Given a GraphViz dot file, create combinations of layouts and output formats; depends on having the dot executable preinstalled

graphGenerator.groovy

import groovyx.gpars.GParsPool

def inputfile = args[0]
def layouts = [ 'twopi', 'sfdp', 'osage']
def formats = [ 'pdf','svg']
def combinations = [layouts, formats].combinations()

GParsPool.withPool(4) {
    combinations.eachParallel { combination ->
        String layout = combination[0]
        String format = combination[1]
        List args = [ '/usr/local/bin/dot', "-K$layout", '-Goverlap=prism', '-Goverlap_scaling=-10', "-T$format",
                '-o', "${inputfile}.${layout}.$format", inputfile ]
        println args
        final Process execute = args.execute()
        execute.waitFor()
        println execute.exitValue()
    }
}