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XQC2175 - Computation Log

Instance Created:  April 26, 2002
Number of Cities:  2175
Optimal Value:  6830
Solved:  December 18, 2008
Solution Method:  Concorde
Solution Time:  22646 seconds, 2.4 GHz AMD Opteron 250


Date Gap Lower Bound Tour
2.2.03 6830 - Found by Keld Helsgaun, using a variant of LKH.
18.12.08 Optimal 6830 - Concorde (root node with -mC40 -Z3, branching with -mC24 -J8) using CPlex as an LP solver. The run was carried out on a 2.4 GHx AMD Opteron 250 in Athlon 1900+ in 22646 seconds, using 31 nodes in the branch-and-bound-tree.


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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Last Updated:  December 18, 2008