Adaptive Rotation for iSOMA: Geometry, Benchmarking, and Noise Robustness in Variational Quantum Objectives
Organizations: Department of Computer Science, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, Ostrava, Czech Republic. · IT4Innovations National Supercomputing Center, VSB-Technical University of Ostrava, Ostrava, 708 00, Czech Republic. · Department of Informatics and Statistics, Marine Research Institute, Klaipeda University, Klaipeda, Lithuania.
Abstract
We study whether the coordinate dependence of the improved Self-Organizing Migrating Algorithm (iSOMA) can be reduced while retaining its inexpensive leader-directed migration mechanism. We introduce iSOMA-AR, which learns a basis from successful migration displacements and selectively applies the standard perturbation mask in that basis. On the complete noiseless BBOB suite, iSOMA- AR significantly outperformed baseline iSOMA across matched conditions, with the largest gains on geometrically difficult landscapes. A targeted ablation shows that the learned orientation is beneficial on a rotated ill-conditioned landscape and that moderate changes of the gate threshold and rotation cap preserve the qualitative result. On CEC 2011 Real World Optimization Problems, iSOMA-AR outperformed iL-SHADE on most problems, although its advantage over baseline iSOMA was not statistically significant. A canonical-jSO rerun is reported as a post-hoc sensitivity check alongside the original jSO-derived comparator. On frustrated-spin variational quantum objectives, adaptive rotation improved most transverse-field conditions, while gains on the diagonal and anisotropic models were absent or selective. Under strong effective sampling noise, the SOMA variants were the most robust population-based methods in the comparison, but iSOMA-AR was not significantly better than baseline iSOMA. Repairing all-zero PRT masks greatly reduced repeated-point evaluations without changing endpoint quality significantly, making this implementation detail unlikely to explain the noise result. Overall, adaptive rotation is most useful on coordinate-sensitive deterministic problems, while the observed noise robustness appears to arise mainly from the underlying SOMA migration mechanism.
Figures & tables
| BBOB | CEC 2011 real-world | |
| Problems | noiseless functions | real-world problems |
| Dimensions | problem-specific ( – ) | |
| Instances | – | fixed problem definitions |
| FE budgets | ||
| Stochastic runs | / condition | / problem |
| Primary optimizers | iSOMA, iSOMA-AR, jSO-derived, iL-SHADE, CMA-ES | |
| Algorithm | Mean rank | Top-1 | Target-hit frac. | Success | Med. FE/D to | s/1000 FE |
|---|---|---|---|---|---|---|
| jSO-derived | 1.86 | 49.9% | 65.4% | 48.9% | 1073 | 0.0279 |
| CMA-ES | 2.49 | 51.0% | 55.1% | 44.4% | 417 | 0.0676 |
| iL-SHADE | 3.13 | 16.9% | 35.8% | 15.0% | 552 | 0.0334 |
| iSOMA-AR | 3.46 | 10.6% | 36.4% | 15.5% | 1212 | 0.0204 |
