This directory contains routines for handling array indices. 

MG_COMPLEMENT, MG_SETUNION, MG_SETINTERSECTION, and MG_SETDIFFERENCE are set
operations for non-negative integers with -1L representing the empty set.
These are ideal for manipulating array indices.

MG_MAKERANGE is an easier way to create regularly spaced arrays by specifying start, stop, and increment values.