Function _contract

python/pathway/stdlib/graphs/graph.py:13–33

r""" This function contracts the clusters of the graph, under the assumption that it was given a full clustering, i.e., all vertices have exactly one cluster in clustering Returns: a graph in which: - each vertex is a cluster from the clustering, - each origi

(edges: pw.Table[Edge], clustering: pw.Table[Clustering])

def _contract(edges: pw.Table[Edge], clustering: pw.Table[Clustering]) -> Graph:
    r"""
    This function contracts the clusters of the graph,
    under the assumption that it was given a full clustering,
    i.e., all vertices have exactly one cluster in clustering

    Returns:
        a graph in which:
        - each vertex is a cluster from the clustering,
        - each original edge now points to clusters containing the original endpoints

    """

    new_vertices = (
        clustering.groupby(clustering.c)
        .reduce(v=clustering.c)
        .with_id(pw.this.v)
        .select()
    )
    new_edges = edges.select(u=clustering.ix(edges.u).c, v=clustering.ix(edges.v).c)
    return Graph(new_vertices, new_edges)


def _contract_weighted(