getfem_error_estimate.h

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/* -*- c++ -*- (enables emacs c++ mode) */
/*===========================================================================
 
 Copyright (C) 1999-2020 Yves Renard, Julien Pommier
 
 This file is a part of GetFEM
 
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 under  the  terms  of the  GNU  Lesser General Public License as published
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 (at your option) any later version along with the GCC Runtime Library
 Exception either version 3.1 or (at your option) any later version.
 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 Lesser General Public
 License and GCC Runtime Library Exception for more details.
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 As a special exception, you  may use  this file  as it is a part of a free
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===========================================================================*/
 
 
/**
   @file getfem_error_estimate.h 
   @author Yves Renard <Yves.Renard@insa-lyon.fr>
   @author Julien Pommier <Julien.Pommier@insa-toulouse.fr>
   @date February 10, 2006.
   @brief Definition of a posteriori error estimates.
*/
 
#ifndef GETFEM_ERROR_ESTIMATE
#define GETFEM_ERROR_ESTIMATE
 
#include "getfem_mesh_im.h"
#include "getfem_mesh_fem.h"
#include "getfem_generic_assembly.h"
 
namespace getfem {
 
  template <typename VECT1, typename VECT2>
  void error_estimate(const mesh_im &mim, const mesh_fem &mf,
                       const VECT1 &UU, VECT2 &err,
                       mesh_region rg = mesh_region::all_convexes()) {
    
    const mesh &m = mim.linked_mesh();
    rg.from_mesh(m);
    GMM_ASSERT3(&m == &mf.linked_mesh() &&
                gmm::vect_size(err) >= m.nb_allocated_convex(), "");
    
    const mesh_fem &mf0 = classical_mesh_fem(m, 0);
 
    getfem::ga_workspace workspace;
    mesh_region inner_faces = inner_faces_of_mesh(m, rg);
    getfem::size_type nbdof = mf0.nb_dof();
    getfem::base_vector Z(nbdof);
    getfem::base_vector U(gmm::vect_size(UU));
    gmm::copy(UU, U);
    workspace.add_fem_constant("u", mf, U);
    workspace.add_fem_variable("z", mf0, gmm::sub_interval(0, nbdof), Z);
    workspace.add_expression
      ("element_size"
       "*Norm_sqr(Grad_u.Normal-Interpolate(Grad_u,neighbor_element).Normal)"
       "*(Test_z+Interpolate(Test_z,neighbor_element))", mim, inner_faces);
    workspace.set_assembled_vector(Z);
    workspace.assembly(1);
    gmm::clear(err);
 
    for (mr_visitor cv1(rg); !cv1.finished(); ++cv1)
      err[cv1.cv()] = Z[mf0.ind_basic_dof_of_element(cv1.cv())[0]];
  }
 
#ifdef EXPERIMENTAL_PURPOSE_ONLY
 
 
  void error_estimate_nitsche(const mesh_im & mim,
                              const mesh_fem &mf_u,
                              const base_vector &U,
                              int GAMMAC,
                              int GAMMAN,
                              scalar_type lambda,
                              scalar_type mu,
                              scalar_type gamma0,
                              scalar_type f_coeff,
                              scalar_type vertical_force,
                              base_vector &ERR);
 
  
 
#endif
 
 
}
 
#endif