To reduce the amount of calculation, we only utilize the query matrices Q l to compute the position vector and coverage scope vector.
for the i-th encoding step in l-th layer, the center position scalar µ i l ∈ R and the coverage scope scalar σ i l ∈ R are calculated by two linear projections, namely: where W p ∈ R dm×dm , and W g ∈ R dm×dm are two shared weight matrices.