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# Lanl Routes

Routes to LANL from 186 sites on the Internet.

The data file can be found at:

- networkx/networkx

This example needs Graphviz and PyGraphviz.

    Graph with 1281 nodes and 1296 edges
    1 connected components

    import matplotlib.pyplot as plt
    import networkx as nx

    def lanl_graph():
        """Return the lanl internet view graph from lanl.edges"""
        try:
            fh = open("lanl_routes.edgelist")
        except OSError:
            print("lanl.edges not found")
            raise

        G = nx.Graph()

        time = {}
        time[0] = 0  # assign 0 to center node
        for line in fh.readlines():
            (head, tail, rtt) = line.split()
            G.add_edge(int(head), int(tail))
            time[int(head)] = float(rtt)

        # get largest component and assign ping times to G0time dictionary
        Gcc = sorted(nx.connected_components(G), key=len, reverse=True)[0]
        G0 = G.subgraph(Gcc)
        G0.rtt = {}
        for n in G0:
            G0.rtt[n] = time[n]

        return G0

    G = lanl_graph()

    print(G)
    print(nx.number_connected_components(G), "connected components")

    plt.figure(figsize=(8, 8))
    # use graphviz to find radial layout
    pos = nx.nx_agraph.graphviz_layout(G, prog="twopi", root=0)
    # draw nodes, coloring by rtt ping time
    options = {"with_labels": False, "alpha": 0.5, "node_size": 15}
    nx.draw(G, pos, node_color=[G.rtt[v] for v in G], **options)
    # adjust the plot limits
    xmax = 1.02 * max(xx for xx, yy in pos.values())
    ymax = 1.02 * max(yy for xx, yy in pos.values())
    plt.xlim(0, xmax)
    plt.ylim(0, ymax)
    plt.show()

Total running time of the script: (0 minutes 0.269 seconds)

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