NETGEN is a general-purpose netlist management system.  It can read
and write several netlist formats, including NTK (Caltech, CMU),
WOMBAT (Berkeley), SIM (Berkeley), ACTEL (Actel Inc., Sunnyvale), and
SPICE (Berkeley).  In addition, a C-language embedded interface exists
for specifying netlists directly.  Please see the documentation file
NETGEN.DOC

NETGEN was intended as an efficient specification language for
hierarchical systems.  Secondary features, such as testing isomorphism
between two netlists, have been added over time.  As netgen has
primarily been used in its capacity as a netlist comparator, this
has essentially become the primary useful feature of netgen.