arXiv Machine Learning

MaRK: Markov-adapted Recurrent Kernels for Dynamic Operator Conditioning in State Space Models

MaRK (Markov‑adapted Recurrent Kernels) is a framework that conditions pre‑trained State Space Models (SSMs) by mapping context vectors into bounded modulations of the SSM’s recurrence, read‑in, read‑out, skip, and discretization parameters. By treating the SSM as a linear‑parameter‑varying system, MaRK generates a context‑indexed family of Markov parameter sequences, enabling each diffusion timestep to reshape the model’s input‑output memory kernel. Implemented on a frozen 111 M‑parameter Hydra SSM, MaRK uses low‑rank adapters (Hypernet, Chebyshev polynomial, or Discrete Cosine Transform) to achieve parameter‑efficient fine‑tuning with only 6.3–11 M trainable auxiliary parameters, while providing an analytic stability certificate and demonstrating stable, timestep‑conditioned memory profiles in experiments.

arXiv Machine Learning
Aug 11

Advancing Intelligent Sequence Modeling: Evolution, Trade-offs, and Applications of State-Space Architectures from S4 to Mamba

arXiv:2503. 18970v4 Announce Type: replace Abstract: Structured State Space Models (SSMs) have become a prominent class of sequence models, developed against two long-standing difficulties: the sequential computation and gradient propagation limits of Recurrent Neural Networks (RNNs), and the quadratic time and memory cost of self-attention in Transformers.

By Shriyank Somvanshi, Md Monzurul Islam, Mahmuda Sultana Mimi, Sazzad Bin Bashar Polock, Gaurab Chhetri, Anandi Dutta, Amir Rafe, Subasish Das
arXiv AI
Sep 3

CHASE: Cache-Hole-Adapted Skip Exit for Looped State-Space Language Models

The paper introduces CHASE, a cache‑hole‑adapted skip‑exit mechanism for looped state‑space language models, specifically Looped Mamba and Looped Hybrid Mamba‑Transformer. It shows that looping these architectures improves performance on controlled reasoning tasks and remains competitive in pre‑training benchmarks while using fewer distinct parameters. The cache‑hole adaptation allows selective skipping of recurrent steps during inference, maintaining perplexity close to full computation and achieving significant speedups.

By Zhenxuan Yu, Takeshi Kojima, Yutaka Matsuo, Yusuke Iwasawa
arXiv Machine Learning
Jul 28

Numerical Investigation of Sequence Modeling Theory using Controllable Memory Functions

arXiv:2506. 05678v3 Announce Type: replace Abstract: The evolution of sequence modeling architectures, from recurrent neural networks and convolutional models to Transformers and structured state-space models, reflects ongoing efforts to address the diverse temporal dependencies inherent in sequential data.

By Haotian Jiang, Zeyu Bao, Shida Wang, Qianxiao Li
arXiv Machine Learning
Aug 31

Fast Weight Attention for Continual Learning

Fast Weight Attention for Continual Learning introduces recurrent fast‑weight memories and selective state‑space models that compress expanding context into a fixed‑size recurrent state, enabling an online learning rule for state transitions. The paper derives normalized first‑order updates for squared‑error regression and negative inner‑product objectives, presenting several variants (Falcon‑1, Falcon‑2, Falcon‑3 and their inner‑product counterparts) with recurrent, masked‑parallel, and chunk‑parallel implementations. These methods demonstrate competitive performance in language modeling and improved length extrapolation on variable‑digit addition tasks.

By Yifan Zhang, Steve Ta, Jasper Zhang, Jichen Feng, Shuzhen Li, Yongxin Zhang, Yifeng Liu, Huizhuo Yuan, Mengdi Wang, Quanquan Gu, Andrew Chi-Chih Yao
arXiv Machine Learning
Sep 18

Elastic Spectral State Space Models for Train-Once Budgeted Inference

Elastic Spectral State Space Models (ES-SSM) are a train‑once, export‑many sequence modeling framework that achieves elasticity by spectrally approximating the state‑space operator. The method builds on Hankel spectral filtering, using fixed spectral channels to represent long‑range token mixing and combining input‑adaptive gates with budget dropout to enable reliable deployment across different resource budgets. ES‑SSM is evaluated on byte‑level language modeling, Long Range Arena, Speech Commands V2, and offline reinforcement learning, showing that a single trained model can be truncated to competitive compact models while maintaining smooth quality‑cost curves across a wide range of truncation levels.

By Dachuan Song, Junyu Yin, Zechen Hu, Xuan Wang
arXiv AI
Sep 10

Kalman Delta Networks: Uncertainty-aware Associative Memory

Kalman Delta Networks (KDNs) extend linear attention models by treating associative memory as a linear–Gaussian state‑space system, enabling the Kalman filter to optimally estimate both memory state and its uncertainty. Two GPU‑friendly approximations—Diagonal KDN and Isotropic KDN—use mean‑field variational inference or a single scalar uncertainty per head, respectively, to maintain tractable uncertainty recurrences during linear‑attention scans. Experiments on 750 M and 1.3 B‑parameter models show that KDN variants consistently lower perplexity and raise downstream accuracy compared to existing linear‑attention baselines.

By Ngoc Bui, Tinglin Huang, Rex Ying
arXiv Machine Learning
Sep 4

Prospective Coding Improves Learning in Deep Continuous-Time Recurrent Networks

The paper introduces Recursive Quadrature Filters (RQFs), complex‑valued temporal filters that act as band‑pass filters within diagonal state‑space models. By making each layer’s bottom‑up input prospective through a parameter‑free two‑tap update, the authors mitigate depth‑dependent gradient attenuation in deep continuous‑time recurrent networks. Experiments on RQFs, S5, and ORGaNICs show that prospective variants match or surpass non‑prospective controls, achieving high accuracy on raw‑audio Speech Commands and the Path‑X task with few parameters.

By Shivang Rawat, Mirko Morello, Flaviano Morone, David J. Heeger