Mamba: Linear-Time Sequence Modeling with Selective State Spaces
Albert Gu Tri Dao
Foundation models, now powering most of the exciting applications in deep
learning, are almost universally based on the Transformer architecture and its
core attention module. Many subquadratic-time architectures such as linear
attention, gated convolution and recurrent models, and structured state space
models (SSMs) have been developed to address Transformers' computational
inefficiency on long sequences, but they have not performed as well as
attention on important modalities such as language. We identify that a key
weakness of such models is their inability to perform content-based reasoning,
and make several improvements. First, simply letting the SSM parameters be
functions of the input addresses their weakness with discrete modalities,
allowing the model to selectively propagate or forget information along the
sequence length dimension depending on the current token. Second, even though
this change prevents the use of efficient convolutions, we design a
hardware-aware parallel algorithm in recurrent mode. We integrate these
selective SSMs into a simplified end-to-end neural network architecture without
attention or even MLP blocks (Mamba). Mamba enjoys fast inference (5$\times$
higher throughput than Transformers) and linear scaling in sequence length, and
its performance improves on real data up to million-length sequences. As a
general sequence model backbone, Mamba achieves state-of-the-art performance
across several modalities such as language, audio, and genomics. On language
modeling, our Mamba-3B model outperforms Transformers of the same size and
matches Transformers twice its size, both in pretraining and downstream
evaluation.