{ "cells": [ { "cell_type": "markdown", "id": "887123a4", "metadata": {}, "source": [ "# Latent Ewald Summation (LES), block by block: reproducing the original implementation with `xnn`\n", "\n", "[LES (Cheng, *npj Comput Mater* **11**, 80, 2025)](https://doi.org/10.1038/s41524-025-01577-7)\n", "adds **long-range interactions to any short-range MLIP**: a small MLP maps each\n", "atom's invariant features to a hidden variable $q$ (eq 2; analogous to\n", "environment-dependent partial charges, but unconstrained), and an Ewald\n", "summation over the structure factor of $q$ supplies the long-range energy\n", "\n", "$$E_{lr} = \\frac{1}{V}\\sum_{0