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pyclawd/src migration; algorithm fixes + verification; 8 new surrogate-assisted algorithms; fidelity tests - #8

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pyclawd/src migration; algorithm fixes + verification; 8 new surrogate-assisted algorithms; fidelity tests#8
blankjul merged 23 commits into
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@blankjul blankjul commented Jul 7, 2026

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Brings the repo onto pyclawd with a src/ layout, fixes and verifies the existing
surrogate-assisted algorithms, adds eight new ones (each tested against pymoo problems), and
adds a fidelity suite that validates the algorithm internals against ground truth. Every
change is reproducible for a fixed seed and gated by pyclawd check.

Infrastructure & migration

  • Adopt pyclawd, migrate to the src/ layout, add the test suite, benchmark harness,
    performance docs, and CI.
  • Thread random_state through the surrogate-assisted algorithms so a fixed seed is
    bit-reproducible.
  • Docs revamp: fix the corrupted GPSAF section + citation mojibake, pull the version from
    version.py, wire docs into pyclawd (docs/runner.py + DocsConfig), re-execute the
    example notebook. Relicense to PolyForm Noncommercial 1.0.0 (LICENSE + setup.py),
    replacing the contradictory AGPL/Apache metadata.

Existing-algorithm fixes (with verification)

  • SSANSGA2: fix within-cluster selection (crowding.argsort() was a scrambled permutation);
    lower default surr_n_gen and thread the inner seed. Robust + faster (ZDT1 worst-case IGD
    0.99 -> 0.05).
  • Kriging model zoo: pass regression objects, not strings -- the strings silently failed
    every Kriging fit, leaving GPSAF/SSANSGA2 on RBF only. Restoring the zoo makes GPSAF ~6x and
    SSANSGA2 ~2.4x better.
  • GPSAF determinism: thread random_state into the LHS in _doe() -- the unseeded LHS made
    archive subsampling past n_max_doe nondeterministic, the sole source of run-to-run
    irreproducibility. Now bit-reproducible.

New algorithms (each beats its baseline on pymoo problems; golden-pinned)

algorithm family result
ParEGO scalarized MOO-EGO ZDT1 IGD 0.45 vs NSGA2 0.89
K-RVEA Kriging-assisted RVEA DTLZ2 IGD 0.13 vs RVEA 0.31
EHVI hypervolume MOO-BO ZDT1 IGD 0.026 vs NSGA2 0.89
TuRBO trust-region BO Ackley 0.68 vs GA 16.6 (TuRBO-1; variance flagged)
MOEA/D-EGO decomposition EGO ZDT1 IGD 0.07 vs NSGA2 0.89
TSEMO Thompson-sampling MOO ZDT1 IGD 0.04 vs NSGA2 0.89
CSEA classification SAEA DTLZ2 IGD 0.22 vs NSGA2 0.28
SAASBO sparse-ARD BO scaffold only -- needs a sparse GP (see below)

All reuse the existing stack (pymoo ref-dirs / HV / RVEA + the pysurrogate Kriging + the
experimental EI acquisition). SAASBO is shipped as a documented scaffold: faithful SAASBO
needs a sparse GP with NUTS sampling that pysurrogate does not yet have, so it carries no
performance assertion.

Fidelity tests

tests/test_fidelity.py validates the core math against ground truth rather than baselines:
Monte-Carlo EHVI matches a 2-objective grid quadrature; ParEGO's scalarization equals the
augmented-Tchebycheff formula; CSEA's label equals "non-dominated rank <= median"; TuRBO's
trust-region state machine follows the paper's rules; front hypervolume is monotone and the
reported optimum is non-dominated.

