• irr(v, [guess])—Returns the internal rate of return for a series of cash flows occurring at regular intervals. If irr cannot find a result that is accurate to within 1×10−5 percent after 20 iterations, an error is returned. If this happens, try a different guess.

• mirr(v, fin_rate, rein_rate)—Returns the modified internal rate of return for a series of cash flows occurring at regular intervals, given a finance rate payable on the cash you borrow and a reinvestment rate earned on the cash you reinvest. There must be at least one positive and one negative number in cash.

• v is a vector of cash flows assigned at regular intervals. Payments are entered as negative numbers and income as positive numbers.

• guess (optional) is a numeric value which approximates the answer. It is used as a starting point for the algorithm. If omitted, guess = 0.1 (10%).

• fin_rate and rein_rate are the real, scalar finance and reinvestment rates.