pytorch tutorial have a bilstm-crf example。But， it isn’t used minibatch。
when i try to make a minibatch in it。I find that， CRF can’t be minibatch?
And, CRF need run in cpu? it will be so slowly！
aspect these，there are also some questiones below：

how pytorch auto deal variable sequence length？padding a same length？but pytorch is dynamic right？
I don’t konw why，but pytorch is slowly so much and the uses of gpu util
is little.

may be all these question is caused by （batch and crf ）
how can CRF read the batch and deal in gpu？