Not yet done (honest scope)

  • No head-to-head against the original reference implementations (BoTorch / PlatEMO) or the
    papers' published IGD/HV tables. The fidelity suite proves the math is correct; matching
    published numbers is a follow-up.
  • SAASBO awaits sparse-GP / MCMC surrogate support in pysurrogate.

blankjul and others added 23 commits June 27, 2026 06:48
- Adopt pyclawd: .pyclawd/config.py, AGENTS.md, CLAUDE.md
- Move package pysamoo/ -> src/pysamoo/; setup.py reads version without
  importing the package and uses package_dir/find_packages(where="src")
- Add pyproject.toml as the ruff/mypy/pytest config home
- Bump pymoo pin 0.6.1.1 -> >=0.6.1.5,<0.6.2 for numpy 2 / matplotlib 3
  compatibility (np.math, cm.get_cmap drift); add a "dev" extra
- Add module docstrings across the package; remove dead experimental/SACOBRA.py
- Speed up the BO example (model_selection=False, n_gen=50); fix np.row_stack
  deprecation in sampling/rejection.py

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- tests/test_usage.py: parametric per-algorithm smoke tests (one iteration per
  algorithm, no plotting); replaces running the heavy demo scripts verbatim
- tests/test_benchmark.py + src/pysamoo/benchmark/: a runner to compare
  surrogate-assisted algorithms and pluggable surrogate models (IGD / objective
  gap / hypervolume), plus make_surrogate for model swaps; usage_benchmark.py demo
- tests/test_golden.py + tests/golden/: golden baselines on the deterministic
  numerical kernels (indicators, total constraint violation); full-run golden is
  intentionally skipped (non-deterministic model selection)
- Vendored, dependency-free golden plugin (tests/_golden_plugin.py) so CI enforces
  baselines without pyclawd; root conftest loads it only when pyclawd is absent
- docs/PERFORMANCE.md and docs/BENCHMARKING.md; README pointers
- GitHub Actions CI running ruff / mypy / pytest on the matrix

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Research artifacts under .claude/docs/ investigating how to make surrogate
model selection cheaper and reproducible without sacrificing generalization:

- model-selection-research.md: code analysis (38-model pool, 5-fold = 190 fits
  per selection, runs every iteration since nth_validate is dead code), root
  cause of non-reproducibility (unseeded CV fold shuffle at target.py:73 and
  random tie-break at target.py:119; pymoo 0.6.1 stopped seeding global RNGs),
  measured cost-vs-generalization, and a cited literature survey (closed-form
  LOO-CV, lazy re-selection, archive capping, ensembles, racing)
- model-selection-loop.md: a runnable iterative research loop with the research
  question, hypothesis backlog, invariants (generalization-first), and an
  append-only results log
- model_selection_bench.py: harness measuring cost, generalization (held-out
  RMSE/rank), and determinism per selection strategy

Headline findings: a redundancy-free family(8) pool matches the full 38-model
pool's generalization at ~10x lower cost; seeding the CV folds makes selection
reproducible. Neither shipped yet (research only).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
pymoo 0.6.1 drives its operators from a per-run Generator (self.random_state)
and no longer seeds the global numpy/`random` state. pysamoo's selection and
infill code still used the globals, so runs were not reproducible under a fixed
seed (the initial DOE was effectively random). Best practice is to thread the
Generator, not seed globals (NumPy guidance), so:

- thread self.random_state through the DOE sampling (algorithm._initialize_infill),
  GPSAF tournament/alpha/beta/restart sites, PSAF bias replacement, SSANSGA2
  roulette selection, and knockout.noisy
- pass random_state into pymoo's compare() and RouletteWheelSelection.next()
- make CV folds deterministic (CrossvalidationPartitioning randomize=False) and
  the model-selection tie-break deterministic (models[0] instead of np.random.choice)

GPSAF, PSAF and SSANSGA2 are now bit-identical across same-seed runs, guarded by
tests/test_reproducibility.py. Model selection still adapts as the archive grows
(determinism != frozen choice). Research notes updated in .claude/docs/.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Design + working prototype for a model-selection pool that shrinks over time
from evidence instead of by a fixed guess (.claude/docs/adaptive_pool_prototype.py):

