Learn about the Peaceman-Rachford splitting method applied to the protein side-chain positioning problem in this 57-minute lecture from the Fields Institute. Explore a simple formulation for the doubly nonnegative relaxation of the problem, leveraging variable splitting from facial reduction in semidefinite relaxation. Discover how this method achieves strong results in solving instances close to optimality. Delve into topics including protein structure, mathematical programming, STP relaxation, facial reduction, model properties, algorithm formulas, and numerical results. Gain insights into rotation, visualization, preprocessing, and RLT nonnegativity in the context of this computational biology challenge.