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Writing study: Mean Flow Policy with Instantaneous Velocity Constraint for One-step Action Generation

← ICLR 2026 oral writing corpus

Guojian Zhan, Letian Tao, Pengcheng Wang, Yixiao Wang, Yuxin Chen, Yiheng Li, Hongyang Li, Masayoshi Tomizuka, Shengbo Li · 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
23 physical pages
Before references / appendix
≈ 9.83 page-equivalents
Main figures / tables
5 / 3
Attached appendix figures / tables
3 / 3
Attached appendix span
≈ 9.89 page-equivalents
Before references / appendix: ≈ 42.74%References / intervening material: ≈ 14.26%Attached appendix: ≈ 43%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 INTRODUCTION1≈ 1.06 pp.4.61%
2 PRELIMINARIES2≈ 0.89 pp.3.87%
3 METHOD3≈ 3.31 pp.14.39%
4 EXPERIMENTS6≈ 3.01 pp.13.09%
5 RELATED WORK9≈ 0.74 pp.3.22%
6 CONCLUSION10≈ 0.19 pp.0.83%
7 ACKNOWLEDGMENT10≈ 0.08 pp.0.35%
REFERENCES10≈ 3.27 pp.14.22%
A THEORETICAL ANALYSIS ON THE MEAN VELOCITY POLICY IMPROVEMENT14≈ 4.12 pp.17.91%
B SUPPLEMENTARY RESULTS18≈ 0.29 pp.1.26%
C ENVIRONMENTS DESCRIPTION18≈ 1.59 pp.6.91%
D VISUALIZATIONS20≈ 1.71 pp.7.43%
E REPRODUCIBILITY STATEMENT21≈ 1.29 pp.5.61%
F LLM USAGE DISCLOSURE23≈ 0.89 pp.3.87%
All detected figure and table locations

Argument and organization

  1. Introduction / Preliminaries

    Connects repeated action-generation cost to flow and RL definitions.

  2. Mean velocity policy / Instantaneous constraint

    Separates imitating a target from selecting a useful target, then motivates a boundary constraint.

  3. Mean flow RL / Experiments

    Combines the pieces in pseudocode before testing success, ablations and timing.

  4. Appendices A–F

    Provides assumptions, numerical ablations, task descriptions, training settings and disclosure.

Problem, claim and contribution

The opening converts a practical control bottleneck into a specific question: whether expressive action distributions require repeated numerical integration. The proposed answer concerns a mean-velocity policy, rather than treating all generative policies as inherently slow.

§1, pp.1–2 · Main paper

Argument and section order

Two explicitly numbered questions separate how to imitate a target action from how to obtain that target. This prevents the reader from confusing the flow-fitting objective with the critic-guided best-of-N improvement procedure.

§3.1, pp.3–4 · Main paper

Figures, captions and visual explanation

Figure 2 uses interval arrows and tangent arrows to distinguish mean from instantaneous velocity. The training plots then retain common axes and mark offline versus online phases, helping readers connect algorithm phases to observed learning.

Figure 2, p.3; Figure 3, p.7 · Main paper

Tables, comparisons and evidence

The experiments isolate the added constraint, compare naive one-step variants and report success alongside training/inference cost. Table 3 importantly shows FQL slightly faster at inference, qualifying the prose's broad fastest-policy language.

§4.2, pp.8–9; Tables 2–3, p.9 · Main paper

Appendix and reproducibility

The proof explicitly states critic-error, smoothness and matching-error assumptions. The reproducibility table exposes best-of-N counts, one-million offline and online updates, and evaluation episodes, which are necessary to interpret the apparently one-step policy.

Appendix A, pp.14–18; Table 6, p.22 · Main paper

Clarity and writing conventions

The conclusion names JVP memory as a limitation and leaves physical-robot validation to future work. However, words such as guaranteed and significant need tighter qualification by approximation error and overlapping seed variability.

§3.3, p.6; §4.1, p.7; §6, p.10 · Main paper

What to reuse—and what not to infer

Transferable lesson: Separate target construction from target fitting; align each claimed mechanism with its own ablation, and report policy quality and deployment cost as independent outcomes.

Boundary: One-step generation still samples 16 or 32 candidates and scores them with a critic. Theorem 1 permits a negative improvement bound when fitting errors dominate. CPU timing disables JAX JIT and is not universal deployment latency. Main text reports the partial-IVC result as 0.45±0.15, whereas Table 4 gives 0.44±0.08; do not silently combine these. The main loss also reverses the stated time-order subscript.

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
PDF pp.1–10, §§1–7; references pp.10–13; page ranges verified with page-specific extraction because the first figure creates spurious form-feed characters
Appendix / supplement
PDF pp.14–23, Appendices A–F, including policy-improvement proof, all ablations, environment definitions, visual trajectories and hyperparameters
Visually inspected PDF pages
3, 8, 9