/**
 * calculate mean square error
 * */
export declare function mse_2arr(inputs: number[], outputs: number[]): number;
export declare function mse_2d(input_outputs: Array<[number, number]>): number;
export declare function mse_object<T>(data: Array<Record<keyof T, number>>, options: {
    input: keyof T;
    output: keyof T;
}): number;
export declare function mse_by<T>(data: T[], options: {
    input: (t: T) => number;
    output: (t: T) => number;
}): number;