At each step, there is a wait-k policy synchronizing the adaptive policy, meaning that they have the same lag at that step.
specifically, at any step t, if the lag of the adaptive policy is k , then we apply the NMT model with the wait-k policy and force it to predict existing target tokens until step t, when the model will make a new prediction as the output of step t. the above method only shows how to simulate the adaptive policy to make a prediction at one step if we would like to write at that step, but it does not tell us at which steps we should write.