gistfile1.txt

    # check required arguments were inputted
    if radial is None:
        print "No radial."
        usage()
        sys.exit
    if  numClusters < 0 or numPoints < 0 or minDistance < 0:
        print "numClusters, numPoints and minDistance must all be 0 or more"
        usage()  
        sys.exit
    if maxValue < 1 or minClusterVariance < 0 or maxClusterVariance < 0:
        print "maxValue should be 1 or more; minclusters and maxClusterVariance 0 or more"
        usage()
        sys.exit
    if        minDistance * numClusters > maxValue:
        print "mindistance * numclusters is > maxvalue: ", minDistance * numClusters, "  " , maxValue
        usage()
        sys.exit
    if output is None:
        print "no output specified"  
        usage()
        sys.exit()