Files
heuropt/examples/compare-results.md
T
swaitsandClaude Opus 4.7 2b453464e7 refactor(compare): realign + sort tables, add combinatorial problems
The terminal output was misaligned: headers and data were right-aligned
with hardcoded column widths and separator lengths, and the mean ± std
cells contained the non-ASCII `±` (plus `ε`, `↑`, `↓`) -- on any terminal
that renders those at a non-1 column width the columns drift, and the
hardcoded `-`.repeat(n) separators didn't match the real table width
anyway.

Changes:
- New `print_table` helper: column widths derived from the actual cell
  contents (header + every row), separator length computed to match.
- All table cells are now ASCII: `+/-` instead of `±`, `eps-MOEA`
  instead of `ε-MOEA`, arrows dropped from headers.
- Every table is sorted best-first by its primary quality metric.
- Added three combinatorial / sequencing problems with their own
  (permutation- / bitstring-native) algorithm rosters: a convex-position
  ring TSP (known optimum), FT06 job-shop makespan (known optimum 55),
  and a bi-objective 0/1 knapsack scored by hypervolume.
- Expanded every problem's preamble: what it is, why it's hard, and the
  best-known / optimal result.
- Regenerated examples/compare-results.md to match.

Continuous-problem quality metrics are unchanged (bit-identical to prior
snapshots); only ms columns and row order move.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-14 07:51:12 -06:00

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# `compare` example — reference output
Snapshot from `cargo run --release --example compare`, refreshed 2026-05-14
for heuropt v0.10.0. 10 seeds per algorithm per problem.
Each table is **sorted best-first** by its primary quality metric. The
live terminal output uses ASCII `+/-` for the mean ± std cells (so column
alignment can't be broken by a terminal that renders `±` at an odd
width); this doc uses `±` since markdown renders it fine.
The **continuous-problem quality metrics** are bit-identical to the
v0.3.0v0.4.0 snapshots — every optimization pass so far (including the
Phase B CPU work) has been verified bit-identical by the `run()` snapshot
tests. The **ms columns** are the post-Phase-B numbers; SMS-EMOA on DTLZ2
in particular fell ~2.7× from the `hypervolume_nd` rework.
This refresh also adds three **combinatorial / sequencing** problems —
TSP, job-shop scheduling, and a bi-objective knapsack — which exercise the
permutation and bitstring operators and a different algorithm roster (the
real-vector methods can't run them).
Wall-clock numbers are from the development machine and will vary; the
*relative* numbers across algorithms are the interesting part.
---
## ZDT1 (dim=30, 25000 evals/run × 10 seeds)
Zitzler-Deb-Thiele 2-objective benchmark: 30 real variables, one smooth
convex Pareto front `f₂ = 1 √f₁`. Hard because 29 of 30 variables must
collapse to 0 before the front is even reachable, and only then can the
population spread along it. Optimum: mean L2 → 0 (the front is known
exactly). Sorted by hypervolume (reference `[11, 11]`).
