4f0a3035e4
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A full audit of `doc/` plus root-level markdown files (27 files) against
the actual ground truth in the C++ code and the local Java repository at
`/Users/tarikmoussa/Desktop/conformallab/` revealed four pre-existing
mis-labels and a stale test count. All are corrected here.
Audit findings — corrected
─────────────────────────
1. **`InversiveDistanceFunctional` mis-labelled as Java port** (4 doc sites)
Empirical verification:
find /Users/tarikmoussa/Desktop/conformallab -iname "*nversive*"
(zero matches)
The class does NOT exist in `de.varylab.discreteconformal`. The C++
implementation is built from Luo 2004 + Glickenstein 2011 + Bowers-
Stephenson 2004 — new research, not a port.
Fixed in: java-parity.md, references.md, add-inversive-distance.md.
2. **HyperIdeal Hessian mis-labelled as "Java has analytic Hessian"**
Empirical verification: `HyperIdealFunctional.java:295-298`:
public boolean hasHessian() { return false; }
Java has NO Hessian at all. Both the FD (Phase 4a) and the block-FD
(Phase 9b) Hessians in C++ are research beyond the Java port. The
chain rule (b,a) → ℓ → ζ → α/β is the *mathematical formulation*
from Springborn 2020, not something Java implements.
Fixed in: java-parity.md.
3. **Stale test count** README:87 said "28 suites, 170 tests" — current
actual is 35 suites, 176 CGAL + 36 non-CGAL. Fixed.
4. **Tutorial framing** — `add-inversive-distance.md` was framed as
"porting an InversiveDistanceFunctional.java" that does not exist.
Rewritten as "Implementing the Inversive-Distance functional from
Luo 2004" with prominent verification block at top.
New document: `doc/roadmap/research-track.md`
─────────────────────────────────────────────
Consolidates everything in conformallab++ that goes beyond a Java port:
* Items already on `main`: HyperIdeal FD Hessian, period matrix τ
partial-research components, Möbius holonomy storage.
* Items on open PRs: CP-Euclidean (PR #8, port), Inversive-Distance
(PR #8, research), block-FD Hessian (PR #9, research).
* Planned research with full citations:
- **Phase 9b-analytic** — full analytic HyperIdeal Hessian via
Schläfli identity (Schläfli 1858/60) and chain rule through
ζ₁₃/ζ₁₄/ζ₁₅, citing Springborn 2020 §4, Cho-Kim 1999,
Glickenstein 2011 §4. Includes acceptance-criteria checklist
(per-case derivative cross-checks, gauge null space, PSD,
measured ≥ 3× speed-up, LaTeX correctness note).
- **Phase 9a.2-analytic** — analytic inversive-distance Hessian
via Glickenstein 2011 eq. (4.6).
- **Phase 10c** — full uniformization for genus g ≥ 2 (Fuchsian
group representation) — fully new research, no Java reference.
- **geometry-central** GC-1/2/3 exploratory track.
* Java backlog summary: 11 worth-porting Java classes identified by
the parallel survey (FundamentalPolygonUtility, DiscreteHarmonicForm-
Utility, DiscreteHolomorphicFormUtility, CanonicalBasisUtility,
HyperbolicCyclicFunctional, QuasiisothermicUtility, KoebePolyhedron, …).
~6 500 Java lines, ~5 months of porting work, organised by phase.
Updated documents
─────────────────
* CLAUDE.md
- New "Port-vs-research maintenance rule" with empirical verification
command and the four corrected mis-labels.
- Doc map: 23 → 24 documents (research-track.md added).
* README.md
- Test count corrected (170 → 176+36).
* doc/math/references.md
- Luo 2004 entry corrected ("new research" instead of "not yet ported").
- New entries for Bowers-Stephenson 2004, Glickenstein 2011,
Bobenko-Pinkall-Springborn 2010, Schläfli 1858/60.
* doc/roadmap/phases.md
- Phase 9 reorganised: 9a split into 9a.1 (port) / 9a.2 (research),
9b clarified as research (Java has no Hessian), 9c expanded with
Java line counts and effort estimates.
- Phase 10 reorganised: 10a/10b/10c with their Java prerequisites
explicitly listed; 10c flagged as "fully new research".
- Phase 10b' added: parallel research track (hyperbolic functional,
quasi-isothermic, Möbius centering).
- Phase 10c' added: optional Java-port additions (Koebe, circle
patterns, electrostatic sphere).
* doc/roadmap/java-parity.md
- Inversive-distance row: ❌ Java, ❌ C++ (Phase 9a.2) — new research.
- CP-Euclidean row added: ✅ Java, ❌ C++ (Phase 9a.1) — port.
- HyperIdeal Hessian row: ❌ Java, ⚠️ FD + block-FD in C++.
- Worth-porting table replaced with the survey results (12 classes,
Java line counts, suggested phases).
- "HyperIdeal Hessian: FD vs analytic" section rewritten with the
correction notice.
* doc/tutorials/add-inversive-distance.md
- Rewritten end-to-end with prominent verification block at top.
- Now correctly framed as "Implementing the Inversive-Distance
functional from Luo 2004" — research, not port.
