void HPCoarsenTest::add_projection(const System & system,
const Elem * elem,
unsigned int var)
{
// If we have children, we need to add their projections instead
if (!elem->active())
{
libmesh_assert(!elem->subactive());
for (unsigned int c = 0; c != elem->n_children(); ++c)
this->add_projection(system, elem->child(c), var);
return;
}
// The DofMap for this system
const DofMap & dof_map = system.get_dof_map();
// The type of finite element to use for this variable
const FEType & fe_type = dof_map.variable_type (var);
const FEContinuity cont = fe->get_continuity();
fe->reinit(elem);
dof_map.dof_indices(elem, dof_indices, var);
const unsigned int n_dofs =
cast_int<unsigned int>(dof_indices.size());
FEInterface::inverse_map (system.get_mesh().mesh_dimension(),
fe_type, coarse, *xyz_values, coarse_qpoints);
fe_coarse->reinit(coarse, &coarse_qpoints);
const unsigned int n_coarse_dofs =
cast_int<unsigned int>(phi_coarse->size());
if (Uc.size() == 0)
{
Ke.resize(n_coarse_dofs, n_coarse_dofs);
Ke.zero();
Fe.resize(n_coarse_dofs);
Fe.zero();
Uc.resize(n_coarse_dofs);
Uc.zero();
}
libmesh_assert_equal_to (Uc.size(), phi_coarse->size());
// Loop over the quadrature points
for (unsigned int qp=0; qp<qrule->n_points(); qp++)
{
// The solution value at the quadrature point
Number val = libMesh::zero;
Gradient grad;
Tensor hess;
for (unsigned int i=0; i != n_dofs; i++)
{
dof_id_type dof_num = dof_indices[i];
val += (*phi)[i][qp] *
system.current_solution(dof_num);
if (cont == C_ZERO || cont == C_ONE)
grad.add_scaled((*dphi)[i][qp],system.current_solution(dof_num));
// grad += (*dphi)[i][qp] *
// system.current_solution(dof_num);
if (cont == C_ONE)
hess.add_scaled((*d2phi)[i][qp], system.current_solution(dof_num));
// hess += (*d2phi)[i][qp] *
// system.current_solution(dof_num);
}
// The projection matrix and vector
for (unsigned int i=0; i != Fe.size(); ++i)
{
Fe(i) += (*JxW)[qp] *
(*phi_coarse)[i][qp]*val;
if (cont == C_ZERO || cont == C_ONE)
Fe(i) += (*JxW)[qp] *
(grad*(*dphi_coarse)[i][qp]);
if (cont == C_ONE)
Fe(i) += (*JxW)[qp] *
hess.contract((*d2phi_coarse)[i][qp]);
// Fe(i) += (*JxW)[qp] *
// (*d2phi_coarse)[i][qp].contract(hess);
for (unsigned int j=0; j != Fe.size(); ++j)
{
Ke(i,j) += (*JxW)[qp] *
(*phi_coarse)[i][qp]*(*phi_coarse)[j][qp];
if (cont == C_ZERO || cont == C_ONE)
Ke(i,j) += (*JxW)[qp] *
(*dphi_coarse)[i][qp]*(*dphi_coarse)[j][qp];
if (cont == C_ONE)
Ke(i,j) += (*JxW)[qp] *
((*d2phi_coarse)[i][qp].contract((*d2phi_coarse)[j][qp]));
}
}
}
}
void HPCoarsenTest::select_refinement (System & system)
{
START_LOG("select_refinement()", "HPCoarsenTest");
// The current mesh
MeshBase & mesh = system.get_mesh();
// The dimensionality of the mesh
const unsigned int dim = mesh.mesh_dimension();
// The number of variables in the system
const unsigned int n_vars = system.n_vars();
// The DofMap for this system
const DofMap & dof_map = system.get_dof_map();
// The system number (for doing bad hackery)
const unsigned int sys_num = system.number();
// Check for a valid component_scale
if (!component_scale.empty())
{
if (component_scale.size() != n_vars)
libmesh_error_msg("ERROR: component_scale is the wrong size:\n" \
<< " component_scale.size()=" \
<< component_scale.size() \
<< "\n n_vars=" \
<< n_vars);
}
else
{
// No specified scaling. Scale all variables by one.
component_scale.resize (n_vars, 1.0);
}
// Resize the error_per_cell vectors to handle
// the number of elements, initialize them to 0.
