  Quadratic Assignment Problem (QAP) is a practical combinatorial optimization
problems that has been studied for several years. Since it is NP-hard, solving
large problem instances of QAP is challenging. Although heuristics can find
semi-optimal solutions, the execution time significantly increases as the
problem size increases. Recently, solving combinatorial optimization problems
by deep learning has been attracting attention as a faster solver than
heuristics. Even with deep learning, however, solving large QAP is still
challenging. In this paper, we propose the deep reinforcement learning model
called the two-stage graph pointer network (GPN) for solving QAP. Two-stage GPN
relies on GPN, which has been proposed for Euclidean Traveling Salesman Problem
(TSP). First, we extend GPN for general TSP, and then we add new algorithms to
that model for solving QAP. Our experimental results show that our two-stage
GPN provides semi-optimal solutions for benchmark problem instances from TSPlib
and QAPLIB.
