A 2-opt tour move removes two boundary arcs and reverses the intervening block to reconnect one tour. Such moves define a local-search neighbourhood; block reversals of length two include adjacent swaps and hence connect permutation schedules. For directed costs the asymmetric 2-opt reversal cost must include every reversed internal arc, not just the boundary changes.
A 2-opt schedule move reverses a consecutive block , reconnecting its boundary arcs. With directed costs, its change isOmitting the internal sum is valid only for symmetric costs. A simulated annealing step accepts an increase with probability ; a strictly positive temperature permits escape from local minima.
Articles by others on the same topic
2-opt is a local search algorithm commonly used to optimize routes in the field of combinatorial optimization, particularly in solving the traveling salesman problem (TSP) and related routing problems. The basic idea of 2-opt is to improve a given tour (or route) by iteratively removing two edges and reconnecting the two segments in a way that results in a shorter total distance.