double_edge_swap¶

double_edge_swap(G, nswap=1, max_tries=100)[source]¶

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

Returns :

G : graph

The graph after double edge swaps.

Notes

Does not enforce any connectivity constraints.

The graph G is modified in place.