Returns a centered-difference of a 2-d array along dimension dim, 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 |
|
| integer(kind=ik), | intent(in) | :: | dim | Dimension along which to differentiate |
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pure function diff_periodic_2d(x,dim) result(dx)
!! Returns a centered-difference of a 2-d array along dimension dim, with
!! periodic boundary conditions. This procedure is overloaded by the generic
!! procedure `diff`.
real(kind=rk),dimension(:,:),intent(in) :: x
!! Input array
integer(kind=ik),intent(in) :: dim
!! Dimension along which to differentiate
real(kind=rk),dimension(:,:),allocatable :: dx
integer(kind=ik) :: idm,jdm
idm = size(x,dim=1)
jdm = size(x,dim=2)
allocate(dx(idm,jdm))
if(idm == 0)then
return
elseif(idm == 1)then
dx = 0
return
endif
if(dim == 1)then
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,:))
elseif(dim == 2)then
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))
else
dx = 0
endif
endfunction diff_periodic_2d