Computes weighted FEM matrices for non-stationary SPDE models where
the range and variance parameters vary spatially. The weights are
per-vertex kappa(s) and tau(s) values, interpolated within each
triangle using the element-average approximation.
Usage
fem_matrices_nonstationary(mesh, kappa, tau)
Arguments
- mesh
A tulpa_mesh object (2D only).
- kappa
Numeric vector of length n_vertices giving the
spatial scale parameter kappa(s) = sqrt(8*nu) / range(s).
- tau
Numeric vector of length n_vertices giving the
precision scaling tau(s).
Value
A list with sparse matrices:
Ck: kappa²-weighted mass matrix
Gk: kappa²-weighted stiffness matrix
Ct: tau²-weighted mass matrix
C: unweighted consistent mass matrix
G: unweighted stiffness matrix
C0: lumped (diagonal) mass matrix
n_mesh: number of mesh vertices