libMesh::DiscontinuityMeasure Class Reference

#include <discontinuity_measure.h>

Inheritance diagram for libMesh::DiscontinuityMeasure:

Public Types

typedef std::map< std::pair< const System *, unsigned int >, ErrorVector * > ErrorMap
 

Public Member Functions

 DiscontinuityMeasure ()
 
 DiscontinuityMeasure (const DiscontinuityMeasure &)=delete
 
DiscontinuityMeasureoperator= (const DiscontinuityMeasure &)=delete
 
 DiscontinuityMeasure (DiscontinuityMeasure &&)=default
 
DiscontinuityMeasureoperator= (DiscontinuityMeasure &&)=default
 
virtual ~DiscontinuityMeasure ()=default
 
void attach_essential_bc_function (std::pair< bool, Real > fptr(const System &system, const Point &p, const std::string &var_name))
 
virtual ErrorEstimatorType type () const override
 
virtual void estimate_error (const System &system, ErrorVector &error_per_cell, const NumericVector< Number > *solution_vector=nullptr, bool estimate_parent_error=false) override
 
virtual void estimate_errors (const EquationSystems &equation_systems, ErrorVector &error_per_cell, const std::map< const System *, SystemNorm > &error_norms, const std::map< const System *, const NumericVector< Number > *> *solution_vectors=nullptr, bool estimate_parent_error=false)
 
virtual void estimate_errors (const EquationSystems &equation_systems, ErrorMap &errors_per_cell, const std::map< const System *, const NumericVector< Number > *> *solution_vectors=nullptr, bool estimate_parent_error=false)
 

Public Attributes

bool scale_by_n_flux_faces
 
SystemNorm error_norm
 

Protected Member Functions

virtual void init_context (FEMContext &c) override
 
virtual void internal_side_integration () override
 
virtual bool boundary_side_integration () override
 
void reinit_sides ()
 
float coarse_n_flux_faces_increment ()
 
void reduce_error (std::vector< ErrorVectorReal > &error_per_cell, const Parallel::Communicator &comm) const
 

Protected Attributes

std::pair< bool, Real >(* _bc_function )(const System &system, const Point &p, const std::string &var_name)
 
bool integrate_boundary_sides
 
std::unique_ptr< FEMContextfine_context
 
std::unique_ptr< FEMContextcoarse_context
 
Real fine_error
 
Real coarse_error
 
unsigned int var
 

Detailed Description

This class measures discontinuities between elements for debugging purposes. It derives from ErrorEstimator just in case someone finds it useful in a DG framework.

Author
Roy H. Stogner
Date
2006

Definition at line 49 of file discontinuity_measure.h.

Member Typedef Documentation

◆ ErrorMap

typedef std::map<std::pair<const System *, unsigned int>, ErrorVector *> libMesh::ErrorEstimator::ErrorMap
inherited

When calculating many error vectors at once, we need a data structure to hold them all

Definition at line 124 of file error_estimator.h.

Constructor & Destructor Documentation

◆ DiscontinuityMeasure() [1/3]

libMesh::DiscontinuityMeasure::DiscontinuityMeasure ( )

Constructor. Responsible for initializing the _bc_function function pointer to nullptr. Defaults to L2 norm; changes to system norm are ignored.

Definition at line 41 of file discontinuity_measure.C.

References libMesh::ErrorEstimator::error_norm, and libMesh::L2.

41  :
43  _bc_function(nullptr)
44 {
45  error_norm = L2;
46 }
std::pair< bool, Real >(* _bc_function)(const System &system, const Point &p, const std::string &var_name)

◆ DiscontinuityMeasure() [2/3]

libMesh::DiscontinuityMeasure::DiscontinuityMeasure ( const DiscontinuityMeasure )
delete

This class cannot be (default) copy constructed/assigned because its base class has unique_ptr members.

◆ DiscontinuityMeasure() [3/3]

libMesh::DiscontinuityMeasure::DiscontinuityMeasure ( DiscontinuityMeasure &&  )
default

Defaulted move ctor, move assignment operator, and destructor.

◆ ~DiscontinuityMeasure()

virtual libMesh::DiscontinuityMeasure::~DiscontinuityMeasure ( )
virtualdefault

Member Function Documentation

◆ attach_essential_bc_function()

void libMesh::DiscontinuityMeasure::attach_essential_bc_function ( std::pair< bool, Real >   fptrconst System &system, const Point &p, const std::string &var_name)

Register a user function to use in computing the essential BCs.

Definition at line 200 of file discontinuity_measure.C.

References _bc_function, and libMesh::JumpErrorEstimator::integrate_boundary_sides.

203 {
204  _bc_function = fptr;
205 
206  // We may be turning boundary side integration on or off
207  if (fptr)
209  else
210  integrate_boundary_sides = false;
211 }
std::pair< bool, Real >(* _bc_function)(const System &system, const Point &p, const std::string &var_name)

◆ boundary_side_integration()

bool libMesh::DiscontinuityMeasure::boundary_side_integration ( )
overrideprotectedvirtual

The function which calculates a normal derivative jump based error term on a boundary side.

Returns
true if the flux bc function is in fact defined on the current side.

Reimplemented from libMesh::JumpErrorEstimator.

Definition at line 129 of file discontinuity_measure.C.

