Lapras: Latent Reasoning for Time Series Language Models
Yuliang Chen, Yu Yvonne Wu, Arvind Pillai, Nicholas C. Jacobson, Andrew Campbell
Summary
Post-training framework for time-series language models (TSLMs): instead of verbalising the signal in an explicit chain-of-thought, the model reasons through continuous "thoughts" in the joint time-series–language space and emits text only for the answer. Trained by teacher–student self-distillation: a CoT-SFT teacher reasons in text, and the student aligns its answer-stage hidden states to the teacher's. Evaluated on four TSLM backbones (ChatTS-7B, OpenTSLM-1B Flamingo variant, SLIP-1B, ITFormer-0.5B) and five QA tasks: ECG (ECG-Reasoning benchmark, Oh et al.
Key facts
- Form Factor
- other
- License
- Not stated
Reported benchmarks
Human activity recognition (IMU)
opentslm-har-cot · Macro-F1 ↑
Multiple-choice HAR QA (OpenTSLM, Langer et al. 2026), 8,222 test items; same-backbone Explicit-CoT 67.27, No-CoT 63.41; OpenTSLM-1B+Lapras 68.20, SLIP-1B+Lapras 70.75.
Sleep staging
opentslm-sleep-cot · Macro-F1 ↑
Multiple-choice sleep-stage QA (OpenTSLM, Langer et al. 2026), 923 test items, 1-ch 1500-step windows; same-backbone No-CoT 78.05, Explicit-CoT 65.48.
Updated: Oct 12, 2026
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