3 papers
math.OC2024
An Exceptionally Difficult Binary Quadratic Optimization Problem with Symmetry: a Challenge for The Largest Unsolved QAP Instance Tai256c
Koichi Fujii, Sunyoung Kim, Masakazu Kojima +2
Tai256c is the largest unsolved quadratic assignment problem (QAP) instance in QAPLIB. It is known that QAP tai256c can be converted into a 256 dimensional binary quadratic optimiz…
cs.DM2023
Solving break minimization problems in mirrored double round-robin tournament with QUBO solver
Koichi Fujii, Tomomi Matsui
The break minimization problem is a fundamental problem in sports scheduling. Recently, its quadratic unconstrained binary optimization (QUBO) formulation has been proposed, which…
math.OC2022
The Largest Unsolved QAP Instance Tai256c Can Be Converted into A 256-dimensional Simple BQOP with A Single Cardinality Constraint
Koichi Fujii, Sunyoung Kim, Masakazu Kojima +2
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 u…