Technology

Thanks for asking. My comment was off the top of my head based on stuff I've read over the years, so first I did a little fact-checking of myself to make sure. There's a lot of black magic still involved in training LLMs so the exact mix of training data varies a lot depending who you ask; in some cases raw data is still used for the initial training of LLMs to get them to the point where they're capable of responding coherently to prompts, and synthetic data is more often used for the fine-tuning phase where LLMs are trained to be good at responding to prompts in particular ways. But there doesn't seem to be any reason why synthetic data can't be used for the whole training run, it's just that well-curated high-quality raw data is already available.

This article on how to use LLMs to generate synthetic data seems to be pretty comprehensive, starting with the basics and then going into detail about how to generate it with a system called DeepEval. In another comment in this thread I pointed to NVIDIA's Nemotron-4 models as another example.