Papers › FlowSeq: Non-Autoregressive Conditional Sequence Generation with Generative Flow

FlowSeq: Non-Autoregressive Conditional Sequence Generation with Generative Flow

5 Sep 2019IJCNLP 2019 11arXiv:1909.02480archive 2025-07-28

Xuezhe Ma, Chunting Zhou, Xi-An Li, Graham Neubig, Eduard Hovy

Most sequence-to-sequence (seq2seq) models are autoregressive; they generate each token by conditioning on previously generated tokens. In contrast, non-autoregressive seq2seq models generate all tokens in one pass, which leads to increased efficiency through parallel processing on hardware such as GPUs. However, directly modeling the joint distribution of all tokens simultaneously is challenging, and even with increasingly complex model structures accuracy lags significantly behind autoregressive models. In this paper, we propose a simple, efficient, and effective model for non-autoregressive sequence generation using latent variable models. Specifically, we turn to generative flow, an elegant technique to model complex distributions using neural networks, and design several layers of flow tailored for modeling the conditional density of sequential latent variables. We evaluate this model on three neural machine translation (NMT) benchmark datasets, achieving comparable performance with state-of-the-art non-autoregressive NMT models and almost constant decoding time w.r.t the sequence length.

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="1909.02480")

Code

Syntology Ran 1 of 1 code samples harvested from 1 repository linked to this paper; 0 have no recorded run. Of those that ran: 1 ran · honoured contract.

By repository: official repository: 1 sample from 1 repository, 1 ran. The run record, sample by sample. “Ran” means executed on a synthesized input, not that the code is correct or reproduces the paper.

XuezheMax/flowseq officialmentioned in papermentioned on GitHubpytorch 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

1 sample harvested; 1 ran; 1 honoured the contract we drafted; 0 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

Licence: 0 of the 1 sample 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 XuezheMax/flowseq. “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.

calc_bleu XuezheMax/flowseq/experiments/translate.py official repository ran · honoured contract Apache-2.0 (permissive) · 6890088b59086e6e · report

Tasks

Machine TranslationNMTTranslation

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Machine Translation IWSLT2015 German-English FlowSeq-base BLEU score 24.75 #12 of 15 Archive leaderboard report
Machine Translation WMT2014 English-German FlowSeq-large (NPD n = 30) BLEU score 23.64 #72 of 91 Archive leaderboard report
Machine Translation WMT2014 English-German FlowSeq-large (NPD n = 15) BLEU score 23.14 #73 of 91 Archive leaderboard report
Machine Translation WMT2014 English-German FlowSeq-large (IWD n = 15) BLEU score 22.94 #74 of 91 Archive leaderboard report
Machine Translation WMT2014 English-German FlowSeq-large BLEU score 20.85 #77 of 91 Archive leaderboard report
Machine Translation WMT2014 English-German FlowSeq-base BLEU score 18.55 #83 of 91 Archive leaderboard report
Machine Translation WMT2014 German-English FlowSeq-large (NPD n = 30) BLEU score 28.29 #9 of 16 Archive leaderboard report
Machine Translation WMT2014 German-English FlowSeq-large (NPD n = 15) BLEU score 27.71 #10 of 16 Archive leaderboard report
Machine Translation WMT2014 German-English FlowSeq-large (IWD n=15) BLEU score 27.16 #11 of 16 Archive leaderboard report
Machine Translation WMT2014 German-English FlowSeq-large BLEU score 25.4 #13 of 16 Archive leaderboard report
Machine Translation WMT2014 German-English FlowSeq-base BLEU score 23.36 #14 of 16 Archive leaderboard report
Machine Translation WMT2016 English-Romanian FlowSeq-large (NPD n = 30) BLEU score 32.35 #3 of 21 Archive leaderboard report
Machine Translation WMT2016 English-Romanian FlowSeq-large (NPD n=15) BLEU score 31.97 #4 of 21 Archive leaderboard report
Machine Translation WMT2016 English-Romanian FlowSeq-large (IWD n = 15) BLEU score 31.08 #5 of 21 Archive leaderboard report
Machine Translation WMT2016 English-Romanian FlowSeq-large BLEU score 29.86 #8 of 21 Archive leaderboard report
Machine Translation WMT2016 English-Romanian FlowSeq-base BLEU score 29.26 #11 of 21 Archive leaderboard report
Machine Translation WMT2016 Romanian-English FlowSeq-large (NPD n = 30) BLEU score 32.91 #11 of 21 Archive leaderboard report
Machine Translation WMT2016 Romanian-English FlowSeq-large (NPD n = 15) BLEU score 32.46 #14 of 21 Archive leaderboard report
Machine Translation WMT2016 Romanian-English FlowSeq-large (IWD n = 15) BLEU score 32.03 #15 of 21 Archive leaderboard report
Machine Translation WMT2016 Romanian-English FlowSeq-large BLEU score 30.69 #18 of 21 Archive leaderboard report
Machine Translation WMT2016 Romanian-English FlowSeq-base BLEU score 30.16 #20 of 21 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

LSTMSeq2SeqSigmoid ActivationTanh Activation

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