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