feat(delphi): acceptance canonicalization — suppress cross-engine ordering artifacts in certify comparer by jucor · Pull Request #2648 · compdemocracy/polis

jucor · 2026-07-22T02:01:57Z

Clojure emits tids/in-conv (and everything positionally aligned to them:
pca center/comps rows/comment arrays, base-clusters columns) in
hash/insertion order; Python emits sorted. Both blobs are internally
consistent, so cross-engine array order is not a semantic divergence.
canonicalize_blob() (crosslang.py) normalizes both sides inside
project_acceptance: tids sorted with tid-aligned pca arrays re-indexed;
in-conv/mod-in/mod-out/meta-tids sorted when lists (None passes through);
base-clusters columns re-indexed by sorted id, members sorted;
group-clusters sorted by id, members sorted. votes-base is deliberately
NOT permuted (already sort-by-:id-aligned on both engines by construction,
conversation.clj:593). Kills ~850 of ~1030 step-0 battery divergences as
ordering artifacts; the residual real roots (sign convention, votes-base
shape, emission gaps) are ledgered in docs/divergences.json.
Also canonicalizes run-arbitrary PCA COMPONENT SIGNS: Clojure's
first-tick power iteration has no start vectors, so its unseeded init
flips component signs between ITS OWN runs (observed on a vw single-cut
re-record: comps[1] + base-clusters.y negated vs the prior recording).
Each component's sign is fixed deterministically (max-|entry| positive,
evaluated after tid alignment) and every component-aligned array flips
with it (comps row, comment-projection row, base-clusters x/y,
group-clusters center[k]); pca.center is a data mean and never flips.
An inconsistent flip (y negated without comps[1]) still diverges.

commit-id:d1ae732b

Stack:

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

…ering artifacts in certify comparer Clojure emits tids/in-conv (and everything positionally aligned to them: pca center/comps rows/comment arrays, base-clusters columns) in hash/insertion order; Python emits sorted. Both blobs are internally consistent, so cross-engine array order is not a semantic divergence. canonicalize_blob() (crosslang.py) normalizes both sides inside project_acceptance: tids sorted with tid-aligned pca arrays re-indexed; in-conv/mod-in/mod-out/meta-tids sorted when lists (None passes through); base-clusters columns re-indexed by sorted id, members sorted; group-clusters sorted by id, members sorted. votes-base is deliberately NOT permuted (already sort-by-:id-aligned on both engines by construction, conversation.clj:593). Kills ~850 of ~1030 step-0 battery divergences as ordering artifacts; the residual real roots (sign convention, votes-base shape, emission gaps) are ledgered in docs/divergences.json. Also canonicalizes run-arbitrary PCA COMPONENT SIGNS: Clojure's first-tick power iteration has no start vectors, so its unseeded init flips component signs between ITS OWN runs (observed on a vw single-cut re-record: comps[1] + base-clusters.y negated vs the prior recording). Each component's sign is fixed deterministically (max-|entry| positive, evaluated after tid alignment) and every component-aligned array flips with it (comps row, comment-projection row, base-clusters x/y, group-clusters center[k]); pca.center is a data mean and never flips. An inconsistent flip (y negated without comps[1]) still diverges. commit-id:d1ae732b