Returns a centered-difference of a 1-d array with periodic boundary
conditions. This procedure is overloaded by the generic procedure diff.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| real(kind=rk), | intent(in), | dimension(:) | :: | x | Input array |
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pure function diff_periodic_1d(x) result(dx)
!! Returns a centered-difference of a 1-d array with periodic boundary
!! conditions. This procedure is overloaded by the generic procedure `diff`.
real(kind=rk),dimension(:),intent(in) :: x !! Input array
real(kind=rk),dimension(:),allocatable :: dx
integer(kind=ik) :: idm
idm = size(x)
allocate(dx(idm))
if(idm == 0)then
return
elseif(idm == 1)then
dx = 0
return
endif
dx(2:idm-1) = 0.5_rk*(x(3:idm)-x(1:idm-2))
dx(1) = 0.5_rk*(x(2)-x(idm))
dx(idm) = 0.5_rk*(x(1)-x(idm-1))
endfunction diff_periodic_1d