record: nss-remainline-mainline-blackjax shipped (PyAutoFit#1492 + workspace_test#86)

active.md

@@ -1,24 +1,5 @@
 # Active Tasks
 
-## nss-remainline-mainline-blackjax
-- issue: https://github.com/PyAutoLabs/PyAutoFit/issues/1491
-- session: Claude Code cloud/mobile (no local worktree)
-- status: pr-open (https://github.com/PyAutoLabs/PyAutoFit/pull/1492) — 17/17 nss tests
-  pass from checkout; CI + human merge pending; session subscribed to PR activity
-- worktree: none — cloud session works on the GitHub clone directly
-- repos:
-  - PyAutoFit: feature/nss-remainline-mainline-blackjax
-  - autofit_workspace_test: feature/nss-searches-integration-test
-- prompt: active/nss_remainline_mainline_blackjax.md
-- integration-test-PR: https://github.com/PyAutoLabs/autofit_workspace_test/pull/86
-  (scripts/searches/NSS.py — truth recovery + logZ ensemble + chunked bit-parity;
-  validated against the #1492 branch in direct and TEST_MODE=1 runs; MERGE AFTER
-  PyAutoFit#1492 — af.NSS absent from main until then)
-- note: human-directed early re-mainlining of af.NSS on mainline blackjax >=1.6
-  (removal reason — git-fork pins — is gone). Port pre-validated on CPU toy
-  (chunked bit-identical to unchunked; logZ within 0.6 sigma of analytic).
-  Gate A still decides baseline adoption; DECISIONS.md entry to follow.
-
 ## stored-sample-reconstruction-guard
 - issue: https://github.com/PyAutoLabs/PyAutoFit/issues/1486
 - status: library-dev — WORKSPACE HALF SHIPPED; the PyAutoFit hardening (#1486) is what remains

