Engineering2026-09-172 min read

state-space-recurrent-models

VDaily Team
Maintainer

State-space & recurrent models

📂 model-architectures

MODEL ARCHITECTURES#

State-space & recurrent models

Update a compact state as tokens arrive instead of retaining an explicit attention relationship between every pair of positions.

MENTAL MODEL#

Stream the sequence through a learned state transition; the state is a compressed memory of the past.

DATA FLOW#

  • Current token + prior state

  • Learned state update

  • Selective gate or recurrent mixer

  • Output hidden state

  • Carry state forward

How it trains#

Sequence modeling losses are paired with recurrence or structured state-space layers. Parallel scans or related formulations can make training more parallel than a naive step-by-step RNN.

How inference runs#

Decode maintains a bounded recurrent state per layer. Hybrid architectures may alternate state-space, convolution, and attention layers to recover capabilities each mechanism handles well.

Strengths#

  • • Linear-time sequence processing in the core recurrence

  • • Compact streaming state at inference

  • • Natural fit for long or continuously arriving sequences

Trade-offs#

  • • Compressed state can lose precise distant details

  • • Tooling and optimized kernels may be less mature than standard attention

  • • Architecture-level complexity claims must be verified end to end

Use it when#

  • Streaming or long-sequence efficiency is a first-order requirement

  • The target runtime has optimized kernels

  • Recall, quality, and throughput are benchmarked on the real workload

Avoid or challenge it when#

  • Exact arbitrary retrieval from long context is assumed without testing

  • The serving stack cannot exploit the architecture

  • A mature Transformer deployment already meets the budget

Illustrative published families#

  • • Mamba selective state-space models

  • • RWKV-style recurrent language models

  • • Hybrid attention–SSM stacks

Commonly combines with#

PRIMARY REFERENCES#

Model Architectures#

Model Architectures#

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state-space-recurrent-models — Blog — VDaily