Instance Created:  April 26, 2002
Number of Cities:  2802
Optimal Value:  8423
Solved:  March 27, 2003

History

Date	Gap	Lower Bound	Tour
6.10.02			8425 - Best of 10 runs of LKH, each with n trials. Total running time 2894 seconds on an AMD Althlon 1900+ processor (1.6 GHz).
2.2.03			8423 - Found by Keld Helsgaun, using a variant of LKH.
27.3.03	Optimal	8423 - Established by Concorde (defaults); 477 nodes in branch-and-cut tree; 69723 seconds on 2.4 GHz Intel Xeon workstation.

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.

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