A Peaceman-Rachford Splitting Method for the Protein Side-Chain Positioning Problem

We formulate a doubly nonnegative (DNN) relaxation of the protein side-chain positioning (SCP) problem. We take advantage of the natural splitting of variables that stems from the facial reduction technique in the semidefinite relaxation, and we solve the relaxation using a variation of the Peaceman-Rachford splitting method. Our numerical experiments show that we solve all our instances of the SCP problem to optimality.