RTF

This repository contains the official implementation of the rational transfer function (RTF) parametrization for state-space layers.

Repository Structure

• rtf.py contains the standalone RTF implementation.
• Experiemnts are located in experiments.
  • experiments/safari: Wikitext103 language modeling experiment.
  • experiments/state-spaces: Long Range Arena (LRA), synthetic memory tasks (Copying and Delay), Speech Commands.
• For each experimental framework, we implement a wrap of the standalone RTF (rtf.py).
  • Wrapper for state-spaces: experiments/state-spaces/src/models/sequence/kernels/rtf_wrapper.py
  • Wrapper for safari: experiments/safari/src/models/sequence/ssm/rtf_wrapper.py

Setup and Usage Guides

Experiment-specific setup and usage guides:

• state-spaces: experiments/state-spaces/README.md
• safari: experiments/safari/README.md

Setup for standalone rtf.py:

pip3 install -r requirements.txt

Example Usage

from rtf import RTF
import torch

seq_len = 1024
d_model = 32
init = "xavier" # Other options: "zeros" (default), "montel"
constraint = "l1_montel" # Other options: "no"|None (default)
batch_size = 1
input = torch.rand(batch_size, seq_len, d_model)

model = RTF(
	d_model=d_model, 
	state_size=128, 
	trunc_len=seq_len, 
	init=init, 
	constraint=constraint)

output = model(input)
print(output.shape)
>>> torch.Size([1, 1024, 32])

Tutorials

• Switching from convolutional mode to recurrent mode

Citation

You can cite our work with:

@article{parnichkun2024statefree,
  title={State-Free Inference of State-Space Models: The Transfer Function Approach}, 
  author={Rom N. Parnichkun and Stefano Massaroli and Alessandro Moro and Jimmy T. H. Smith and Ramin Hasani and Mathias Lechner and Qi An and Christopher Ré and Hajime Asama and Stefano Ermon and Taiji Suzuki and Atsushi Yamashita and Michael Poli},
  journal={International Conference on Machine Learning},
  year={2024}
}