equation_systems.c

一个用来实现偏微分方程中网格的计算库

// $Id: equation_systems.C 2925 2008-07-10 13:34:46Z jwpeterson $

// The libMesh Finite Element Library.
// Copyright (C) 2002-2007  Benjamin S. Kirk, John W. Peterson
  
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
  
// This library 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 for more details.
  
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


// System includes
#include <sstream>

// Local Includes
#include "explicit_system.h"
#include "fe_interface.h"
#include "frequency_system.h"
#include "linear_implicit_system.h"
#include "mesh_refinement.h"
#include "newmark_system.h"
#include "nonlinear_implicit_system.h"
#include "parallel.h"
#include "transient_system.h"
#include "dof_map.h"
#include "mesh_base.h"
#include "elem.h"
#include "libmesh_logging.h"

// Include the systems before this one to avoid
// overlapping forward declarations.
#include "equation_systems.h"

// Forward Declarations




// ------------------------------------------------------------
// EquationSystems class implementation
EquationSystems::EquationSystems (MeshBase& m, MeshData* mesh_data) :
  _mesh      (m),
  _mesh_data (mesh_data)
{
  // Set default parameters
  this->parameters.set<Real>        ("linear solver tolerance") = TOLERANCE * TOLERANCE;
  this->parameters.set<unsigned int>("linear solver maximum iterations") = 5000;
}



EquationSystems::~EquationSystems ()
{
  this->clear ();
}



void EquationSystems::clear ()
{
  // Clear any additional parameters
  parameters.clear ();

  // clear the systems.  We must delete them
  // since we newed them!
  while (!_systems.empty())
    {
      system_iterator pos = _systems.begin();
      
      System *sys = pos->second;
      delete sys;
      sys = NULL;
      
      _systems.erase (pos);
    }
}



void EquationSystems::init ()
{
  const unsigned int n_sys = this->n_systems();

  libmesh_assert (n_sys != 0);

  // Distribute the mesh if possible
  if (libMesh::n_processors() > 1)
    _mesh.delete_remote_elements();
  
  // Tell all the \p DofObject entities how many systems
  // there are.
  {
    MeshBase::node_iterator       node_it  = _mesh.nodes_begin();
    const MeshBase::node_iterator node_end = _mesh.nodes_end();

    for ( ; node_it != node_end; ++node_it)
      (*node_it)->set_n_systems(n_sys);
    
    MeshBase::element_iterator       elem_it  = _mesh.elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.elements_end();
    
    for ( ; elem_it != elem_end; ++elem_it)
      (*elem_it)->set_n_systems(n_sys);
  }

  for (unsigned int i=0; i != this->n_systems(); ++i)
    this->get_system(i).init();
}



void EquationSystems::reinit ()
{
  libmesh_assert (this->n_systems() != 0);
  
#ifdef DEBUG
  // Make sure all the \p DofObject entities know how many systems
  // there are.
  {
    // All the nodes
    MeshBase::node_iterator       node_it  = _mesh.nodes_begin();
    const MeshBase::node_iterator node_end = _mesh.nodes_end();

    for ( ; node_it != node_end; ++node_it)
      libmesh_assert((*node_it)->n_systems() == this->n_systems());
    
    // All the elements
    MeshBase::element_iterator       elem_it  = _mesh.elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.elements_end();
    
    for ( ; elem_it != elem_end; ++elem_it)
      libmesh_assert((*elem_it)->n_systems() == this->n_systems());
  }
#endif

  // Localize each system's vectors
  for (unsigned int i=0; i != this->n_systems(); ++i)
    this->get_system(i).re_update();

#ifdef ENABLE_AMR

  bool dof_constraints_created = false;
  bool mesh_changed = false;

  // FIXME: For backwards compatibility, assume
  // refine_and_coarsen_elements or refine_uniformly have already
  // been called
  {
    for (unsigned int i=0; i != this->n_systems(); ++i)
      {
	System &sys = this->get_system(i);
        sys.get_dof_map().distribute_dofs(_mesh);
        sys.get_dof_map().create_dof_constraints(_mesh);
        sys.prolong_vectors();
      }
    mesh_changed = true;
    dof_constraints_created = true;
  }
  
  // FIXME: Where should the user set maintain_level_one now??
  // Don't override previous settings, for now

  MeshRefinement mesh_refine(_mesh);

  mesh_refine.face_level_mismatch_limit() = false;

  // Try to coarsen the mesh, then restrict each system's vectors
  // if necessary
  if (mesh_refine.coarsen_elements())
    {
      for (unsigned int i=0; i != this->n_systems(); ++i)
        {
	  System &sys = this->get_system(i);
          if (!dof_constraints_created)
            {
              sys.get_dof_map().distribute_dofs(_mesh);
              sys.get_dof_map().create_dof_constraints(_mesh);
            }
          sys.restrict_vectors();
        }
      mesh_changed = true;
      dof_constraints_created = true;
    }

  // Once vectors are all restricted, we can delete
  // children of coarsened elements
  if (mesh_changed)
    this->get_mesh().contract();
  
  // Try to refine the mesh, then prolong each system's vectors
  // if necessary
  if (mesh_refine.refine_elements())
    {
      for (unsigned int i=0; i != this->n_systems(); ++i)
        {
	  System &sys = this->get_system(i);
          if (!dof_constraints_created)
            {
              sys.get_dof_map().distribute_dofs(_mesh);
              sys.get_dof_map().create_dof_constraints(_mesh);
            }
          sys.prolong_vectors();
        }
      mesh_changed = true;
      dof_constraints_created = true;
    }