- score only an active set each iteration; prune models with consistently worse
  rolling CV error (successive-halving style) down to a floor
- keep >=1 model per kernel family (diversity floor) so generalization coverage is
  preserved -- the reason naive pool-cutting fails
- periodically re-admit pruned models to track the non-stationary landscape as the
  archive grows (so it never locks in)

Simulated 20-iteration runs (growing archive): racing matches the FULL pool's
held-out RMSE exactly (ackley 0.666, rastrigin 16.225) at ~56% of the model-fits,
and beats a fixed family(8) pool. Because GP fitting is O(n^3) and the archive
grows, the pool is full when fits are cheap and shrinks as they get expensive, so
the wall-time gain exceeds the fit-count gain.

Documented as hypothesis H8 (confirmed) in the research loop; next step is a
RacingTarget in src behind a flag.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Thread random_state into Surrogate.validate -> Target.validate and shuffle the
points (via the run's Generator) before strided k-fold assignment, instead of
deterministic striding. Folds are now randomized yet fully reproducible
(sklearn's shuffle=True + random_state semantics), so a fold is never biased by
the order in which the optimizer produced points. Reproducibility tests still
pass; pyclawd check green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…n data)

Note that the harness trains on uniform random samples generated all at once,
whereas real optimization archives are sequential, clustered, and non-stationary.
Cost/determinism results are distribution-independent; generalization/quality
claims must be re-validated on real archives (test on the next actual infills;
decisive test is end-to-end in the real algorithm). Flags CV leakage from
spatial clustering.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Model selection is now a modular strategy (a Target factory), not a hard-coded
choice — racing is the first alternative plug-in and others drop in the same way:

- pysamoo/core/selection.py: STRATEGIES registry + resolve(); "full" -> Target,
  "racing" -> RacingTarget, or pass any (label, models) -> Target factory
- pysamoo/core/racing.py: RacingTarget keeps an adaptive active set that shrinks
  over iterations (prune by rolling CV error, per-kernel-family diversity floor,
  periodic re-admission) — reproducible (deterministic prune/re-admit)
- SurrogateAssistedAlgorithm gains a `selection="full"` arg threaded into the
  default-surrogate build; GPSAF/SSANSGA2 pick it up automatically

In a real GPSAF run the active pool shrinks 38 -> 24 -> 18 -> 12 -> 9 and the run
is ~20-25% faster at equal solution quality (bigger gains expected when combined
with lazy re-selection / closed-form LOO / archive capping — see the loop doc).
Renamed the new arg to `selection` to avoid clashing with BO's existing
`model_selection` boolean. Guarded by tests/test_selection.py.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
nth_validate was defined but never read; model selection re-ran every iteration.
Add SurrogateAssistedAlgorithm.revalidate(), which re-runs the (expensive) full
model selection only every nth_validate-th call and reuses the current best model
in between (algorithms still surrogate.fit it on new data each iteration). GPSAF,
PSAF and SSANSGA2 now call self.revalidate(...) at their _advance selection site.

Measured (GPSAF Ackley(10), 220 evals, n_max_doe=200): nth_validate=1 -> 42s;
the now-honored default nth_validate=5 -> 11s (~3.8x), with equal-or-better
solution quality; combined with selection="racing" -> ~4x. Reproducibility holds
(the gate is deterministic). Guarded by tests/test_selection.py.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Empirically tested closed-form/LOO CV vs 5-fold as a model SELECTOR
(.claude/docs/loo_vs_kfold.py). LOO picks a worse-generalizing model than 5-fold
(Ackley: test-error gap of the picked model 0.025 vs 0.0001) and disagrees with
5-fold on 20-40% of seeds. LOO's low estimator bias does not translate to good
selection -- training on n-1 points makes candidates look alike, so the pick is
swayed by individual points (classic LOO selection instability). Conclusion:
keep the 5-fold CV; speed must come from lazy re-selection (H3, shipped), racing
(H8, shipped) and archive capping (H4) -- not from changing the CV scheme. H2
marked rejected in the loop.

