Sparse attention without dense warmup signals midtraining absorption, analyst argues

stochasticchasm · x · 2026-09-11

Blogger stochasticchasm reads sparse attention training progress: when a sparse variant no longer needs a dense-attention warmup, it's a good sign. Long-context pretraining is likely enabled by lower prefill FLOPs, and agentic traces can probably be introduced much earlier in training — suggesting midtraining is being absorbed. The thread also notes engram making it into the model, an mHC simplification (mega-mHC), and speculation about dspark use during pretraining pending the paper.

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