| iSOMA | 4.05 | 8.3% | 29.5% | 12.2% | 1154 | 0.0182 |
| Group | Most frequent condition winner | AR/base W/T/L | AR/base ratio | AR/iL-SHADE W/T/L | AR/iL-SHADE ratio |
|---|---|---|---|---|---|
| G1 separable | jSO-derived 115/150 | 84/39/27 | 0.93 | 71/33/46 | 1.00 |
| G2 low/moderate conditioning | CMA-ES 90/120 | 99/0/21 | 0.55 | 45/0/75 | 1.32 |
| G3 high-conditioning unimodal | CMA-ES 131/150 | 137/0/13 | 0.45 | 45/0/105 | 2.53 |
| G4 multimodal, adequate structure | jSO-derived 80/150 | 100/0/50 | 0.90 | 21/0/129 | 2.44 |
| G5 multimodal, weak structure | jSO-derived 67/150 | 87/3/60 | 0.99 | 69/3/78 | 1.01 |
| Algorithm | Mean rank | Top-1 | Target-hit frac. | Success | Success | s/1000 FE |
|---|---|---|---|---|---|---|
| jSO-derived | 1.50 | 77.3% | 63.1% | 59.5% | 29.1% | 0.0202 |
| CMA-ES | 2.77 | 18.2% | 48.6% | 45.5% | 7.7% | 0.0834 |
| iSOMA-AR | 3.27 | 13.6% | 42.0% | 33.2% | 11.8% | 0.0193 |
| iSOMA | 3.41 | 9.1% | 43.2% | 34.1% | 12.3% | 0.0110 |
| iL-SHADE | 4.05 | 9.1% | 18.3% | 11.4% | 6.8% | 0.0224 |
| Group | Most frequent problem winner | AR/base W/T/L | AR/base ratio | AR/iL-SHADE W/T/L | AR/iL-SHADE ratio |
|---|---|---|---|---|---|
| A1 control / parameter estimation | jSO-derived 3/3 | 0/2/1 | 1 | 1/2/0 | 1 |
| A2 molecular / material potentials | jSO-derived 3/3 | 0/0/3 | 1.3 | 1/0/2 | 1.9 |
| A3 signal / antenna design | CMA-ES 1/2, iL-SHADE 1/2 | 2/0/0 | 0.97 | 0/0/2 | 4.9 |
| A4 power systems | jSO-derived 10/12 | 8/1/3 | 0.87 | 10/0/2 | 0.0002 |
| A5 spacecraft trajectory | iSOMA-AR 1/2, jSO-derived 1/2 | 1/0/1 | 0.88 | 2/0/0 | 0.038 |
| Study | Comparison | W/T/L | Median ratio | |
|---|---|---|---|---|
| BBOB | iSOMA-AR / iSOMA | 507/42/171 | 0.814 | 1.34e-50 |
| BBOB | iSOMA-AR / iL-SHADE | 251/36/433 | 1.35 | 8.44e-12 |
| BBOB | iSOMA-AR / CMA-ES | 198/46/476 | 2.78 | 2.34e-45 |
| BBOB | iSOMA-AR / jSO-derived | 58/54/608 | 22 | 1.91e-101 |
| BBOB | jSO-derived / CMA-ES | 310/115/295 | 1 | 0.99 |
| CEC2011 | iSOMA-AR / iSOMA | 11/3/8 | 0.99 | 0.338 |
| Model | Condition | iSOMA | iSOMA-AR | AR/base | Best core method |
|---|---|---|---|---|---|
| Q1 | , 10k | 9.708 | jSO-derived | ||
| Q1 | , 30k | 0 | – | iSOMA | |
| Q1 | , 10k | 7.360 | jSO-derived | ||
| Q1 | , 30k | 0 | 0 | – | iSOMA |
| Q1 | , 10k | 0.458 | 0.458 | 1.000 | iSOMA |
| Q1 | , 30k | 0.458 | 0.458 | 1.000 | jSO-derived |
| Noise | Model | Budget | iSOMA | iSOMA-AR | jSO-derived | iL-SHADE | CMA-ES | SPSA |
|---|---|---|---|---|---|---|---|---|
| Low | Q1 | 10k | 0.066 | 0.087 | 0.115 | 0.177 | 1.712 | 2.022 |
| Low | Q1 | 30k | 0.062 | 0.080 | 0.083 | 0.158 | 1.755 | 2.017 |
| Low | Q2 | 10k | 0.317 | 0.308 | 0.374 | 0.446 | 0.342 | 0.587 |
| Low | Q2 | 30k | 0.319 | 0.316 | 0.260 | 0.272 | 0.322 | 0.203 |
| Low | Q3 | 10k | 1.928 | 1.927 | 3.689 | 1.555 | 1.382 | 0.356 |
| Low | Q3 | 30k | 1.907 | 1.910 | 1.960 | 1.244 | 1.216 | 0.166 |
Appendix figures & tables13 assets
Supplementary material from the paper’s appendix.
