Instance Created:  May 6, 2002
Number of Cities:  104,815
Status:  OPEN
Best Tour:  251,342
Best Lower Bound:  xxx

History

Date	Gap	Lower Bound	Tour
12.02.02			251,433 - Found by Keld Helsgaun using variants of his LKH code.
21.3.03			251,426 - Found by Hung Dinh Nguyen using a hybrid genetic algorithm, starting with the above tour.
9.12.04			251,365 - Found by Keld Helsgaun using variants of his LKH code.
7.4.08			251,359 - Found by Keld Helsgaun using variants of his LKH code.
19.7.08			251,357 - Found by Changxing Dong, Gerold Jaeger, Paul Molitor, Dirk Richter on an AMD Opteron 2,6 GHz by a variant of LKH.
29.08.08			251,349 - Found by Changxing Dong and Paul Molitor, using a variant of LKH with Karp partitioning.
29.09.08			251,347 - Found by Keld Helsgaun using variants of his LKH code.
28.10.08			251,346 - Found by Changxing Dong and Paul Molitor, using a variant of LKH with Karp partitioning.
27.11.08			251,345 - Found by Keld Helsgaun using variants of his LKH code.
4.10.12			251,342 - Found by Xavier Clarist

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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