Bring the relational-neighborhood geometry OPERATORS from the viz proxy
(engram-geometry-proxy.py §5) into the C runtime as reusable primitives, and
expose each as an EL builtin so any CGI app / el program can use them — not just
the engram service internals.
engram_geometry.{h,c} (pure, libm-only, read-only over descriptors):
- engram_geo_overlap : shared-member Jaccard + centroid/scale proximity
score + intersection centroid.
- engram_geo_subtract : orthogonal-complement residual (project A onto
I - V_B V_Bᵀ), closed-form variance_explained_by_B,
residual ellipsoid + centroid-diff; set-diff variant.
- engram_geo_combine : pooled descriptor (exact law-of-total-variance mean +
covariance), re-eigendecomposed.
- engram_geo_distance : centroid L2 + cosine + closed-form Wasserstein-2
(Bures) — mirrors the proxy _wasserstein2.
- engram_geo_analogy : orthogonal Procrustes R = UVᵀ (SVD) aligning A's
principal frame to B's + apply helper.
The C descriptor is full-dim/centered with a low-rank covariance from its top
axes; operators mirror the proxy FORMULAS and do the Wasserstein/combine eigen
work inside the small joint-axis subspace (exact there). Reuses jacobi_sym.
EL builtins (el_runtime.{h,c}, el_seed.c native wrappers):
engram_geo_{descriptor,overlap,subtract,combine,distance,analogy}_json —
take comma-separated seed-id set(s), build the CENTERED descriptor against the
true store-wide mean (ad-hoc path), run the operator, return JSON. Additive:
no flag, no effect on activation/retrieval. Surfacing via engram.el + the elc
fold is a cutover step (same elc-drift deferral as the P0/P5 builtins); the C
table wiring is registered now.
Tested: synthetic closed-form unit suite (20/20) — Wasserstein, Jaccard/score,
orthogonal residual, set-diff, pooled combine, Procrustes recovery. ASan+UBSan
clean; 0 leaks. Read-only; no activation/retrieval behavior change.
will.anderson
5336cfe0a6