Line data    Source code

       1            0 : // Distributed under the MIT License.
       2              : // See LICENSE.txt for details.
       3              : 
       4              : #pragma once
       5              : 
       6              : #include <iosfwd>
       7              : 
       8            0 : namespace evolution::BoundaryConditions {
       9              : /*!
      10              :  * \brief The type of boundary condition.
      11              :  *
      12              :  * There are generally two categories or types of boundary conditions. Those
      13              :  * that:
      14              :  *
      15              :  * 1. set up additional cells or elements (called ghost cells or ghost elements)
      16              :  *    outside the computational domain and then apply boundary corrections the
      17              :  *    same way that is done in the the interior. For example, in a discontinuous
      18              :  *    Galerkin scheme these would impose boundary conditions through a numerical
      19              :  *    flux boundary correction term.
      20              :  *
      21              :  * 2. change the time derivatives at the external boundary
      22              :  */
      23            1 : enum class Type {
      24              :   /// Impose boundary conditions by setting values on ghost cells/elements.
      25              :   ///
      26              :   /// The ghost cell values can come either from internal data or from an
      27              :   /// analytic prescription
      28              :   Ghost,
      29              :   /// Impose boundary conditions on the time derivative of the evolved
      30              :   /// variables.
      31              :   ///
      32              :   /// These are imposed after all internal and external boundaries using a ghost
      33              :   /// cell prescription have been handled.
      34              :   TimeDerivative,
      35              :   /// Impose ghost boundary conditions on some of the evolved variables and time
      36              :   /// derivative boundary conditions on others.
      37              :   GhostAndTimeDerivative,
      38              :   /// Require all characteristics to be outgoing on the boundary.
      39              :   ///
      40              :   /// Typically this boundary condition should only check that all
      41              :   /// characteristic speeds are out of the domain.
      42              :   DemandOutgoingCharSpeeds
      43              : };
      44              : 
      45            0 : std::ostream& operator<<(std::ostream& os, Type boundary_condition_type);
      46              : }  // namespace evolution::BoundaryConditions