Performance comparison of understand_sentiment model in Fluid and Paddle V2 (GPU version)

[ranqiu92]

Training Set Pass accuracy

Pass	Paddle V2	Fluid
0	0.83468	0.8312
1	0.90696	0.89579
2	0.9388	0.92891
3	0.96404	0.95559
4	0.983	0.9788
5	0.99064	0.99043
6	0.99544	0.99407
7	0.99716	0.99519
8	0.99692	0.99711
9	0.99628	0.9982

Test set accuracy

Pass	Paddle V2	Fluid
0	0.87836	0.8696
1	0.89091	0.88339
2	0.88772	0.88537
3	0.88567	0.87996
4	0.87432	0.87703
5	0.88031	0.87267
6	0.88111	0.87703
7	0.8782	0.87992
8	0.87764	0.87967
9	0.87968	0.8768

reference #6650