Instance Created:  July 29, 2001
Number of Cities:  9,847
Optimal Value:  491,924
Solved:  April 7, 2002
Solution Method:  Concorde -C 24, QSopt LP solver, LKH tour
Solution Time:  12.0 million seconds, AMD Athlon 1900+

History

Date	Gap	Lower Bound	Tour
8.23.01			491,929 - Best of 10 linkerh tours. The 10 linkern runs took a total of 118,232 seconds on a 500 MHz EV6 Alpha. Merging the 10 tours (16.06 seconds) did not make an improvement.
8.27.01	0.012%	491,869 - Established by Concorde with -C 20 (used 611 nodes in the branch-and-cut tree, 820,938 seconds on a 500 MHz EV6 Alpha).
10.10.01	0.011%		491,924 - - Found by Keld Helsgaun using variants of his LKH code. The running time was approximately 2 days a 400 MHz Macintosh PowerBook G3.
4.7.02	Optimal	491,924 - Established by Concorde with -C 24 (root node was run with -C 42). The run used 3,573 nodes in the branch-and-cut tree and 12.0 million seconds on an AMD Athlon 1900+ (ran in parallel on a network of 15 workstations). The LP solver was QSopt.

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.
4. linkerh is an implementation of the Lin-Kernighan heuristic, making use of a number of the ideas introduced in Keld Helsgaun's LKH code.

Back to TSP home.