问题
It's common to add a custom dictionary to a machine translator to ensure that terminology from a specific domain is correctly translated. For example, the term server should be translated differently when the document is about data centers, vs when the document is about restaurants.
With a transformer model, this is not very obvious to do, since words are not aligned 1:1. I've seen a couple of papers on this topic, but I'm not sure which would be the best one to use. What are the best practices for this problem?
回答1:
I am afraid you cannot easily do that. You cannot easily add new words to the vocabulary because you don't know what embedding it would get during training. You can try to remove some words, or alternatively you can manually change the bias in the final softmax layer to prevent some words from appearing in the translation. Anything else would be pretty difficult to do.
What you want to do is called domain adaptation. To get an idea of how domain adaptation is usually done, you can have a look at a survey paper.
The most commonly used approaches are probably model finetuning or ensembling with a language model. If you want to have parallel data in your domain, you can try to fine-tune your model on that parallel data (with simple SGD, small learning rate).
If you only have monolingual data in the target language, you train a language model on that data. During the decoding, you can mix the probabilities from the domain-specific language and the translation model. Unfortunately, I don't know of any tool that could do this out of the box.
来源：https://stackoverflow.com/questions/58334235/what-is-currently-the-best-way-to-add-a-custom-dictionary-to-a-neural-machine-tr