std::vector<ErrorVectorReal> h_error_per_cell(mesh.max_elem_id(), 0.);
std::vector<ErrorVectorReal> p_error_per_cell(mesh.max_elem_id(), 0.);
// Loop over all the variables in the system
for (unsigned int var=0; var<n_vars; var++)
{
// Possibly skip this variable
if (!component_scale.empty())
if (component_scale[var] == 0.0) continue;
// The type of finite element to use for this variable
const FEType & fe_type = dof_map.variable_type (var);
// Finite element objects for a fine (and probably a coarse)
// element will be needed
fe = FEBase::build (dim, fe_type);
fe_coarse = FEBase::build (dim, fe_type);
// Any cached coarse element results have expired
coarse = libmesh_nullptr;
unsigned int cached_coarse_p_level = 0;
const FEContinuity cont = fe->get_continuity();
libmesh_assert (cont == DISCONTINUOUS || cont == C_ZERO ||
cont == C_ONE);
// Build an appropriate quadrature rule
qrule = fe_type.default_quadrature_rule(dim);
// Tell the refined finite element about the quadrature
// rule. The coarse finite element need not know about it
fe->attach_quadrature_rule (qrule.get());
// We will always do the integration
// on the fine elements. Get their Jacobian values, etc..
JxW = &(fe->get_JxW());
xyz_values = &(fe->get_xyz());
// The shape functions
phi = &(fe->get_phi());
phi_coarse = &(fe_coarse->get_phi());
// The shape function derivatives
if (cont == C_ZERO || cont == C_ONE)
{
dphi = &(fe->get_dphi());
dphi_coarse = &(fe_coarse->get_dphi());
}
#ifdef LIBMESH_ENABLE_SECOND_DERIVATIVES
// The shape function second derivatives
if (cont == C_ONE)
{
d2phi = &(fe->get_d2phi());
d2phi_coarse = &(fe_coarse->get_d2phi());
}
#endif // defined (LIBMESH_ENABLE_SECOND_DERIVATIVES)
// Iterate over all the active elements in the mesh
// that live on this processor.
MeshBase::const_element_iterator elem_it =
mesh.active_local_elements_begin();
const MeshBase::const_element_iterator elem_end =
mesh.active_local_elements_end();
for (; elem_it != elem_end; ++elem_it)
{
const Elem * elem = *elem_it;
// We're only checking elements that are already flagged for h
// refinement
if (elem->refinement_flag() != Elem::REFINE)
continue;
const dof_id_type e_id = elem->id();
// Find the projection onto the parent element,
// if necessary
if (elem->parent() &&
(coarse != elem->parent() ||
cached_coarse_p_level != elem->p_level()))
{
Uc.resize(0);
coarse = elem->parent();
cached_coarse_p_level = elem->p_level();
unsigned int old_parent_level = coarse->p_level();
(const_cast<Elem *>(coarse))->hack_p_level(elem->p_level());
this->add_projection(system, coarse, var);
(const_cast<Elem *>(coarse))->hack_p_level(old_parent_level);
// Solve the h-coarsening projection problem
Ke.cholesky_solve(Fe, Uc);
}
fe->reinit(elem);
// Get the DOF indices for the fine element
dof_map.dof_indices (elem, dof_indices, var);
// The number of quadrature points
const unsigned int n_qp = qrule->n_points();
// The number of DOFS on the fine element
const unsigned int n_dofs =
cast_int<unsigned int>(dof_indices.size());
// The number of nodes on the fine element
const unsigned int n_nodes = elem->n_nodes();
// The average element value (used as an ugly hack
// when we have nothing p-coarsened to compare to)
// Real average_val = 0.;
Number average_val = 0.;
// Calculate this variable's contribution to the p
// refinement error
if (elem->p_level() == 0)
{
unsigned int n_vertices = 0;
for (unsigned int n = 0; n != n_nodes; ++n)
if (elem->is_vertex(n))
{
n_vertices++;
const Node * const node = elem->get_node(n);
average_val += system.current_solution
(node->dof_number(sys_num,var,0));
}
average_val /= n_vertices;
}
else
{
unsigned int old_elem_level = elem->p_level();
