The Largest Unsolved QAP Instance Tai256c Can Be Converted into A 256-dimensional Simple BQOP with A Single Cardinality Constraint
Optimization and Control
2022-10-31 v1
Abstract
Tai256c is the largest unsolved quadratic assignment problem (QAP) instance in QAPLIB; a 1.48\% gap remains between the best known feasible objective value and lower bound of the unknown optimal value. This paper shows that the instance can be converted into a 256 dimensional binary quadratic optimization problem (BQOP) with a single cardinality constraint which requires the sum of the binary variables to be 92. The converted BQOP is much simpler than the original QAP tai256c and it also inherits some of the symmetry properties. However, it is still very difficult to solve. We present an efficient branch and bound method for improving the lower bound effectively. A new lower bound with 1.36\% gap is also provided.
Keywords
Cite
@article{arxiv.2210.15963,
title = {The Largest Unsolved QAP Instance Tai256c Can Be Converted into A 256-dimensional Simple BQOP with A Single Cardinality Constraint},
author = {Koichi Fujii and Sunyoung Kim and Masakazu Kojima and Hans D. Mittelmann and Yuji Shinano},
journal= {arXiv preprint arXiv:2210.15963},
year = {2022}
}
Comments
13 pages, 6 figures