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# maximum_spanning_edges

maximum_spanning_edges(G, algorithm='kruskal', weight='weight', keys=True, data=True, ignore_nan=False)

  Generate edges in a maximum spanning forest of an undirected weighted graph.

  A maximum spanning tree is a subgraph of the graph (a tree) with the maximum possible sum of edge weights. A spanning forest is a union of the spanning trees for each connected component of the graph.

  Parameters:
    G undirected Graph

      An undirected graph. If `G` is connected, then the algorithm finds a spanning tree. Otherwise, a spanning forest is found.

    algorithm string

      The algorithm to use when finding a maximum spanning tree. Valid choices are ‘kruskal’, ‘prim’, or ‘boruvka’. The default is ‘kruskal’.

    weight string

      Edge data key to use for weight (default ‘weight’).

    keys bool

      Whether to yield edge key in multigraphs in addition to the edge. If `G` is not a multigraph, this is ignored.

    data bool, optional

      If True yield the edge data along with the edge.

    ignore_nan bool (default: False)

      If a NaN is found as an edge weight normally an exception is raised. If `ignore_nan is True` then that edge is ignored instead.

  Returns:
    edges iterator

      An iterator over edges in a maximum spanning tree of `G`. Edges connecting nodes `u` and `v` are represented as tuples: `(u, v, k, d)` or `(u, v, k)` or `(u, v, d)` or `(u, v)`

      If `G` is a multigraph, `keys` indicates whether the edge key `k` will be reported in the third position in the edge tuple. `data` indicates whether the edge datadict `d` will appear at the end of the edge tuple.

      If `G` is not a multigraph, the tuples are `(u, v, d)` if `data` is True or `(u, v)` if `data` is False.

  Notes

  For Borůvka’s algorithm, each edge must have a weight attribute, and each edge weight must be distinct.

  For the other algorithms, if the graph edges do not have a weight attribute a default weight of 1 will be used.

  Modified code from David Eppstein, April 2006 http://www.ics.uci.edu/~eppstein/PADS/

  Examples

      >>> from networkx.algorithms import tree

  Find maximum spanning edges by Kruskal’s algorithm

      >>> G = nx.cycle_graph(4)
      >>> G.add_edge(0, 3, weight=2)
      >>> mst = tree.maximum_spanning_edges(G, algorithm="kruskal", data=False)
      >>> edgelist = list(mst)
      >>> sorted(sorted(e) for e in edgelist)
      [[0, 1], [0, 3], [1, 2]]

  Find maximum spanning edges by Prim’s algorithm

      >>> G = nx.cycle_graph(4)
      >>> G.add_edge(0, 3, weight=2)  # assign weight 2 to edge 0-3
      >>> mst = tree.maximum_spanning_edges(G, algorithm="prim", data=False)
      >>> edgelist = list(mst)
      >>> sorted(sorted(e) for e in edgelist)
      [[0, 1], [0, 3], [2, 3]]