#说明
此源代码改写自 https://github.com/lisa-groundhog/GroundHog/blob/master/experiments/nmt/sample.py 和 https://github.com/lisa-groundhog/GroundHog/blob/master/experiments/nmt/encdec.py
用途见博客文章 http://polarlion.github.io/nmt/2016/06/06/ground-show-alignment.html