OLMo-2-7B-DCO-10k

DCO (Liu et al., ICML 2026): label-free cross-lingual consistency preference optimisation on 10,000 facts.

A LoRA adapter (r=128, alpha=256) over allenai/OLMo-2-1124-7B, trained for the paper Improving Cross-Lingual Factual Recall via Consistency-Driven Reinforcement Learning. It is one arm of a controlled comparison in which SFT, DCO, CM-Align and GRPO all see the same 10,000 facts from jvonrad/PolyFact-Clean across the same 12 languages, so the methods differ only in objective.

Evaluation

Accuracy (%) unless noted. PolyFact-Clean is the 2,039-fact curated test split with byte-normalised log-likelihood scoring; TotCons is the fraction of facts answered correctly in all 12 languages; RankC is RankC@4 (floor 9.02, chance 37.68). KLAR is free-form generation over 17 languages, split into the 7 seen in training and the 10 held out.

Model	PolyFact	TotCons	RankC	BMLAMA-53	G-MMLU-Lite	KLAR seen	KLAR held-out
Base (allenai/OLMo-2-1124-7B)	44.43	1.72	57.29	17.89	44.45	24.56	13.30
This model	45.58	6.42	63.23	20.39	44.84	30.85	17.32

Usage

from peft import PeftModel
from transformers import AutoModelForCausalLM, AutoTokenizer

base = AutoModelForCausalLM.from_pretrained("allenai/OLMo-2-1124-7B", dtype="bfloat16",
                                            device_map="auto")
model = PeftModel.from_pretrained(base, "jvonrad/OLMo-2-7B-DCO-10k")
tok = AutoTokenizer.from_pretrained("jvonrad/OLMo-2-7B-DCO-10k")

Evaluation used the closed-book prompt Question: {q}\nAnswer: with the options hidden, matching evaluate/evaluate_crosslingual_consistency.py.

Citation

@misc{polyfact2026,
  title  = {Improving Cross-Lingual Factual Recall via Consistency-Driven
            Reinforcement Learning},
  author = {von Rad, Jonathan},
  year   = {2026},
  eprint = {2606.06586},
  archivePrefix = {arXiv}
}