| algorithm | hypervolume ↑ | spacing ↓ | mean L2 ↓ | front | ms |
|---|---|---|---|---|---|
| MOPSO | **120.6149 ± 0.0529** | 0.0125 ± 0.0025 | **0.0005 ± 0.0001** | 100 | 80 |
| IBEA | 120.0167 ± 0.3112 | 0.0130 ± 0.0027 | 0.0448 ± 0.0168 | 73 | 130 |
| MOEA/D | 119.9450 ± 0.4953 | 0.0118 ± 0.0013 | 0.0065 ± 0.0020 | 96 | 27 |
| PESA-II | 119.3670 ± 0.3261 | **0.0095 ± 0.0011** | 0.0802 ± 0.0354 | 100 | 67 |
| eps-MOEA | 118.8742 ± 0.6835 | 0.0167 ± 0.0058 | 0.0493 ± 0.0227 | 45 | 46 |
| NSGA-II | 118.3336 ± 0.7750 | 0.0112 ± 0.0022 | 0.1891 ± 0.0599 | 96 | 40 |
| SPEA2 | 118.0823 ± 0.5973 | 0.0111 ± 0.0023 | 0.2408 ± 0.0509 | 97 | 226 |
| NSGA-III | 115.1612 ± 0.4745 | 0.0139 ± 0.0029 | 0.4314 ± 0.0582 | 86 | 47 |
| RVEA | 111.7151 ± 1.8195 | 0.0308 ± 0.0099 | 0.8399 ± 0.1569 | 47 | 62 |
| HypE | 105.6489 ± 0.9789 | 0.0266 ± 0.0053 | 1.4820 ± 0.1003 | 72 | 30 |
| PAES | 104.1887 ± 0.8953 | 0.0351 ± 0.0067 | 1.3195 ± 0.0558 | 33 | 27 |
| SMS-EMOA | 102.8871 ± 1.0543 | 0.0263 ± 0.0039 | 1.4937 ± 0.1192 | 40 | 54 |
| RandomSearch | 99.5691 ± 0.9383 | 0.0937 ± 0.0347 | 2.3621 ± 0.1428 | 28 | 88 |
**MOPSO and MOEA/D dominate** convergence (mean L2 to true front ≤ 0.01).
PESA-II edges spacing.
## ZDT3 (dim=30, 25000 evals × 10 seeds)
Zitzler-Deb-Thiele 2-objective with a **disconnected** front: five
separate arcs rather than one curve. Hard because an algorithm has to
discover and populate every arc while not stranding solutions in the
dominated gaps between them.
| algorithm | hypervolume ↑ | spacing ↓ | front | ms |
|---|---|---|---|---|
| **IBEA** | **126.2072 ± 1.2280** | 0.0164 ± 0.0036 | 48 | 131 |
| MOEA/D | 125.2413 ± 2.1647 | 0.0198 ± 0.0043 | 92 | 27 |
| NSGA-II | 123.1826 ± 1.5829 | **0.0092 ± 0.0020** | 98 | 40 |
| AGE-MOEA | 119.5132 ± 1.2732 | 0.0136 ± 0.0023 | 90 | 171 |
## DTLZ2 (3-obj, dim=12, 30000 evals/run × 10 seeds)
Deb-Thiele-Laumanns-Zitzler 3-objective; the Pareto front is the
unit-sphere octant (`Σf² = 1, all f ≥ 0`) — a curved 2-D surface embedded
in 3-D objective space. `mean dist = |‖f‖ 1|`, so 0 means perfectly on
the sphere (the known optimum).
| algorithm | mean dist ↓ | spacing ↓ | front | ms |
|---|---|---|---|---|
| **IBEA** | **0.0014 ± 0.0002** | 0.0607 ± 0.0047 | 87 | 148 |
| MOEA/D | 0.0037 ± 0.0003 | 0.0886 ± 0.0024 | 78 | 23 |
| HypE | 0.0113 ± 0.0033 | **0.0269 ± 0.0172** | 80 | 41 |
| NSGA-III | 0.0197 ± 0.0015 | 0.0735 ± 0.0052 | 92 | 91 |
| eps-MOEA | 0.0325 ± 0.0104 | 0.0572 ± 0.0170 | 136 | 88 |
| NSGA-II | 0.0332 ± 0.0068 | 0.0577 ± 0.0109 | 92 | 60 |
| SPEA2 | 0.0368 ± 0.0021 | 0.0288 ± 0.0038 | 92 | 530 |
| PESA-II | 0.0395 ± 0.0033 | 0.0616 ± 0.0051 | 100 | 372 |
| SMS-EMOA | 0.0484 ± 0.0134 | 0.0764 ± 0.0081 | 40 | 483 |
| RVEA | 0.0510 ± 0.0044 | 0.0631 ± 0.0024 | 68 | 66 |
| MOPSO | 0.0566 ± 0.0048 | 0.0687 ± 0.0084 | 100 | 66 |
| RandomSearch | 0.3949 ± 0.0152 | 0.0797 ± 0.0083 | 239 | 530 |
**IBEA wins decisively** (14× closer to the true front than NSGA-III).
SMS-EMOA's wall-clock fell ~2.7× from the v0.4.0 snapshot — the
`hypervolume_nd` rework.
