Instance Created:  July 29, 2001
Number of Cities:  14,185
Solved:  June 21, 2009
Solution Method:  Concorde

History

Date	Gap	Lower Bound	Tour
8.21.01			427,378 - Found by merging 10 LKH tours (each with n trials). The total time to find the tours was 341,825 seconds on a 500 MHz EV6 Alpha; merging required an additional 265.52 seconds).
8.26.01	0.031%	427,246 - Established by Concorde with -C 20 (used 99 nodes in the branch-and-cut tree, 114,000 seconds on a 500 MHz EV6 Alpha).
9.30.01	0.031%		427,377 - Found by Keld Helsgaun using variants of his LKH code, working with the 427,378 tour. The running time was approximately 10 hours on a 400 MHz PowerMac G4.

Notes

1. Concorde is our linear-programming based TSP solver.

2. linkern is an implementation of Martin, Otto, and Felten's Chained Lin-Kernighan heuristic. It is included in the Concorde code.

3. LKH is Keld Helsgaun's powerful implementation of the Lin-Kernighan heuristic.

Back to TSP home.