What actually happens at each stage of training a large language model — what data, what objective, what the model learns, and why the stages are ordered the way they are.
Training a model to handle 128K context isn't just running inference on longer sequences — it requires a dedicated mid-training phase because positional encoding, attention entropy, and information retrieval all break in distinct ways beyond the training window.
What actually happens at each stage of training a large language model — what data, what objective, what the model learns, and why the stages are ordered the way they are.
Training a model to handle 128K context isn't just running inference on longer sequences — it requires a dedicated mid-training phase because positional encoding, attention entropy, and information retrieval all break in distinct ways beyond the training window.