## DTLZ1 (3-obj, dim=7, 30000 evals × 10 seeds)
Deb-Thiele-Laumanns-Zitzler 3-objective; the Pareto front is the linear
simplex `Σf = 0.5` in the positive octant. Hard because a deceptive
multimodal `g` term riddles the approach with a huge number of local
fronts — only fully-converged runs land on the simplex.
| algorithm | mean dist ↓ | spacing ↓ | front | ms |
|---|---|---|---|---|
| **GrEA** | **1.7725 ± 0.9897** | **0.0719 ± 0.0438** | 72 | 62 |
| MOEA/D | 2.8022 ± 1.7807 | 0.2279 ± 0.2247 | 78 | 22 |
| AGE-MOEA | 4.5395 ± 2.2114 | 0.3930 ± 0.2864 | 90 | 193 |
| NSGA-III | 5.9130 ± 2.8212 | 0.4375 ± 0.2212 | 92 | 81 |
**GrEA shines on linear fronts** — the grid-based niching matches the
geometry better than reference points.
## Rastrigin (dim=5, 50000 evals/run × 10 seeds)
Highly multimodal trap: `f = 10n + Σ(xᵢ² 10·cos(2π·xᵢ))`. Hard because a
near-quadratic global bowl is overlaid with ~10⁵ regularly spaced local
minima — any greedy step lands in the nearest dimple. Global optimum
`f = 0` at the origin.
| algorithm | best f | ms |
|---|---|---|
| **(1+1)-ES** | **0.0000e0 ± 0.00e0** | 4 |
| **DE** | **0.0000e0 ± 0.00e0** | 6 |
| GA | 7.0913e-8 ± 5.50e-8 | 15 |
| NSGA-II | 4.9270e-5 ± 5.04e-5 | 60 |
| IPOP-CMA-ES | 1.3423e-1 ± 2.71e-1 | 61 |
| PSO | 7.9598e-1 ± 8.67e-1 | 5 |
| CMA-ES | 2.3453e0 ± 1.49e0 | 10 |
| SimulatedAnneal | 3.8540e0 ± 1.48e0 | 7 |
| RandomSearch | 1.1064e1 ± 2.54e0 | 14 |
| HillClimber | 1.5966e1 ± 6.25e0 | 6 |
| PAES | 1.5966e1 ± 6.25e0 | 10 |
(1+1)-ES and DE tie for `f = 0`. **IPOP-CMA-ES drops vanilla CMA-ES from
2.35 → 0.13** — the restart logic does what it should.
## Rosenbrock (dim=5, 30000 evals × 10 seeds)
Rosenbrock's banana valley: `f = Σ(100·(xᵢ₊₁ xᵢ²)² + (1 − xᵢ)²)`. Hard
because the minimum sits in a long, bent, near-flat valley — easy to
enter, very slow to crawl along to the tip. Global optimum `f = 0` at the
all-ones point.
| algorithm | best f | ms |
|---|---|---|
| **Nelder-Mead** | **0.0000e0 ± 0.00e0** | 1 |
| CMA-ES | 3.6207e-29 ± 2.35e-29 | 5 |
| TLBO | 1.8458e-3 ± 1.91e-3 | 1 |
| DE | 3.3345e-1 ± 3.01e-1 | 2 |
| PSO | 8.2124e-1 ± 1.58e0 | 2 |
| (1+1)-ES | 2.2115e0 ± 2.70e0 | 1 |
| BO (60 evals) | 3.1725e3 ± 2.92e3 | 39 |
Nelder-Mead **= 0 exactly**, CMA-ES at machine epsilon. BO at only 60
evaluations is honestly bad on 5-D Rosenbrock (no kernel hyperparameter
tuning) — included as a reminder that BO needs more evaluations than a
smooth problem actually requires for these other methods.
