Exemple #1
0
  void testRestart()
  {
    SlitFunc slitfunc;

    _mesh->write("slit_mesh.xda");
    _es->write("slit_solution.xda",
               EquationSystems::WRITE_DATA |
               EquationSystems::WRITE_SERIAL_FILES);

    Mesh mesh2(*TestCommWorld);
    mesh2.read("slit_mesh.xda");
    EquationSystems es2(mesh2);
    es2.read("slit_solution.xda");

    System & sys2 = es2.get_system<System> ("SimpleSystem");

    unsigned int dim = 2;

    CPPUNIT_ASSERT_EQUAL( sys2.n_vars(), 1u );

    FEMContext context(sys2);
    FEBase * fe = NULL;
    context.get_element_fe( 0, fe, dim );
    const std::vector<Point> & xyz = fe->get_xyz();
    fe->get_phi();

    MeshBase::const_element_iterator       el     =
      mesh2.active_local_elements_begin();
    const MeshBase::const_element_iterator end_el =
      mesh2.active_local_elements_end();

    for (; el != end_el; ++el)
      {
        const Elem * elem = *el;
        context.pre_fe_reinit(sys2, elem);
        context.elem_fe_reinit();

        const unsigned int n_qp = xyz.size();

        for (unsigned int qp=0; qp != n_qp; ++qp)
          {
            const Number exact_val = slitfunc(context, xyz[qp]);

            const Number discrete_val = context.interior_value(0, qp);

            CPPUNIT_ASSERT_DOUBLES_EQUAL(libmesh_real(exact_val),
                                         libmesh_real(discrete_val),
                                         TOLERANCE*TOLERANCE);
          }
      }
  }
  void testSystem()
  {
    SlitFunc slitfunc;

    unsigned int dim = 2;

    CPPUNIT_ASSERT_EQUAL( _sys->n_vars(), 1u );

    FEMContext context(*_sys);
    FEBase * fe = NULL;
    context.get_element_fe( 0, fe, dim );
    const std::vector<Point> & xyz = fe->get_xyz();
    fe->get_phi();

    MeshBase::const_element_iterator       el     =
      _mesh->active_local_elements_begin();
    const MeshBase::const_element_iterator end_el =
      _mesh->active_local_elements_end();

    for (; el != end_el; ++el)
      {
        const Elem * elem = *el;
        context.pre_fe_reinit(*_sys, elem);
        context.elem_fe_reinit();

        const unsigned int n_qp = xyz.size();

        for (unsigned int qp=0; qp != n_qp; ++qp)
          {
            const Number exact_val = slitfunc(context, xyz[qp]);

            const Number discrete_val = context.interior_value(0, qp);

            CPPUNIT_ASSERT_DOUBLES_EQUAL(libmesh_real(exact_val),
                                         libmesh_real(discrete_val),
                                         TOLERANCE*TOLERANCE);
          }
      }
  }
Exemple #3
0
void HeatSystem::init_context(DiffContext & context)
{
  FEMContext & c = libmesh_cast_ref<FEMContext &>(context);

  const std::set<unsigned char> & elem_dims =
    c.elem_dimensions();

  for (std::set<unsigned char>::const_iterator dim_it =
         elem_dims.begin(); dim_it != elem_dims.end(); ++dim_it)
    {
      const unsigned char dim = *dim_it;

      FEBase * fe = libmesh_nullptr;

      c.get_element_fe(T_var, fe, dim);

      fe->get_JxW();  // For integration
      fe->get_dphi(); // For bilinear form
      fe->get_xyz();  // For forcing
      fe->get_phi();  // For forcing
    }

  FEMSystem::init_context(context);
}
Exemple #4
0
bool HeatSystem::element_time_derivative (bool request_jacobian,
                                          DiffContext & context)
{
  FEMContext & c = libmesh_cast_ref<FEMContext &>(context);

  const unsigned int mesh_dim =
    c.get_system().get_mesh().mesh_dimension();

  // First we get some references to cell-specific data that
  // will be used to assemble the linear system.
  const unsigned int dim = c.get_elem().dim();
  FEBase * fe = libmesh_nullptr;
  c.get_element_fe(T_var, fe, dim);

  // Element Jacobian * quadrature weights for interior integration
  const std::vector<Real> & JxW = fe->get_JxW();

  const std::vector<Point> & xyz = fe->get_xyz();

  const std::vector<std::vector<Real> > & phi = fe->get_phi();

  const std::vector<std::vector<RealGradient> > & dphi = fe->get_dphi();

