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/variational_smoother_constraint.h"
      33             : #include "libmesh/parallel_ghost_sync.h"
      34             : 
      35             : // C++ includes
      36             : #include <time.h> // for clock_t, clock()
      37             : #include <cstdlib> // *must* precede <cmath> for proper std:abs() on PGI, Sun Studio CC
      38             : #include <cmath>
      39             : #include <iomanip>
      40             : #include <limits>
      41             : 
      42             : namespace libMesh
      43             : {
      44             : 
      45             : // Optimization at -O2 or greater seem to break Intel's icc. So if we are
      46             : // being compiled with icc let's dumb-down the optimizations for this file
      47             : #ifdef __INTEL_COMPILER
      48             : #  pragma optimize ( "", off )
      49             : #endif
      50             : 
      51             : // Member functions for the Variational Smoother
      52         852 : VariationalMeshSmoother::VariationalMeshSmoother(UnstructuredMesh & mesh,
      53             :                                                  Real dilation_weight,
      54         852 :                                                  const bool preserve_subdomain_boundaries) :
      55             :   MeshSmoother(mesh),
      56         804 :   _dilation_weight(dilation_weight),
      57         852 :   _preserve_subdomain_boundaries(preserve_subdomain_boundaries)
      58         852 : {}
      59             : 
      60             : 
      61         852 : void VariationalMeshSmoother::smooth(unsigned int)
      62             : {
      63             :   // Check for multiple dimensions
      64         876 :   if (_mesh.elem_dimensions().size() > 1)
      65           0 :     libmesh_not_implemented_msg("Meshes containing elements of differing dimension are not yet supported.");
      66             : 
      67             :   /*
      68             :   Ideally we'd want to update _mesh directly even if it already has an
      69             :   EquationSystems attached and doing work on it ... and that's thwarted by the
      70             :   problems:
      71             : 
      72             :   1. We can't easily tell if there's already an EquationSystems attached.
      73             :   2. We can't attach a second EquationSystems safely (if it already has a system 0)
      74             :      because the DoF indexing will need to be overwritten by our system.
      75             :   3. The destructor of es won't even clean up after itself (we generally expect
      76             :      a mesh to go unused after its EquationSystems is destroyed), much less know
      77             :      how to restore anything from a previous EquationSystems.
      78             : 
      79             :   To avoid these issues, we'll just construct a new DistributedMesh mesh_copy
      80             :   from _mesh, then do the solve on mesh_copy, then copy its node locations back
      81             :   to _mesh after the solve is done. That'll be slightly less memory-efficient
      82             :   and somewhat more CPU-efficient in the case where _mesh is serial, though
      83             :   it'll be significantly less memory-efficient when _mesh is already distributed,
      84             :   but either way the robustness is probably worth it.
      85             :   */
      86             : 
      87             :   // Create a new mesh, EquationSystems, and System
      88         900 :   DistributedMesh mesh_copy(_mesh);
      89         900 :   EquationSystems es(mesh_copy);
      90         852 :   VariationalSmootherSystem & sys = es.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             :   //sys.extra_quadrature_order = 0;
      96             : 
      97             :   // Uncomment these to debug
      98             :   //sys.print_element_solutions=true;
      99             :   //sys.print_element_residuals=true;
     100             :   //sys.print_element_jacobians=true;
     101             : 
     102             :   // Add boundary node and hanging node constraints
     103         852 :   VariationalSmootherConstraint constraint(sys, _preserve_subdomain_boundaries);
     104         852 :   sys.attach_constraint_object(constraint);
     105             : 
     106             :   // Set system parameters
     107         852 :   sys.get_dilation_weight() = _dilation_weight;
     108             : 
     109             :   // Set up solver
     110             :   sys.time_solver =
     111         852 :     std::make_unique<SteadySolver>(sys);
     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             :   //sys.time_solver->diff_solver() = std::make_unique<PetscDiffSolver>(sys);
     117             : 
     118         852 :   es.init();
     119             : 
     120             :   // More debugging options
     121             :   //DiffSolver & solver = *(sys.time_solver->diff_solver().get());
     122             :   //solver.quiet = false;
     123             :   //solver.verbose = true;
     124             : 
     125         852 :   sys.time_solver->diff_solver()->relative_residual_tolerance = TOLERANCE*TOLERANCE;
     126             : 
     127         852 :   sys.solve();
     128             : 
     129             :   // Update _mesh from mesh_copy
     130       88074 :   for (auto * node_copy : mesh_copy.local_node_ptr_range())
     131             :   {
     132       47124 :     auto & node = _mesh.node_ref(node_copy->id());
     133      223914 :     for (const auto d : make_range(mesh_copy.mesh_dimension()))
     134      137520 :       node(d) = (*node_copy)(d);
     135         804 :   }
     136             : 
     137         852 :   SyncNodalPositions sync_object(_mesh);
     138        1680 :   Parallel::sync_dofobject_data_by_id (_mesh.comm(), _mesh.nodes_begin(), _mesh.nodes_end(), sync_object);
     139         852 : }
     140             : 
     141             : } // namespace libMesh
     142             : 
     143             : #endif // defined(LIBMESH_ENABLE_VSMOOTHER)