/**
 * Internal Rate of Return (IRR) is the discount rate often used in capital budgeting that makes the net present value of all cash flows from a particular project equal to zero.
 *
 * @see http://www.investopedia.com/terms/i/irr.asp
 * @param depth
 * @param cashFlow
 * @returns
 */
export declare function IRR(cashFlow: number[], depth?: number): number;