LISA: Linear-Indexed Sparse Attention for Efficient Long-Context Reasoning
However, the O(n^2) computational complexity of standard self-attention causes inference costs to grow sharply with long sequences, limiting the deployment of long-CoT reasoning in production settings. To address this, we propose LISA (Linear-Indexed Sparse Attention), a plug-and-play attention replacement module that requires no pretraining from scratch. LISA integrates two lightweight components in parallel within the original model: (1) a Linear Attention module that provides long-range memory with O(n) time complexity; (2) a Lightning Indexer that selects the top-M important tokens from the full context to feed into a Sparse Self-Attention.
- ▪However, the O(n^2) computational complexity of standard self-attention causes inference costs to grow sharply with long sequences, limiting the deployment of long-CoT reasoning in production settings.
- ▪To address this, we propose LISA (Linear-Indexed Sparse Attention), a plug-and-play attention replacement module that requires no pretraining from scratch.
- ▪LISA integrates two lightweight components in parallel within the original model: (1) a Linear Attention module that provides long-range memory with O(n) time complexity; (2) a Lightning Indexer that selects the top-M important tokens from
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Computer Science > Artificial Intelligence arXiv:2607.19358 (cs) [Submitted on 29 May 2026] Title:LISA: Linear-Indexed Sparse Attention for Efficient Long-Context Reasoning Authors:Yu Zhao, Zekun Zhang, Fan Jiang, Bo Zeng, Linlong Xu, Shimin Shan, Yu Liu, Longyue Wang, Weihua Luo View a PDF of the paper titled LISA: Linear-Indexed Sparse Attention for Efficient Long-Context Reasoning, by Yu Zhao and 8 other authors View PDF HTML (experimental) Abstract:Recent advances in long chain-of-thought reasoning models such as DeepSeek-R1 have led to increasingly longer inference context lengths under the test-time scaling paradigm.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at arXiv.org.