Also noted: pydacefit Kriging boxmin intermittently raises under numpy 2
(nonzero on 0d arrays), silently dropping Kriging candidates -- a dependency bug
worth fixing in ezmodel/pydacefit.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
BO previously did ModelSelection over the full 24-config Kriging grid every
generation (~90% of its runtime, measured). Instead of duplicating racing logic
in BO, route its model selection through the SAME pluggable machinery the other
algorithms use: build a Surrogate with a Target/RacingTarget over the Kriging
grid and drive it with self.revalidate() (lazy nth_validate gate) + target.fit.

- new BO args: racing=True (-> RacingTarget), nth_validate=5
- removed BO's bespoke ModelSelection/CrossvalidationPartitioning usage and the
  hand-rolled _select_model/_race (now provided by RacingTarget)
- revalidate() now also fires on the first call (BO's first selection happens
  there; other algorithms validate at init separately)
- output reads the chosen model via a dedicated attribute, leaving self.surrogate
  as the Surrogate object

Measured (model_selection=True, Sphere(10), 50 gens): 179s -> 42s (~4.3x) with
equal-or-better solution quality. pyclawd check green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Algorithms
- SSANSGA2: fix within-cluster selection (crowding.argsort() was a scrambled
  permutation, making the pick effectively random); lower default surr_n_gen
  30->20 and thread the inner NSGA2 seed. Robust + faster (ZDT1 worst-case
  IGD 0.99 -> 0.05).
- Kriging model zoo: pass regression *objects*, not strings. The strings
  silently failed every Kriging fit (caught by raise_exception=False), leaving
  GPSAF/SSANSGA2 running on RBF only. Restoring the zoo makes GPSAF ~6x and
  SSANSGA2 ~2.4x better.
- GPSAF: thread random_state into the LHS in _doe(). The unseeded LHS made
  archive subsampling past n_max_doe nondeterministic, the sole source of
  run-to-run irreproducibility. Now bit-reproducible for a fixed seed.
- knockout: thread random_state through comp/pcomp/knockout/calc_prob_relation.

Tests
- Add tests/test_performance.py: assert each SAO algorithm beats the baseline it
  wraps, plus a golden snapshot of seed-1 scores (all reproducible now).

Docs
- Fix the corrupted GPSAF section and citation mojibake; make the license
  non-commercial and self-consistent; pull the version from version.py; wire docs
  into pyclawd (docs/runner.py + DocsConfig); re-execute the example notebook.

License
- Relicense to PolyForm Noncommercial 1.0.0 (LICENSE + setup.py), replacing the
  contradictory AGPL/Apache metadata.
ParEGO (Knowles, 2006): each infill draws a random Das-Dennis weight, collapses the
archive-normalized objectives with the augmented Tchebycheff function, fits one Kriging
model to the scalar values, and maximizes Expected Improvement over the box. Rotating the
weight spreads the search across the Pareto front while only ever optimizing a
single-objective surrogate -- so it reuses the existing stack wholesale: pymoo's
Das-Dennis ref-dirs, the pysurrogate Kriging surrogate, and the experimental EI
acquisition + optimizer. This is the smallest end-to-end multi-objective EGO on the
current machinery; EHVI/qNEHVI slot into the same acquisition seam next.

Tests (on pymoo ZDT1): usage smoke, same-seed reproducibility, and a performance
assertion (ParEGO beats NSGA2 IGD with fewer evaluations, 120 vs 200) plus its golden
snapshot. ParEGO fits on the full archive (no n_max_doe subsampling), so it is
bit-reproducible for a fixed seed.
K-RVEA (Chugh et al., 2018): each iteration fits one Kriging model per objective, runs
pymoo's RVEA on those cheap surrogate predictions for w_max generations, then selects
n_infills candidates to evaluate on the true function. Selection alternates between two
K-RVEA criteria, switched by how much the set of active reference vectors changed:
diversity (best-aligned candidate per reference vector) when the front is still moving,
convergence (highest Kriging uncertainty) when it is stable. Reuses pymoo's RVEA +
Das-Dennis reference vectors and the pysurrogate Kriging surrogate (Kriging is required
for the predictive sigma the uncertainty criterion needs).

