It is designed to improve alignment stability and mitigate token-level probability collapse during fine-tuning by incorporating entropy-aware adaptive weighting into the training objective.
More details could check our paper
ICLR 2026 "TS^2: Training with Sparsemax+, Testing with Softmax for Accurate and Diverse LLM Fine-Tuning"
Instead of applying uniform likelihood maximization across all tokens (as in standard SFT), this model introduces an adaptive weighting mechanism that dynamically adjusts training emphasis based on the predictive entropy of the model.
This approach is inspired by recent observations in preference alignment that overconfident likelihood training may lead to:
1from transformers import AutoTokenizer, AutoModelForCausalLM
2
3tokenizer = AutoTokenizer.from_pretrained(
4 "xzybit/llama3.1-8b-ts2"
5)
6
7model = AutoModelForCausalLM.from_pretrained(
8 "xzybit/llama3.1-8b-ts2",
9 device_map="auto"
10)