Model

BLEU-1/2/3/4

F1

BERT-Score

P-Cover

P-EM

S2SA

10.02/2.81/0.85/0.27

16.72

-0.196

9.03

50.39

PGN

13.01/2.62/0.58/0.11

15.17

-0.160

8.36

54.13

Transformer

19.18/8.57/4.71/2.52

19.16

0.111

13.31

70.57

TransferTransfo

16.77/7.60/3.95/2.08

17.47

0.154

12.87

71.49

LIC

18.07/7.77/3.88/1.97

18.74

0.180

12.28

69.68

BERT2BERT

20.66/9.90/5.91/3.40

20.43

0.118

13.41

70.99

BERT-HCM

21.73/10.71/6.39/3.62

21.24

0.122

13.69

73.40