  // If the mesh has changed, systems will need to create new dof
  // constraints and update their global solution vectors
  if (mesh_changed)
    {
      for (unsigned int i=0; i != this->n_systems(); ++i)
        this->get_system(i).reinit();
    }
#endif // #ifdef ENABLE_AMR
}



void EquationSystems::allgather ()
{
  // A serial mesh means nothing needs to be done
  if (_mesh.is_serial())
    return;

  const unsigned int n_sys = this->n_systems();

  libmesh_assert (n_sys != 0);

  // Gather the mesh
  _mesh.allgather();
  
  // Tell all the \p DofObject entities how many systems
  // there are.
  {
    MeshBase::node_iterator       node_it  = _mesh.nodes_begin();
    const MeshBase::node_iterator node_end = _mesh.nodes_end();

    for ( ; node_it != node_end; ++node_it)
      (*node_it)->set_n_systems(n_sys);
    
    MeshBase::element_iterator       elem_it  = _mesh.elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.elements_end();
    
    for ( ; elem_it != elem_end; ++elem_it)
      (*elem_it)->set_n_systems(n_sys);
  }

  // And distribute each system's dofs
  for (unsigned int i=0; i != this->n_systems(); ++i)
    this->get_system(i).get_dof_map().distribute_dofs(_mesh);
}




void EquationSystems::update ()
{
  START_LOG("update()","EquationSystems");
  
  // Localize each system's vectors
  for (unsigned int i=0; i != this->n_systems(); ++i)
    this->get_system(i).update();
  
  STOP_LOG("update()","EquationSystems");
}



System & EquationSystems::add_system (const std::string& sys_type,
				      const std::string& name)
{
  // Build a Newmark system
  if      (sys_type == "Newmark")
    this->add_system<NewmarkSystem> (name);

  // Build an Explicit system
  else if ((sys_type == "Explicit"))
    this->add_system<ExplicitSystem> (name);

  // Build an Implicit system
  else if ((sys_type == "Implicit") ||
	   (sys_type == "Steady"  ))
    this->add_system<ImplicitSystem> (name);

  // build a transient implicit linear system
  else if ((sys_type == "Transient") ||
	   (sys_type == "TransientImplicit") ||
	   (sys_type == "TransientLinearImplicit"))
    this->add_system<TransientLinearImplicitSystem> (name);

  // build a transient implicit nonlinear system
  else if (sys_type == "TransientNonlinearImplicit")
    this->add_system<TransientNonlinearImplicitSystem> (name);

  // build a transient explicit system
  else if (sys_type == "TransientExplicit")
    this->add_system<TransientExplicitSystem> (name);

  // build a linear implicit sytsem
  else if (sys_type == "LinearImplicit")
    this->add_system<LinearImplicitSystem> (name);

#if defined(USE_COMPLEX_NUMBERS)
  // build a frequency system
  else if (sys_type == "Frequency")
    this->add_system<FrequencySystem> (name);
#endif

  else
    {
      std::cerr << "ERROR: Unknown system type: "
		<< sys_type
		<< std::endl;
      libmesh_error();
    }

  // Return a reference to the new system
  //return (*this)(name);
  return this->get_system(name);
}






void EquationSystems::delete_system (const std::string& name)
{
  deprecated();

  if (!_systems.count(name))
    {
      std::cerr << "ERROR: no system named "
                << name  << std::endl;

      libmesh_error();
    }
  
  delete _systems[name];
  
  _systems.erase (name);
}



void EquationSystems::solve ()
{
  libmesh_assert (this->n_systems());

  for (unsigned int i=0; i != this->n_systems(); ++i)
    this->get_system(i).solve();
}
 
 
void EquationSystems::build_variable_names (std::vector<std::string>& var_names) const
{
  libmesh_assert (this->n_systems());
  
  var_names.resize (this->n_vars());

  unsigned int var_num=0;
  
  const_system_iterator       pos = _systems.begin();
  const const_system_iterator end = _systems.end();

  for (; pos != end; ++pos)
    for (unsigned int vn=0; vn<pos->second->n_vars(); vn++)
      var_names[var_num++] = pos->second->variable_name(vn);       
}



void EquationSystems::build_solution_vector (std::vector<Number>&,
					     const std::string&,
					     const std::string&) const
{
  //TODO:[BSK] re-implement this from the method below
  libmesh_error();

//   // Get a reference to the named system
//   const System& system = this->get_system(system_name);

//   // Get the number associated with the variable_name we are passed
//   const unsigned short int variable_num = system.variable_number(variable_name);

//   // Get the dimension of the current mesh
//   const unsigned int dim = _mesh.mesh_dimension();

//   // If we're on processor 0, allocate enough memory to hold the solution.
//   // Since we're only looking at one variable, there will be one solution value
//   // for each node in the mesh.
//   if (_mesh.processor_id() == 0)
//     soln.resize(_mesh.n_nodes());

//   // Vector to hold the global solution from all processors
//   std::vector<Number> sys_soln;
  
//   // Update the global solution from all processors
//   system.update_global_solution (sys_soln, 0);
  
//   // Temporary vector to store the solution on an individual element.
//   std::vector<Number>       elem_soln;   

//   // The FE solution interpolated to the nodes
//   std::vector<Number>       nodal_soln;  

//   // The DOF indices for the element
//   std::vector<unsigned int> dof_indices; 

//   // Determine the finite/infinite element type used in this system 
//   const FEType& fe_type    = system.variable_type(variable_num);

//   // Define iterators to iterate over all the elements of the mesh
//   const_active_elem_iterator       it (_mesh.elements_begin());
//   const const_active_elem_iterator end(_mesh.elements_end());

//   // Loop over elements
//   for ( ; it != end; ++it)
//     {
//       // Convenient shortcut to the element pointer