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GravOpt — Adaptive MAX-CUT Meta-Engine

95.91% of best-known solutions on Gset · G81 (20,000 nodes) · under 5 minutes · CPU only · <80 MB RAM

DOI License: MIT

An adaptive local-search selector for the MAX-CUT problem. The Meta-Engine chooses perturbation intensity (1%, 3%, or 10% vertex flips) based on current solution quality, reaching near-best-known cuts on large sparse graphs using only commodity CPU hardware.


Empirical observation: a perturbation-regime transition

Using the Meta-Engine, we observe that the optimal perturbation operation changes sharply near a threshold of solution quality: T_empirical = 0.950 ± 0.001 (255 measurements, 6 topologies, 5 sizes) This threshold is stable across graph topology and size. We note that it falls numerically close to the Håstad inapproximability bound 16/17 ≈ 0.9412 (Δ = 0.009), but our size-convergence test shows T_emp does not converge to 16/17 as n grows (slope ≈ -6e-8) — they appear to be distinct phenomena, not a single underlying constant. We make no claim of a proven connection; this is an empirical observation inviting theoretical investigation.


Results on the Gset benchmark

Graph Vertices Cut % of Best-Known Time
G62 7,000 4,656 95.61% 2 min
G66 9,000 6,076 95.47% 2 min
G67 10,000 6,664 96.02% 2 min
G70* 10,000 9,347 97.97% 2 min
G72 10,000 6,690 95.46% 2 min
G77 14,000 9,476 95.33% 3 min
G81 20,000 13,428 95.50% 5 min
Mean 95.91% <5 min

All results: single CPU core · <80 MB RAM · no GPU · fixed thresholds T₁ = 0.85, T₂ = 0.92, no graph-specific tuning.

*G70 is a near-tree instance (|E| ≈ |V|−1) and behaves differently; see preprint.


Honest comparison

Algorithm % of Best-Known Time Hardware
Cosm (Zick, 2025) 100% specialized CMOS
BLS (Benlic & Hao, 2013) 99.8% up to 5.6 h CPU
GravOpt Meta-Engine 95.5% 5 min standard CPU
Fixed Perturb-10% 91.3% 2 min CPU

GravOpt does not beat state-of-the-art solvers on solution quality. Its value is reaching ~96% of best-known quickly on commodity hardware with no tuning — a practical trade-off, not a record.


Meta-Engine logic

quality < 85% → perturb 10% + local search (coarse)

quality 85–92% → perturb 3% + local search (medium)

quality > 92% → perturb 1% + local search (fine) This gives +4.39% over a fixed Perturb-10% strategy under equal time budget.


Quick start

pip install numpy numba
python meta_engine.py G81.txt run 300
python threshold_discovery.py

Repository structure

meta_engine.py Adaptive Meta-Engine (main solver)

threshold_discovery.py Perturbation-regime threshold measurement

vlsi_bipartition.py Experimental: VLSI partitioning trial

GravOpt_Demo.ipynb Interactive demo notebook

Reproducibility

All benchmark data, seeds, and code are in the Zenodo record:

  • Zenodo: doi.org/YOUR_CANONICAL_DOI
  • 255 measurements across 9 conditions
  • Seeds: [1, 2, 3, 4, 5]; sizes: [500, 1000, 2000, 5000, 10000]

Preprint (not peer-reviewed): Research Square, DOI 10.21203/rs.3.rs-9763617/v1


License

MIT License — free for research and commercial use with attribution.


Citation

@misc{kretski2026maxcut,
  author = {Kretski, Dimitar Vasilev},
  title  = {An Empirical Perturbation-Regime Transition in MAX-CUT
            Local Search: Evidence from a Multi-Topology Benchmark},
  year   = {2026},
  doi    = {YOUR_CANONICAL_DOI},
  note   = {Preprint, Research Square}
}

Independent research · Varna, Bulgaria · kretski1@gmail.com