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networkx.algorithms.swap.double_edge_swap

double_edge_swap(G, nswap=1, max_tries=100, seed=None)

Swap two edges in the graph while keeping the node degrees fixed.

A double-edge swap removes two randomly chosen edges u-v and x-y and creates the new edges u-x and v-y:

u--v            u  v
       becomes  |  |
x--y            x  y

If either the edge u-x or v-y already exist no swap is performed and another attempt is made to find a suitable edge pair.

Parameters

• G (graph) – An undirected graph

• nswap (integer (optional, default=1)) – Number of double-edge swaps to perform

• max_tries (integer (optional)) – Maximum number of attempts to swap edges

• seed (integer, random_state, or None (default)) – Indicator of random number generation state. See Randomness.

Returns

G – The graph after double edge swaps.

Return type

graph

Notes

Does not enforce any connectivity constraints.

The graph G is modified in place.