import type { Matrix3x3 } from '../math';
import type { BornChargeData, PhononModeData } from './types';
export declare const eigenvector_norm_sq: (eigenvector: [number, number][][]) => number;
export declare function parse_phonon_modes(content: string): PhononModeData;
export declare function parse_born(content: string): BornChargeData;
export declare function born_charge_sum(born_charges: Matrix3x3[]): Matrix3x3;
export declare function apply_born_sum_rule(born_charges: Matrix3x3[]): Matrix3x3[];