Fig. 9
From: Newton–Raphson preconditioner for Krylov type solvers on GPU devices
Convergence histories of each preconditioner on the \(20 \times 20 \times 500\) problem. The vertical axis shows the residual norm \(\Vert \mathbf {r} \Vert _2 / \Vert \mathbf {b} \Vert _2\), and the horizontal axis shows the number of iterations. The plot is truncated at the 8000th iteration