lib(graphviz)


    This library provides an interface to the Graphviz Graph Drawing Programs
    from AT&T (www.graphviz.org).

    Graphviz itself must be downloaded and installed separately.  It is
    readily available for most operating systems, and subject to the
    open-source Eclipse Public Licence.

    The predicates in this library take graph data structures as defined by
    library(graph_algorithms), invoke graphviz's layout tools, and output
    the generated drawing in various file formats (which can then be viewed
    in a browser of dedicated viewer), or invoke a simple viewer directly.
    

