boundary conditions

• hyperboundary :
            Header: subroutine hyperboundary(u, dxu, dyu, dzu, udot, v, w, imask, par)
                                type(gridfunction), dimension(NU), intent(inout) :: u, dxu,dyu,dzu,udot
                                type(gridfunction), dimension(NV) :: v
                                type(gridfunction), dimension(NW) :: w
                                CCTK_REAL, dimension(:) :: par
                                CCTK_INT, dimension(:,:,:) :: imask
  
• prim2char
            Header: subroutine prim2char(par,v,w,direction,u,w_in,w_out,w_0,T,uevolved,uexact,dxu,dyu,dzu,sources)
                                CCTK_REAL, dimension(:), intent(in) :: par
                                CCTK_REAL, dimension(:), intent(in) :: w,v
                                character(len=*), intent(in):: direction
                                CCTK_REAL, dimension(:), intent(in) :: u,uevolved,uexact,dxu,dyu,dzu
                                CCTK_REAL, dimension(:), intent(out) :: w_in, w_out
                                CCTK_REAL, dimension(:), intent(out) :: sources
                                CCTK_REAL, dimension(:), intent(out) :: w_0
                                CCTK_REAL, dimension(3):: n_down
                                CCTK_REAL, dimension(3,3) :: T
  
• char2prim
            Header: subroutine char2prim(par,v,w,direction,u,w_in,w_out,w_0,T,uevolved,uexact)
                                CCTK_REAL, dimension(:), intent(in) :: par
                                CCTK_REAL, dimension(:), intent(in):: w,uevolved,uexact,v
                                character(len=*), intent(in):: direction
                                CCTK_REAL, dimension(:), intent(out) :: u
                                CCTK_REAL, dimension(:), intent(in) :: w_in, w_out
                                CCTK_REAL, dimension(:), intent(in) :: w_0
                                CCTK_REAL, dimension(3) :: n_down
                                CCTK_REAL, dimension(3,3) :: T
  
• exactu

• boundary_conditions: this parameter is used in controlling the type of penalty method boundary condition used ( if any ). To use these boundary conditions, the user must supply the characteristic decomposition for the user-defined application equations in the routines prim2char and char2prim. The user must also explicitly call the function char_boundary in the user-supplied hyperboundary routine.
                boundary_conditions = 1 --> Boundary conditions to the incoming characteristic variables
                boundary_conditions = 2 --> Boundary conditions to the incoming characteristic variables (nonlinear principal part)
                boundary_conditions = 3 --> Penalty boundary (maximally dissipative)
                       If boundary_conditions = 3 then another tuning parameter must also be set: penalty = 0.0 (default). Usually, penalty = ~1.0
                boundary_conditions = 4 --> Carpenter boundary (penalty method)
                boundary_conditions = 5 --> Olson's boundary (maximally dissipative)
                boundary_conditions = 7 --> Constraint preserving boundary condition (incomplete)
                boundary_conditions = 8 --> Constraint preserving boundary condition (incomplete)
  
  When parameter runge_kutta_type = 1 or runge_kutta_type = 3, that is, when using standard rk3 integration or rk3tvd for finite volumes, the parameter boundary_conditions also controls when the routine hyperboundary is called.
  For runge_kutta_type = 1 or runge_kutta_type = 3:
                hyperboundary is called just before the rk3 update if boundary_conditions > 2 and boundary_conditions ≠ 8
                hyperboundary is called just after the rk3 update if boundary_conditions = 8
                hyperboundary is called at the start of each rk3 iteration if boundary_conditions = 1,2,7
  For runge_kutta_type = 2 (rk3tvd), see parameter runge_kutta_bound.
• runge_kutta_bound: this parameter is set by the driver in rk3tvd. It is only used when parameter runge_kutta_type = 2. It has a value of either 1 or 2. Certain boundary conditions need to be applied, either just before or after the rk3 update. This parameter gives the freedom to the user to specify when the boundary condition should be applied.
  
  If runge_kutta_bound is 1, hyperboundary is called just prior to an rk3 update--after the time and spatial derivatives necessary for the rk3 update have been calculated but before the actual update.
  
  If runge_kutta_bound is 2, hyperboundary is called just after the rk3 update.
  
  For example, if one wanted a certain boundary condition applied just before an rk3 update, write something like this in hyperboundary:
  
                if (nint(par(P_RUNGE_KUTTA_BOUND)) == 1) then
                     call my_own_boundary_condition()
                end if
  Continuing the example, if one wanted a certain boundary condition applied just after an rk3 update, write something like this in hyperboundary:
  
                if (nint(par(P_RUNGE_KUTTA_BOUND)) == 2) then
                     call my_own_boundary_condition2()
                end if
  
• bc_type: this parameter is deprecated. It is active only when runge_kutta_type = 1,3 and when bc_type = 3. It is used only for testing and debugging purposes.
  

• outflow_boundary
• fixed_boundary
• PWN2D_boundary
• PWN3D_boundary

Notes

• Modifications to the scheduling of the boundary condition are trivial to make. Simply modify when the call to hyperboundary is made in the integration scheme in "had/src/hyper".

See Also

Examples