/**
 * Parabolic SAR (PSAR) indicator.
 * @param high High price series
 * @param low Low price series
 * @param step Acceleration step increment (>0)
 * @param maxStep Maximum acceleration value (>= step)
 * @param skipna When true ignore NaNs; when false use dense fast-path
 * @returns Float64Array PSAR values (NaN for undefined positions)
 */
export declare function psar(high: ArrayLike<number>, low: ArrayLike<number>, step: number, maxStep: number, skipna?: boolean): Float64Array;