References _bc_function, libMesh::Elem::dim(), libMesh::ErrorEstimator::error_norm, libMesh::JumpErrorEstimator::fine_context, libMesh::JumpErrorEstimator::fine_error, libMesh::FEAbstract::get_JxW(), libMesh::FEGenericBase< OutputType >::get_phi(), libMesh::FEAbstract::get_xyz(), libMesh::Elem::hmax(), libMesh::FEAbstract::n_quadrature_points(), libMesh::TensorTools::norm_sq(), libMesh::Real, libMesh::JumpErrorEstimator::var, and libMesh::SystemNorm::weight().

130 {
131  const Elem & fine_elem = fine_context->get_elem();
132 
133  FEBase * fe_fine = nullptr;
134  fine_context->get_side_fe( var, fe_fine, fine_elem.dim() );
135 
136  const std::string & var_name =
137  fine_context->get_system().variable_name(var);
138 
139  std::vector<std::vector<Real>> phi_fine = fe_fine->get_phi();
140  std::vector<Real> JxW_face = fe_fine->get_JxW();
141  std::vector<Point> qface_point = fe_fine->get_xyz();
142 
143  // The reinitialization also recomputes the locations of
144  // the quadrature points on the side. By checking if the
145  // first quadrature point on the side is on an essential boundary
146  // for a particular variable, we will determine if the whole
147  // element is on an essential boundary (assuming quadrature points
148  // are strictly contained in the side).
149  if (this->_bc_function(fine_context->get_system(),
150  qface_point[0], var_name).first)
151  {
152  const Real h = fine_elem.hmax();
153 
154  // The number of quadrature points
155  const unsigned int n_qp = fe_fine->n_quadrature_points();
156 
157  // The error contribution from this face
158  Real error = 1.e-30;
159 
160  // loop over the integration points on the face.
161  for (unsigned int qp=0; qp<n_qp; qp++)
162  {
163  // Value of the imposed essential BC at this quadrature point.
164  const std::pair<bool,Real> essential_bc =
165  this->_bc_function(fine_context->get_system(), qface_point[qp],
166  var_name);
167 
168  // Be sure the BC function still thinks we're on the
169  // essential boundary.
170  libmesh_assert_equal_to (essential_bc.first, true);
171 
172  // The solution value on each point
173  Number u_fine = fine_context->side_value(var, qp);
174 
175  // The difference between the desired BC and the approximate solution.
176  const Number jump = essential_bc.second - u_fine;
177 
178  // The flux jump squared. If using complex numbers,
179  // norm_sq(z) returns |z|^2, where |z| is the modulus of z.
180  const Real jump2 = TensorTools::norm_sq(jump);
181 
182  // Integrate the error on the face. The error is
183  // scaled by an additional power of h, where h is
184  // the maximum side length for the element. This
185  // arises in the definition of the indicator.
186  error += JxW_face[qp]*jump2;
187 
188  } // End quadrature point loop
189 
190  fine_error = error*h*error_norm.weight(var);
191 
192  return true;
193  } // end if side on flux boundary
194  return false;
195 }
std::unique_ptr< FEMContext > fine_context
std::pair< bool, Real >(* _bc_function)(const System &system, const Point &p, const std::string &var_name)
FEGenericBase< Real > FEBase
Real weight(unsigned int var) const
Definition: system_norm.C:132
DIE A HORRIBLE DEATH HERE typedef LIBMESH_DEFAULT_SCALAR_TYPE Real

◆ coarse_n_flux_faces_increment()

float libMesh::JumpErrorEstimator::coarse_n_flux_faces_increment ( )
protectedinherited

A utility function to correctly increase n_flux_faces for the coarse element

Definition at line 462 of file jump_error_estimator.C.

References libMesh::JumpErrorEstimator::coarse_context, and libMesh::JumpErrorEstimator::fine_context.

Referenced by libMesh::JumpErrorEstimator::estimate_error().

463 {
464  // Keep track of the number of internal flux sides found on each
465  // element
466  unsigned short dim = coarse_context->get_elem().dim();
467 
468  const unsigned int divisor =
469  1 << (dim-1)*(fine_context->get_elem().level() -
470  coarse_context->get_elem().level());
471 
472  // With a difference of n levels between fine and coarse elements,
473  // we compute a fractional flux face for the coarse element by adding:
474  // 1/2^n in 2D
475  // 1/4^n in 3D
476  // each time. This code will get hit 2^n times in 2D and 4^n
477  // times in 3D so that the final flux face count for the coarse
478  // element will be an integer value.
479 
480  return 1.0f / static_cast<float>(divisor);
481 }
std::unique_ptr< FEMContext > fine_context
std::unique_ptr< FEMContext > coarse_context

◆ estimate_error()

void libMesh::JumpErrorEstimator::estimate_error ( const System system,
ErrorVector error_per_cell,
const NumericVector< Number > *  solution_vector = nullptr,
bool  estimate_parent_error = false 
)
overridevirtualinherited

This function uses the derived class's jump error estimate formula to estimate the error on each cell. The estimated error is output in the vector error_per_cell

Conventions for assigning the direction of the normal:

  • e & f are global element ids

Case (1.) Elements are at the same level, e<f Compute the flux jump on the face and add it as a contribution to error_per_cell[e] and error_per_cell[f]


| | |

f
e —> n

Case (2.) The neighbor is at a higher level. Compute the flux jump on e's face and add it as a contribution to error_per_cell[e] and error_per_cell[f]


| | | | | | e |—> n | | | | | |--------—| f |


Implements libMesh::ErrorEstimator.