## Ackley (dim=5, 30000 evals × 10 seeds)
Ackley's function: a near-flat outer plateau with shallow ripples
surrounding a single deep, narrow global basin. Hard because the gradient
is almost zero far from the optimum, giving local search little to
follow. Global optimum `f = 0` at the origin.
| algorithm | best f | ms |
|---|---|---|
| **DE** | **4.4409e-16 ± 0.00e0** | 3 |
| PSO | 1.5099e-15 ± 1.63e-15 | 3 |
| CMA-ES | 1.5099e-15 ± 1.63e-15 | 5 |
| TLBO | 2.2204e-15 ± 1.78e-15 | 2 |
| BO (60 evals) | 1.9622e1 ± 1.23e0 | 38 |
All conventional methods reach machine precision. BO at 60 evals
struggles — same caveat as Rosenbrock.
---
## TSP ring-15 (8000 evals/run × 10 seeds)
15 equally-spaced cities on the unit circle; minimize the closed tour
length. The space is `(151)!/2` distinct tours, but cities in convex
position have no 2-opt local optima — so this instance cleanly separates
methods with good neighbourhood moves (inversion = 2-opt) from blind
recombination / sampling. Known optimum (the polygon perimeter):
**6.2374**.
| algorithm | tour length ↓ | ms |
|---|---|---|
| **HillClimber** | **6.2374 ± 0.0000** | 0 |
| **SimulatedAnneal** | **6.2374 ± 0.0000** | 0 |
| **TabuSearch** | **6.2374 ± 0.0000** | 0 |
| **AntColony** | **6.2374 ± 0.0000** | 8 |
| GA | 7.0133 ± 0.6725 | 2 |
| RandomSearch | 12.1474 ± 0.6797 | 1 |
Every local-search method (and Ant Colony) hits the exact optimum — as
theory predicts for convex-position TSP under 2-opt. The GA's order
crossover drifts off the optimum, and random sampling is hopeless.
## JSS FT06 (8000 evals/run × 10 seeds)
Fisher & Thompson 1963 6-job × 6-machine job-shop; minimize makespan.
Hard because every job has a fixed machine order, so swapping two
operations can ripple delays across the whole schedule. Known optimum:
**55**.
| algorithm | makespan ↓ | ms |
|---|---|---|
| **SimulatedAnneal** | **55.2000 ± 0.6000** | 1 |
| TabuSearch | 55.9000 ± 1.4457 | 1 |
| GA | 56.0000 ± 1.5492 | 4 |
| RandomSearch | 58.5000 ± 1.2042 | 4 |
| HillClimber | 62.5000 ± 4.3186 | 0 |
Simulated annealing gets within 0.4% of the known optimum on average;
greedy hill-climbing stalls in operation-order local optima.
## Knapsack (30 items, bi-objective, 20000 evals/run × 10 seeds)
Zitzler-Thiele style 0/1 knapsack: two profit vectors, one capacity (half
the total weight). Hard because the two profit objectives conflict and
the capacity constraint carves feasible regions out of the `2³⁰`
bitstrings. No closed-form optimum; scored by hypervolume vs reference
`[0, 0]` (higher is better).
| algorithm | hypervolume ↑ | front | ms |
|---|---|---|---|
| **NSGA-II** | **1360468.3 ± 11619.6** | 100 | 39 |
| SPEA2 | 1355615.5 ± 9266.8 | 100 | 213 |
| IBEA | 1352595.5 ± 10183.6 | 99 | 101 |
| NSGA-III | 1346446.0 ± 6922.1 | 100 | 39 |
| RandomSearch | 1118233.1 ± 34150.3 | 9 | 17 |
The three Pareto EAs land within ~1% of each other; random search finds a
front of only ~9 points and trails badly.