Appendix
| Method | Role / implementation | Settings used | Notes |
|---|---|---|---|
| iSOMA | Baseline SOMA used in all three benchmark families. | Pop ; ; Step ; , , ; masks regenerated every proposal; ; path ; first non-worsening proposal accepted; box clipping; 10% pop reinitialization after failed attempts without global best improvement. | FE budget is effective stopping rule. BBOB/CEC driver uses nonbinding migration cap of ; VQE wrapper uses . |
| iSOMA-AR | Proposed variant; identical baseline selection, path, repair, and acceptance with occasional rotated masking. | All iSOMA settings above plus , success update scale (cap ), eigenspace update every 5 accepted improving steps, ridge , min. successful-step count , off-axis threshold , max rotation probability . | No extra FEs spent on basis learning. Covariance memory and rotation gate reset at baseline stagnation restart. |
| jSO-derived | Fixed custom DE used throughout BBOB/CEC and VQE comparison. | , linear reduction to ; ; , ; Cauchy (scale ), Gaussian ( ); decreases linearly ; external archive with pop capacity; binomial crossover; clipping repair; improvement-weighted memory. | Trial mutation: . Reported as jSO-derived ; specific differences are listed below. |
| jSO-canonical | Post-hoc BBOB/CEC implementation-sensitivity comparator following the published jSO/iL-SHADE mechanisms. | , linear reduction to ; ; , with the special final memory entry; ; early lower bounds and cap; weighted current-to- best mutation; external archive; midpoint-to-parent bound repair. | Uses the paper-prose schedule. Run on the complete BBOB and CEC 2011 grids as a sensitivity comparator; VQE uses jSO-derived. |
| iL-SHADE | Standardized adaptive-DE reference through PyADE. | pyade.ilshade.get_default_params(D) with pop size , explicit box bounds, supplied replicate seed, and max_evals . All other settings are package defaults. | No internal fallback results are included in reported experiments. |
| CMA-ES | Covariance-adaptation reference. | BBOB/CEC: pycma , uniform , , maxfevals , box bounds, supplied seed. VQE: fixed wrapper with , , tolx = tolfun = , generation cap . | Objective-level FE guard enforces VQE budget if internal termination occurs later. |
| Algorithm | BBOB s/1000 FE | vs base | CEC s/1000 FE | vs base |
|---|---|---|---|---|
| iSOMA | 0.0182 | 1.00 | 0.0110 | 1.00 |
| iSOMA-AR | 0.0204 | 1.12 | 0.0193 | 1.75 |
| jSO-derived | 0.0279 | 1.54 | 0.0202 | 1.83 |
| jSO-canonical † | 0.0304 | 1.67 | 0.0253 | 2.30 |
| iL-SHADE | 0.0334 | 1.84 | 0.0224 | 2.03 |
| CMA-ES | 0.0676 | 3.72 | 0.0834 | 7.55 |
| Problem | Control / default AR | W/T/L | Median ratio | Wilcoxon | AR rotation frac. |
|---|---|---|---|---|---|