Definition at line 53 of file jump_error_estimator.C.

References libMesh::Elem::active(), libMesh::JumpErrorEstimator::boundary_side_integration(), libMesh::Elem::child_ref_range(), libMesh::JumpErrorEstimator::coarse_context, libMesh::JumpErrorEstimator::coarse_error, libMesh::JumpErrorEstimator::coarse_n_flux_faces_increment(), libMesh::FEGenericBase< OutputType >::coarsened_dof_values(), libMesh::ParallelObject::comm(), libMesh::ErrorEstimator::error_norm, libMesh::ErrorVectorReal, libMesh::FEType::family, libMesh::JumpErrorEstimator::fine_context, libMesh::JumpErrorEstimator::fine_error, libMesh::System::get_dof_map(), libMesh::System::get_mesh(), libMesh::FEAbstract::get_xyz(), libMesh::DofObject::id(), libMesh::index_range(), libMesh::JumpErrorEstimator::init_context(), libMesh::JumpErrorEstimator::integrate_boundary_sides, libMesh::JumpErrorEstimator::internal_side_integration(), libMesh::Elem::level(), libMesh::libmesh_ignore(), mesh, n_vars, libMesh::System::n_vars(), libMesh::Elem::neighbor_ptr(), libMesh::Elem::parent(), libMesh::ErrorEstimator::reduce_error(), libMesh::JumpErrorEstimator::reinit_sides(), libMesh::SCALAR, libMesh::JumpErrorEstimator::scale_by_n_flux_faces, libMesh::Elem::side_index_range(), libMesh::DenseVector< T >::size(), libMesh::System::solution, libMesh::NumericVector< T >::swap(), libMesh::JumpErrorEstimator::var, libMesh::System::variable_type(), and libMesh::SystemNorm::weight().

