Efficient algorithms for solving the p-Laplacian in polynomial time

The p-Laplacian is a nonlinear partial differential equation, parametrized by $$p \in [1,\infty ]$$ p ∈ [ 1 , ∞ ] . We provide new numerical algorithms, based on the barrier method, for solving the p-Laplacian numerically in $$O(\sqrt{n}\log n)$$ O ( n log n ) Newton iterations for all $$p \in [1,\infty ]$$ p ∈ [ 1 , ∞ ] , where n is the number of grid points. We confirm our estimates with numerical experiments.

On an Aitken-Steffensen-Newton type method

We consider an Aitken-Steffensen type method in which the nodes are controlled by Newton and two-step Newton iterations. We prove a local convergence result showing the q-convergence order 7 of the iterations. Under certain supplementary conditions, we obtain monotone convergence of the iterations, providing an alternative to the usual ball attraction theorems. Numerical examples show that this method may, in some cases, have larger (possibly sided) convergence domains than other methods with similar convergence orders.