Solving Small TSPs with Constraints

This paper presents a set of techniques that makes constraint programming a technique of choice for solving small (up to 30 nodes) traveling salesman problems. These techniques include a propagation scheme to avoid intermediate cycles (a global constraint), a branching scheme and a redundant constraint that can be used as a bounding method. The resulting improvement is that we can solve problems twice larger than those solved previously with constraint programming tools. We evaluate the use of Lagrangean Relaxation to narrow the gap between constraint programming and other Operations Research techniques and we show that improved constraint propagation has now a place in the array of techniques that should be used to solve a traveling salesman problem.

• Type: Conference
• Year: 1997
• Where: ICLP
• Authors: Yves Caseau, François Laburthe
• Keywords: Automated Reasoning, Constraint Programming, Constraint Programming Tools, ICLP 1997, Traveling Salesman Problem