57 {
58  LOG_SCOPE("estimate_error()", "JumpErrorEstimator");
59 
96  // This parameter is not used when !LIBMESH_ENABLE_AMR.
97  libmesh_ignore(estimate_parent_error);
98 
99  // The current mesh
100  const MeshBase & mesh = system.get_mesh();
101 
102  // The number of variables in the system
103  const unsigned int n_vars = system.n_vars();
104 
105  // The DofMap for this system
106 #ifdef LIBMESH_ENABLE_AMR
107  const DofMap & dof_map = system.get_dof_map();
108 #endif
109 
110  // Resize the error_per_cell vector to be
111  // the number of elements, initialize it to 0.
112  error_per_cell.resize (mesh.max_elem_id());
113  std::fill (error_per_cell.begin(), error_per_cell.end(), 0.);
114 
115  // Declare a vector of floats which is as long as
116  // error_per_cell above, and fill with zeros. This vector will be
117  // used to keep track of the number of edges (faces) on each active
118  // element which are either:
119  // 1) an internal edge
120  // 2) an edge on a Neumann boundary for which a boundary condition
121  // function has been specified.
122  // The error estimator can be scaled by the number of flux edges (faces)
123  // which the element actually has to obtain a more uniform measure
124  // of the error. Use floats instead of ints since in case 2 (above)
125  // f gets 1/2 of a flux face contribution from each of his
126  // neighbors
127  std::vector<float> n_flux_faces;
129  n_flux_faces.resize(error_per_cell.size(), 0);
130 
131  // Prepare current_local_solution to localize a non-standard
132  // solution vector if necessary
133  if (solution_vector && solution_vector != system.solution.get())
134  {
135  NumericVector<Number> * newsol =
136  const_cast<NumericVector<Number> *>(solution_vector);
137  System & sys = const_cast<System &>(system);
138  newsol->swap(*sys.solution);
139  sys.update();
140  }
141 
142  fine_context.reset(new FEMContext(system));
143  coarse_context.reset(new FEMContext(system));
144 
145  // Loop over all the variables we've been requested to find jumps in, to
146  // pre-request
147  for (var=0; var<n_vars; var++)
148  {
149  // Skip variables which aren't part of our norm,
150  // as well as SCALAR variables, which have no jumps
151  if (error_norm.weight(var) == 0.0 ||
152  system.variable_type(var).family == SCALAR)
153  continue;
154 
155  // FIXME: Need to generalize this to vector-valued elements. [PB]
156  FEBase * side_fe = nullptr;
157 
158  const std::set<unsigned char> & elem_dims =
159  fine_context->elem_dimensions();
160 
161  for (const auto & dim : elem_dims)
162  {
163  fine_context->get_side_fe( var, side_fe, dim );
164 
165  side_fe->get_xyz();
166  }
167  }
168 
169  this->init_context(*fine_context);
171 
172  // Iterate over all the active elements in the mesh
173  // that live on this processor.
174  for (const auto & e : mesh.active_local_element_ptr_range())
175  {
176  const dof_id_type e_id = e->id();
177 
178 #ifdef LIBMESH_ENABLE_AMR
179  // See if the parent of element e has been examined yet;
180  // if not, we may want to compute the estimator on it
181  const Elem * parent = e->parent();
182 
183  // We only can compute and only need to compute on
184  // parents with all active children
185  bool compute_on_parent = true;
186  if (!parent || !estimate_parent_error)
187  compute_on_parent = false;
188  else
189  for (auto & child : parent->child_ref_range())
190  if (!child.active())
191  compute_on_parent = false;
192 
193  if (compute_on_parent &&
194  !error_per_cell[parent->id()])
195  {
196  // Compute a projection onto the parent
197  DenseVector<Number> Uparent;
199  (*(system.solution), dof_map, parent, Uparent, false);
200 
201  // Loop over the neighbors of the parent
202  for (auto n_p : parent->side_index_range())
203  {
204  if (parent->neighbor_ptr(n_p) != nullptr) // parent has a neighbor here
205  {
206  // Find the active neighbors in this direction
207  std::vector<const Elem *> active_neighbors;
208  parent->neighbor_ptr(n_p)->
209  active_family_tree_by_neighbor(active_neighbors,
210  parent);
211  // Compute the flux to each active neighbor
212  for (std::size_t a=0,
213  n_active_neighbors = active_neighbors.size();
214  a != n_active_neighbors; ++a)
215  {
216  const Elem * f = active_neighbors[a];
217  // FIXME - what about when f->level <
218  // parent->level()??
219  if (f->level() >= parent->level())
220  {
221  fine_context->pre_fe_reinit(system, f);
222  coarse_context->pre_fe_reinit(system, parent);
223  libmesh_assert_equal_to
224  (coarse_context->get_elem_solution().size(),
225  Uparent.size());
226  coarse_context->get_elem_solution() = Uparent;
227 
228  this->reinit_sides();
229 
230  // Loop over all significant variables in the system
231  for (var=0; var<n_vars; var++)
232  if (error_norm.weight(var) != 0.0 &&
233  system.variable_type(var).family != SCALAR)
234  {
236 
237  error_per_cell[fine_context->get_elem().id()] +=
238  static_cast<ErrorVectorReal>(fine_error);
239  error_per_cell[coarse_context->get_elem().id()] +=
240  static_cast<ErrorVectorReal>(coarse_error);
241  }
242 
243  // Keep track of the number of internal flux
244  // sides found on each element
246  {
247  n_flux_faces[fine_context->get_elem().id()]++;
248  n_flux_faces[coarse_context->get_elem().id()] +=
250  }
251  }
252  }
253  }
254  else if (integrate_boundary_sides)
255  {
256  fine_context->pre_fe_reinit(system, parent);
257  libmesh_assert_equal_to
258  (fine_context->get_elem_solution().size(),
259  Uparent.size());
260  fine_context->get_elem_solution() = Uparent;
261  fine_context->side = cast_int<unsigned char>(n_p);
262  fine_context->side_fe_reinit();
263 
264  // If we find a boundary flux for any variable,
265  // let's just count it as a flux face for all
266  // variables. Otherwise we'd need to keep track of
267  // a separate n_flux_faces and error_per_cell for
268  // every single var.
269  bool found_boundary_flux = false;
