/**
 * Natural Outlier Factor
 */
export default class NOF {
    /**
     * @param {number} [k] Number of neighborhoods
     */
    constructor(k?: number);
    _k: number;
    _d(a: any, b: any): number;
    /**
     * Returns anomaly degrees.
     * @param {Array<Array<number>>} datas Training data
     * @returns {number[]} Predicted values
     */
    predict(datas: Array<Array<number>>): number[];
}