arXiv Computation and Language

Rethinking LLM Pruning via Test-Time Scaling

The paper investigates how structured pruning of large language models affects reasoning performance and sampling efficiency. Across expert, feed‑forward, and layer pruning on mathematical and coding benchmarks, the authors find that heavily pruned models can match or surpass the original model’s reasoning coverage, yet they often require more attempts to sample correct answers, leading to higher token usage. The study highlights a trade‑off between maintaining problem coverage and the cost of obtaining accurate solutions, suggesting that pruning should be evaluated on both dimensions.

arXiv AI
Aug 25

Revisiting the Effectiveness of LLM Pruning for Test-Time Scaling

The paper revisits the impact of pruning on large language models (LLMs) during test-time scaling (TTS). While prior work found that structured pruning degrades reasoning performance, this study shows that unstructured pruning—removing only specific redundant weights—can actually improve TTS performance on reasoning benchmarks for models s1.1-7B and Qwen3-8B, sometimes surpassing the full-weight models. The authors also examine how different layer-wise sparsity allocation strategies affect these outcomes.

By Ocean Monjur, Shahriar Kabir Nahin, Anshuman Chhabra
arXiv AI
Jun 15

Fractured Chain-of-Thought Reasoning

arXiv:2505. 12992v4 Announce Type: replace-cross Abstract: Inference-time scaling techniques have significantly bolstered the reasoning capabilities of large language models (LLMs) by harnessing additional computational effort at inference without retraining.

By Baohao Liao, Hanze Dong, Yuhui Xu, Doyen Sahoo, Christof Monz, Junnan Li, Caiming Xiong
arXiv Computation and Language
Oct 23

Direct Pass@$k$ Optimization for Thought Pruning: Balancing Quality and Diversity in Test-Time Reasoning

The paper introduces a pruning method for test-time reasoning that directly optimizes pass@$k$ by selecting a pool of partial solutions that maximizes the chance of at least one correct final answer. This approach balances quality and diversity automatically, avoiding separate design choices for each. Experiments on eight open-weight reasoning models show that the method outperforms existing quality-based and diversity-based pruning strategies, especially when a moderate number of partial solutions are retained.

By Mahdi Salmani, Adel Javanmard, Devansh Gupta, Meisam Razaviyayn
arXiv AI
Sep 17

Higher-order pruning of experts in mixture-of-experts language models

The paper introduces HOPE, a second‑order pruning method for Mixture‑of‑Experts language models that accounts for cooperative interactions between experts. Unlike first‑order methods such as REAP, HOPE derives an objective that provably bounds pruning error and is shown to outperform baselines across three large MoE models, multiple calibration sets, and diverse benchmarks, especially at high pruning rates and on agentic tasks. The results demonstrate that preserving expert interactions allows aggressive compression with minimal performance loss on complex workloads.

By Alex M. Tseng, Prannay Kaul, Luca Zancato, Wei Xia, Stefano Soatto
arXiv Computation and Language
Aug 31

Pruning Laws for Large Language Models

arXiv:2504.04342v2 Announce Type: replace Abstract: Scaling up model parameters and training data consistently improves the performance of large language models (LLMs), but at the cost of rapidly gro...

By Ayan Sengupta, Siddhant Chaudhary, Tanmoy Chakraborty
arXiv AI
Sep 17

OBC-Prune: Outcome-Based Calibration for Large Reasoning Model Pruning

OBC‑Prune introduces an outcome‑based calibration approach for pruning large reasoning models, focusing on the causal importance of each reasoning sentence rather than uniform activation salience. By pairing correct and incorrect rollouts and using intervention‑based analysis, it assigns per‑token weights that guide one‑shot pruning methods such as SparseGPT, Wanda, and ALPS. Experiments on DeepSeek‑R1‑Distill‑Qwen models show consistent accuracy gains and shorter reasoning traces across multiple benchmarks at 40‑50% sparsity.

By Ha Lan Nguyen, Huy Hoang Tran, Trac-Duy Tran, Dung D. Le