TY - JOUR T1 - Newton-Anderson at Singular Points AU - Dallas , Matt AU - Pollock , Sara JO - International Journal of Numerical Analysis and Modeling VL - 5 SP - 667 EP - 692 PY - 2023 DA - 2023/09 SN - 20 DO - http://doi.org/10.4208/ijnam2023-1029 UR - https://global-sci.org/intro/article_detail/ijnam/22007.html KW - Anderson acceleration, Newton’s method, safeguarding, singular problems. AB -

In this paper we develop convergence and acceleration theory for Anderson acceleration applied to Newton’s method for nonlinear systems in which the Jacobian is singular at a solution. For these problems, the standard Newton algorithm converges linearly in a region about the solution; and, it has been previously observed that Anderson acceleration can substantially improve convergence without additional a priori knowledge, and with little additional computation cost. We present an analysis of the Newton-Anderson algorithm in this context, and introduce a novel and theoretically supported safeguarding strategy. The convergence results are demonstrated with the Chandrasekhar H-equation and a variety of benchmark examples.