Class Graph

python/pathway/stdlib/graphs/graph.py:77–117

r""" Basic class representing undirected, unweighted (multi)graph.

@dataclass
class Graph:
    r"""
    Basic class representing undirected, unweighted (multi)graph.
    """

    V: pw.Table[Vertex]
    E: pw.Table[Edge]

    def contracted_to_unweighted_simple_graph(
        self,
        clustering: pw.Table[Clustering],
        **reducer_expressions: pw.ReducerExpression,
    ) -> Graph:
        contracted_graph = self.contracted_to_multi_graph(clustering)
        contracted_graph.E = contracted_graph.E.groupby(
            contracted_graph.E.u, contracted_graph.E.v
        ).reduce(contracted_graph.E.u, contracted_graph.E.v)

        return contracted_graph

    def contracted_to_weighted_simple_graph(
        self,
        clustering: pw.Table[Clustering],
        **reducer_expressions: pw.ReducerExpression,
    ) -> WeightedGraph:
        contracted_graph = self.contracted_to_multi_graph(clustering)
        WE = contracted_graph.E.groupby(
            contracted_graph.E.u, contracted_graph.E.v
        ).reduce(contracted_graph.E.u, contracted_graph.E.v, **reducer_expressions)

        return WeightedGraph.from_vertices_and_weighted_edges(contracted_graph.V, WE)

    def contracted_to_multi_graph(
        self,
        clustering: pw.Table[Clustering],
    ) -> Graph:
        full_clustering = _extended_to_full_clustering(self.V, clustering)
        return _contract(self.E, full_clustering)

    def without_self_loops(self) -> Graph:
        return Graph(self.V, self.E.filter(self.E.u != self.E.v))


@dataclass