Octant-Based Stencil Selection for Meshless Finite Difference Methods in 3D

We study a simple meshless stencil selection algorithm in 3D for supporting the meshless finite difference method based on radial basis functions (RBF-FD) to solve the Dirichlet problem for the Poisson equation. Our numerical experiments show that the proposed method produces solutions that differ very little from the solutions by the finite element method with Courant's piecewise linear basis functions, when the domain is discretized by the vertices of the respective tetrahedral triangulation.