67 "--enable-petsc, --enable-trilinos, or --enable-eigen");
69 #ifndef LIBMESH_ENABLE_AMR 70 libmesh_example_requires(
false,
"--enable-amr");
74 #ifndef LIBMESH_ENABLE_DIRICHLET 75 libmesh_example_requires(
false,
"--enable-dirichlet");
79 libmesh_example_requires(
sizeof(
Real) > 4,
"--disable-singleprecision");
82 GetPot infile(
"fem_system_ex4.in");
85 infile.parse_command_line(argc, argv);
88 const Real global_tolerance = infile(
"global_tolerance", 0.);
89 const unsigned int nelem_target = infile(
"n_elements", 400);
90 const Real deltat = infile(
"deltat", 0.005);
91 const unsigned int coarsegridsize = infile(
"coarsegridsize", 20);
92 const unsigned int coarserefinements = infile(
"coarserefinements", 0);
93 const unsigned int max_adaptivesteps = infile(
"max_adaptivesteps", 10);
94 const unsigned int dim = infile(
"dimension", 2);
97 libmesh_example_requires(
dim <= LIBMESH_DIM,
"2D/3D support");
108 mesh_refinement.coarsen_by_parents() =
true;
109 mesh_refinement.absolute_global_tolerance() = global_tolerance;
110 mesh_refinement.nelem_target() = nelem_target;
111 mesh_refinement.refine_fraction() = 0.3;
112 mesh_refinement.coarsen_fraction() = 0.3;
113 mesh_refinement.coarsen_threshold() = 0.1;
146 std::set<boundary_id_type> bcids;
156 for (
auto & elem :
mesh.element_ptr_range())
157 if (elem->dim() <
dim)
158 elem->subdomain_id() = 1;
160 mesh_refinement.uniformly_refine(coarserefinements);
170 equation_systems.add_system<
HeatSystem> (
"Heat");
173 system.
time_solver = std::make_unique<SteadySolver>(system);
176 equation_systems.init ();
183 solver.
quiet = infile(
"solver_quiet",
true);
195 equation_systems.print_info();
198 unsigned int a_step = 0;
199 for (; a_step != max_adaptivesteps; ++a_step)
207 std::unique_ptr<ErrorEstimator> error_estimator;
211 if (global_tolerance != 0.)
215 libmesh_assert_equal_to (nelem_target, 0);
217 auto u = std::make_unique<UniformRefinementEstimator>();
222 error_estimator = std::move(u);
228 libmesh_assert_greater (nelem_target, 0);
234 error_estimator = std::make_unique<KellyErrorEstimator>();
237 error_estimator->estimate_error(system, error);
246 if (global_tolerance != 0.)
251 if (global_tolerance != 0.)
258 if (global_tolerance != 0.)
262 if (global_error < global_tolerance)
264 mesh_refinement.flag_elements_by_error_tolerance(error);
270 if (mesh_refinement.flag_elements_by_nelem_target(error))
272 mesh_refinement.refine_and_coarsen_elements();
273 equation_systems.reinit();
274 a_step = max_adaptivesteps;
280 mesh_refinement.refine_and_coarsen_elements();
281 equation_systems.reinit();
285 <<
" active elements and " 286 << equation_systems.n_active_dofs()
291 if (a_step == max_adaptivesteps)
299 #ifdef LIBMESH_HAVE_EXODUS_API 301 (
"out.e", equation_systems);
302 #endif // #ifdef LIBMESH_HAVE_EXODUS_API 304 #ifdef LIBMESH_HAVE_GMV 306 (
"out.gmv", equation_systems);
307 #endif // #ifdef LIBMESH_HAVE_GMV 309 #ifdef LIBMESH_HAVE_FPARSER 312 const std::string exact_str = (
dim == 2) ?
313 "sin(pi*x)*sin(pi*y)" :
"sin(pi*x)*sin(pi*y)*sin(pi*z)";
315 exact_sol.attach_exact_value(0, &exact_func);
316 exact_sol.compute_error(
"Heat",
"T");
318 Real err = exact_sol.l2_error(
"Heat",
"T");
323 libmesh_assert_less(
err, 2e-3);
325 #endif // #ifdef LIBMESH_HAVE_FPARSER 327 #endif // #ifndef LIBMESH_ENABLE_AMR virtual T maximum() const
This class handles the computation of the L2 and/or H1 error for the Systems in the EquationSystems o...
This is the EquationSystems class.
virtual dof_id_type n_active_elem() const =0
void add_elements(const std::set< boundary_id_type > &requested_boundary_ids, UnstructuredMesh &boundary_mesh, bool store_parent_side_ids=false)
Generates elements along the boundary of our _mesh, which use pre-existing nodes on the boundary_mesh...
A Function generated (via FParser) by parsing a mathematical expression.
virtual void write_equation_systems(const std::string &, const EquationSystems &, const std::set< std::string > *system_names=nullptr)
This method implements writing a mesh with data to a specified file where the data is taken from the ...
bool quiet
The DiffSolver should not print anything to libMesh::out unless quiet is set to false; default is tru...
virtual Real l2_norm() const
The ErrorVector is a specialization of the StatisticsVector for error data computed on a finite eleme...
The ExodusII_IO class implements reading meshes in the ExodusII file format from Sandia National Labs...
unsigned int max_nonlinear_iterations
The DiffSolver should exit in failure if max_nonlinear_iterations is exceeded and continue_after_max_...
void prepare_for_use(const bool skip_renumber_nodes_and_elements, const bool skip_find_neighbors)
Prepare a newly ecreated (or read) mesh for use.
Real absolute_residual_tolerance
The DiffSolver should exit after the residual is reduced to either less than absolute_residual_tolera...
std::unique_ptr< TimeSolver > time_solver
A pointer to the solver object we're going to use.
The LibMeshInit class, when constructed, initializes the dependent libraries (e.g.
This class implements writing meshes in the GMV format.
const BoundaryInfo & get_boundary_info() const
The information about boundary ids on the mesh.
SolverPackage default_solver_package()
This is a generic class that defines a solver to handle ImplicitSystem classes, including NonlinearIm...
Implements (adaptive) mesh refinement algorithms for a MeshBase.
Real deltat
For time-dependent problems, this is the amount delta t to advance the solution in time...
unsigned int max_linear_iterations
Each linear solver step should exit after max_linear_iterations is exceeded.
void print_info(std::ostream &os=libMesh::out, const unsigned int verbosity=0, const bool global=true) const
Prints relevant information about the mesh.
void init(triangulateio &t)
Initializes the fields of t to nullptr/0 as necessary.
virtual void postprocess() override
Runs a postprocessing loop over all elements, and if postprocess_sides is true over all sides...
bool verbose
The DiffSolver may print a lot more to libMesh::out if verbose is set to true; default is false...
DIE A HORRIBLE DEATH HERE typedef LIBMESH_DEFAULT_SCALAR_TYPE Real
virtual void solve() override
Invokes the solver associated with the system.
The Mesh class is a thin wrapper, around the ReplicatedMesh class by default.
double initial_linear_tolerance
Any required linear solves will at first be done with this tolerance; the DiffSolver may tighten the ...
Real relative_residual_tolerance
Real relative_step_tolerance
virtual Real mean() const override