| Ellipsoid (axis-aligned) | random basis / AR default | 10/0/15 | 1.41 | 0.692 | 7.4% |
| Ellipsoid (axis-aligned) | iSOMA / AR default | 7/0/18 | 12.74 | 0.0451 | 7.4% |
| Ellipsoid (rotated) | random basis / AR default | 3/0/22 | 3.16 | 22.5% | |
| Ellipsoid (rotated) | iSOMA / AR default | 6/0/19 | 4.33 | 22.5% | |
| Rastrigin (axis-aligned) | random basis / AR default | 11/0/14 | 1.00 | 0.874 | 12.4% |
| Rastrigin (axis-aligned) | iSOMA / AR default | 14/0/11 | 0.90 | 0.491 | 12.4% |
| Problem | Variant | W/T/L | Median ratio | Wilcoxon |
|---|---|---|---|---|
| Ellipsoid (axis-aligned) | AR | 11/0/14 | 2.85 | 0.23 |
| Ellipsoid (axis-aligned) | AR | 13/0/12 | 0.79 | 0.916 |
| Ellipsoid (axis-aligned) | AR | 15/0/10 | 0.45 | 0.474 |
| Ellipsoid (axis-aligned) | AR | 9/0/16 | 8.51 | 0.21 |
| Ellipsoid (rotated) | AR | 6/0/19 | 1.98 | 0.0125 |
| Ellipsoid (rotated) | AR | 12/0/13 | 1.07 | 0.23 |
| Function | base W/T/L | base/AR | random W/T/L | random/AR | ||
|---|---|---|---|---|---|---|
| 6/0/14 | 6.88 | 0.0973 | 14/0/6 | 0.05 | 0.0637 | |
| 10/0/10 | 1.00 | 0.784 | 10/0/10 | 1.00 | 0.898 | |
| 4/0/16 | 3.53 | 0.00639 | 8/0/12 | 1.79 | 0.245 | |
| 4/0/16 | 1.41 | 0.00365 | 3/0/17 | 1.67 | ||
| 4/0/16 | 1.94 | 0.00315 | 4/0/16 | 3.01 | 0.00315 | |
| 6/0/14 | 1.37 | 0.114 | 11/0/9 | 0.84 | 0.596 |
| Model | Algorithm | FE | W/T/L | Error ratio | Wilcoxon | Same-point allowed | Same-point repaired |
|---|---|---|---|---|---|---|---|
| Q1 | iSOMA | 10k | 14/0/11 | 0.90 | 0.833 | 2.34% | 0.50% |
| Q1 | iSOMA | 30k | 15/0/10 | 0.88 | 0.596 | 2.71% | 0.92% |
| Q2 | iSOMA | 10k | 10/0/15 | 1.18 | 0.396 | 0.49% | 0.46% |
| Q2 | iSOMA | 30k | 9/0/16 | 1.15 | 0.252 | 0.91% | 0.40% |
| Q1 | iSOMA-AR | 10k | 14/0/11 | 0.82 | 0.672 | 2.26% | 0.37% |
| Q1 | iSOMA-AR | 30k | 14/0/11 | 0.96 | 0.833 | 2.56% | 0.53% |
| Study | Algorithm | Mean rank | Top-1 | All targets | Tight target | Tight runtime |
| BBOB | jSO-derived | 2.00 | 46.8% | 65.4% | 48.8% | |
| BBOB | jSO-canonical | 3.33 | 18.6% | 57.8% | 36.8% | |
| Direct derived/canonical: 557/104/59 W/T/L; median error ratio 0.48; Wilcoxon 6.32\text{\times}{10}^{-79}$$ . | ||||||
| CEC 2011 | jSO-derived | 1.77 | 63.6% | 62.9% | 29.1% | 0.504 |
| CEC 2011 | jSO-canonical | 2.73 | 27.3% | 56.7% | 23.6% | 0.222 |
| Direct derived/canonical: 15/2/5 W/T/L; median regret ratio 0.47; Wilcoxon . | ||||||
| Group | Frequent winner | AR/base W/T/L | AR/base ratio | AR/iLS W/T/L | AR/iLS ratio |
|---|---|---|---|---|---|
| C1 ill-conditioned / anisotropic | CMA-ES 137/210 | 186/2/22 | 0.49 | 60/2/148 | 2.72 |
| C2 valley / ridge path-following | CMA-ES 122/150 | 109/0/41 | 0.80 | 35/0/115 | 1.76 |
| C3 structured multimodality | jSO-derived 125/210 | 138/0/72 | 0.91 | 80/0/130 | 1.42 |
