Ferrolith is a standalone C++17/CUDA library for computing the demagnetizing field on tetrahedral finite-element meshes. It implements the Fredkin-Koehler scalar potential decomposition with FEM-BEM coupling and is fully GPU-accelerated via cuSPARSE and AMGCL.

Features#

• Demagnetizing field via the Fredkin-Koehler method with multiple BEM backends (GPU FMM, H2Lib, dense, Galerkin)
• Shell-transform and volume FMM solvers as alternatives to BEM
• Exchange field via FEM stiffness matrix with GPU SpMV
• Magnetocrystalline anisotropy (uniaxial and cubic) via CUDA kernels
• Zeeman (external) field with GPU accumulate support
• Composable effective field that owns named field components and evaluates their sum
• Python interface via pybind11 with NumPy array interop

What You’ll Find Here#

• Getting Started – Building the Python module and computing your first demagnetizing field
• Python API Reference – Field classes, parameter structs, and enums
• Resources – Test meshes and supporting data