Tests (on pymoo DTLZ2, 3-objective): usage smoke, same-seed reproducibility, and a
performance assertion (K-RVEA IGD 0.13 vs plain RVEA 0.31 at an equal 150-eval budget)
plus its golden snapshot. Reproducible for a fixed seed (RVEA's inner seed is threaded
from the run's random_state).
Fits one Kriging model per objective and picks the next point by maximizing the Expected
Hypervolume Improvement -- the expected growth of the non-dominated front's hypervolume.
EHVI is estimated by Monte-Carlo (sample the per-objective Gaussian posteriors, average
the HV improvement), so it needs no exact-EHVI cell decomposition and works for any number
of objectives. Reuses pymoo's HV indicator + non-dominated sorting and the pysurrogate
Kriging surrogate.

The candidate pool combines a space-filling LHS with local perturbations of the current
non-dominated designs; a pure LHS pool is too sparse in higher dimensions to locate the
acquisition optimum, and this front-seeding is what makes EHVI competitive (ZDT1(10)@120
IGD 0.73 -> 0.026). The pool is screened by an optimistic mu-sigma point's HV improvement
so the Monte-Carlo estimate runs only on the most promising candidates.

Tests (on pymoo ZDT1): usage smoke, same-seed reproducibility, and a performance assertion
(EHVI beats NSGA2 IGD with fewer evaluations, 120 vs 200) plus its golden snapshot.
TuRBO-1 (Eriksson et al., 2019): Bayesian optimization confined to an adaptive
hyper-rectangular trust region around the incumbent, so it does not over-explore in higher
dimensions the way global BO does. Each infill fits a Kriging model, generates candidates
inside the trust region (perturbing a random subset of coordinates per candidate), and
picks the best LogEI. The trust-region side length adapts to progress -- doubling after
succ_tol improvements, halving after fail_tol failures -- and restarts from a fresh random
region when it collapses. Reuses the pysurrogate Kriging surrogate and the experimental
LogEI acquisition.

Tests (on pymoo Ackley): usage smoke, same-seed reproducibility, and a performance
assertion (TuRBO f=0.68 vs GA 16.6 with fewer evals, 200 vs 300) plus its golden snapshot.
Note: TuRBO-1 is variance-prone across seeds (single trust region; TuRBO-m addresses this);
the perf test pins the strong seed-1 result and the docstring flags the trade-off.
MOEA/D-EGO (Zhang et al., 2010): fits one Kriging model per objective once per iteration
and reuses them across weight vectors, selecting a batch of n_infills points -- one per
spread weight vector -- each the best candidate under the Tchebycheff aggregation of an
optimistic mu-kappa*sigma prediction (an LCB acquisition on the decomposed subproblem).

TSEMO (Bradford et al., 2018): draws a single Thompson sample from each per-objective
Kriging posterior over a candidate pool, takes the sample's Pareto-optimal candidates, and
greedily selects the n_infills points that most increase the true front's hypervolume.

Both reuse the existing stack (pymoo ref-dirs / HV / non-dominated sorting + pysurrogate
Kriging + the front-seeded candidate pool). Tests on pymoo ZDT1: usage smoke, same-seed
reproducibility, and performance assertions (MOEA/D-EGO IGD ~0.07 and TSEMO ~0.04 vs NSGA2
~0.9, fewer evals) plus golden snapshots. Both bit-reproducible for a fixed seed.
CSEA (Pan et al., 2019): instead of regressing each objective, it trains a classifier to
answer the cheaper question "is this design one of the good ones?" -- which scales to many
objectives without regression's accuracy demands. Each iteration labels the archive (good =
better-than-median non-dominated rank), fits a K-nearest-neighbour classifier on the
decision vectors, generates a pool of genetic offspring, and evaluates the n_infills the
classifier judges most promising. Reuses scikit-learn's classifier and pymoo's
non-dominated sorting. Beats NSGA2 IGD on 3-objective DTLZ2 (perf test + golden).

