Methods › Sequential › Recurrent Neural Networks › Unitary RNN

Unitary RNN

3 papers tagged archive 2025-07-28

Introduced by Martin Arjovsky et al. in Unitary Evolution Recurrent Neural Networks

archive 2025-07-28 Description, source and code snippet are the archive's method entry.

A Unitary RNN is a recurrent neural network architecture that uses a unitary hidden to hidden matrix. Specifically they concern dynamics of the form:

hₜ = f(Whₜ₋₁ + Vxₜ)

where W is a unitary matrix (W^†W = I). The product of unitary matrices is a unitary matrix, so W can be parameterised as a product of simpler unitary matrices:

hₜ = f(D₃R₂F⁻¹D₂PR₁FD₁hₜ₋₁ + Vxt)

where D₃, D₂, D₁ are learned diagonal complex matrices, and R₂, R₁ are learned reflection matrices. Matrices F and F⁻¹ are the discrete Fourier transformation and its inverse. P is any constant random permutation. The activation function f(h) applies a rectified linear unit with a learned bias to the modulus of each complex number. Only the diagonal and reflection matrices, D and R, are learned, so Unitary RNNs have fewer parameters than LSTMs with comparable numbers of hidden units.

Source: Associative LSTMs

PaperSource

Papers archive 2025-07-28

3 shown of 3, newest first. Repository counts are the archive's code-links table. A Syntology line states what Syntology ran from that paper's harvested code; it is per sample and not a correctness claim.

Tasks archive 2025-07-28

6 tasks the archive attaches to papers tagged with this method, by distinct papers. A task without a page in the catalog is plain text.

TaskPapers
AutoML1
Marketing1
Multimodal Sentiment Analysis1
Recommendation Systems1
Sentiment Analysis1
Sequential Image Classification1

Usage over time archive 2025-07-28

Papers per year tagged with Unitary RNN: 2015 to 2021, peak 1 1 0 2015: 1 paper 2015 2016: 0 papers 2016 2017: 0 papers 2017 2018: 1 paper 2018 2019: 0 papers 2019 2020: 0 papers 2020 2021: 1 paper 2021
Papers per year the archive tags with this method, by the paper's archive date (3 dated). Bars are counts, not a trend claim.

Components: the archive holds no method-to-method composition, so PwC's Components table cannot be rebuilt; the Papers list carries no Results column for the same reason (the archive does not join its leaderboard rows to method tags).

Categories archive 2025-07-28

Recurrent Neural Networks

Report a problem or propose a change · a person checks every report against the paper or source before anything changes; decisions are listed on /corrections