C++ Facet::dim方法代码示例

//-----------------------------------------------------------------------------
bool DirichletBC::on_facet(const double* coordinates, const Facet& facet) const
{
  // Check if the coordinates are on the same line as the line segment
  if (facet.dim() == 1)
  {
    // Create points
    Point p(coordinates[0], coordinates[1]);
    const Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
    const Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();

    // Create vectors
    const Point v01 = v1 - v0;
    const Point vp0 = v0 - p;
    const Point vp1 = v1 - p;

    // Check if the length of the sum of the two line segments vp0 and
    // vp1 is equal to the total length of the facet
    if ( std::abs(v01.norm() - vp0.norm() - vp1.norm()) < DOLFIN_EPS )
      return true;
    else
      return false;
  }
  // Check if the coordinates are in the same plane as the triangular
  // facet
  else if (facet.dim() == 2)
  {
    // Create points
    const Point p(coordinates[0], coordinates[1], coordinates[2]);
    const Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
    const Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();
    const Point v2 = Vertex(facet.mesh(), facet.entities(0)[2]).point();

    // Create vectors
    const Point v01 = v1 - v0;
    const Point v02 = v2 - v0;
    const Point vp0 = v0 - p;
    const Point vp1 = v1 - p;
    const Point vp2 = v2 - p;

    // Check if the sum of the area of the sub triangles is equal to
    // the total area of the facet
    if (std::abs(v01.cross(v02).norm() - vp0.cross(vp1).norm()
                 - vp1.cross(vp2).norm() - vp2.cross(vp0).norm()) < DOLFIN_EPS)
    {
      return true;
    }
    else
      return false;
  }

  dolfin_error("DirichletBC.cpp",
               "determine if given point is on facet",
               "Not implemented for given facet dimension");

  return false;
}

//-----------------------------------------------------------------------------
bool NewDirichletBC::onFacet(real* coordinates, Facet& facet)
{
  // Check if the coordinates are on the same line as the line segment
  if ( facet.dim() == 1 )
  {
    // Create points
    Point p(coordinates[0], coordinates[1]);
    Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
    Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();

    // Create vectors
    Point v01 = v1 - v0;
    Point vp0 = v0 - p;
    Point vp1 = v1 - p;

    // Check if the length of the sum of the two line segments vp0 and vp1 is
    // equal to the total length of the facet
    if ( std::abs(v01.norm() - vp0.norm() - vp1.norm()) < DOLFIN_EPS )
      return true;
    else
      return false;
  }
  // Check if the coordinates are in the same plane as the triangular facet
  else if ( facet.dim() == 2 )
  {
    // Create points
    Point p(coordinates[0], coordinates[1], coordinates[2]);
    Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
    Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();
    Point v2 = Vertex(facet.mesh(), facet.entities(0)[2]).point();

    // Create vectors
    Point v01 = v1 - v0;
    Point v02 = v2 - v0;
    Point vp0 = v0 - p;
    Point vp1 = v1 - p;
    Point vp2 = v2 - p;

    // Check if the sum of the area of the sub triangles is equal to the total
    // area of the facet
    if ( std::abs(v01.cross(v02).norm() - vp0.cross(vp1).norm() - vp1.cross(vp2).norm()
        - vp2.cross(vp0).norm()) < DOLFIN_EPS )
      return true;
    else
      return false;
  }

  error("Unable to determine if given point is on facet (not implemented for given facet dimension).");

  return false;
}

//-----------------------------------------------------------------------------
void NewDirichletBC::computeBCTopological(std::map<uint, real>& boundary_values,
                                       Facet& facet,
                                       BoundaryCondition::LocalData& data)
{
  // Get cell to which facet belongs (there may be two, but pick first)
  Cell cell(_mesh, facet.entities(facet.dim() + 1)[0]);
  UFCCell ufc_cell(cell);
  
  // Get local index of facet with respect to the cell
  const uint local_facet = cell.index(facet);
  
  // Interpolate function on cell
  g.interpolate(data.w, ufc_cell, *data.finite_element, cell, local_facet);
  
  // Tabulate dofs on cell
  data.dof_map->tabulate_dofs(data.cell_dofs, ufc_cell);

  // Tabulate which dofs are on the facet
  data.dof_map->tabulate_facet_dofs(data.facet_dofs, local_facet);
  
  // Pick values for facet
  for (uint i = 0; i < data.dof_map->num_facet_dofs(); i++)
  {
    const uint dof = data.offset + data.cell_dofs[data.facet_dofs[i]];
    const real value = data.w[data.facet_dofs[i]];
    boundary_values[dof] = value;
  }
}