* when evaluating something on the surface of a cell. All the data
* that is available in the interior of cells is also available here.
*
- * On surfaces of mesh cells, boundary forms are
- * additional values that can be computed. This class provides the
- * interface to access those. Implementations are in derived classes
- * FEFaceValues and FESubfaceValues.
- *
- * The boundary form is the cross product of the images of the unit
- * tangential vectors. Therefore, it is the unit normal vector
- * multiplied with the surface element. Since it may be cheaper to
- * compute the boundary form immediately, use this value to integrate
- * <tt>n.ds</tt>.
- *
* See FEValuesBase
*
* @author Wolfgang Bangerth, 1998, Guido Kanschat, 2000, 2001
* Boundary form of the
* transformation of the cell at
* the <tt>i</tt>th quadrature point.
- *
- * The boundary form is the cross
- * product of the images of the
- * unit tangential
- * vectors. Therefore, it is the
- * unit normal vector multiplied
- * with the surface
- * element. Since it may be
- * cheaper to compute the
- * boundary form immediately, use
- * this value to integrate
- * <tt>n.ds</tt>.
+ * See @ref GlossBoundaryForm .
*/
const Tensor<1,spacedim> & boundary_form (const unsigned int i) const;
/**
- * Performs the same as @p fill_fe_values
- * on a face.
- * Additionally, @p boundary_form and
- * @p normal_vectors can be
- * computed on surfaces. The
- * boundary form is the vector
- * product of the image of
- * coordinate vectors on the
- * surface of the unit
- * cell. It is a
- * vector normal to the surface,
- * pointing outwards and having
- * the length of the surface
- * element.
- * Therefore, it is more economic
- * to use the boundary form
- * instead of the product of the
- * unit normal and the
- * transformed quadrature weight.
+ * Performs the same as @p
+ * fill_fe_values on a face.
+ * Additionally, @p boundary_form
+ * (see @ref GlossBoundaryForm)
+ * and @p normal_vectors can be
+ * computed on surfaces. Since
+ * the boundary form already
+ * contains the determinant of
+ * the Jacobian of the
+ * transformation, it is
+ * sometimes more economic to use
+ * the boundary form instead of
+ * the product of the unit normal
+ * and the transformed quadrature
+ * weight.
*/
virtual void
fill_fe_face_values (const typename Triangulation<dim,spacedim>::cell_iterator &cell,