Audit during Phase 9a preparation revealed:
* The Java repo `varylab/conformallab` does NOT contain
`InversiveDistanceFunctional.java`. The original roadmap mention
was based on a misreading.
* The closest existing Java class is `CPEuclideanFunctional.java`
(260 lines, with FunctionalTest), implementing the Bobenko-Pinkall-
Springborn 2010 face-based circle-packing functional.
These two functionals are mathematically distinct (face-dual vs vertex-
based) but related: BPS-CP generalises inversive-distance via the
intersection angle parameter θ_e (I_ij = cos θ_e for orthogonal
limit, I_ij = 1 for tangential).
The roadmap is now split into:
- 9a.1 CPEuclideanFunctional (Java port + test, BPS 2010 reference)
- 9a.2 InversiveDistanceFunctional (from-literature, Luo 2004
+ Glickenstein 2011)
Both belong in Phase 9a; cross-validation between them in the
tangential limit (θ=0 ⇔ I=1) becomes a Phase 9a acceptance test.
The tutorial `doc/tutorials/add-inversive-distance.md` is corrected:
it no longer claims `InversiveDistanceFunctional.java` exists upstream,
and cites Luo 2004 + Glickenstein 2011 + Bowers-Stephenson 2004 instead.
Updated edge-length formula from incorrect hyperbolic cosh form to
the correct Luo §3 Euclidean form:
ℓ_ij² = exp(2u_i) + exp(2u_j) + 2 I_ij exp(u_i + u_j)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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