A fast spectral/difference method without pole conditions for Poisson-type equations in cylindrical and spherical geometries

[[abstract]]A simple and efficient FFT-based fast direct solver for Poisson-type equations on 3D cylindrical and spherical geometries is presented. The solver relies on the truncated Fourier series expansion, where the differential equations of Fourier coefficients are solved using second-order finite difference discretizations without pole conditions. Three different boundary conditions (Dirichlet, Neumann and Robin conditions) can be handled without substantial differences.[[fileno]]2010223010093[[department]]數學