StaRMAP (Staggered grid Radiation Moment Approximation) is a simple, yet powerful, methodology to solve spherical harmonics moment systems, such as the time-dependent PN and SPN equations, of radiative transfer. The implementation allows the user to selected arbitrary moment order N, and the moment matrices and stable time step sizes are generated/chosen automatically. The numerical methods makes use of the specific coupling between the moments in the PN equations. The methodology is implemented in Matlab in a fully vectorized fashion, yielding highly competitive computational efficiency. The code can effectively handle 1D, 2D, and 3D spatial geometries with one single implementation.

Numerical convergence analysis using manufactured solution in 2D.

Temporal evolution of discrete L2 norm of numerical solution in 2D.

2D Checkerboard test case with various momnet orders (P₃, P₅, P₁₅, P₃₉)

3D Lattice test case with P₇.

3D Point Source test case with SP₃₉.