270 
271  for (var=0; var<n_vars; var++)
272  if (error_norm.weight(var) != 0.0 &&
273  system.variable_type(var).family != SCALAR)
274  {
275  if (this->boundary_side_integration())
276  {
277  error_per_cell[fine_context->get_elem().id()] +=
278  static_cast<ErrorVectorReal>(fine_error);
279  found_boundary_flux = true;
280  }
281  }
282 
283  if (scale_by_n_flux_faces && found_boundary_flux)
284  n_flux_faces[fine_context->get_elem().id()]++;
285  }
286  }
287  }
288 #endif // #ifdef LIBMESH_ENABLE_AMR
289 
290  // If we do any more flux integration, e will be the fine element
291  fine_context->pre_fe_reinit(system, e);
292 
293  // Loop over the neighbors of element e
294  for (auto n_e : e->side_index_range())
295  {
296  if ((e->neighbor_ptr(n_e) != nullptr) ||
298  {
299  fine_context->side = cast_int<unsigned char>(n_e);
300  fine_context->side_fe_reinit();
301  }
302 
303  if (e->neighbor_ptr(n_e) != nullptr) // e is not on the boundary
304  {
305  const Elem * f = e->neighbor_ptr(n_e);
306  const dof_id_type f_id = f->id();
307 
308  // Compute flux jumps if we are in case 1 or case 2.
309  if ((f->active() && (f->level() == e->level()) && (e_id < f_id))
310  || (f->level() < e->level()))
311  {
312  // f is now the coarse element
313  coarse_context->pre_fe_reinit(system, f);
314 
315  this->reinit_sides();
316 
317  // Loop over all significant variables in the system
318  for (var=0; var<n_vars; var++)
319  if (error_norm.weight(var) != 0.0 &&
320  system.variable_type(var).family != SCALAR)
321  {
323 
324  error_per_cell[fine_context->get_elem().id()] +=
325  static_cast<ErrorVectorReal>(fine_error);
326  error_per_cell[coarse_context->get_elem().id()] +=
327  static_cast<ErrorVectorReal>(coarse_error);
328  }
329 
330  // Keep track of the number of internal flux
331  // sides found on each element
333  {
334  n_flux_faces[fine_context->get_elem().id()]++;
335  n_flux_faces[coarse_context->get_elem().id()] +=
337  }
338  } // end if (case1 || case2)
339  } // if (e->neighbor(n_e) != nullptr)
340 
341  // Otherwise, e is on the boundary. If it happens to
342  // be on a Dirichlet boundary, we need not do anything.
343  // On the other hand, if e is on a Neumann (flux) boundary
344  // with grad(u).n = g, we need to compute the additional residual
345  // (h * \int |g - grad(u_h).n|^2 dS)^(1/2).
346  // We can only do this with some knowledge of the boundary
347  // conditions, i.e. the user must have attached an appropriate
348  // BC function.
349  else if (integrate_boundary_sides)
350  {
351  bool found_boundary_flux = false;
352 
353  for (var=0; var<n_vars; var++)
354  if (error_norm.weight(var) != 0.0 &&
355  system.variable_type(var).family != SCALAR)
356  if (this->boundary_side_integration())
357  {
358  error_per_cell[fine_context->get_elem().id()] +=
359  static_cast<ErrorVectorReal>(fine_error);
360  found_boundary_flux = true;
361  }
362 
363  if (scale_by_n_flux_faces && found_boundary_flux)
364  n_flux_faces[fine_context->get_elem().id()]++;
365  } // end if (e->neighbor_ptr(n_e) == nullptr)
366  } // end loop over neighbors
367  } // End loop over active local elements
368 
369 
370  // Each processor has now computed the error contributions
371  // for its local elements. We need to sum the vector
372  // and then take the square-root of each component. Note
373  // that we only need to sum if we are running on multiple
374  // processors, and we only need to take the square-root
375  // if the value is nonzero. There will in general be many
376  // zeros for the inactive elements.
377 
378  // First sum the vector of estimated error values
379  this->reduce_error(error_per_cell, system.comm());
380 
381  // Compute the square-root of each component.
382  for (auto i : index_range(error_per_cell))
383  if (error_per_cell[i] != 0.)
384  error_per_cell[i] = std::sqrt(error_per_cell[i]);
385 
386 
387  if (this->scale_by_n_flux_faces)
388  {
389  // Sum the vector of flux face counts
390  this->reduce_error(n_flux_faces, system.comm());
391 
392  // Sanity check: Make sure the number of flux faces is
393  // always an integer value
394 #ifdef DEBUG
395  for (const auto & val : n_flux_faces)
396  libmesh_assert_equal_to (val, static_cast<float>(static_cast<unsigned int>(val)));
397 #endif
398 
399  // Scale the error by the number of flux faces for each element
400  for (auto i : index_range(n_flux_faces))
401  {
402  if (n_flux_faces[i] == 0.0) // inactive or non-local element
403  continue;
404 
405  error_per_cell[i] /= static_cast<ErrorVectorReal>(n_flux_faces[i]);
406  }
407  }
408 
409  // If we used a non-standard solution before, now is the time to fix
410  // the current_local_solution
411  if (solution_vector && solution_vector != system.solution.get())
412  {
413  NumericVector<Number> * newsol =
414  const_cast<NumericVector<Number> *>(solution_vector);
415  System & sys = const_cast<System &>(system);
416  newsol->swap(*sys.solution);
417  sys.update();
418  }
419 }
std::unique_ptr< FEMContext > fine_context
MeshBase & mesh
IntRange< std::size_t > index_range(const std::vector< T > &vec)
Definition: int_range.h:104
virtual void internal_side_integration()=0
const unsigned int n_vars
Definition: tecplot_io.C:69
DIE A HORRIBLE DEATH HERE typedef float ErrorVectorReal
static void coarsened_dof_values(const NumericVector< Number > &global_vector, const DofMap &dof_map, const Elem *coarse_elem, DenseVector< Number > &coarse_dofs, const unsigned int var, const bool use_old_dof_indices=false)
Definition: fe_base.C:791
void libmesh_ignore(const Args &...)
void reduce_error(std::vector< ErrorVectorReal > &error_per_cell, const Parallel::Communicator &comm) const
std::unique_ptr< FEMContext > coarse_context
FEGenericBase< Real > FEBase
Real weight(unsigned int var) const
Definition: system_norm.C:132
virtual void init_context(FEMContext &c)
uint8_t dof_id_type
Definition: id_types.h:64

