Default: max_N_stencil_INTERIOR = 40
Defines the maximum number of accepted neighbor points for the pure numerics (stencil computation, differential operators).
Only interior points are concerned.
Out of the complete neighbor list, MESHFREE selects the max_N_stencil_INTERIOR closest ones.
Additionally, we have the constraint
max_N_stencil_INTERIOR = min( max_N_stencil, max_N_stencil_INTERIOR )