What is calculation logic use for ADX

Hi

May i know what is the calculation logic used for ADX?
Basically while using ADX in condition builder i just get to provide length - which i assume is the DI length
Whereas ADX has a smoothening period as well, what is that period taken into calculation at tradetron?
Also what is the smoothening function used? is it SMA/EMA/RMA/WMA ?

@Ujjwal @vikram.bajaj