Attention mask for computation of replace and append operation

[rivaldinho123]

Hi, you mentioned in the papar that we calculate r_{i}^{l} over h_{j}^{l} for all j except i, but calculate a_{i}^{l} over h_{j}^{l} for all j including i. Why there is such a difference that we can't have information about the current token x_{i} when dealing with the replace operation but have access to the current token for append operation on the contrary?