MLM vs Bridge Training

For how they differ, the arg mapping tables, gotchas, and translation script, see:

• docs/megatron-lm-to-megatron-bridge.md

Correlation Testing

Use vanilla_gpt_pretrain_config for loss-correlation testing. This recipe uses bare GPTModelProvider defaults (LayerNorm, GeLU, learned_absolute position embeddings, vocab_size inherited from tokenizer) — matching MLM pretrain_gpt.py defaults with no args.

MLM Correlation Run (2L/256H, 1 GPU)