The constraints on a single loop nest characterize the
loops that are assigned to the same processor.
These constraints are used to initialize the computation partition for
each loop nest.
As this algorithm considers only forall loops,
the initial computation partition for a loop nest of depth l
is the span of a set of l-dimensional
elementary basis vectors
representing the sequential loops in the loop nest.
If a loop at nesting level k is sequential, then 
is included in
the initial computation partition.