arXiv Machine Learning
Oct 22

A Diagnostic Study of Faithfulness in Diffusion Language Models for Table-to-Text Generation

The paper investigates how diffusion language models maintain factual fidelity when generating text from tables, comparing masked diffusion models (MDLM, LLaDA) to autoregressive models (GPT‑2, GPT‑Neo) on the ToTTo dataset. Using a retrieval‑based few‑shot protocol, the study finds that while diffusion models score higher on reference similarity (BLEU), they exhibit lower source grounding and different failure modes—autoregressive models drift from the table, whereas diffusion models stay on topic but swap entities. The authors conclude that reference‑based metrics alone are insufficient for assessing faithfulness in table‑to‑text generation.

By Zaynab Merimi, Noussayba El Marrakchi, Arthur Satouf
arXiv Computation and Language
Oct 23

Hacking Generative Perplexity: Why Unconditional Text Evaluation Needs New Metrics

The paper critiques generative perplexity (gen‑PPL) as an unreliable metric for evaluating unconditional text generation, showing that it can be minimized by trivial, non‑diverse outputs. The authors demonstrate this by constructing simple samplers that achieve low gen‑PPL yet produce incoherent text, and they propose alternative evaluation tools—including distributional discrepancies, diversity diagnostics, and a compression‑based KL divergence measure—to better assess generative language models. They argue that future progress in diffusion language models should rely on a suite of metrics that capture diverse aspects of generated text quality.

By Antonio Franca, Alexander Tong
arXiv Computation and Language
5d ago

The Generative Gap Between Speculative Drafter and Continuous Diffusion Language Model

The study compares continuous diffusion language models (CDLMs) and speculative drafters by training them from scratch on unconditional OpenWebText generation at lengths 16, 128, and 1024. Using LangFlow for CDLMs and adapted DSpark Markov and recurrent-head architectures for standalone generation, the authors evaluate generation perplexity (GenPPL) and MAUVE similarity. Results show LangFlow outperforms both DSpark variants at longer lengths (128 and 1024), while DSpark-RNN leads at length 16; recurrent memory and teacher probability matching improve metrics but the longer‑sequence gap remains, highlighting iterative full‑sequence refinement as a key advantage.

By Yujian Chen, Hao Jiang, Guang Cheng, Weijian Luo, Tianyang Hu