How do you compute L-R Consistency

[hurricane2018]

    # L-R Consistency
    right_left_disp = [self.generate_image_left(disp_right_est[i],
                       disp_left_est[i]) for i in range(self.n)]
    left_right_disp = [self.generate_image_right(disp_left_est[i],
                       disp_right_est[i]) for i in range(self.n)]


    # L-R Consistency
    lr_left_loss = [torch.mean(torch.abs(right_left_disp[i]
                    - disp_left_est[i])) for i in range(self.n)]
    lr_right_loss = [torch.mean(torch.abs(left_right_disp[i]
                     - disp_right_est[i])) for i in range(self.n)]
    lr_loss = sum(lr_left_loss + lr_right_loss)

Can you explain how did you compute it?