@vince62s Yes, I completely understand where you are coming from. It is a delicate balance of creating something useful and not adding too much complexity. If translation after N epochs is where you want to draw the line, then that's fine, I will drop it. It's not difficult for me to continue adding this hack to newer version of OpenNMT, since it is very useful for me (and a few others I suppose).
I am using OpenNMT as part of a pipeline for building a spelling correction service, so perplexity and BLEU score are kind of useless in this case. I want to know a true accuracy, ie. how often these correct sequence of letters are predicted exactly. This cannot be done without the translated portion.
You are also right, I could simply pick a large GPU instance, but now you are effectively saying to spend more money when a simple software solution exists that doesn't require the spending of money. I don't need that extra GPU until after each epoch is done training, so why pay for it and let it sit idle most of the time?