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2 Commits

Author SHA1 Message Date
Tarik Moussa
194effba97 feat(phase3f+3g): analytical Hessians + PI consolidation
Phase 3g — constants.hpp:
  - Introduce conformallab::PI and TWO_PI in a single constants.hpp
  - Remove scattered local PI/pi definitions from hyper_ideal_geometry.hpp,
    hyper_ideal_utility.hpp, euclidean_functional.hpp, mesh_builder.hpp,
    spherical_geometry.hpp (backward-compatible PI_SPHER alias kept)

Phase 3f — Euclidean Hessian (euclidean_hessian.hpp):
  - Cotangent-Laplace operator (Pinkall–Polthier 1993)
  - euclidean_cot_weights() helper + euclidean_hessian() + hessian_check_euclidean()
  - Correct Pinkall–Polthier 1/2 normalization factor
  - 8 tests: cot weights, symmetry, null-space (H·1=0), PSD, FD × 4 meshes

Phase 3f — Spherical Hessian (spherical_hessian.hpp):
  - Derives ∂α_i/∂u_j directly from the spherical law of cosines:
      ∂α1/∂l_opp  = sin(l_opp) / [sin(l_a)·sin(l_b)·sin(α1)]
      ∂α1/∂l_adj  = [cot(l_adj)·cos(α1) − cot(l_other)] / sin(α1)
    then chains with ∂l/∂λ = tan(l/2)
  - spherical_cot_weights() kept as a standalone helper (tested separately)
  - 8 tests: cot weights, symmetry, correct null-space & sign-convention
    (H·1 ≠ 0; H is NSD at equilibrium), FD × 3 meshes

All 62 cgal tests pass (3 skipped as before).

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2026-05-12 17:22:28 +02:00
Tarik Moussa
a4c2a89e7e feat(phase3c): port SphericalFunctional onto ConformalMesh; update README
New headers:
- spherical_geometry.hpp: spherical arc length l(λ) and half-angle formula
  for interior angles of a spherical triangle (SphericalFaceAngles struct)
- spherical_functional.hpp: SphericalMaps bundle, setup/assign DOF helpers,
  compute_lambda0_from_mesh(), gradient (Θ_v − Σα_v; Schläfli edge formula),
  energy via 10-point Gauss-Legendre path integral, gradient_check_spherical()

Updated:
- mesh_builder.hpp: add make_spherical_tetrahedron() (vertices on unit sphere)
  and make_octahedron_face() (single right-angled spherical triangle)
- tests/cgal/CMakeLists.txt: enable test_spherical_functional.cpp
- README.md: rewrite for CGAL-package goal, two test targets, all headers,
  updated project tree, Phase progress table, key design decisions

Tests (cgal.SphericalFunctional.*): 8 active + 1 skip
- OctaFaceAnglesAreRightAngles, SpherTetAngleSumExceedsPi
- GradientCheck_{OctaFaceVertex, SpherTetVertex, SpherTetAllDofs,
  SpherFan4Vertex, MixedPinnedVertices}
- AnglesFiniteAtKnownPoint
All 30 cgal.* tests pass (2 @Ignore skips).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-12 00:01:24 +02:00