1303.1886 (Hiroshi Watanabe)

Difficult Sudoku Puzzles Created by Replica Exchange Monte Carlo Method    [PDF]

Hiroshi Watanabe

An algorithm to create difficult Sudoku puzzles is proposed. An Ising spin-glass like Hamiltonian describing difficulty of puzzles is defined, and difficult puzzles are created by minimizing the energy of the Hamiltonian. We adopt the replica exchange Monte Carlo method with simultaneous temperature adjustments to search lower energy states efficiently, and we succeed in creating a puzzle which is the world hardest ever created in our definition, to our best knowledge.

View original: http://arxiv.org/abs/1303.1886