arXiv:2501.14850cs.CLcs.AI2025-01被引 2

LRA benchmarks overstate long-range modeling能力,实则依赖短程依赖。

On the locality bias and results in the Long Range Arena

  • 发现LRA任务主要靠局部信息,非真正长程建模。
  • 改进位置编码后,Transformer可达到顶尖性能。
  • SSMs优势源于学习效率而非架构革新,适合特定任务。

Long Range Arena(LRA)基准旨在评估Transformer改进与替代架构在长程依赖建模任务中的表现。以往研究表明,Transformer及其主流变体在该基准上表现不佳,而状态空间模型(SSMs)等新架构则显著优于Transformer。近期工作表明,通过去噪预训练,Transformer可在LRA中取得竞争力结果。本文揭示了MEGA和SSMs在LRA中表现优越的原因,以及近期Transformer性能提升的根源,指出这些任务本质上具有位置性和局部性特征。我们证明,尽管LRA是为长程依赖建模设计的,但其性能主要来自短程依赖。通过训练技术缓解数据效率问题,结合恰当的位置编码,Transformer能达到当前最优水平。此外,使用相同技术,我们成功移除了SSM卷积核的所有约束,学习全参数化卷积而未损失性能,表明SSMs的设计选择仅引入归纳偏置与学习效率优势。我们的分析提示需谨慎解读LRA结果,并呼吁重新设计该基准。

原文摘要 · Abstract (English)

The Long Range Arena (LRA) benchmark was designed to evaluate the performance of Transformer improvements and alternatives in long-range dependency modeling tasks. The Transformer and its main variants performed poorly on this benchmark, and a new series of architectures such as State Space Models (SSMs) gained some traction, greatly outperforming Transformers in the LRA. Recent work has shown that with a denoising pre-training phase, Transformers can achieve competitive results in the LRA with these new architectures. In this work, we discuss and explain the superiority of architectures such as MEGA and SSMs in the Long Range Arena, as well as the recent improvement in the results of Transformers, pointing to the positional and local nature of the tasks. We show that while the LRA is a benchmark for long-range dependency modeling, in reality most of the performance comes from short-range dependencies. Using training techniques to mitigate data inefficiency, Transformers are able to reach state-of-the-art performance with proper positional encoding. In addition, with the same techniques, we were able to remove all restrictions from SSM convolutional kernels and learn fully parameterized convolutions without decreasing performance, suggesting that the design choices behind SSMs simply added inductive biases and learning efficiency for these particular tasks. Our insights indicate that LRA results should be interpreted with caution and call for a redesign of the benchmark.

Transformer长程建模基准评估位置编码

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