“…The main difficulties encountered while studying these methods lead the authors either to consider the discretized equation in the angular variable [5], or the continuous equation with a truncated expansion of h with respect to this angular variable [5,7]. The idea in [1,2] is to introduce and study various algorithms, relying on a splitting of the collision operator, and adapted from the methods of Jacobi, Gauss-Seidel, SOR and the Generalized Minimal Residual, in the infinite dimensional case. The SOR algorithm gives excellent results, but it needs the computation of its optimal parameter, which in turn can be very slow in the critical case.…”