pub fn diffusion_2d_explicit_step(
u: &[f64],
nx: usize,
ny: usize,
dx: f64,
dy: f64,
dt: f64,
alpha: f64,
) -> Vec<f64>Expand description
One explicit 2D diffusion step using the FTCS scheme.
Solves ∂u/∂t = α (∂²u/∂x² + ∂²u/∂y²). Boundary nodes are not updated.