  // The number of local degrees of freedom in each variable
  const unsigned int n_T_dofs = c.get_dof_indices(T_var).size();

  // The subvectors and submatrices we need to fill:
  DenseSubMatrix<Number> & K = c.get_elem_jacobian(T_var, T_var);
  DenseSubVector<Number> & F = c.get_elem_residual(T_var);

  // Now we will build the element Jacobian and residual.
  // Constructing the residual requires the solution and its
  // gradient from the previous timestep.  This must be
  // calculated at each quadrature point by summing the
  // solution degree-of-freedom values by the appropriate
  // weight functions.
  unsigned int n_qpoints = c.get_element_qrule().n_points();

  for (unsigned int qp=0; qp != n_qpoints; qp++)
    {
      // Compute the solution gradient at the Newton iterate
      Gradient grad_T = c.interior_gradient(T_var, qp);

      const Number k = _k[dim];

      const Point & p = xyz[qp];

      // solution + laplacian depend on problem dimension
      const Number u_exact = (mesh_dim == 2) ?
        std::sin(libMesh::pi*p(0)) * std::sin(libMesh::pi*p(1)) :
        std::sin(libMesh::pi*p(0)) * std::sin(libMesh::pi*p(1)) *
        std::sin(libMesh::pi*p(2));

      // Only apply forcing to interior elements
      const Number forcing = (dim == mesh_dim) ?
        -k * u_exact * (dim * libMesh::pi * libMesh::pi) : 0;

      const Number JxWxNK = JxW[qp] * -k;

      for (unsigned int i=0; i != n_T_dofs; i++)
        F(i) += JxWxNK * (grad_T * dphi[i][qp] + forcing * phi[i][qp]);
      if (request_jacobian)
        {
          const Number JxWxNKxD = JxWxNK *
            context.get_elem_solution_derivative();

          for (unsigned int i=0; i != n_T_dofs; i++)
            for (unsigned int j=0; j != n_T_dofs; ++j)
              K(i,j) += JxWxNKxD * (dphi[i][qp] * dphi[j][qp]);
        }
    } // end of the quadrature point qp-loop

  return request_jacobian;
}
Exemple #5
0
bool SolidSystem::side_time_derivative(bool request_jacobian,
    DiffContext &context) {
  FEMContext &c = libmesh_cast_ref<FEMContext&>(context);

  // Apply displacement boundary conditions with penalty method

  // Get the current load step
  Real ratio = this->get_equation_systems().parameters.get<Real>("progress")
      + 0.001;

  // The BC are stored in the simulation parameters as array containing sequences of
  // four numbers: Id of the side for the displacements and three values describing the
  // displacement. E.g.: bc/displacement = '5 nan nan -1.0'. This will move all nodes of
  // side 5 about 1.0 units down the z-axis while leaving all other directions unrestricted

  // Get number of BCs to enforce
  unsigned int num_bc = args.vector_variable_size("bc/displacement");
  if (num_bc % 4 != 0) {
    libMesh::err
        << "ERROR, Odd number of values in displacement boundary condition.\n"
        << std::endl;
    libmesh_error();
  }
  num_bc /= 4;

  // Loop over all BCs
  for (unsigned int nbc = 0; nbc < num_bc; nbc++) {
    // Get IDs of the side for this BC
    short int positive_boundary_id = args("bc/displacement", 1, nbc * 4);

    // The current side may not be on the boundary to be restricted
    if (!this->get_mesh().boundary_info->has_boundary_id
	  (c.elem,c.side,positive_boundary_id))
      continue;

    // Read values from configuration file
    Point diff_value;
    for (unsigned int d = 0; d < c.dim; ++d) {
      diff_value(d) = args("bc/displacement", NAN, nbc * 4 + 1 + d);
    }
    // Scale according to current load step
    diff_value *= ratio;

    Real penalty_number = args("bc/displacement_penalty", 1e7);

    FEBase * fe = c.side_fe_var[var[0]];
    const std::vector<std::vector<Real> > & phi = fe->get_phi();
    const std::vector<Real>& JxW = fe->get_JxW();
    const std::vector<Point>& coords = fe->get_xyz();

    unsigned int n_x_dofs = c.dof_indices_var[this->var[0]].size();

