Performs a Migration pair death move (Ewing et al. 2004). Deletes two
migration nodes if they lie between two edges in the same deme.
Usage
migration_pair_death(ED, n_deme, node_indices)
Arguments
- ED
Extended data object; matrix with columns Node ID, parent, child 1, child 2, deme, node age
- n_deme
Number of distinct demes in the population
Value
Updated extended data object with the proposal from the migration pair death move