arXiv Machine Learning

baseVultra: Compact Nonlinear Recurrence with Reallocated Capacity

The paper introduces baseVultra, a compact recurrent neural network cell that reallocates most of its recurrent capacity to a single dense candidate‑generation matrix while simplifying gate operations to O(H) diagonal interactions. On character‑level language modeling benchmarks such as TinyShakespeare and text8, baseVultra matches or slightly outperforms parameter‑matched LSTM and GRU cells, achieving lower validation loss and competitive bits‑per‑character scores. The authors find that the advantages of this candidate‑focused design are most pronounced in low‑capacity regimes, whereas full‑gate cells remain competitive when hidden size is increased.

arXiv AI
Oct 19

M$^2$RNN: Non-Linear RNNs with Matrix-Valued States for Scalable Language Modeling

M$^2$RNN introduces matrix‑valued hidden states and expressive non‑linear transitions for recurrent neural networks, addressing the limited expressive power of transformers. The architecture scales efficiently with tensor cores, achieving perfect state‑tracking generalization on unseen sequence lengths and outperforming hybrid Gated DeltaNet models by 0.4–0.5 perplexity points on a 7B MoE model while using three‑times smaller recurrent states. Even a single M$^2$RNN layer in a hybrid architecture yields accuracy gains comparable to full Hybrid M$^2$RNN, and improves long‑context performance on LongBench by up to 8 points over state‑of‑the‑art hybrid linear attention models.

By Mayank Mishra, Shawn Tan, Ion Stoica, Joseph E. Gonzalez, Tri Dao
arXiv Machine Learning
Aug 27

Gated Recurrent Transformers: Expressive Depth through Recurrent Modulation

The paper introduces Gated Recurrent Transformers, a depth‑sharing architecture that brackets a single shared core with fixed prelude and coda blocks and uses a lightweight projection and element‑wise update gate to modulate recurrent updates. This design allows functional specialization across recurrences while reducing memory footprint. Experiments show that, under equal FLOPs or parameter budgets, the recurrent model matches or surpasses deeper GPT‑2 Small baselines, achieving similar or better accuracy with fewer parameters and lower peak decoding memory.

By Amr Hegazy, Amr Alanwar, Mostafa Elhoushi
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 Machine Learning
Aug 4

Structured Recurrent Mixers for Massively Parallelized Sequence Generation

arXiv:2605. 08696v4 Announce Type: replace-cross Abstract: Over the last two decades, language modeling has experienced a shift from the use of predominantly recurrent architectures that process tokens sequentially during training and inference to non-recurrent models that process sequence elements in parallel during training, which results in greater training efficiency and stability at the expense of lower inference throughput.

By Benjamin L. Badger
arXiv AI
Oct 2

Reshape and Recur: Improving SSMs with Input Reshaping and Depth Recurrence

The paper proposes two extensions to State Space Models (SSMs) to reduce memory usage and improve performance. First, it introduces depth recurrence, allowing a looped SSM with fewer parameters to match the performance of a larger, non-recurrent model. Second, it advocates using a fixed time granularity across tasks by reshaping input sequences, which enhances how information is presented to the model. Both techniques consistently benefit four representative SSM architectures (LRU, S5, LinOSS, LrcSSM).

By M\'onika Farsang, Ramin Hasani, Daniela Rus, Radu Grosu
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 Computation and Language
Sep 23

LatentPort: Beyond KV Cache - Cross-Model Transfer of Recurrent Memory in Hybrid Language Models: A 4B-to-9B Hybrid-State Handoff Without Target Prefix Replay

The paper introduces LatentPort, a method that allows a language model to transfer its live memory to another model without requiring the receiver to reread the context. Experiments on a Qwen3.5 4B-to-9B sibling pair show that adding a Gated DeltaNet (GDN) persistent-state package reduces negative log‑likelihood by 0.747 nats/token and improves performance across 64 PG19 documents. The study also demonstrates that direct recurrent and convolution reuse outperforms learned GDN maps, and a 434,176‑parameter correction further narrows the performance gap to the native 9B model.

By Simon P. Villani