◆ estimate_errors() [1/2]

void libMesh::ErrorEstimator::estimate_errors ( const EquationSystems equation_systems,
ErrorVector error_per_cell,
const std::map< const System *, SystemNorm > &  error_norms,
const std::map< const System *, const NumericVector< Number > *> *  solution_vectors = nullptr,
bool  estimate_parent_error = false 
)
virtualinherited

This virtual function can be redefined in derived classes, but by default computes the sum of the error_per_cell for each system in the equation_systems.

Currently this function ignores the error_norm member variable, and uses the function argument error_norms instead.

This function is named estimate_errors instead of estimate_error because otherwise C++ can get confused.

Reimplemented in libMesh::UniformRefinementEstimator.

Definition at line 47 of file error_estimator.C.

References libMesh::ErrorEstimator::error_norm, libMesh::ErrorEstimator::estimate_error(), libMesh::EquationSystems::get_system(), libMesh::index_range(), and libMesh::EquationSystems::n_systems().

52 {
53  SystemNorm old_error_norm = this->error_norm;
54 
55  // Sum the error values from each system
56  for (unsigned int s = 0; s != equation_systems.n_systems(); ++s)
57  {
58  ErrorVector system_error_per_cell;
59  const System & sys = equation_systems.get_system(s);
60  if (error_norms.find(&sys) == error_norms.end())
61  this->error_norm = old_error_norm;
62  else
63  this->error_norm = error_norms.find(&sys)->second;
64 
65  const NumericVector<Number> * solution_vector = nullptr;
66  if (solution_vectors &&
67  solution_vectors->find(&sys) != solution_vectors->end())
68  solution_vector = solution_vectors->find(&sys)->second;
69 
70  this->estimate_error(sys, system_error_per_cell,
71  solution_vector, estimate_parent_error);
72 
73  if (s)
74  {
75  libmesh_assert_equal_to (error_per_cell.size(), system_error_per_cell.size());
76  for (auto i : index_range(error_per_cell))
77  error_per_cell[i] += system_error_per_cell[i];
78  }
79  else
80  error_per_cell = system_error_per_cell;
81  }
82 
83  // Restore our old state before returning
84  this->error_norm = old_error_norm;
85 }
IntRange< std::size_t > index_range(const std::vector< T > &vec)
Definition: int_range.h:104
virtual void estimate_error(const System &system, ErrorVector &error_per_cell, const NumericVector< Number > *solution_vector=nullptr, bool estimate_parent_error=false)=0

◆ estimate_errors() [2/2]

void libMesh::ErrorEstimator::estimate_errors ( const EquationSystems equation_systems,
ErrorMap errors_per_cell,
const std::map< const System *, const NumericVector< Number > *> *  solution_vectors = nullptr,
bool  estimate_parent_error = false 
)
virtualinherited

This virtual function can be redefined in derived classes, but by default it calls estimate_error repeatedly to calculate the requested error vectors.

Currently this function ignores the error_norm.weight() values because it calculates each variable's error individually, unscaled.

The user selects which errors get computed by filling a map with error vectors: If errors_per_cell[&system][v] exists, it will be filled with the error values in variable v of system

FIXME: This is a default implementation - derived classes should reimplement it for efficiency.

Reimplemented in libMesh::UniformRefinementEstimator.

Definition at line 93 of file error_estimator.C.

References libMesh::ErrorEstimator::error_norm, libMesh::ErrorEstimator::estimate_error(), libMesh::EquationSystems::get_system(), libMesh::EquationSystems::n_systems(), n_vars, libMesh::System::n_vars(), and libMesh::SystemNorm::type().

97 {
98  SystemNorm old_error_norm = this->error_norm;
99 
100  // Find the requested error values from each system
101  for (unsigned int s = 0; s != equation_systems.n_systems(); ++s)
102  {
103  const System & sys = equation_systems.get_system(s);
104 
105  unsigned int n_vars = sys.n_vars();
106 
107  for (unsigned int v = 0; v != n_vars; ++v)
108  {
109  // Only fill in ErrorVectors the user asks for
110  if (errors_per_cell.find(std::make_pair(&sys, v)) ==
111  errors_per_cell.end())
112  continue;
113 
114  // Calculate error in only one variable
115  std::vector<Real> weights(n_vars, 0.0);
116  weights[v] = 1.0;
117  this->error_norm =
118  SystemNorm(std::vector<FEMNormType>(n_vars, old_error_norm.type(v)),
119  weights);
120 
121  const NumericVector<Number> * solution_vector = nullptr;
122  if (solution_vectors &&
123  solution_vectors->find(&sys) != solution_vectors->end())
124  solution_vector = solution_vectors->find(&sys)->second;
125 
126  this->estimate_error
127  (sys, *errors_per_cell[std::make_pair(&sys, v)],
128  solution_vector, estimate_parent_error);
129  }
130  }
131 
132  // Restore our old state before returning
133  this->error_norm = old_error_norm;
134 }
virtual void estimate_error(const System &system, ErrorVector &error_per_cell, const NumericVector< Number > *solution_vector=nullptr, bool estimate_parent_error=false)=0
const unsigned int n_vars
Definition: tecplot_io.C:69

◆ init_context()

void libMesh::DiscontinuityMeasure::init_context ( FEMContext c)
overrideprotectedvirtual

An initialization function, for requesting specific data from the FE objects

Reimplemented from libMesh::JumpErrorEstimator.

Definition at line 59 of file discontinuity_measure.C.

References libMesh::FEMContext::elem_dimensions(), libMesh::ErrorEstimator::error_norm, libMesh::JumpErrorEstimator::fine_context, libMesh::FEGenericBase< OutputType >::get_phi(), n_vars, libMesh::DiffContext::n_vars(), and libMesh::SystemNorm::weight().

60 {
61  const unsigned int n_vars = c.n_vars();
62  for (unsigned int v=0; v<n_vars; v++)
63  {
64  // Possibly skip this variable
65  if (error_norm.weight(v) == 0.0) continue;
66 
67  // FIXME: Need to generalize this to vector-valued elements. [PB]
68  FEBase * side_fe = nullptr;
69 
70  const std::set<unsigned char> & elem_dims =
71  c.elem_dimensions();
72 
73  for (const auto & dim : elem_dims)
74  {
75  fine_context->get_side_fe( v, side_fe, dim );
76 
77  // We'll need values on both sides for discontinuity computation
78  side_fe->get_phi();
79  }
80  }
81 }
std::unique_ptr< FEMContext > fine_context
const unsigned int n_vars
Definition: tecplot_io.C:69
FEGenericBase< Real > FEBase
Real weight(unsigned int var) const
Definition: system_norm.C:132

◆ internal_side_integration()

void libMesh::DiscontinuityMeasure::internal_side_integration ( )
overrideprotectedvirtual

The function which calculates a normal derivative jump based error term on an internal side

Implements libMesh::JumpErrorEstimator.

