Class UndirectedGraph

numpy_ml/utils/graphs.py:266–294

class UndirectedGraph(Graph):
    def __init__(self, V, E):
        """
        A generic undirected graph object.

        Parameters
        ----------
        V : list
            A list of vertex IDs.
        E : list of :class:`Edge <numpy_ml.utils.graphs.Edge>` objects
            A list of edges connecting pairs of vertices in ``V``. For any edge
            connecting vertex `u` to vertex `v`, :class:`UndirectedGraph
            <numpy_ml.utils.graphs.UndirectedGraph>` will assume that there
            exists a corresponding edge connecting `v` to `u`, even if this is
            not present in `E`.
        """
        super().__init__(V, E)
        self.is_directed = False

    def _build_adjacency_list(self):
        """Encode undirected, unweighted graph as an adjancency list"""
        # assumes no parallel edges
        # each edge appears twice as (u,v) and (v,u)
        for e in self.edges:
            fr_i = self._V2I[e.fr]
            to_i = self._V2I[e.to]

            self._G[fr_i].add(e)
            self._G[to_i].add(e.reverse())


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