提出三种实值位置编码,支持高效哈达玛乘积绑定与精确时移变换。
Real-Valued Hyperdimensional Sequence Representations with Hadamard Product Binding and Shift Equivariance

- 基于随机傅里叶特征设计实值编码,兼容哈达玛乘积操作
- 正弦编码实现显式代数时移算子,无需重编码即可应用时移
- 在时间序列分类上性能媲美原版,且计算更高效
在超维计算中,编码时序顺序是序列表示的基本要求。分数幂编码提供保持相似性的位置向量,其内积近似平移不变核,并支持编码序列表示的平移等变变换。然而,标准分数幂编码主要针对循环卷积或复数乘法等绑定操作设计,限制了其与实值向量哈达玛乘积绑定的兼容性。本文受随机傅里叶特征启发,提出三种实值位置编码:基于逆傅里叶变换的实值基线,以及从随机傅里叶特征导出的正弦和余弦仅表示。其中,正弦变体提供了显式的代数时移算子,可直接对向量编码的序列表示应用时移,而无需重新编码。在时间序列分类数据集上的实验表明,所提实值表示性能可媲美标准分数幂编码,同时支持计算高效的哈达玛乘积绑定。正弦变体在效率与精确平移等变性之间取得最佳平衡。
原文摘要 · Abstract (English)
Encoding temporal order is a fundamental requirement for sequence representations in Hyperdimensional Computing. Fractional Power Encoding provides similarity-preserving position vectors whose inner products approximate shift-invariant kernels, and it supports shift-equivariant transformations of encoded sequence representations. However, standard formulations of Fractional Power Encoding are primarily designed for binding operations such as circular convolution or complex-valued multiplication, which limits their compatibility with Hadamard product binding of real-valued vectors. This paper develops real-valued position encodings motivated by Random Fourier Features, aiming to retain the desirable properties of Fractional Power Encoding while supporting Hadamard-based operations. We propose three real-valued position-encoding variants: a real-valued baseline based on the inverse Fourier transform, and Sinusoid and Cosine-only representations derived from Random Fourier Features. Among them, the Sinusoid variant provides an explicit algebraic shift operator, allowing temporal shifts to be applied directly to the vector-encoded sequence representation without re-encoding the shifted sequence. Experiments on time-series classification datasets show that the proposed real-valued representations achieve performance comparable to standard Fractional Power Encoding while enabling computationally efficient Hadamard product binding. The Sinusoid variant offers the most favorable trade-off, combining efficient real-valued implementation with exact shift-equivariant transformations.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。