| C4 basin selection / weak structure | jSO-derived 60/120 | 72/3/45 | 0.99 | 65/3/52 | 0.92 |
| C5 plateau / nonsmooth / rugged | jSO-derived 48/120 | 83/0/37 | 0.86 | 24/0/96 | 1.67 |
| C6 asymmetry / deception | CMA-ES 42/90 | 63/0/27 | 0.92 | 39/0/51 | 1.37 |
| Function | Landscape feature | Frequent winner | AR/base | AR/iLS | jSO-derived/CMA | |
|---|---|---|---|---|---|---|
| 1 | Sphere | smooth, isotropic, unimodal | CMA-ES 30/30 | 19/9/2 | 1/10/19 | 0/20/10 |
| 2 | Ellipsoidal (sep.) | separable; unimodal; | CMA-ES 25/30 | 27/0/3 | 4/0/26 | 5/15/10 |
| 3 | Rastrigin (sep.) | separable; regular multimodality; optima | jSO-derived 23/30 | 22/0/8 | 29/0/1 | 28/0/2 |
| 4 | Bueche–Rastrigin | asymmetric/deceptive Rastrigin; optima | jSO-derived 22/30 | 16/0/14 | 30/0/0 | 29/0/1 |
| 5 | Linear Slope | linear; optimum at domain boundary | 4-way tie (30/30) | 0/30/0 | 7/23/0 | 0/30/0 |
| 6 | Attractive Sector | strongly asymmetric unimodal | CMA-ES 30/30 | 29/0/1 | 9/0/21 | 0/10/20 |
| Problem | Application family | Frequent winner | AR/base | AR/iLS | jSO-derived/CMA | ||
|---|---|---|---|---|---|---|---|
| 1 | FM sound parameter estimation | A1 Control & param. | 6 | jSO-derived 1/1 | 0/0/1 | 1/0/0 | 1/0/0 |
| 2 | Lennard–Jones potential | A2 Materials | 30 | jSO-derived 1/1 | 0/0/1 | 0/0/1 | 1/0/0 |
| 3 † | Bifunctional catalyst opt. control | A1 Control & param. | 1 | All tied (1/1) | 0/1/0 | 0/1/0 | 0/1/0 |
| 4 † | Stirred-tank reactor opt. control | A1 Control & param. | 1 | jSO-derived 1/1 | 0/1/0 | 0/1/0 | 1/0/0 |
| 5 | Tersoff potential Si(B) | A2 Materials | 30 | jSO-derived 1/1 | 0/0/1 | 0/0/1 | 1/0/0 |
| 6 | Tersoff potential Si(C) | A2 Materials | 30 | jSO-derived 1/1 | 0/0/1 | 1/0/0 | 1/0/0 |
| Model | Condition | iSOMA median | AR median | Effect | |
| Q1 | , 10k | 0.886 | -0.136 | ||
| Q1 | , 30k | 0 | 0.005 | -0.485 | |
| Q1 | , 10k | 0.159 | -0.341 | ||
| Q1 | , 30k | 0 | 0 | 1.000 | -0.110 |
| Q1 | , 10k | 0.458 | 0.458 | 1.000 | 0.014 |
| Q1 | , 30k | 0.458 | 0.458 | 0.030 | -0.469 |
| (a) Condition-wise mean rank | (b) Median selection penalty | ||||
|---|---|---|---|---|---|
| Optimizer | Low noise | High noise | Low noise | High noise | |
| iSOMA | 3.00 | 2.17 | 0.034 | 0.313 | |
| iSOMA-AR | 3.00 | 1.83 | 0.046 | 0.381 | |
| jSO-derived | 4.00 | 3.67 | 0.069 | 0.620 | |
| iL-SHADE | 3.67 | 3.50 | 0.073 | 0.583 | |
| CMA-ES | 3.83 | 4.50 | 0.044 | 0.410 | |
| Model | Budget | iSOMA median | AR median | Effect | |
|---|---|---|---|---|---|
| High noise | |||||
| Q1 | 10k | 1.037 | 0.958 | 1.000 | 0.181 |
| Q1 | 30k | 0.719 | 0.649 | 1.000 | 0.034 |
| Q2 | 10k | 0.593 | 0.707 | 0.898 | -0.043 |
| Q2 | 30k | 0.433 | 0.522 | 0.664 | -0.162 |
| Q3 | 10k | 2.318 | 2.425 | 0.923 | 0.018 |