To partition the mesh, it is necessary to calculate the connection
graph connecting the points. This variable selects which stencil
is used to do this.
An order-one star stencil.
The stencil used for the Laplacian is used to calculate the
partition. This in principle should give a better partition, but
it is slower and requires more memory.
grid/mesh_partition.F90 : 183
call parse_variable(namespace, 'MeshPartitionStencil', STAR, stencil_to_use)