Inverse-Square Adaptive Parameter Reset
Implementation & benchmark of arXiv:2608.27090 — Localization Delocalization Transition in Diffusion with Adaptive Resetting
Source paper: Localization Delocalization Transition in Diffusion with Adaptive Resetting arXiv:2608.27090 ⓘ · analyzed Sep 1, 2026
AI-generated research hypothesis, automatically tested. Not peer-reviewed.
Idea description
Add a state-dependent stochastic reset to a neural-network parameter vector, optimizer state, or recurrent hidden state. The reset hazard is weak at large displacement but has the marginal inverse-square scaling that produces a predicted power-law excursion distribution and a sharp transition between localized training and runaway parameter drift.
Formulas
Mathematical statement
Approximate one scalar training excursion coordinate z by noisy diffusion dz = square root of 2D times dW, where D is effective minibatch-noise diffusivity and W is standard Brownian motion. Reset z to zero with hazard r(z) = r0 divided by z squared plus epsilon squared, where r0 is reset strength and epsilon prevents a singularity at the origin. Away from the reset point, the stationary Fokker-Planck equation is D times p double-prime minus r times p equals zero. For large absolute z, substituting p(z) proportional to |z| raised to minus beta gives beta times beta plus one equal to r0 divided by D. Therefore beta equals (square root of (1 + 4 r0/D) minus 1) divided by 2. The stationary distribution is normalizable only for beta greater than 1, equivalently r0/D greater than 2. The predicted delocalization boundary is therefore r0 = 2D. More generally, reset rates scaling as |z| raised to lambda produce stretched-exponential tails for lambda greater than -2, power-law tails at lambda equal to -2, and asymptotic nonlocalization for lambda less than -2.
Implementation notes
First, integrate the mechanism as an outer wrapper around SGD or Adam on a small model, resetting the full parameter vector to the best validation checkpoint. A safer first variant applies it only to optimizer momentum or to an RNN/SSM hidden state. Define the scalar excursion z = norm(theta - theta_ref), where theta_ref is the current reference checkpoint. After every optimizer update, compute the reset probability q = 1 - exp(-delta_t times r0 divided by (z squared plus epsilon squared)). Draw a uniform random number U; if U < q, restore theta to theta_ref and optionally set Adam moments to zero. Pseudocode is: compute minibatch gradient; perform baseline optimizer update; compute z; compute q; sample U; restore the checkpoint if U < q; otherwise continue. Keep theta_ref fixed initially, then test a version updated only after validation improvement. The paper supplies the inverse-square hazard, the power-law exponent, and the critical ratio r0/D = 2. Estimate D empirically from the covariance of parameter increments after subtracting their local mean drift: D approximately equals trace of the increment covariance divided by twice the step duration. The first cheap experiment should use a two-layer MLP on MNIST, comparing ordinary SGD, constant-rate checkpoint resets, and inverse-square resets across a grid of r0 values. Record excursion histograms, reset rates, validation loss, maximum excursion, and fitted tail exponent. The quantitative prediction is a transition near r0/D = 2: above it, excursions remain localized; below it, the complementary cumulative excursion distribution follows a power law with exponent approximately beta minus 1. The measured boundary should be within 20 percent of 2. As controls, a hazard proportional to z raised to minus 3 should fail to localize, while a hazard proportional to z raised to minus 1 should produce stretched-exponential rather than power-law tails.
Verification
Stage 1 · Toy mechanism gate: Failed ✗
Stage 2 · Mechanism transferred to benchmark: Not tested
Stage 2 · Practical benchmark result: Not run
Methodology: Toy-system gate first; the benchmark stage runs only after a pass. How verification works
Stage 1 — Mechanism check agent confidence 9/10
Built an inverse-square stochastic reset diffusion simulator, parameter sweeps, lambda controls, and a small SGD checkpoint-reset wrapper in experiment.py. The algebraic beta formula and critical ratio r0/D=2 are internally consistent, but measured tail exponents stayed near 4 across the sweep and did not track predicted beta values; the lambda classification was also not observed. The optimizer appeared better in one confounded sine-regression test, but this is not evidence for the proposed mechanism because it used online best-validation checkpoint restoration and an arbitrary hazard scale.
- Agent confidence
- 9/10
- Baseline
- SGD validation MSE 6.2002 on the small noisy sine-regression stress test
- Idea
- Inverse-square checkpoint-reset wrapper validation MSE 0.5158 with 353 resets; toy fitted density exponents approximately 3.90-4.70 for predicted beta values 0.366-2.372, with no confirmed transition near r0/D=2
Limitations: The diffusion experiment used shortened trajectories and a finite reflecting box after the initial timeout, so asymptotic tail estimation was noisy and finite-time effects may matter. No MNIST experiment, rigorous stationary-distribution solver, fair multi-seed optimizer benchmark, or empirical estimation of D from minibatch parameter increments was performed.
How to run: python3 experiment.py
Verdict computed by deterministic test code from paired-seed statistics — not by the language model.
Artifacts
- experiment.py 5.0 KB View Raw
- report.md 1.6 KB View
- results.json 3.8 KB View Raw