refine dot-product attention according to the comments
refine dot-product attention according to the comments

reyoung/Paddle,QiJune/Paddle,PaddlePaddle/Paddle,jacquesqiao/Paddle,QiJune/Paddle,Canpio/Paddle,luotao1/Paddle,reyoung/Paddle,pkuyym/Paddle,baidu/Paddle,tensor-tang/Paddle,pkuyym/Paddle,jacquesqiao/Paddle,PaddlePaddle/Paddle,QiJune/Paddle,pkuyym/Paddle,lcy-seso/Paddle,tensor-tang/Paddle,jacquesqiao/Paddle,putcn/Paddle,pengli09/Paddle,pengli09/Paddle,Canpio/Paddle,lcy-seso/Paddle,baidu/Paddle,Canpio/Paddle,Canpio/Paddle,luotao1/Paddle,luotao1/Paddle,jacquesqiao/Paddle,putcn/Paddle,baidu/Paddle,luotao1/Paddle,QiJune/Paddle,Canpio/Paddle,PaddlePaddle/Paddle,reyoung/Paddle,lcy-seso/Paddle,putcn/Paddle,QiJune/Paddle,reyoung/Paddle,reyoung/Paddle,baidu/Paddle,pengli09/Paddle,QiJune/Paddle,pengli09/Paddle,putcn/Paddle,pengli09/Paddle,pengli09/Paddle,Canpio/Paddle,pkuyym/Paddle,lcy-seso/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,tensor-tang/Paddle,chengduoZH/Paddle,chengduoZH/Paddle,luotao1/Paddle,Canpio/Paddle,jacquesqiao/Paddle,lcy-seso/Paddle,lcy-seso/Paddle,PaddlePaddle/Paddle,reyoung/Paddle,tensor-tang/Paddle,putcn/Paddle,putcn/Paddle,pengli09/Paddle,baidu/Paddle,tensor-tang/Paddle,Canpio/Paddle,PaddlePaddle/Paddle,pkuyym/Paddle,pengli09/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,chengduoZH/Paddle,jacquesqiao/Paddle,chengduoZH/Paddle,luotao1/Paddle,pkuyym/Paddle