pub(crate) fn lpcnn_dipole_kernel(
grid: &Grid,
bdir: (f64, f64, f64),
) -> Vec<f64>Expand description
LPCNN dipole kernel D = 1/3 − (k·B̂)²/|k|² with k from fftfreq (DC at the
array corner, D[0,0,0]=0) — the convention the model’s ortho-FFT expects.