The rainflow-counting algorithm is used in the analysis of fatigue data in order to reduce a spectrum of varying stress into an equivalent set of simple stress reversals. The method successively extracts the smaller interruption cycles from a sequence, which models the material memory effect seen with stress-strain hysteresis cycles. This simplification allows the "fatigue life" of a component to be determined for each rainflow cycle using either Miner's rule to calculate the "fatigue damage", or in a crack growth equation to calculate the crack increment. The algorithm was developed by Tatsuo Endo and M. Matsuishi in 1968.