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c $Header$
#include "cctk.h"
subroutine apply_dissipation (var, rhs, ni, nj, nk, dx, dt, order, epsdis)
implicit none
integer ni, nj, nk
CCTK_REAL var(ni,nj,nk), rhs(ni,nj,nk)
CCTK_REAL dx(3), dt
CCTK_INT order
CCTK_REAL epsdis
integer i, j, k
if (order .eq. 1) then
do k = 2, nk-1
do j = 2, nj-1
do i = 2, ni-1
rhs(i,j,k) = rhs(i,j,k) + epsdis
$ * (+ (var(i-1,j,k) - 2*var(i,j,k) + var(i+1,j,k)) / dx(1)
$ + (var(i,j-1,k) - 2*var(i,j,k) + var(i,j+1,k)) / dx(2)
$ + (var(i,j,k-1) - 2*var(i,j,k) + var(i,j,k+1)) / dx(3))
end do
end do
end do
else if (order .eq. 3) then
do k = 3, nk-2
do j = 3, nj-2
do i = 3, ni-2
rhs(i,j,k) = rhs(i,j,k) - epsdis / 16
$ * (+ (var(i-2,j,k) - 4*var(i-1,j,k) + 6*var(i,j,k) - 4*var(i+1,j,k) + var(i+2,j,k)) / dx(1)
$ + (var(i,j-2,k) - 4*var(i,j-1,k) + 6*var(i,j,k) - 4*var(i,j+1,k) + var(i,j+2,k)) / dx(2)
$ + (var(i,j,k-2) - 4*var(i,j,k-1) + 6*var(i,j,k) - 4*var(i,j,k+1) + var(i,j,k+2)) / dx(3))
end do
end do
end do
else
call CCTK_WARN (0, "internal error")
end if
end
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