This function selects edges to be re-wired when simulating random graphs. It is based on the algorithm by Bansal et al. (2009), BMC Bioinformatics.
The random graph that has been generated
A data frame with four elements; two edges will be removed and two edges will be added between the four vertices.
Bansal S., Khandelwal S., Meyers L.A. (2009) Exploring biological network structure with clustered random networks. BMC Bioinformatics, 10:405-421.