/**
 * LOESS (Locally Weighted Scatterplot Smoothing) regression.
 *
 * For each x-point, fits a local weighted linear regression using tricube
 * weights, producing a smooth curve that follows the data more closely
 * than global polynomial regression.
 *
 * @param points - Array of [x, y] pairs (need not be sorted)
 * @param bandwidth - Smoothing parameter 0-1. Lower = more local detail,
 *                    higher = smoother. Default 0.3.
 * @returns Array of [x, y_smoothed] pairs sorted by x
 */
export declare function loess(points: [number, number][], bandwidth?: number): [number, number][];
