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Can we change an AI model’s architecture without retraining it from scratch?
Summary
The Transformer architecture’s memory cost scales with token count, making long-context AI agents expensive. In controlled comparisons of three state space models - Gated KalmaNet, Gated DeltaNet, and Mamba-2 - Gated KalmaNet performed best, offering variable-length inference without retraining. Priming identifies which attention layers can be replaced by state space models using a sliding-window attention proxy, then reuses pre-trained weights to convert them into hybrid architectures without retraining, reducing pretraining cost by over 99%. A 32-billion-parameter hybrid model matches the original Transformer’s reasoning quality while decoding up to twice as fast or reaching correct answers in two-thirds of wall-clock time. The team extended hybrid context to 256K tokens without additional training and released primed models at 8B and 32B scales along with training code, kernels, and a vLLM plugin under Apache 2.0.
Context
The post from Amazon Web Services describes the high cost of training hybrid AI architectures that combine attention and state space models, and introduces ‘priming’ as a method to convert pre-trained Transformers into such hybrids without training from scratch.
Approach / What changed
Priming proceeds in three stages: 1) layer selection using a sliding-window attention proxy to identify which attention layers can be replaced by state space models; 2) weight transfer and alignment, where SSM layers are initialized from the corresponding attention weights and a short distillation aligns each SSM to the behavior of the replaced layer; 3) end-to-end fine-tuning on next-token prediction. This avoids the need for pretraining from scratch.
Takeaways
Priming reduces the pretraining cost of hybrid architectures by over 99% compared to training from scratch.
A 32-billion-parameter hybrid model using GKA matches Transformer quality while decoding up to twice as fast or reaching answers in two-thirds of wall-clock time.
Under controlled comparisons, Gated KalmaNet outperforms Gated DeltaNet and Mamba-2, and offers variable-length inference without retraining.
Source and freshness
- Source
- amazon.science
- Published
- Added to Yomu
Summaries are generated from the original by a language model. Check the original before relying on it.
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