void ParsedInteriorQoI::element_qoi_derivative( AssemblyContext& context,
const unsigned int qoi_index )
{
libMesh::FEBase* element_fe;
context.get_element_fe<libMesh::Real>(0, element_fe);
const std::vector<libMesh::Real> &JxW = element_fe->get_JxW();
const std::vector<libMesh::Point>& x_qp = element_fe->get_xyz();
// Local DOF count and quadrature point count
const unsigned int n_u_dofs = context.get_dof_indices().size();
unsigned int n_qpoints = context.get_element_qrule().n_points();
// Local solution vector - non-const version for finite
// differenting purposes
libMesh::DenseVector<libMesh::Number>& elem_solution =
const_cast<libMesh::DenseVector<libMesh::Number>&>
(context.get_elem_solution());
/*! \todo Need to generalize this to the multiple QoI case */
libMesh::DenseVector<libMesh::Number> &Qu =
context.get_qoi_derivatives()[qoi_index];
for( unsigned int qp = 0; qp != n_qpoints; qp++ )
{
// Central finite differencing to approximate derivatives.
// FIXME - we should hook the FParserAD stuff into
// ParsedFEMFunction
for( unsigned int i = 0; i != n_u_dofs; ++i )
{
libMesh::Number ¤t_solution = elem_solution(i);
const libMesh::Number original_solution = current_solution;
current_solution = original_solution + libMesh::TOLERANCE;
const libMesh::Number plus_val =
(*qoi_functional)(context, x_qp[qp], context.get_time());
current_solution = original_solution - libMesh::TOLERANCE;
const libMesh::Number minus_val =
(*qoi_functional)(context, x_qp[qp], context.get_time());
Qu(i) += (plus_val - minus_val) *
(0.5 / libMesh::TOLERANCE) * JxW[qp];
// Don't forget to restore the correct solution...
current_solution = original_solution;
}
}
}
void Vorticity::element_qoi_derivative( libMesh::DiffContext &context, const libMesh::QoISet & )
{
libMesh::FEMContext &c = libmesh_cast_ref<libMesh::FEMContext&>(context);
if( _subdomain_ids.find( (c.elem)->subdomain_id() ) != _subdomain_ids.end() )
{
// Element
libMesh::FEBase* element_fe;
c.get_element_fe<libMesh::Real>(this->_u_var, element_fe);
// Jacobian times integration weights
const std::vector<libMesh::Real> &JxW = element_fe->get_JxW();
// Grad of basis functions
const std::vector<std::vector<libMesh::RealGradient> >& du_phi =
c.element_fe_var[_u_var]->get_dphi();
const std::vector<std::vector<libMesh::RealGradient> >& dv_phi =
c.element_fe_var[_v_var]->get_dphi();
// Local DOF count and quadrature point count
const unsigned int n_T_dofs = c.dof_indices_var[0].size();
unsigned int n_qpoints = (c.get_element_qrule())->n_points();
// Warning: we assume here that vorticity is the only QoI!
// This should be consistent with the assertion in grins_mesh_adaptive_solver.C
/*! \todo Need to generalize this to the multiple QoI case */
libMesh::DenseSubVector<Number> &Qu = *c.elem_qoi_subderivatives[0][0];
libMesh::DenseSubVector<Number> &Qv = *c.elem_qoi_subderivatives[0][1];
// Integration loop
for( unsigned int qp = 0; qp != n_qpoints; qp++ )
{
for( unsigned int i = 0; i != n_T_dofs; i++ )
{
Qu(i) += - dv_phi[i][qp](1) * JxW[qp];
Qv(i) += du_phi[i][qp](0) * JxW[qp];
}
}
}
return;
}
