Instance Created:  April 26, 2002
Number of Cities:  28268
Status:  OPEN
Best Tour:  72608
Best Lower Bound:  xxx

History

Date	Gap	Lower Bound	Tour
2.2.03			72617 - Found by Keld Helsgaun, using a variant of LKH.
3.10.03			72611 - Found by Hung Dinh Nguyen using a parallel hybrid genetic algorithm. The running time was 98878 seconds on a Sun Ultra 80 with four 450-MHz processors (taking the best of five runs).
3.16.03			72609 - Found by Hung Dinh Nguyen using a hybrid genetic algorithm, starting with the above tour (12897 seconds).
18.3.03			72608 - Found by Keld Helsgaun, using a variant of LKH.

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.