Commit Graph

2 Commits

Author SHA1 Message Date
Tarik Moussa
3f124eb071 feat(phase4): HyperIdeal Newton solver, SparseQR fallback, examples, docs
Phase 4 complete — 87 CGAL tests pass, 2 skipped.

Newton solver (phase4a):
- hyper_ideal_hessian.hpp: symmetric FD Hessian (O(ε²), PSD by convexity)
- newton_hyper_ideal(): Newton + backtracking for the HyperIdeal functional
- detail::solve_with_fallback(): optional bool* fallback_used parameter
- solve_linear_system(): public API exposing LDLT→SparseQR fallback

SparseQR fallback tests (SparseQRFallback.*):
- FullRankSystem_CorrectSolution: LDLT path, fallback_used=false
- SingularMatrix_FallbackActivated: zero-pivot → QR activated, fallback_used=true
- Euclidean_ClosedMeshNoPinConverges: gauge-mode null space handled via QR

HyperIdeal Newton tests (NewtonSolver.HyperIdeal_*):
- ConvergesTriangleAllVariable, ResultFieldsConsistent,
  ConvergesTetrahedron, SparseQRFallbackNoCrash
- Natural-target base point (b=1.0, a=0.5) — x=0 is degenerate in log-space

Pipeline tests (test_pipeline.cpp):
- End-to-end: all three geometries, mesh I/O round-trip, solve+export

Example programs (code/examples/):
- example_euclidean.cpp:   headless Euclidean pipeline
- example_hyper_ideal.cpp: headless HyperIdeal pipeline
- example_viewer.cpp:      interactive libigl viewer with jet colour map

README:
- Mathematical scope table: C++ vs Java original (18 rows)
- "For mathematicians" section: mental model, step-by-step new-functional
  guide, half-edge traversal snippets, recommended reading

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-13 00:11:25 +02:00
Tarik Moussa
516ac89bd8 feat(phase3b): port HyperIdealFunctional energy + gradient onto ConformalMesh
Implements the hyper-ideal discrete conformal map functional on
CGAL::Surface_mesh. The energy and analytic gradient are ported directly
from HyperIdealFunctional.java; correctness is verified via a
finite-difference gradient check (same eps=1E-5 / tol=1E-4 as Java).

New files:
  include/hyper_ideal_geometry.hpp    — ζ, ζ₁₃, ζ₁₄, ζ₁₅, lij, αij, σi, σij
  include/hyper_ideal_functional.hpp  — HyperIdealMaps, evaluate_hyper_ideal,
                                        gradient_check
  tests/cgal/test_hyper_ideal_functional.cpp  — 6 tests (1 skipped @Ignore)

Test results (local, -DWITH_CGAL=ON):
  conformallab_cgal_tests: 21 registered | 20 passed | 1 skipped | 0 failed
    - GradientCheck_AllHyperIdealTriangle   ✓
    - GradientCheck_ExtendedDomain          ✓
    - GradientCheck_TetrahedronAllVariable  ✓
    - EnergyFiniteAtTestPoint               ✓
    - GradientCheck_MixedIdealHyperIdeal    ✓
    - GradientCheck_Fan6AllVariable         ✓

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-11 23:10:23 +02:00