Organizations: Division of Applied Mathematics Brown University Providence, RI, USA 02912 · Department of Statistical Sciences University of Toronto Toronto, ON, Canada M5G 1X6 · Sakana AI Tokyo, Japan
Diffusion models are highly developed in continuous spaces for image and video domains. Recently, major advances have been made for discrete diffusion models for categorical data, specifically in the language domain. In contrast, diffusion models for discrete integer-valued data are less developed, despite the prevalence of this modality, ranging from images and music to gene counts. We introduce Jumping Up and Down (JUD)---a new family of denoiser-based diffusion models for discrete ordinal data. This is the first family of diffusion models for ordinal data which centers around training denoisers, which at the same time allows for bi-directional (up and down) perturbations of the data. The simplicity of the training objective, combined with the flexibility of bi-directional perturbations, leads us to obtain competitive results across different data modalities.
Figures & tables
Binomial–Poisson (ours)
Count Bridge ( Fishman et al., 2026 )
Binomial ( Shenfeld et al., 2026 )
Count Flow ( Wei & Pearson, 2026 )
Poisson
SEDD ( Lou et al., 2024 )
Figure 1: Sample paths for several noising processes in discrete diffusion models and the resulting histogram of generated samples (blue) relative to the true data distribution (black) Negative Binomial Mixture . We observe closest agreement in W1 distance to the data with the Binomial-Poisson process proposed in this work. See Appendix F for details.
Binomial-only
Binomial-Poisson
Poisson-Poisson
Count Bridges
count-FM
SEDD
Distribution
Shenfeld et al. (2026)
(Ours)
(Ours)
Fishman et al. (2026)
Wei & Pearson (2026)
Lou et al. (2024)
Poisson
0.31±
0.05
0.13 ±
0.02
0.35±
0.02
0.22±
0.02
0.28±
0.06
0.46±
0.08
Poisson Mixture
1.52±
0.21
1.39 ±
0.30
89.71±
0.34
1.69±
0.34
1.68±
0.41
1.96±
0.33
Zero-Inflated Poisson
0.20±
0.03
0.12 ±
0.01
0.32±
0.02
0.16±
0.03
0.33±
0.06
0.53±
0.08
Negative Binomial Mixture
1.68±
0.23
1.62 ±
0.56
17.73±
0.41
1.80±
0.74
2.45±
0.46
2.35±
0.33
Beta Negative Binomial
0.87±
0.07
0.65 ±
0.06
6.14±
0.14
0.73±
0.07
1.52±
0.14
2.57±
0.14
Table 1: Wasserstein-1 distance across distributions and sampling methods (mean ± std). Our process is denoted in bold and the best results are highlighted in orange.
Figure 2: Target dataset and the generated samples using the Binomial-Poisson process for all eight synthetic distributions.
Table 4
Method
Accuracy (%) ↑
Autoregressive models
AR (sampled)
0.6
AR (greedy)
1.0
Discrete diffusion models
MDLM
30.2
Duo
58.4
Table 3: Hard Sudoku exact-board accuracy. Baselines are from Table 1 of Deschenaux & Gulcehre (2026) . Our scores are means (not best) over eight independent training runs.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
cin(σ)
vY(σ)1
sin(σ)
−vY(σ)μY(σ)
cskip(σ)
vY(σ)covA,Y(σ)
cbias(σ)
μA(σ)−cskip(σ)μY(σ)
C(σ)
vA(σ)−vY(σ)covA,Y2(σ)
cout(σ)
C(σ)
w2(σ)
C(σ)1
Appendix
Table 4: EDM scalings for target Aσ and input Yσ .
Target At
μA(t)
vA(t)
covA,Y(t)=Cov(Ati,Yti)
Bt
ltμ
VB(t)
VB(t)
xdata
μ
v
ltv
Nt
ut
ut
ut
Lt
(1−lt)μ
VL(t)
lt(1−lt)(v−μ)
Appendix
Table 5: Moments of the regression targets for the Binomial-Poisson perturbation Xt=Bt+Nt .
Target At
μA(t)
vA(t)
covA,Y(t)=Cov(Ati,Yti)
Ut
ut
ut
ut
Dt
lt
lt
−lt
Appendix
Table 6: Moments of the regression targets for the Poisson-Poisson perturbation Yt=xdata−Dt+Ut .
Method
Reference distribution
Binomial-Poisson
Poisson(20)
Binomial ( Shenfeld et al., 2026 )
δ0
Poisson
Poisson(196)
Count Bridge ( Fishman et al., 2026 )
Skellam(20,20)
Count Flow ( Wei & Pearson, 2026 )
Unif{0,…,149}
SEDD ( Lou et al., 2024 )
Unif{0,…,149}
Appendix
Table 7: Reference distributions used by different methods.
Sampler
256
512
1024
2048
Euler
7.07
2.22
2.15
2.09
tau-leaping
3.27
2.29
2.11
2.07
tau-leaping + marginal-preserving rates
5.46
2.95
2.34
2.20
Appendix
Table 8: CIFAR-10 FID at different numbers of sampling steps (NFE).
Massachusetts Institute of Technology (MIT), Cambridge, MA, USA · Laboratory for Information and Decision Systems (LIDS), MIT, Cambridge, MA, USA · Eric and Wendy Schmidt Center, Broad Institute, Cambridge, MA, USA +1