mod_functions_bfield.t

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module mod_functions_bfield
 
  implicit none
  private
 
  public :: get_divb
 
  !> Indices of the magnetic field
  integer, allocatable, public :: mag(:)
 
contains
 
  !> Calculate div B within ixO
  subroutine get_divb(w,ixI^L,ixO^L,divb,nth_in)
    use mod_global_parameters
    use mod_geometry
 
    integer, intent(in)             :: ixi^l, ixo^l
    double precision, intent(in)    :: w(ixi^s,1:nw)
    double precision, intent(inout) :: divb(ixi^s)
    integer, intent(in), optional   :: nth_in
    integer                         :: ixc^l, idir, nth
 
    if(present(nth_in)) then
      nth=nth_in
    else
      nth=1
    endif
 
    if(stagger_grid) then
      divb(ixo^s)=0.d0
      do idir=1,ndim
        ixc^l=ixo^l-kr(idir,^d);
        divb(ixo^s)=divb(ixo^s)+block%ws(ixo^s,idir)*block%surfaceC(ixo^s,idir)-&
                                block%ws(ixc^s,idir)*block%surfaceC(ixc^s,idir)
      end do
      divb(ixo^s)=divb(ixo^s)/block%dvolume(ixo^s)
    else
      select case(typediv)
      case("central")
        call divvector(w(ixi^s,mag(1:ndir)),ixi^l,ixo^l,divb,nth)
      case("limited")
        call divvectors(w(ixi^s,mag(1:ndir)),ixi^l,ixo^l,divb)
      end select
    end if
  end subroutine get_divb
 
 
end module mod_functions_bfield