コード例 #1
0
  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 &current_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;
          }
      }
  }
コード例 #2
0
  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;
  }