Here, R(P ) is defined as the KL divergence between Pr(p i |q, P ) and a probability distribution X where X i = 1 c P (c P is the number of paragraphs containing correct answer in P ) if the paragraph contains correct answer, otherwise 0.
r(P ) is defined as: To solve the optimization problem, we adopt Adamax to minimize the objective function as described in (Kingma and Ba, 2015).