The hyper-ideal vertex scale b is floored to keep the geometry valid. The
original clamp `b<0 → 0.01` mirrors the Java oracle but is only C⁰ (in fact
value-discontinuous at b=0): a Newton step crossing the feasibility boundary
hits a kink that can stall convergence (numerical-stability audit N3).
Rather than replace the Java-faithful behaviour (which would break the golden
parity tests), make the floor a selectable mode so BOTH the Java standpoint
and the clean mathematics are available:
- HyperIdealScaleClamp::HardJava (DEFAULT) — the original snap, bit-for-bit
faithful to HyperIdealFunctional.java → all parity tests unchanged.
- HyperIdealScaleClamp::SmoothBarrier — C¹ softplus floor
b ↦ floor + softplus_β(b−floor), β = HYPER_IDEAL_SCALE_SHARPNESS (=100);
≈ identity away from the floor, smooth across b=0. Opt-in.
clamp_hyper_ideal_scale centralises the logic (also folds in the N4 nachzügler:
compute_face_angles used a bare 0.01). The mode threads with a defaulted
trailing parameter through compute_face_angles, face_angles_from_local_dofs,
evaluate_hyper_ideal, the four hyper_ideal_hessian* variants and
newton_hyper_ideal — so every existing call site keeps HardJava behaviour.
Tests (+4): clamp-function C¹/floor/identity contract, mode-equivalence away
from the boundary, and end-to-end SmoothBarrier convergence to the same Java
golden vector (LawsonHyperIdeal). 296/296 CGAL tests pass.
Documented in doc/math/geometry-modes.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit closes the remaining red gates so `run-all.sh --fast` is
green end-to-end on the canonical dev machine.
New gates
─────────
1. cmake-format / cmake-lint
* scripts/quality/cmake-format.sh — dry-run by default,
--strict to fail on drift, --fix to apply
* .cmake-format.yaml — policy (lowercase commands, UPPERCASE
keywords, 100-col loose limit; matches .clang-format choices)
* Uses the pip-installed `cmakelang` package
(`pip3 install --user cmakelang`)
2. codespell
* scripts/quality/codespell.sh — exit 1 on any typo, --fix
interactively
* .codespellrc — extensive ignore-words-list capturing the
project's British-English-leaning style (centre, behaviour,
specialise, normalise, …) plus domain abbreviations (DOF,
iff, fuchsiens), so the gate flags real typos only.
* Validated: 0 typos across docs + code/include + scripts +
code/{src,tests}.
SPDX rollout (license-headers --fix)
────────────────────────────────────
license-headers.sh gained a --fix mode that auto-inserts the
two-line header at the correct place (below `#pragma once` if
present, above the include guard otherwise, plain prepend for
.cpp). Ran it on 60 of 66 files — 100 %-licensed now.
Verified the build is still clean after the textual edits:
cmake -S code -B build-verify -DWITH_CGAL_TESTS=ON
ctest --test-dir build-verify → 257/257 PASS
run-all.sh + README updated to include the two new gates.
End-to-end style/convention block status (on this commit, this branch):
✅ license-headers (66/66 carry MIT SPDX)
✅ cgal-conventions (0/6 violations)
✅ clang-format (0 drift; warn-mode for safety)
✅ cmake-format/-lint (warn-mode for safety)
✅ codespell (0 typos)
✅ markdown-links (122/122 resolve)
The slow correctness/quality block (sanitizers, coverage, clang-tidy,
multi-compiler, cgal-version-matrix, reproducible-build) is left as
follow-up — toolchain is now installed locally, scripts are syntax-
clean, the slow runs themselves are a separate matter of patience.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Replaces the O(n·F) full-FD Hessian with an O(F·36) block-local variant
that exploits the per-face locality of the hyper-ideal functional. Both
variants are kept (full-FD as correctness reference, block-FD as default)
and proven to match to FD rounding tolerance on all test configurations.
Java parity note
────────────────
HyperIdealFunctional.java line 295-298 declares:
public boolean hasHessian() { return false; }
i.e. the upstream Java functional has NO Hessian implementation, analytic
or numerical. Both Hessian variants in this file are conformallab++
extensions beyond the Java port. Analytic Hessian via Schläfli-type
differentiation through (b_i, a_e) → l_ij → ζ_13/ζ_14/ζ_15 → α_ij/β_i
is deferred to a future PR.
Implementation
──────────────
* code/include/hyper_ideal_functional.hpp
- New pure-math helper face_angles_from_local_dofs() takes 6 input DOFs
(b1, b2, b3, a12, a23, a31) + variability flags and returns the 6
output angles (β1, β2, β3, α12, α23, α31).
- Used by block-FD Hessian as the inner loop; identical semantics to
the existing compute_face_angles().
* code/include/hyper_ideal_hessian.hpp
- hyper_ideal_hessian_block_fd() — new, default production path
- hyper_ideal_hessian_block_fd_sym() — symmetrised variant
- hyper_ideal_hessian() — full-FD baseline, kept for cross-validation
- hyper_ideal_hessian_sym() — symmetrised baseline
- Header docblock documents speed-up curve: ~33× at cathead.obj scale,
~1166× at brezel.obj scale.
Tests (7 new in test_hyper_ideal_hessian.cpp)
─────────────────────────────────────────────
* PureHelperMatchesMeshHelper — refactor sanity
* BlockFD_MatchesFullFD_ClosedTetrahedron
* BlockFD_MatchesFullFD_Open3FaceMesh (boundary edge path)
* BlockFD_MatchesFullFD_PinnedDOFs (partial-DOF path)
* BlockFD_IsPSD (Springborn 2020 convexity)
* BlockFD_SparsityMatchesFaceAdjacency (structural correctness)
* BlockFD_FasterThanFullFD (performance assertion: ≥ 3×)
Measured speed-up on the 200-face tet strip (603 DOFs):
full-FD: 226 591 µs
block-FD: 2 347 µs
ratio: 96.5×
The assertion uses ≥ 3× to leave wide CI-hardware tolerance.
Test count
──────────
CGAL suite: 184 → 191 (+7). Zero skips.
Why not full analytic now
─────────────────────────
Full analytic Hessian via the chain rule
(b_i, a_e) → l_ij → ζ_{13,14,15} → α_ij / β_i
requires Schläfli-type differentiation with multiple cases for the
ideal / hyper-ideal vertex mix. It would add another ~6× over
block-FD but at significantly higher implementation and verification
cost. Block-FD already removes the practical bottleneck for meshes
up to ~10k faces; analytic optimisation can land later when justified
by a concrete profiling result.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
