Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : #include "libmesh/libmesh_config.h"
      19             : #if defined(LIBMESH_ENABLE_VSMOOTHER)
      20             : 
      21             : // Local includes
      22             : #include "libmesh/mesh_smoother_vsmoother.h"
      23             : #include "libmesh/mesh_tools.h"
      24             : #include "libmesh/elem.h"
      25             : #include "libmesh/unstructured_mesh.h"
      26             : #include "libmesh/utility.h"
      27             : #include "libmesh/boundary_info.h"
      28             : #include "libmesh/equation_systems.h"
      29             : #include "libmesh/distributed_mesh.h"
      30             : #include "libmesh/steady_solver.h"
      31             : #include "libmesh/diff_solver.h"
      32             : #include "libmesh/parallel_ghost_sync.h"
      33             : 
      34             : // C++ includes
      35             : #include <time.h> // for clock_t, clock()
      36             : #include <cstdlib> // *must* precede <cmath> for proper std:abs() on PGI, Sun Studio CC
      37             : #include <cmath>
      38             : #include <iomanip>
      39             : #include <limits>
      40             : 
      41             : namespace libMesh
      42             : {
      43             : 
      44             : // Optimization at -O2 or greater seem to break Intel's icc. So if we are
      45             : // being compiled with icc let's dumb-down the optimizations for this file
      46             : #ifdef __INTEL_COMPILER
      47             : #  pragma optimize ( "", off )
      48             : #endif
      49             : 
      50             : // Member functions for the Variational Smoother
      51        1349 : VariationalMeshSmoother::VariationalMeshSmoother(UnstructuredMesh & mesh,
      52             :                                                  Real dilation_weight,
      53        1349 :                                                  const bool preserve_subdomain_boundaries)
      54             :   : MeshSmoother(mesh),
      55        1273 :     _dilation_weight(dilation_weight),
      56        1273 :     _preserve_subdomain_boundaries(preserve_subdomain_boundaries),
      57        1387 :     _setup_called(false)
      58        1349 : {}
      59             : 
      60        1349 : void VariationalMeshSmoother::setup()
      61             : {
      62             :   // Check for multiple dimensions
      63        1387 :   if (_mesh.elem_dimensions().size() > 1)
      64           0 :     libmesh_not_implemented_msg("Meshes containing elements of differing dimension are not yet supported.");
      65             : 
      66             :   /*
      67             :   Ideally we'd want to update _mesh directly even if it already has an
      68             :   EquationSystems attached and doing work on it ... and that's thwarted by the
      69             :   problems:
      70             : 
      71             :   1. We can't easily tell if there's already an EquationSystems attached.
      72             :   2. We can't attach a second EquationSystems safely (if it already has a system 0)
      73             :      because the DoF indexing will need to be overwritten by our system.
      74             :   3. The destructor of es won't even clean up after itself (we generally expect
      75             :      a mesh to go unused after its EquationSystems is destroyed), much less know
      76             :      how to restore anything from a previous EquationSystems.
      77             : 
      78             :   To avoid these issues, we'll just construct a new DistributedMesh _mesh_copy
      79             :   from _mesh, then do the solve on _mesh_copy, then copy its node locations back
      80             :   to _mesh after the solve is done. That'll be slightly less memory-efficient
      81             :   and somewhat more CPU-efficient in the case where _mesh is serial, though
      82             :   it'll be significantly less memory-efficient when _mesh is already distributed,
      83             :   but either way the robustness is probably worth it.
      84             :   */
      85             : 
      86             :   // Create a new mesh, EquationSystems, and System
      87        2660 :   _mesh_copy = std::make_unique<DistributedMesh>(_mesh);
      88        2660 :   _equation_systems = std::make_unique<EquationSystems>(*_mesh_copy);
      89        1349 :   _system =
      90        1349 :       &(_equation_systems->add_system<VariationalSmootherSystem>("variational_smoother_system"));
      91             : 
      92             :   // Set this to something > 0 to add more quadrature points than the default
      93             :   // rule that integrates order 2 * fe_order + 1 polynomials exactly.
