C++ (Cpp) FEMContext::get_elem_jacobian Examples

Example #1

File: assembly.C Project: YSB330/libmesh

void AssemblyA0::interior_assembly(FEMContext & c)
{
  const unsigned int n_components = rb_sys.n_vars();

  // make sure we have three components
  libmesh_assert_equal_to (n_components, 3);

  const unsigned int u_var = rb_sys.u_var;
  const unsigned int v_var = rb_sys.v_var;
  const unsigned int w_var = rb_sys.w_var;

  FEBase * elem_fe = libmesh_nullptr;
  c.get_element_fe(u_var, elem_fe);

  const std::vector<Real> & JxW = elem_fe->get_JxW();

  // The velocity shape function gradients at interior
  // quadrature points.
  const std::vector<std::vector<RealGradient> > & dphi = elem_fe->get_dphi();

  // Now we will build the affine operator
  unsigned int n_qpoints = c.get_element_qrule().n_points();

  std::vector<unsigned int> n_var_dofs(n_components);
  n_var_dofs[u_var] = c.get_dof_indices(u_var).size();
  n_var_dofs[v_var] = c.get_dof_indices(v_var).size();
  n_var_dofs[w_var] = c.get_dof_indices(w_var).size();

  for (unsigned int C_i = 0; C_i < n_components; C_i++)
    {
      unsigned int C_j = 0;
      for (unsigned int C_k = 0; C_k < n_components; C_k++)
        for (unsigned int C_l = 1; C_l < n_components; C_l++)
          {
            Real C_ijkl = elasticity_tensor(C_i, C_j, C_k, C_l);
            for (unsigned int qp=0; qp<n_qpoints; qp++)
              for (unsigned int i=0; i<n_var_dofs[C_i]; i++)
                for (unsigned int j=0; j<n_var_dofs[C_k]; j++)
                  (c.get_elem_jacobian(C_i,C_k))(i,j) +=
                    JxW[qp]*(C_ijkl * dphi[i][qp](C_j)*dphi[j][qp](C_l));
          }
    }

  for (unsigned int C_i = 0; C_i < n_components; C_i++)
    for (unsigned int C_j = 1; C_j < n_components; C_j++)
      for (unsigned int C_k = 0; C_k < n_components; C_k++)
        {
          unsigned int C_l = 0;

          Real C_ijkl = elasticity_tensor(C_i, C_j, C_k, C_l);
          for (unsigned int qp=0; qp<n_qpoints; qp++)
            for (unsigned int i=0; i<n_var_dofs[C_i]; i++)
              for (unsigned int j=0; j<n_var_dofs[C_k]; j++)
                (c.get_elem_jacobian(C_i,C_k))(i,j) +=
                  JxW[qp]*(C_ijkl * dphi[i][qp](C_j)*dphi[j][qp](C_l));
        }

}

Example #2

void InnerProductAssembly::interior_assembly(FEMContext &c)
{
  const unsigned int u_var = rb_sys.u_var;
  const unsigned int v_var = rb_sys.v_var;
  const unsigned int w_var = rb_sys.w_var;

  const std::vector<Real> &JxW =
    c.element_fe_var[u_var]->get_JxW();

  // The velocity shape function gradients at interior
  // quadrature points.
  const std::vector<std::vector<RealGradient> >& dphi =
    c.element_fe_var[u_var]->get_dphi();

  // The number of local degrees of freedom in each variable
  const unsigned int n_u_dofs = c.dof_indices_var[u_var].size();
  const unsigned int n_v_dofs = c.dof_indices_var[v_var].size();
  const unsigned int n_w_dofs = c.dof_indices_var[w_var].size();

  // Now we will build the affine operator
  unsigned int n_qpoints = (c.get_element_qrule())->n_points();

  DenseSubMatrix<Number>& Kuu = c.get_elem_jacobian(u_var,u_var);
  DenseSubMatrix<Number>& Kvv = c.get_elem_jacobian(v_var,v_var);
  DenseSubMatrix<Number>& Kww = c.get_elem_jacobian(w_var,w_var);

  for (unsigned int qp=0; qp<n_qpoints; qp++)
  {
      for (unsigned int i=0; i<n_u_dofs; i++)
        for (unsigned int j=0; j<n_u_dofs; j++)
        {
          Kuu(i,j) += JxW[qp]*(dphi[i][qp]*dphi[j][qp]);
        }

      for (unsigned int i=0; i<n_v_dofs; i++)
        for (unsigned int j=0; j<n_v_dofs; j++)
        {
          Kvv(i,j) += JxW[qp]*(dphi[i][qp]*dphi[j][qp]);
        }

      for (unsigned int i=0; i<n_w_dofs; i++)
        for (unsigned int j=0; j<n_w_dofs; j++)
        {
          Kww(i,j) += JxW[qp]*(dphi[i][qp]*dphi[j][qp]);
        }
  }
}