where η n {\displaystyle \eta _{n}} is the learning rate at iteration n {\displaystyle n} , η 0 {\displaystyle \eta _{0}} is the initial learning rate, d {\displaystyle d} is how much the learning rate should change at each drop (0.5 corresponds to a halving) and r {\displaystyle r} corresponds to the droprate, or how often the rate should be dropped (10 corresponds to a drop every 10 iterations). The floor function here drops the value of its input to 0 for all values smaller than 1.