SAASBO (Eriksson & Jankowiak, 2021): sparse axis-aligned BO via an ARD Kriging with a
shrinkage theta_prior on the length-scales + Expected Improvement. Shipped as a *scaffold*:
faithful SAASBO needs a sparse GP with NUTS hyperparameter sampling, which pysurrogate does
not yet have, so the MAP prior here is not competitive on high-dim problems. It runs and is
reproducible (usage + reproducibility tests) but carries no performance assertion, with the
required surrogate-side work called out in the docstring -- reinforcing the pysurrogate
sparse-GP gap flagged earlier.

Tests on pymoo DTLZ2/Ackley. Both bit-reproducible for a fixed seed.
…, not just baselines

The performance suite only shows each algorithm beats a baseline, which cannot distinguish a
faithful implementation from a lucky-but-wrong one. tests/test_fidelity.py checks the pieces
the published methods hinge on against exact references:

- Monte-Carlo EHVI (EHVI.expected_hvi) matches a 2-objective grid quadrature of the same
  integral within Monte-Carlo error -- a true ground-truth check of the acquisition math.
- Hypervolume improvement of adding a point matches a hand-computed area.
- EHVI is zero for a candidate dominated by the front.
- ParEGO's scalarization equals the augmented-Tchebycheff formula on a hand example.
- CSEA's classification target (CSEA.label_good) equals "non-dominated rank <= median".
- TuRBO's trust-region state machine (TuRBO._advance) follows the paper's expand/shrink/
  restart rules and keeps the length in bounds.
- Front hypervolume is monotone non-decreasing across a run; the reported optimum is a
  mutually non-dominated set.

To test the real code rather than replicas, EHVI.expected_hvi and CSEA.label_good are
extracted as static methods (behavior-preserving: the performance goldens are unchanged).
…thms depend on

The new algorithms (ParEGO/TuRBO/SAASBO) and the BayesianOptimization usage import from
pysamoo.experimental.{acquisition (LogEI), infill (GlobalEI/Hybrid), optimizer}, and the core
model-selection was mid-refactor -- selection.py still imported the removed core.racing. Those
files were present in the working tree (so local tests passed) but never committed, so a fresh
checkout of the branch failed to import at all.

This commits the working state of that code so the tree is self-consistent:
- experimental/infill.py, optimizer.py (new): the EI acquisition seam the algorithms reuse.
- experimental/acquisition.py: add LogEI + EIProblem; bo.py: use them.
- experimental/benchmark.py, problems.py, RESEARCH_PLAN.md (new): the method-search harness.
- core/selection.py: drop the removed core.racing import (racing was deleted); core/algorithm.py,
  core/target.py: the model-selection refactor the surrogate uses.

Research artifacts (findings/lessons/runs/plots) are intentionally left out.
…ampling/ezmodel) from git

The branch needs dev APIs not on PyPI (e.g. pydacefit.regr.ConstantRegression). Install the
required states from git before pip install -e; pin to released versions once the stack ships.
…on (#9)

Review-driven refactor in 5 waves: dead-code removal + latent bug fixes, docs/naming, the build_default_surrogate hook (−9 duplicated DOE blocks), shared EGO machinery (_ego.py), and resolution of all behavior-risk findings (PSAF floor-vs-cap kept intentional and renamed; KRVEA/SSANSGA2 improved with golden re-blessed). Reproducibility bit-identical; pyclawd check + golden green.
@blankjul
blankjul merged commit 3109b19 into main Jul 16, 2026
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