *    assembled by Gaussian quadrature (Ern, Finite Elements II, 2021, p.71):
 *      M_ij = integral of phi_i * phi_j
 *    accumulated as mat(i,j) += coef[e] * M_ij / dt and the corresponding RHS term.
 *
 * The temporal coefficient (e.g., density) is applied via appliquer_coef() before
 * the loop, and the medium porosity is used as the base coefficient array.
 *
 * @param matrices              Map of matrix name → Matrice_Morse pointer to accumulate into.
 * @param secmem                Right-hand side to accumulate into.
 * @param dt                    Current time step size.
 * @param semi_impl             Map of semi-implicit field values; if the unknown is present,
 *                              its values are used as u^n instead of the stored past values.
 * @param resoudre_en_increments If 1, the system is solved for the increment (u^{n+1} - u^n);
 *                              the current solution is subtracted from the RHS accordingly.
 */
void Masse_DG_base::ajouter_blocs(matrices_t matrices, DoubleTab& secmem, double dt, const tabs_t& semi_impl, int resoudre_en_increments) const
{
  const Nom& nom_inco = equation().inconnue().le_nom();
  const std::string& nom_inco_str = equation().inconnue().le_nom().getString();
  const DoubleTab& passe = semi_impl.count(nom_inco_str) ? semi_impl.at(nom_inco_str) : equation().inconnue().passe();
  const DoubleTab& inco = equation().inconnue().valeurs();
  Matrice_Morse *mat = matrices.count(nom_inco_str) ? matrices.at(nom_inco_str) : nullptr;
 
  int order = Option_DG::Get_order_for(nom_inco);
  int dim = nom_inco.debute_par("vitesse") ? Objet_U::dimension : 1;
 
  const BasisFunction& bfunc = le_dom_dg_->get_basisFunction(order);
  const int nb_bfunc = bfunc.nb_bfunc();
 
  assert(nb_bfunc*dim == inco.line_size());
 
  const int quad_order = bfunc.get_default_quadrature_order();
  const Quadrature_base& quad = le_dom_dg_->get_quadrature(quad_order);
 
  const DoubleVect& volume = le_dom_dg_->volumes();
  const int nb_elem_tot = inco.dimension_tot(0);
 
  int nb_pts_integ_max = quad.nb_pts_integ_max();
  const IntTab& tab_pts_integ= quad.get_tab_nb_pts_integ();
 
  DoubleTab fbase(nb_bfunc, nb_pts_integ_max);
  DoubleTab product(nb_pts_integ_max);
 
  DoubleTrav coef(equation().milieu().porosite_elem());
  coef = 1.;
  appliquer_coef(coef);
 
  int current_indice = 0;
  if (le_dom_dg_->gram_schmidt())
    {
      for (int e = 0; e < nb_elem_tot; e++)
        {
          for (int i=0; i<nb_bfunc; i++)
            {
              for (int d = 0; d<dim; d++)
                {
                  if (mat)
                    (*mat)(current_indice+i+d*nb_bfunc, current_indice+i+d*nb_bfunc) += coef[e]*volume[e] / dt;
                  secmem(e,i+d*nb_bfunc) += coef[e]*volume[e]*(passe(e,i+d*nb_bfunc) - resoudre_en_increments*inco(e,i+d*nb_bfunc))/ dt;
                }
            }
          current_indice+=nb_bfunc*dim;
        }
    }
  else
    {
      for (int e = 0; e < nb_elem_tot; e++)
        {
          if (order == 0)
            for (int d = 0; d<dim; d++)
              {
                if (mat)
                  (*mat)(current_indice+d, current_indice+d) += coef[e]*volume[e] / dt;
                secmem(e,d) += coef[e]*volume[e]*(passe(e,d)-resoudre_en_increments*inco(e,d)) / dt;
                current_indice+=nb_bfunc;
              }
          else
            {
              bfunc.eval_bfunc(quad, e, fbase);
              /****************************************************************/
              /* Quadrature formula: Ern, Finite Elements II, 2021, p 71      */
              /****************************************************************/
              for (int i=0; i<nb_bfunc; i++)
                {
                  for (int j=0; j<nb_bfunc; j++)
                    {
                      product = 0.;
                      for (int k = 0; k < tab_pts_integ(e) ; k++)
                        product(k) = fbase(i, k) * fbase(j, k);
 
                      double integral = quad.compute_integral_on_elem(e, product);
 
                      for (int d = 0; d<dim; d++)
                        {
                          if (mat)
                            (*mat)(current_indice+i+d*nb_bfunc, current_indice+j+d*nb_bfunc) += coef[e]*integral / dt;
                          secmem(e,i+d*nb_bfunc) += coef[e]*integral*(passe(e,j+d*nb_bfunc) - resoudre_en_increments*inco(e,j+d*nb_bfunc)) / dt;
                        }
                    }
                }
              current_indice+=nb_bfunc*dim;
            }
        }
    }
}