      94             :   // Using higher quadrature orders has not had a significant effect on observed solutions.
      95             :   //system()->extra_quadrature_order = 0;
      96             : 
      97             :   // Uncomment these to debug
      98             :   //system()->print_element_solutions=true;
      99             :   //system()->print_element_residuals=true;
     100             :   //system()->print_element_jacobians=true;
     101             : 
     102             :   // Add boundary node and hanging node constraints
     103             :   _constraint =
     104        2622 :       std::make_unique<VariationalSmootherConstraint>(*_system, _preserve_subdomain_boundaries);
     105        1387 :   system()->attach_constraint_object(*_constraint);
     106             : 
     107             :   // Set system parameters
     108        1349 :   system()->get_dilation_weight() = _dilation_weight;
     109             : 
     110             :   // Set up solver
     111        1387 :   system()->time_solver = std::make_unique<SteadySolver>(*_system);
     112             : 
     113             :   // Uncomment this line and use -snes_test_jacobian and -snes_test_jacobian_view
     114             :   // flags to compare the hand-coded jacobian in VariationalSmootherSystem
     115             :   // to finite difference jacobians.
     116             :   //system()->time_solver->diff_solver() = std::make_unique<PetscDiffSolver>(*_system);
     117             : 
     118        1349 :   _equation_systems->init();
     119             : 
     120             :   // More debugging options
     121             :   // DiffSolver & solver = *(system()->time_solver->diff_solver().get());
     122             :   // solver.quiet = false;
     123             :   // solver.verbose = true;
     124             : 
     125        1387 :   system()->time_solver->diff_solver()->relative_residual_tolerance = TOLERANCE * TOLERANCE;
     126        1387 :   system()->time_solver->diff_solver()->absolute_residual_tolerance = TOLERANCE * TOLERANCE;
     127             : 
     128        1349 :   _setup_called = true;
     129        1349 : }
     130             : 
     131        1349 : void VariationalMeshSmoother::smooth(unsigned int)
     132             : {
     133        1349 :   if (!_setup_called)
     134        1207 :     setup();
     135             : 
     136        1349 :   system()->solve();
     137             : 
     138             :   // Update _mesh from _mesh_copy
     139       32822 :   for (auto * node_copy : _mesh_copy->local_node_ptr_range())
     140             :     {
     141       16452 :       auto & node = _mesh.node_ref(node_copy->id());
     142       78729 :       for (const auto d : make_range(_mesh_copy->mesh_dimension()))
     143       47196 :         node(d) = (*node_copy)(d);
     144        1273 :     }
     145             : 
     146        1349 :   SyncNodalPositions sync_object(_mesh);
     147        2660 :   Parallel::sync_dofobject_data_by_id (_mesh.comm(), _mesh.nodes_begin(), _mesh.nodes_end(), sync_object);
     148             : 
     149             :   // Release memory occupied by _mesh_copy
     150             :   // Destruct this before _mesh_copy because it references _mesh_copy
     151          38 :   _equation_systems.reset();
     152          38 :   _mesh_copy.reset();
     153             :   // We'll need to call setup again since we'll have to reconstruct _mesh_copy
     154        1349 :   _setup_called = false;
     155        1349 : }
     156             : 
     157         142 : const MeshQualityInfo & VariationalMeshSmoother::get_mesh_info() const
     158             : {
     159         142 :   libmesh_error_msg_if(!_setup_called, "Need to first call the setup() method of "
     160             :       << "this VariationalMeshSmoother object, then call get_mesh_info() prior "
     161             :       << "to calling smooth().");
     162         142 :   return _system->get_mesh_info();
     163             : }
     164             : 
     165             : } // namespace libMesh
     166             : 
     167             : #endif // defined(LIBMESH_ENABLE_VSMOOTHER)