“…To design implicit finite difference schemes, iterative methods are needed to reduce the problem to a sequence of linear systems. Iterative methods employed in solving MFGs include Newton's method [6,7,9,28], fixed point iteration, fictitious play, policy iteration [15,29], smoothed policy iteration [34], etc. In particular, numerical solution of MFGs with non-separable Hamiltonian have been discussed in, e.g., [6,7,23,28,29].…”