Decides what kind of stencil is used, i.e. which points, around each point in the mesh, are the neighboring points used in the expression of the differential operator.
If curvilinear coordinates are to be used, then only the stencil_starplus
or the stencil_cube may be used. We only recommend the stencil_starplus,
since the cube typically needs far too much memory.
A star around each point (i.e., only points on the axis).
Same as the star, but with coefficients built in a different way.
A cube of points around each point.
The star, plus a number of off-axis points.
The general star. Default for non-orthogonal grids.
grid/derivatives.F90 : 210
call parse_variable(namespace, 'DerivativesStencil', default_stencil, der%stencil_type)