Papers › Deep Equilibrium Models

Deep Equilibrium Models

3 Sep 2019NeurIPS 2019 12arXiv:1909.01377archive 2025-07-28

Shaojie Bai, J. Zico Kolter, Vladlen Koltun

We present a new approach to modeling sequential data: the deep equilibrium model (DEQ). Motivated by an observation that the hidden layers of many existing deep sequence models converge towards some fixed point, we propose the DEQ approach that directly finds these equilibrium points via root-finding. Such a method is equivalent to running an infinite depth (weight-tied) feedforward network, but has the notable advantage that we can analytically backpropagate through the equilibrium point using implicit differentiation. Using this approach, training and prediction in these networks require only constant memory, regardless of the effective "depth" of the network. We demonstrate how DEQs can be applied to two state-of-the-art deep sequence models: self-attention transformers and trellis networks. On large-scale language modeling tasks, such as the WikiText-103 benchmark, we show that DEQs 1) often improve performance over these state-of-the-art models (for similar parameter counts); 2) have similar computational requirements to existing models; and 3) vastly reduce memory consumption (often the bottleneck for training large sequence models), demonstrating an up-to 88% memory reduction in our experiments. The code is available at https://github.com/locuslab/deq .

PaperPDFConference PDFCodeCode Syntology ran

In Syntology Open this paper in Syntology's Atlas, the map of the papers in Syntology's graph and their citations.

For agents, Syntology's MCP tool lists every function and class Syntology harvested from this paper and whether it ran (how to connect): get_harvested_code_for_paper(arxiv_id="1909.01377")

Code

Syntology Ran 3 of 12 code samples harvested from 3 repositories linked to this paper; 9 have no recorded run. Of those that ran: 1 ran · honoured contract; 2 ran · our draft was wrong.

By repository: community (archive-listed): 11 samples from 3 repositories, 3 ran; 1 identical to code first harvested elsewhere. The run record, sample by sample. “Ran” means executed on a synthesized input, not that the code is correct or reproduces the paper.

locuslab/deq officialmentioned in papermentioned on GitHubpytorch report
SinclairHudson/DeepEquilibrium mentioned on GitHubpytorch report
cgoemaere/hamdeq mentioned on GitHubpytorchApache-2.0 report
cgoemaere/hopdeq mentioned on GitHubpytorchApache-2.0 report
locuslab/impsq mentioned on GitHubpytorch report
locuslab/monotone_op_net mentioned on GitHubpytorch report
lufanma/ifr mentioned on GitHubpytorch report
martaskrt/qdeq mentioned on GitHubpytorch report
prolearner/hypertorch mentioned on GitHubpytorch report
reacho/deep-equilibrium-vs-bilevel mentioned on GitHubpytorchMIT report
sciml/fastdeq.jl mentioned on GitHubMIT report

Repository list and official/mentioned flags are the archive's, frozen 2025-07-28. Reachability, where shown, is from one Syntology probe window (2026-09-16 to 2026-09-18); repositories not probed show nothing. GitHub stars are not tracked.

Code Syntology ran Syntology

12 samples harvested; 3 ran; 1 honoured the contract we drafted; 9 have no recorded run. Read from Syntology's graph 2026-09-24; that is when this build read the record, not when the samples ran.

1ran · honoured contract
2ran · our draft was wrong
9unverified

Licence: 4 of the 12 samples are pointer only, meaning Syntology does not serve that copy's text. This page shows no code text for any sample; each one links to its file in the repository.

Harvested from 3 repositories linked to this paper, official or community; each sample names its own and says which. Some samples are identical code Syntology first harvested from another repository; for those, this paper's copy is not located and its licence is not recorded. “Ran” means the sample executed on a synthesized input. It does not mean the output is correct, and nothing here reproduces the paper's results. “Honoured” and “violated” refer to a contract Syntology drafted from the code itself; “our draft was wrong” and “fixture could not drive it” are failures of Syntology's instrument, not of the code.

Each sample ends with its code_sha256, Syntology's identity for that exact code. An agent fetches the stored sample with Syntology's MCP tool get_code(code_sha256="…") (how to connect); click an identity to copy that call.