Definition at line 86 of file discontinuity_measure.C.

References libMesh::JumpErrorEstimator::coarse_context, libMesh::JumpErrorEstimator::coarse_error, libMesh::Elem::dim(), libMesh::ErrorEstimator::error_norm, libMesh::JumpErrorEstimator::fine_context, libMesh::JumpErrorEstimator::fine_error, libMesh::FEAbstract::get_JxW(), libMesh::FEGenericBase< OutputType >::get_phi(), libMesh::Elem::hmax(), libMesh::FEAbstract::n_quadrature_points(), libMesh::TensorTools::norm_sq(), libMesh::Real, libMesh::JumpErrorEstimator::var, and libMesh::SystemNorm::weight().

87 {
88  const Elem & coarse_elem = coarse_context->get_elem();
89  const Elem & fine_elem = fine_context->get_elem();
90 
91  FEBase * fe_fine = nullptr;
92  fine_context->get_side_fe( var, fe_fine, fine_elem.dim() );
93 
94  FEBase * fe_coarse = nullptr;
95  coarse_context->get_side_fe( var, fe_coarse, fine_elem.dim() );
96 
97  Real error = 1.e-30;
98  unsigned int n_qp = fe_fine->n_quadrature_points();
99 
100  std::vector<std::vector<Real>> phi_coarse = fe_coarse->get_phi();
101  std::vector<std::vector<Real>> phi_fine = fe_fine->get_phi();
102  std::vector<Real> JxW_face = fe_fine->get_JxW();
103 
104  for (unsigned int qp=0; qp != n_qp; ++qp)
105  {
106  // Calculate solution values on fine and coarse elements
107  // at this quadrature point
108  Number
109  u_fine = fine_context->side_value(var, qp),
110  u_coarse = coarse_context->side_value(var, qp);
111 
112  // Find the jump in the value
113  // at this quadrature point
114  const Number jump = u_fine - u_coarse;
115  const Real jump2 = TensorTools::norm_sq(jump);
116  // Accumulate the jump integral
117  error += JxW_face[qp] * jump2;
118  }
119 
120  // Add the h-weighted jump integral to each error term
121  fine_error =
122  error * fine_elem.hmax() * error_norm.weight(var);
123  coarse_error =
124  error * coarse_elem.hmax() * error_norm.weight(var);
125 }
std::unique_ptr< FEMContext > fine_context
std::unique_ptr< FEMContext > coarse_context
FEGenericBase< Real > FEBase
Real weight(unsigned int var) const
Definition: system_norm.C:132
DIE A HORRIBLE DEATH HERE typedef LIBMESH_DEFAULT_SCALAR_TYPE Real

◆ operator=() [1/2]

DiscontinuityMeasure& libMesh::DiscontinuityMeasure::operator= ( const DiscontinuityMeasure )
delete

◆ operator=() [2/2]

DiscontinuityMeasure& libMesh::DiscontinuityMeasure::operator= ( DiscontinuityMeasure &&  )
default

◆ reduce_error()

void libMesh::ErrorEstimator::reduce_error ( std::vector< ErrorVectorReal > &  error_per_cell,
const Parallel::Communicator comm 
) const
protectedinherited

This method takes the local error contributions in error_per_cell from each processor and combines them to get the global error vector.

Definition at line 32 of file error_estimator.C.

References libMesh::Parallel::Communicator::sum().

Referenced by libMesh::UniformRefinementEstimator::_estimate_error(), libMesh::WeightedPatchRecoveryErrorEstimator::estimate_error(), libMesh::PatchRecoveryErrorEstimator::estimate_error(), libMesh::JumpErrorEstimator::estimate_error(), libMesh::AdjointRefinementEstimator::estimate_error(), and libMesh::ExactErrorEstimator::estimate_error().

34 {
35  // This function must be run on all processors at once
36  // parallel_object_only();
37 
38  // Each processor has now computed the error contributions
39  // for its local elements. We may need to sum the vector to
40  // recover the error for each element.
41 
42  comm.sum(error_per_cell);
43 }

◆ reinit_sides()

void libMesh::JumpErrorEstimator::reinit_sides ( )
protectedinherited

A utility function to reinit the finite element data on elements sharing a side

Definition at line 424 of file jump_error_estimator.C.

References libMesh::JumpErrorEstimator::coarse_context, libMesh::ErrorEstimator::error_norm, libMesh::JumpErrorEstimator::fine_context, libMesh::FEAbstract::get_fe_type(), libMesh::FEInterface::inverse_map(), n_vars, libMesh::FEAbstract::reinit(), libMesh::SCALAR, and libMesh::SystemNorm::weight().

Referenced by libMesh::JumpErrorEstimator::estimate_error().