(const_cast<Elem *>(elem))->hack_p_level(old_elem_level - 1);
fe_coarse->reinit(elem, &(qrule->get_points()));
const unsigned int n_coarse_dofs =
cast_int<unsigned int>(phi_coarse->size());
(const_cast<Elem *>(elem))->hack_p_level(old_elem_level);
Ke.resize(n_coarse_dofs, n_coarse_dofs);
Ke.zero();
Fe.resize(n_coarse_dofs);
Fe.zero();
// Loop over the quadrature points
for (unsigned int qp=0; qp<qrule->n_points(); qp++)
{
// The solution value at the quadrature point
Number val = libMesh::zero;
Gradient grad;
Tensor hess;
for (unsigned int i=0; i != n_dofs; i++)
{
dof_id_type dof_num = dof_indices[i];
val += (*phi)[i][qp] *
system.current_solution(dof_num);
if (cont == C_ZERO || cont == C_ONE)
grad.add_scaled((*dphi)[i][qp], system.current_solution(dof_num));
// grad += (*dphi)[i][qp] *
// system.current_solution(dof_num);
if (cont == C_ONE)
hess.add_scaled((*d2phi)[i][qp], system.current_solution(dof_num));
// hess += (*d2phi)[i][qp] *
// system.current_solution(dof_num);
}
// The projection matrix and vector
for (unsigned int i=0; i != Fe.size(); ++i)
{
Fe(i) += (*JxW)[qp] *
(*phi_coarse)[i][qp]*val;
if (cont == C_ZERO || cont == C_ONE)
Fe(i) += (*JxW)[qp] *
grad * (*dphi_coarse)[i][qp];
if (cont == C_ONE)
Fe(i) += (*JxW)[qp] *
hess.contract((*d2phi_coarse)[i][qp]);
for (unsigned int j=0; j != Fe.size(); ++j)
{
Ke(i,j) += (*JxW)[qp] *
(*phi_coarse)[i][qp]*(*phi_coarse)[j][qp];
if (cont == C_ZERO || cont == C_ONE)
Ke(i,j) += (*JxW)[qp] *
(*dphi_coarse)[i][qp]*(*dphi_coarse)[j][qp];
if (cont == C_ONE)
Ke(i,j) += (*JxW)[qp] *
((*d2phi_coarse)[i][qp].contract((*d2phi_coarse)[j][qp]));
}
}
}
// Solve the p-coarsening projection problem
Ke.cholesky_solve(Fe, Up);
}
// loop over the integration points on the fine element
for (unsigned int qp=0; qp<n_qp; qp++)
{
Number value_error = 0.;
Gradient grad_error;
Tensor hessian_error;
for (unsigned int i=0; i<n_dofs; i++)
{
const dof_id_type dof_num = dof_indices[i];
value_error += (*phi)[i][qp] *
system.current_solution(dof_num);
if (cont == C_ZERO || cont == C_ONE)
grad_error.add_scaled((*dphi)[i][qp], system.current_solution(dof_num));
// grad_error += (*dphi)[i][qp] *
// system.current_solution(dof_num);
if (cont == C_ONE)
hessian_error.add_scaled((*d2phi)[i][qp], system.current_solution(dof_num));
// hessian_error += (*d2phi)[i][qp] *
// system.current_solution(dof_num);
}
if (elem->p_level() == 0)
{
value_error -= average_val;
}
else
{
for (unsigned int i=0; i<Up.size(); i++)
{
value_error -= (*phi_coarse)[i][qp] * Up(i);
if (cont == C_ZERO || cont == C_ONE)
grad_error.subtract_scaled((*dphi_coarse)[i][qp], Up(i));
// grad_error -= (*dphi_coarse)[i][qp] * Up(i);
if (cont == C_ONE)
hessian_error.subtract_scaled((*d2phi_coarse)[i][qp], Up(i));
// hessian_error -= (*d2phi_coarse)[i][qp] * Up(i);
}
}
p_error_per_cell[e_id] += static_cast<ErrorVectorReal>
(component_scale[var] *
(*JxW)[qp] * TensorTools::norm_sq(value_error));
if (cont == C_ZERO || cont == C_ONE)
p_error_per_cell[e_id] += static_cast<ErrorVectorReal>
(component_scale[var] *
(*JxW)[qp] * grad_error.norm_sq());
if (cont == C_ONE)
p_error_per_cell[e_id] += static_cast<ErrorVectorReal>
(component_scale[var] *
(*JxW)[qp] * hessian_error.norm_sq());
}
// Calculate this variable's contribution to the h
// refinement error
if (!elem->parent())
{
// For now, we'll always start with an h refinement
h_error_per_cell[e_id] =
std::numeric_limits<ErrorVectorReal>::max() / 2;
}
else
{
FEInterface::inverse_map (dim, fe_type, coarse,
*xyz_values, coarse_qpoints);
unsigned int old_parent_level = coarse->p_level();
(const_cast<Elem *>(coarse))->hack_p_level(elem->p_level());
fe_coarse->reinit(coarse, &coarse_qpoints);
(const_cast<Elem *>(coarse))->hack_p_level(old_parent_level);
