@Override
    public void execute(GraphModel graphModel) {
        Graph graph;
        if (isDirected) {
            graph = graphModel.getDirectedGraphVisible();
        } else {
            graph = graphModel.getUndirectedGraphVisible();
        }
        execute(graph);
    }
@Test
    public void testColumnReplace() {
        GraphModel graphModel = GraphGenerator.generateNullUndirectedGraph(1);

        graphModel.getNodeTable().addColumn(PageRank.PAGERANK, String.class);

        PageRank pr = new PageRank();
        pr.execute(graphModel);
    }