Concorde is a computer code for the traveling salesman problem (TSP)
and some related network optimization problems.  The code is written
in the ANSI C programming language and it is available for academic
research use; for other uses, contact bico@isye.gatech.edu for
licensing options.

Concorde's TSP solver has been used to obtain the optimal solutions to
106 of the 110 TSPLIB instances; the largest having 15,112 cities.

The Concorde callable library includes over 700 functions permitting
users to create specialized codes for TSP-like problems.  All Concorde
functions are thread-safe for programming in shared-memory parallel
environments; the main TSP solver includes code for running over
networks of Unix workstations.

WWW: http://www.tsp.gatech.edu/concorde.html