/**
 * On-Balance Volume (OBV).
 * Accumulates volume by sign of price change: add volume when price rises,
 * subtract when price falls; NaNs in inputs yield NaN outputs for that index.
 * @param price Price series
 * @param volume Volume series
 * @returns Float64Array of OBV values
 */
export declare function obv(price: ArrayLike<number>, volume: ArrayLike<number>): Float64Array;