    // get mappings for dofs for auxiliary system for original mesh positions
    const System & auxsys = this->get_equation_systems().get_system(
        "auxiliary");
    const DofMap & auxmap = auxsys.get_dof_map();
    std::vector<dof_id_type> undefo_dofs[3];
    for (unsigned int d = 0; d < c.dim; ++d) {
      auxmap.dof_indices(c.elem, undefo_dofs[d], undefo_var[d]);
    }

    for (unsigned int qp = 0; qp < c.side_qrule->n_points(); ++qp) {
      // calculate coordinates of qp on undeformed mesh
      Point orig_point;
      for (unsigned int i = 0; i < n_x_dofs; ++i) {
        for (unsigned int d = 0; d < c.dim; ++d) {
          Number orig_val = auxsys.current_solution(undefo_dofs[d][i]);

#if LIBMESH_USE_COMPLEX_NUMBERS
          orig_point(d) += phi[i][qp] * orig_val.real();
#else
          orig_point(d) += phi[i][qp] * orig_val;
#endif
        }
      }

      // Calculate displacement to be enforced.
      Point diff = coords[qp] - orig_point - diff_value;

      // Assemble
      for (unsigned int i = 0; i < n_x_dofs; ++i) {
        for (unsigned int d1 = 0; d1 < c.dim; ++d1) {
          if (libmesh_isnan(diff(d1)))
            continue;
          Real val = JxW[qp] * phi[i][qp] * diff(d1) * penalty_number;
          c.elem_subresiduals[var[d1]]->operator ()(i) += val;
        }
        if (request_jacobian) {
          for (unsigned int j = 0; j < n_x_dofs; ++j) {
            for (unsigned int d1 = 0; d1 < c.dim; ++d1) {
              if (libmesh_isnan(diff(d1)))
                continue;
              Real val = JxW[qp] * phi[i][qp] * phi[j][qp] * penalty_number;
              c.elem_subjacobians[var[d1]][var[d1]]->operator ()(i, j) += val;
            }
          }
        }
      }
    }
  }

  return request_jacobian;
}
  void testRestart()
  {
    SlitFunc slitfunc;

    _mesh->write("slit_mesh.xda");
    _es->write("slit_solution.xda",
               EquationSystems::WRITE_DATA |
               EquationSystems::WRITE_SERIAL_FILES);

    Mesh mesh2(*TestCommWorld);
    mesh2.read("slit_mesh.xda");
    EquationSystems es2(mesh2);
    es2.read("slit_solution.xda");

    System & sys2 = es2.get_system<System> ("SimpleSystem");

    unsigned int dim = 2;

    CPPUNIT_ASSERT_EQUAL( sys2.n_vars(), 1u );

    FEMContext context(sys2);
    FEBase * fe = NULL;
    context.get_element_fe( 0, fe, dim );
    const std::vector<Point> & xyz = fe->get_xyz();
    fe->get_phi();

    // While we're in the middle of a unique id based test case, let's
    // make sure our unique ids were all read in correctly too.
    UniquePtr<PointLocatorBase> locator = _mesh->sub_point_locator();

    MeshBase::const_element_iterator       el     =
      mesh2.active_local_elements_begin();
    const MeshBase::const_element_iterator end_el =
      mesh2.active_local_elements_end();

    for (; el != end_el; ++el)
      {
        const Elem * elem = *el;

        const Elem * mesh1_elem = (*locator)(elem->centroid());
        if (mesh1_elem)
          {
            CPPUNIT_ASSERT_EQUAL( elem->unique_id(),
                                  mesh1_elem->unique_id() );

            for (unsigned int n=0; n != elem->n_nodes(); ++n)
              {
                const Node & node       = elem->node_ref(n);
                const Node & mesh1_node = mesh1_elem->node_ref(n);
                CPPUNIT_ASSERT_EQUAL( node.unique_id(),
                                      mesh1_node.unique_id() );
              }
          }

        context.pre_fe_reinit(sys2, elem);
        context.elem_fe_reinit();

        const unsigned int n_qp = xyz.size();

        for (unsigned int qp=0; qp != n_qp; ++qp)
          {
            const Number exact_val = slitfunc(context, xyz[qp]);

            const Number discrete_val = context.interior_value(0, qp);

            CPPUNIT_ASSERT_DOUBLES_EQUAL(libmesh_real(exact_val),
                                         libmesh_real(discrete_val),
                                         TOLERANCE*TOLERANCE);
          }
      }
  }