Framework documentation

Below is a list of the documentation pages for the framework introducing various concepts.

Section	Description
Model / Partial Differential Equations	Core PDE formulation and governing equations.
Grid Structure	Grids, subdomains, allocation, kernels, Kokkos, etc.
Finite Element Discretization	Overview of the FEM approach and element definitions.
Linear Algebra	Matrix and vector representations, solvers, and preconditioners (including multigrid).
Thick Spherical Shell	Details on the thick spherical shell mesh.
Parallelization	Parallel execution patterns.
Communication	Data exchange patterns and MPI communication strategies.
Flag Fields and Masks	Use of masks and flag grids for selective operations and boundary tagging.
Boundary Conditions	Definition and application of boundary conditions.
Input and Output	Data formats, visualization, radial profiles, checkpoints, logging, etc.