/**
 * Product of array elements, ignoring NaNs. Returns NaN if no valid entries.
 * @param source Input array
 * @returns Product of values or NaN
 */
export declare function prod(source: ArrayLike<number>): number;
/**
 * Cumulative product (NaN-preserving). At each index the product of all prior valid elements.
 * @param source Input array
 * @returns Float64Array of cumulative products (NaN where input was NaN)
 */
export declare function cumprod(source: ArrayLike<number>): Float64Array;
/**
 * Rolling product over a window. NaN-aware: windows with no valid entries produce NaN.
 * Zeros are handled efficiently by tracking counts.
 * @param source Input array
 * @param period Window length (must be > 0)
 * @returns Float64Array of rolling products (NaN for positions before window fills)
 */
export declare function rollprod(source: ArrayLike<number>, period: number): Float64Array;