How did you come about the epochs formula for the schedulers?

[timothylimyl]

In cycle based schedulers, the length of the epochs was given as:

 def get_cycle_length(self, cycles=0):
        cycles = max(1, cycles or self.cycle_limit)
        if self.cycle_mul == 1.0:
            return self.t_initial * cycles
        else:
            return int(math.floor(-self.t_initial * (self.cycle_mul ** cycles - 1) / (1 - self.cycle_mul)))

It makes sense to me if the cycle_limit is 1 and the cycle_mul =1 then it will just return the initial number of epochs set (self.t_initial). However, the formula: int(math.floor(-self.t_initial * (self.cycle_mul ** cycles - 1) / (1 - self.cycle_mul))) is not very clear to me. I search through the docs and there are no info regarding this, also there could be an error with the variable name (t_mul -> cycle_mul) Reference Link