complete/2026/08/nss-remainline-mainline-blackjax.md

@@ -0,0 +1,98 @@
+Re-mainlined `af.NSS` (nested slice sampling) into PyAutoFit as a proper
+first-class search on **mainline blackjax ≥1.6**, with integration-test
+coverage restored — human-directed 2026-08-18, executed entirely from a
+mobile/cloud session on CPU.
+
+- **PRs (both merged):** PyAutoFit#1492 (`401e666`, closes #1491) — the
+  search, tests, `__init__` export, optional-extra blackjax floor
+  ≥1.2.0 → ≥1.6.2; autofit_workspace_test#86 (`12da16d`) —
+  `scripts/searches/NSS.py` integration script.
+- **Why now:** the search was removed in PyAutoFit#1356/#1357 solely because
+  its dependencies were unshippable git-fork pins; nested sampling merged
+  into mainline blackjax 1.6, so the removal reason vanished. Implementation
+  restored verbatim from the `autofit_workspace_developer/searches/nss/`
+  stash (whose README's re-mainlining checklist this executes).
+- **The mainline port (3 diffs):** `from nss.ns import log_weights, finalise`
+  → `blackjax.ns.utils`; `SliceInfo.num_steps` → `num_expansions` (eval
+  counter); the chunked GPU-memory builder recomposed from mainline public
+  helpers (`build_slice_kernel`/`slice_constrained_step`/
+  `build_adaptive_kernel`/`live_covariance`) since mainline `build_kernel`
+  dropped the fork's `update_strategy=` seam. `_chunked_update.py` needed no
+  logic change (byte-equivalent to mainline's `update_with_mcmc_take_last`
+  bar the vmap→lax.map swap).
+- **Validation:** port proven on a 2D analytic toy BEFORE any source change
+  (logZ −4.558 ± 0.078 vs analytic −4.605; **chunked bit-identical to
+  unchunked at fixed seed**); 17/17 restored unit tests + full CI green
+  (3.12/3.13/docs); integration script validated in direct and
+  PYAUTO_TEST_MODE=1 runs against the PR branch (logZ −72.16 ± 0.42, ESS
+  417, chunked ≡ unchunked) — merged after #1492 per the library-first gate.
+- **Traps for the record:** (1) a quick-update Fitness-wiring convention test
+  added after the removal (`test_quick_update_wiring.py`) tripped on the
+  restored search — NSS never samples through Fitness, so the fix is an
+  EXEMPT entry with reason, not forwarding the kwarg to a dead path.
+  (2) PyAutoFit#1494 (clipper identifiers) landed on main mid-PR — its
+  nested-sampler identifier tripwire pins a fixed search list, so NSS is
+  unaffected; verified by merging main locally and running all 55 affected
+  tests before pressing merge. (3) blackjax is an optional extra, not a hard
+  autofit dep — environments must install/upgrade it explicitly.
+- **Programme tie-in:** scope-change entry in the inference DECISIONS.md
+  (autolens_profiling#144): re-mainlined ahead of Gate A per human direction;
+  Gate A still decides GPU-baseline adoption. Phase 2 can now drive `af.NSS`
+  directly (the "profiling-local runner first" hedge is obsolete).
+- **Follow-ups:** restore the `Search: NSS` tutorial section in
+  `autofit_workspace/scripts/searches/nest.py` (stash checklist item 5,
+  user-facing docs); blackjax ≥1.6.2 upgrades in the local venvs + RAL stack
+  (re-run `autolens_profiling/scripts/misc/searches/nss_smoke.py` there);
+  Phase 2 GPU re-benchmarking campaign.
+
+## Original prompt
+
+# Re-mainline af.NSS as a proper PyAutoFit search on mainline blackjax ≥1.6
+
+Type: feature
+Target: autofit
+Repos:
+- @PyAutoFit
+Difficulty: small
+Autonomy: supervised
+Priority: high
+
+Human-directed 2026-08-18 (mobile session): the parked `af.NSS` nested slice
+sampler — removed from PyAutoFit on 2026-07-11 (PyAutoFit#1356/#1357) solely
+because its dependencies were unshippable git-fork pins — should be
+reimplemented as a proper first-class search now that nested sampling is in
+**mainline blackjax 1.6** (the whole removal reason is gone). The full
+working implementation is preserved verbatim at
+`autofit_workspace_developer/searches/nss/` with a re-mainlining checklist
+in its README.
+
+Port surface (validated on CPU 2026-08-18 in the cloud session before any
+source change; see autolens_profiling#142 for the environment validation):
+
+- `from nss.ns import log_weights, finalise` → `blackjax.ns.utils`.
+- SliceInfo eval counter: fork `num_steps` → mainline `num_expansions`.
+- Chunked GPU-memory path: the fork's `build_kernel(update_strategy=)` seam
+  is gone — recompose from mainline public helpers (`build_slice_kernel`,
+  `slice_constrained_step`, `build_adaptive_kernel`, `live_covariance`);
+  `_chunked_update.py` is already byte-equivalent to mainline's
+  `update_with_mcmc_take_last` bar the vmap→lax.map swap.
+- End-to-end validation on a 2D analytic toy through the full search
+  pipeline: logZ −4.558 ± 0.078 vs analytic −4.605; **chunked path
+  bit-identical to unchunked** (same logZ/evals/ESS at fixed seed).
+
+Task (stash README checklist, PyAutoFit side):
+1. Restore `autofit/non_linear/search/nest/nss/` (search.py, samples.py,
+   _chunked_nss.py, _chunked_update.py, __init__.py) with the mainline port
+   and fork-era prose removed.
+2. Restore `test_autofit/non_linear/search/nest/nss/` (kept verbatim against
+   library import paths; one ImportError match-string update).
+3. `autofit/__init__.py`: re-export `NSS`.
+4. `pyproject.toml`: bump the `optional` extra's blackjax floor to ≥1.6.2
+   (no cap exists).
+5. Run the nss test subset + smoke the search end-to-end from the checkout.
+
+Note the programme-plan interaction: PROGRAMME §7 gated "af.NSS re-mainlined
+on blackjax.nss" behind Gate A — the human has directed early re-mainlining;
+Gate A still decides whether NSS becomes the GPU nested-sampling *baseline*.
+Record the scope change in the inference DECISIONS.md. The workspace
+tutorial restoration (checklist item 5) is a separate follow-up task.

complete/index.md

@@ -6,7 +6,7 @@ Token-light navigation over the finished-work records (schema:
 only then grep a dated bucket. Curators: edit the band between the CURATED
 markers; everything below GENERATED is rebuilt.
 
-1014 records across 7 buckets.
+1015 records across 7 buckets.
 
 <!-- CURATED:START -->
 ## Highlights
@@ -88,6 +88,7 @@ _(curate hard-won records here — survives regeneration.)_
 - [nautilus-1core-serial-pool](2026/08/nautilus-1core-serial-pool.md) — corrective for the Heart RED "release validation FAILED (stage
 - [normalise-auto-simulate-guard-idiom](2026/08/normalise-auto-simulate-guard-idiom.md)
 - [notebook-setup-notebook-regen-drift](2026/08/notebook-setup-notebook-regen-drift.md)
+- [nss-remainline-mainline-blackjax](2026/08/nss-remainline-mainline-blackjax.md)
 - [nufft-parity-full-datasets](2026/08/nufft-parity-full-datasets.md)
 - [numerical-hazard-profiling](2026/08/numerical-hazard-profiling.md) — Phase 1 established the reusable numerical-hazard profiling framework, typed risk measurements, reachability a…
 - [per-parameter-step-scaling](2026/08/per-parameter-step-scaling.md)