425 {
426  fine_context->side_fe_reinit();
427 
428  unsigned short dim = fine_context->get_elem().dim();
429  libmesh_assert_equal_to(dim, coarse_context->get_elem().dim());
430 
431  FEBase * fe_fine = nullptr;
432  fine_context->get_side_fe( 0, fe_fine, dim );
433 
434  // Get the physical locations of the fine element quadrature points
435  std::vector<Point> qface_point = fe_fine->get_xyz();
436 
437  // Find the master quadrature point locations on the coarse element
438  FEBase * fe_coarse = nullptr;
439  coarse_context->get_side_fe( 0, fe_coarse, dim );
440 
441  std::vector<Point> qp_coarse;
442 
444  (coarse_context->get_elem().dim(), fe_coarse->get_fe_type(),
445  &coarse_context->get_elem(), qface_point, qp_coarse);
446 
447  // The number of variables in the system
448  const unsigned int n_vars = fine_context->n_vars();
449 
450  // Calculate all coarse element shape functions at those locations
451  for (unsigned int v=0; v<n_vars; v++)
452  if (error_norm.weight(v) != 0.0 &&
453  fine_context->get_system().variable_type(v).family != SCALAR)
454  {
455  coarse_context->get_side_fe( v, fe_coarse, dim );
456  fe_coarse->reinit (&coarse_context->get_elem(), &qp_coarse);
457  }
458 }
std::unique_ptr< FEMContext > fine_context
const unsigned int n_vars
Definition: tecplot_io.C:69
static Point inverse_map(const unsigned int dim, const FEType &fe_t, const Elem *elem, const Point &p, const Real tolerance=TOLERANCE, const bool secure=true)
Definition: fe_interface.C:590
std::unique_ptr< FEMContext > coarse_context
FEGenericBase< Real > FEBase
Real weight(unsigned int var) const
Definition: system_norm.C:132

◆ type()

ErrorEstimatorType libMesh::DiscontinuityMeasure::type ( ) const
overridevirtual
Returns
The type for the ErrorEstimator subclass.

Implements libMesh::ErrorEstimator.

Definition at line 51 of file discontinuity_measure.C.

References libMesh::DISCONTINUITY_MEASURE.

Member Data Documentation

◆ _bc_function

std::pair<bool,Real>(* libMesh::DiscontinuityMeasure::_bc_function) (const System &system, const Point &p, const std::string &var_name)
protected

Pointer to function that provides BC information.

Definition at line 108 of file discontinuity_measure.h.

Referenced by attach_essential_bc_function(), and boundary_side_integration().

◆ coarse_context

◆ coarse_error

◆ error_norm

SystemNorm libMesh::ErrorEstimator::error_norm
inherited

When estimating the error in a single system, the error_norm is used to control the scaling and norm choice for each variable. Not all estimators will support all norm choices. The default scaling is for all variables to be weighted equally. The default norm choice depends on the error estimator.

Part of this functionality was supported via component_scale and sobolev_order in older libMesh versions, and a small part was supported via component_mask in even older versions. Hopefully the encapsulation here will allow us to avoid changing this API again.

Definition at line 161 of file error_estimator.h.

Referenced by libMesh::UniformRefinementEstimator::_estimate_error(), libMesh::AdjointRefinementEstimator::AdjointRefinementEstimator(), boundary_side_integration(), libMesh::KellyErrorEstimator::boundary_side_integration(), DiscontinuityMeasure(), libMesh::JumpErrorEstimator::estimate_error(), libMesh::AdjointResidualErrorEstimator::estimate_error(), libMesh::ExactErrorEstimator::estimate_error(), libMesh::ErrorEstimator::estimate_errors(), libMesh::ExactErrorEstimator::ExactErrorEstimator(), libMesh::ExactErrorEstimator::find_squared_element_error(), libMesh::LaplacianErrorEstimator::init_context(), init_context(), libMesh::KellyErrorEstimator::init_context(), libMesh::LaplacianErrorEstimator::internal_side_integration(), internal_side_integration(), libMesh::KellyErrorEstimator::internal_side_integration(), libMesh::KellyErrorEstimator::KellyErrorEstimator(), libMesh::LaplacianErrorEstimator::LaplacianErrorEstimator(), libMesh::WeightedPatchRecoveryErrorEstimator::EstimateError::operator()(), libMesh::PatchRecoveryErrorEstimator::EstimateError::operator()(), libMesh::PatchRecoveryErrorEstimator::PatchRecoveryErrorEstimator(), libMesh::JumpErrorEstimator::reinit_sides(), and libMesh::UniformRefinementEstimator::UniformRefinementEstimator().

◆ fine_context

◆ fine_error

◆ integrate_boundary_sides

bool libMesh::JumpErrorEstimator::integrate_boundary_sides
protectedinherited

A boolean flag, by default false, to be set to true if integrations with boundary_side_integration() should be performed

Definition at line 138 of file jump_error_estimator.h.

Referenced by attach_essential_bc_function(), libMesh::KellyErrorEstimator::attach_flux_bc_function(), and libMesh::JumpErrorEstimator::estimate_error().

◆ scale_by_n_flux_faces

bool libMesh::JumpErrorEstimator::scale_by_n_flux_faces
inherited

This boolean flag allows you to scale the error indicator result for each element by the number of "flux faces" the element actually has. This tends to weight more evenly cells which are on the boundaries and thus have fewer contributions to their flux. The value is initialized to false, simply set it to true if you want to use the feature.

Definition at line 99 of file jump_error_estimator.h.

Referenced by libMesh::JumpErrorEstimator::estimate_error().

◆ var


The documentation for this class was generated from the following files: