GTSP Instances Library

The Generalized Traveling Salesman Problem (GTSP) is an extension of the Traveling Salesman Problem (TSP), where the node set is partitioned into clusters, and the objective is to find the shortest cycle that visits exactly (or, in some variations) at least) one node in each cluster. The problem is NP-hard. In 1997, Fischetti, Salazar Gonzalez and Toth [2] introduced a simple clustering procedure that can be used for creating GTSP instances out of TSP instances. The TSP instances were taken from a well known TSP instances library, TSPLIB, created by Gerhard Reinelt [3]. Since then, such a testbed became a de facto standard that was used in virtually all the GTSP literature. On this website, you will find these instances in several formats. You will also find the best known solutions for each of these instances.