rostlabs/rost-126m-base

126M parameter nanochat GPT (base stage), research tag ro30, checkpoint step 001920.

Part of the rost model zoo — the full set of trained variants behind the rost research series, published for reproducibility. This is a research model, not a product.

architecture	nanochat GPT, 8 layers, 512 embed, 2048 context
tokenizer	included under tokenizer/ (32,768 vocab)
training mixture	30% Romanian (FineWeb2-ro) / 70% English (ClimbMix), interleaved at document level
stage	base
val bpb (own split)	1.01113

The bilingual base of the rost RO:EN ratio sweep (research tag ro30, the selected 30:70 arm). Companion SFT: rost-126m-sft.

Validation bits-per-byte is measured on this arm's own validation split and is not comparable across arms — cross-arm comparisons in the rost write-ups are always cross-evaluated on identical text.

Licence

CC-BY-NC-4.0, non-commercial, inherited from the most restrictive component of the training data.