// The number of DOFS on the coarse element
unsigned int n_coarse_dofs =
cast_int<unsigned int>(phi_coarse->size());
// Loop over the quadrature points
for (unsigned int qp=0; qp<n_qp; qp++)
{
// The solution difference at the quadrature point
Number value_error = libMesh::zero;
Gradient grad_error;
Tensor hessian_error;
for (unsigned int i=0; i != n_dofs; ++i)
{
const dof_id_type dof_num = dof_indices[i];
value_error += (*phi)[i][qp] *
system.current_solution(dof_num);
if (cont == C_ZERO || cont == C_ONE)
grad_error.add_scaled((*dphi)[i][qp], system.current_solution(dof_num));
// grad_error += (*dphi)[i][qp] *
// system.current_solution(dof_num);
if (cont == C_ONE)
hessian_error.add_scaled((*d2phi)[i][qp], system.current_solution(dof_num));
// hessian_error += (*d2phi)[i][qp] *
// system.current_solution(dof_num);
}
for (unsigned int i=0; i != n_coarse_dofs; ++i)
{
value_error -= (*phi_coarse)[i][qp] * Uc(i);
if (cont == C_ZERO || cont == C_ONE)
// grad_error -= (*dphi_coarse)[i][qp] * Uc(i);
grad_error.subtract_scaled((*dphi_coarse)[i][qp], Uc(i));
if (cont == C_ONE)
hessian_error.subtract_scaled((*d2phi_coarse)[i][qp], Uc(i));
// hessian_error -= (*d2phi_coarse)[i][qp] * Uc(i);
}
h_error_per_cell[e_id] += static_cast<ErrorVectorReal>
(component_scale[var] *
(*JxW)[qp] * TensorTools::norm_sq(value_error));
if (cont == C_ZERO || cont == C_ONE)
h_error_per_cell[e_id] += static_cast<ErrorVectorReal>
(component_scale[var] *
(*JxW)[qp] * grad_error.norm_sq());
if (cont == C_ONE)
h_error_per_cell[e_id] += static_cast<ErrorVectorReal>
(component_scale[var] *
(*JxW)[qp] * hessian_error.norm_sq());
}
}
}
}
// Now that we've got our approximations for p_error and h_error, let's see
// if we want to switch any h refinement flags to p refinement
// Iterate over all the active elements in the mesh
// that live on this processor.
MeshBase::element_iterator elem_it =
mesh.active_local_elements_begin();
const MeshBase::element_iterator elem_end =
mesh.active_local_elements_end();
for (; elem_it != elem_end; ++elem_it)
{
Elem * elem = *elem_it;
// We're only checking elements that are already flagged for h
// refinement
if (elem->refinement_flag() != Elem::REFINE)
continue;
const dof_id_type e_id = elem->id();
unsigned int dofs_per_elem = 0, dofs_per_p_elem = 0;
// Loop over all the variables in the system
for (unsigned int var=0; var<n_vars; var++)
{
// The type of finite element to use for this variable
const FEType & fe_type = dof_map.variable_type (var);
// FIXME: we're overestimating the number of DOFs added by h
// refinement
FEType elem_fe_type = fe_type;
elem_fe_type.order =
static_cast<Order>(fe_type.order + elem->p_level());
dofs_per_elem +=
FEInterface::n_dofs(dim, elem_fe_type, elem->type());
elem_fe_type.order =
static_cast<Order>(fe_type.order + elem->p_level() + 1);
dofs_per_p_elem +=
FEInterface::n_dofs(dim, elem_fe_type, elem->type());
}
const unsigned int new_h_dofs = dofs_per_elem *
(elem->n_children() - 1);
const unsigned int new_p_dofs = dofs_per_p_elem -
dofs_per_elem;
/*
libMesh::err << "Cell " << e_id << ": h = " << elem->hmax()
<< ", p = " << elem->p_level() + 1 << "," << std::endl
<< " h_error = " << h_error_per_cell[e_id]
<< ", p_error = " << p_error_per_cell[e_id] << std::endl
<< " new_h_dofs = " << new_h_dofs
<< ", new_p_dofs = " << new_p_dofs << std::endl;
*/
const Real p_value =
std::sqrt(p_error_per_cell[e_id]) * p_weight / new_p_dofs;
const Real h_value =
std::sqrt(h_error_per_cell[e_id]) /
static_cast<Real>(new_h_dofs);
if (p_value > h_value)
{
elem->set_p_refinement_flag(Elem::REFINE);
elem->set_refinement_flag(Elem::DO_NOTHING);
}
}
STOP_LOG("select_refinement()", "HPCoarsenTest");
}