Signature Description
enum class exponential_decay_spec : unsigned char {
 center_of_gravity = 1, // decay = 1 / (1 + value), for value >= 0
 span = 2, // decay = 2 / (1 + value), for value >= 1
 halflife = 3, // decay = 1 − exp(log(0.5) / value), for value > 0
 fixed = 4, // decay = value, for 0 < value <= 1
};
This spec determines how an exponentially moving stat decays. It is used as a parameter to the ExponentialRollAdopter adopter constructor. Based on this spec, the value parameter is converted to decay.