Instance Created:  April 26, 2002
Number of Cities:  28924
Status:  OPEN
Best Tour:  79622
Best Lower Bound:  xxx

History

Date	Gap	Lower Bound	Tour
2.2.03			79639 - Found by Keld Helsgaun, using a variant of LKH.
3.10.03			79634 - Found by Hung Dinh Nguyen using a parallel hybrid genetic algorithm. The running time was 129963 seconds on a Sun Ultra 80 with four 450-MHz processors (taking the best of five runs).
3.16.03			79631 - Found by Hung Dinh Nguyen using a hybrid genetic algorithm, starting with the above tour (15234 seconds).
18.3.03			79628 - Found by Keld Helsgaun, using a variant of LKH.
15.5.07			79624 - Found by Keld Helsgaun, using a variant of LKH.
15.3.08			79623 - Found by Changxing Dong, Gerold Jaeger, Paul Molitor, Dirk Richter by a variant of LKH based an backbone contraction. The running time was 845940 seconds on a AMD Opteron Processor 852 (2.5 GHz).
24.6.08			79622 - Found by Changxing Dong, Gerold Jaeger, Paul Molitor, Dirk Richter by a variant of LKH based an backbone contraction.

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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