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Writing study: Half-order Fine-Tuning for Diffusion Model: A Recursive Likelihood Ratio Optimizer

← ICLR 2026 oral writing corpus

Tao Ren, Zishi Zhang, Jinyang Jiang, Zehao Li, Shentao Qin, Yi Zheng, Guanghao Li, Qianyou Sun, Yan Li, Jiafeng Liang, Xinping Li, Yijie Peng · Official ICLR 2026 oral record

Figure, table and section ledger

Editorial contribution type: Learning & optimization algorithms (primary) · Inference, algorithms & systems efficiency.

Layout extraction, not a required paper template. Counts are distinct caption labels; a multi-panel figure counts once. Section spans are estimated from heading positions, including floats and whitespace. Method and limitations.

Canonical PDF
27 physical pages
Before references / appendix
≈ 9.2 page-equivalents
Main figures / tables
6 / 5
Attached appendix figures / tables
5 / 5
Attached appendix span
≈ 12.89 page-equivalents
Before references / appendix: ≈ 34.07%References / intervening material: ≈ 18.19%Attached appendix: ≈ 47.74%Estimated layout envelopes, not text/artwork area. Unresolved appendix boundaries remain within the undivided post-body material.
Section-by-section lengths and source pages

The title/abstract/front matter precede the first numbered heading. A span ends at the next detected top-level heading, not at the last sentence; end-page whitespace is included. References and statements are listed separately. These are not measurements of text-only or artwork area.

Top-level headingStarts on PDF pageEstimated spanShare of entire PDF
1 INTRODUCTION2≈ 1.36 pp.5.04%
2 RELATED WORK3≈ 0.2 pp.0.74%
3 UNBIASED MINIMAL VARIANCE GRADIENT ESTIMATOR FOR DIFFUSION3≈ 1.14 pp.4.22%
4 SOLVING THE VARIANCE MINIMIZATION PROBLEM: RECURSIVE4≈ 1.57 pp.5.81%
5 EXPERIMENTS6≈ 2.3 pp.8.52%
6 THEORETICAL PROPERTIES OF GRADIENT ESTIMATORS: BIAS, VARIANCE,8≈ 1.08 pp.4%
7 CONCLUSION9≈ 0.34 pp.1.26%
ACKNOWLEDGMENTS10≈ 0.09 pp.0.33%
REFERENCES10≈ 4.91 pp.18.19%
A EXTENDED RELATED WORKS15≈ 0.49 pp.1.81%
B EXPERIMENTS SETTINGS15≈ 2.11 pp.7.81%
C HYPEPARAMETERS17≈ 0.41 pp.1.52%
D QUALITATIVE RESULTS OF TEXT2IMAGE18≈ 1 pp.3.7%
E QUALITATIVE RESULTS OF TEXT2VIDEO19≈ 1 pp.3.7%
F DETAILS FOR DIFFUSIVE CHAIN-OF-THOUGHT EXPERIMENT20≈ 1.3 pp.4.81%
G MEMORY PROFILE, TIME COMPLEXITY, AND DIFFERENT DIFFUSION21≈ 0.89 pp.3.3%
H ABLATIONS ON THE SUB-CHAIN LENGTH h22≈ 0.35 pp.1.3%
I MORE RESULTS ON VBENCH22≈ 0.87 pp.3.22%
J PROOFS23≈ 4.49 pp.16.63%
All detected figure and table locations

Argument and organization

  1. Estimator design space

    Explains the memory–bias–variance tradeoff before introducing the hybrid estimator.

  2. RLR and diffusion experiments

    Pairs local-gradient design with image/video reward experiments and a restricted prompt-decomposition demonstration.

  3. Theory and implementation appendix

    Separates regularity assumptions, estimator proofs, memory/time accounting and sampler settings.

Problem, claim and contribution

The opening compares full differentiation, truncated differentiation and policy gradients as competing resource tradeoffs; this gives the hybrid design an intelligible motivation before its equations.

Sections 1 and 3, pages 1–4 · Main paper

Argument and section order

The paper first defines the recursive generation process, then narrows a large estimator design space to a local half-order subchain plus zeroth-order and direct terms.

Sections 3–4, pages 3–5 · Main paper

Figures, captions and visual explanation

Figure 4 overlays a symbolic denoising chain and image examples, using separate arrows for forward computation, perturbation and differentiation. The legend makes the three gradient-estimation regions readable.

Figure 4, page 3 · Main paper

Tables, comparisons and evidence

The appendix distinguishes per-step speed from time to reach a common aesthetic score and reports host RAM separately from GPU memory. Those are more informative comparisons than an isolated memory-saving percentage.

Appendix G, Tables 6–7, page 21 · Main paper

Appendix and reproducibility

A contents page routes readers to hyperparameters, prompt templates, qualitative samples, solver checks, subchain ablations and proofs. The same-score timing and longer-subchain costs belong near the main efficiency claim.

Appendix contents page 14; Appendices C and G–J · Main paper

Clarity and writing conventions

Some theoretical statements need narrower wording: the perturbation proof concerns its explicitly randomized process, and the variance appendix's claim that the direct term has zero variance is not a general consequence of having no injected parameter noise.

Appendix J.3–J.4, pages 24–26 · Main paper

What to reuse—and what not to infer

Transferable lesson: Make an optimizer's tradeoff concrete with one computation-graph legend and a table separating peak device memory, host memory, step time and time to a common target.

Boundary: Do not repeat an unconditional minimum-variance or unbiased-for-the-unperturbed-model claim. The proof uses a perturbed recursion, regularity assumptions and a restricted estimator construction; automatic reward gains are not a human preference study.

Apply this lesson using the argument and evidence worksheet.

Inspection record and sources

Checked
2026-09-19
Reading status
Full text + selected visuals inspected
Main text
Pages 1–9, Sections 1–7; reference list on pages 10–13 checked for source organization
Appendix / supplement
Pages 14–27, contents and Appendices A–J including all proof and resource tables
Visually inspected PDF pages
3, 21