Instance Created:  July 29, 2001
Number of Cities:  9,976
Status:  OPEN
Best Tour:  1,061,881
Best Lower Bound:  1,061,387

History

Date	Gap	Lower Bound	Tour
8.23.01			1,061,882 - Merging 40 LKH tours (n trials per run). The 40 LKH runs took a total of 417,212 seconds on a 500 MHz EV6 Alpha, merging took an additional 34.70 seconds. The best of the LKH tours had length 1,061,892.
8.28.01	0.047%	1,061,387 - Established by Concorde with -C 20 (used 353 nodes in the branch-and-cut tree, 657314 seconds on a 500 MHz EV6 Alpha).
10.18.01	0.047%		1,061,881 - Keld Helsgaun using variants of his LKH code. The running time was approximately 3 days on a 400 MHz Macintosh PowerBook G3.

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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