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# Articulation Points

This example shows how to compute and visualize the articulation points in a graph using `igraph.GraphBase.articulation_points()`. For an example on bridges instead, see Bridges.

    import igraph as ig
    import matplotlib.pyplot as plt

First, we construct a graph. This example shows usage of graph formulae:

    g = ig.Graph.Formula(
        "0-1-2-0, 3:4:5:6 - 3:4:5:6, 2-3-7-8",
    )

Now we are aready to find the articulation points as a vertex sequence

    articulation_points = g.vs[g.articulation_points()]

Finally, we can plot the graph

    fig, ax = plt.subplots()
    ig.plot(
        g,
        target=ax,
        vertex_size=30,
        vertex_color="lightblue",
        vertex_label=range(g.vcount()),
        vertex_frame_color = ["red" if v in articulation_points else "black" for v in g.vs],
        vertex_frame_width = [3 if v in articulation_points else 1 for v in g.vs],
        edge_width=0.8,
        edge_color='gray'
    )
    plt.show()

Total running time of the script: ( 0 minutes 0.189 seconds)

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