Left Panel: relation between the coasting time t _MAD to reach the MAD state and the initial magnetic field. We show the results for aM94b100, aM94b200, aM94b100h, aM94b400, and aM94b800 in blue circles. The coasting time depends linearly on the initial magnetic field. We use a linear function to fit it, and the best-fit result is shown by the dashed red line. Right Panel: t _MAD as a function of the value of the spin a. We use a third-order polynomial function to fit this relation, and the best-fit result is shown by the dashed red line.