xnn.common.models.electrostatics.ewald_real

xnn.common.models.electrostatics.ewald_real(charges, edge_index, r, alpha, cutoff)

Per-atom share of the screened real-space sum sum q_i q_j erfc(alpha r) / r.

Parameters:

• charges (Tensor) – Charges (N,).

• edge_index (Tensor) – Ordered pairs (2, E) as [src, dst], both directions present.

• r (Tensor) – Pair distances (E,).

• alpha (float) – Splitting parameter.

• cutoff (float) – Pairs at or beyond it are ignored.

Returns:

(N,) in e^2 / Angstrom, float64.

Return type:

Tensor