Repository labels, per sample. official repository: The archive marks this repository official for the paper. named in the paper: The archive records that the paper mentions this repository; it is not marked official. community (archive-listed): In the archive's code links for this paper, not marked official and not recorded as mentioned in the paper. found in paper text by Syntology: Syntology found this repository in the paper's own text; whether it is the authors' implementation is not asserted. community: Not in the archive's code links for this paper; a community repository Syntology harvested. Samples from a repository marked official are listed first. Licence labels name the repository's licence as recorded at harvest. “Pointer only” means Syntology does not serve that copy's text, for one of four reasons: no licence file was found; the licence was not identified; the licence is recorded as permissive but that copy's record is not marked cleared; or the licence is outside the permissive list Syntology serves text under (MIT, Apache-2.0, BSD and similar). Some licences outside that list permit redistribution, such as WTFPL, and GPL-3.0 under its conditions; they are simply not on the list. Hover a licence label for the reason. File links open the file on GitHub at the default branch, which may have changed since the harvest.

load_dataset locuslab/impsq/scripts/train_2d_image.py community (archive-listed) ran · our draft was wrong no licence file found · pointer only · 635c8fdeade67cba · report
postprocess locuslab/impsq/scripts/train_2d_image.py community (archive-listed) ran · our draft was wrong no licence file found · pointer only · 81a8d0038b2d548a · report
preprocess locuslab/impsq/scripts/train_2d_image.py community (archive-listed) ran · honoured contract fingerprinted no licence file found · pointer only · 1194fc2f2f213578 · report
anderson cgoemaere/hamdeq/hopdeq/deq_core/solvers.py community (archive-listed) unverified Apache-2.0 (permissive) · 799e823c70a9d96b · report
backprop cgoemaere/hamdeq/hopdeq/deq_core/backward.py community (archive-listed) unverified Apache-2.0 (permissive) · d9164060df059089 · report
damped cgoemaere/hamdeq/hopdeq/deq_core/utils/fixed_point_utils.py community (archive-listed) unverified Apache-2.0 (permissive) · 1ec688ed87b414c9 · report
full_adjoint cgoemaere/hamdeq/hopdeq/deq_core/backward.py community (archive-listed) unverified Apache-2.0 (permissive) · 8b3921143c779266 · report
get_function_from_package cgoemaere/hamdeq/hopdeq/deq_core/utils/import_utils.py community (archive-listed) unverified Apache-2.0 (permissive) · 06ee28cae377b42a · report
picard cgoemaere/hamdeq/hopdeq/deq_core/solvers.py community (archive-listed) unverified Apache-2.0 (permissive) · a0f601462ac10944 · report
power_iteration_torch_T reacho/deep-equilibrium-vs-bilevel/CelebA/DEQ-vs-bilevel-conv2d.py community (archive-listed) unverified MIT (permissive) · 20e21defecd44b23 · report
track_states cgoemaere/hamdeq/hopdeq/deq_core/utils/fixed_point_utils.py community (archive-listed) unverified Apache-2.0 (permissive) · 641ed886ac5440c1 · report
evaluate identical code first harvested elsewhere unverified licence of this copy not recorded · ee0aeb0dbfe062f7 · report

Tasks

Language ModelingLanguage Modelling

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Language Modelling Penn Treebank (Word Level) DEQ-TrellisNet Params 24M #29 of 43 Archive leaderboard report
Language Modelling Penn Treebank (Word Level) DEQ-TrellisNet Test perplexity 57.1 #29 of 43 Archive leaderboard report
Language Modelling WikiText-103 DEQ-Transformer (medium, adaptive embed) Number of params 110M #50 of 89 Archive leaderboard report
Language Modelling WikiText-103 DEQ-Transformer (medium, adaptive embed) Test perplexity 23.2 #50 of 89 Archive leaderboard report
Language Modelling WikiText-103 DEQ-TrellisNet Number of params 180M #66 of 89 Archive leaderboard report
Language Modelling WikiText-103 DEQ-TrellisNet Test perplexity 29.0 #66 of 89 Archive leaderboard report
Language Modelling WikiText-103 DEQ-Transformer (small) Number of params 138M #73 of 89 Archive leaderboard report
Language Modelling WikiText-103 DEQ-Transformer (small) Test perplexity 32.4 #73 of 89 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

Methods

Introduced by this paper: DEQ

DEQ

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