- Includes the four required cross-validations:
limit cases, Bowers-Stephenson round-trip, FD-vs-analytic,
cross-validation against euclidean_functional at u=0.
- New "How to know if it's a port or research" closing section
with the empirical verification command.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
139 lines
7.3 KiB
Markdown
139 lines
7.3 KiB
Markdown
# conformallab++
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[](https://git.eulernest.eu/conformallab/ConformalLabpp/actions)
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[](LICENSE)
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[](https://depositonce.tu-berlin.de/items/8e2988b2-d991-45b5-aad5-9fb7988f3b2f)
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C++17 reimplementation of [ConformalLab](https://github.com/varylab/conformallab) —
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Stefan Sechelmann's Java research library for discrete conformal geometry (TU Berlin).
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The long-term goal is a **CGAL package** for discrete conformal maps.
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Algorithmic foundation:
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> Stefan Sechelmann — *Variational Methods for Discrete Surface Parameterization: Applications and Implementation*, TU Berlin 2016.
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> DOI: [10.14279/depositonce-5415](https://depositonce.tu-berlin.de/items/8e2988b2-d991-45b5-aad5-9fb7988f3b2f) · CC BY-SA 4.0 ·
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> [Java original](https://github.com/varylab/conformallab) · [sechel.de](https://sechel.de/)
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**Status:** Phase 7 complete. Newton solver for all three geometries (Euclidean / Spherical / HyperIdeal), priority-BFS layout in ℝ²/S²/Poincaré disk, Gauss–Bonnet, tree-cotree cut graph, Möbius holonomy, period matrix (genus 1), fundamental domain, halfedge_uv texture atlas, JSON/XML serialisation, CLI app. **176 CGAL tests + 36 non-CGAL tests.**
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---
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## Quick start
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```bash
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git clone https://codeberg.org/TMoussa/ConformalLabpp && cd ConformalLabpp
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# Fast tests — no system dependencies
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cmake -S code -B build && cmake --build build --target conformallab_tests -j$(nproc)
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ctest --test-dir build --output-on-failure
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# CGAL tests headless (apt install libboost-dev / brew install boost)
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cmake -S code -B build -DWITH_CGAL_TESTS=ON
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cmake --build build --target conformallab_cgal_tests -j$(nproc)
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ctest --test-dir build -R "^cgal\." --output-on-failure
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# Full build with CLI + viewer (requires Wayland/X11 dev headers)
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cmake -S code -B build -DWITH_CGAL=ON && cmake --build build -j$(nproc)
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./bin/conformallab_core -i input.off -g euclidean -o layout.off -j result.json
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# API documentation (requires doxygen: brew/apt install doxygen)
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cmake --build build --target doc
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open doc/doxygen/html/index.html
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```
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---
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## Minimal usage
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```cpp
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#include "conformal_mesh.hpp"
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#include "mesh_io.hpp"
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#include "euclidean_functional.hpp"
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#include "gauss_bonnet.hpp"
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#include "newton_solver.hpp"
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#include "layout.hpp"
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using namespace conformallab;
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ConformalMesh mesh = load_mesh("input.off");
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EuclideanMaps maps = setup_euclidean_maps(mesh);
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compute_euclidean_lambda0_from_mesh(mesh, maps);
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// Assign DOFs — pin first vertex (gauge fix)
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auto vit = mesh.vertices().begin();
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maps.v_idx[*vit++] = -1;
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int idx = 0;
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for (; vit != mesh.vertices().end(); ++vit) maps.v_idx[*vit] = idx++;
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// Natural equilibrium target: x* = 0 by construction
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std::vector<double> x0(idx, 0.0);
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auto G0 = euclidean_gradient(mesh, x0, maps);
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for (auto v : mesh.vertices())
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if (maps.v_idx[v] >= 0) maps.theta_v[v] -= G0[maps.v_idx[v]];
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check_gauss_bonnet(mesh, maps);
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NewtonResult res = newton_euclidean(mesh, x0, maps);
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Layout2D layout = euclidean_layout(mesh, res.x, maps);
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```
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---
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## Documentation
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| **Getting started** — build modes, single-test invocation, CLI, Docker | [doc/getting-started.md](doc/getting-started.md) |
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| **Pipeline API** — all three geometries, holonomy, serialisation | [doc/api/pipeline.md](doc/api/pipeline.md) |
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| **Public headers** — all 24 headers with descriptions | [doc/api/headers.md](doc/api/headers.md) |
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| **Test suites** — 35 suites, 176+36 tests, individual counts | [doc/api/tests.md](doc/api/tests.md) |
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| **Extending** — new functionals, geometry modes, porting from Java | [doc/api/extending.md](doc/api/extending.md) |
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| **Processing unit contracts** — preconditions / provides table | [doc/api/contracts.md](doc/api/contracts.md) |
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| **CGAL package design** — Phase 8 target, YAML pipeline | [doc/api/cgal-package.md](doc/api/cgal-package.md) |
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| **Architecture & pipeline diagram** | [doc/architecture/overall_pipeline.md](doc/architecture/overall_pipeline.md) |
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| **geometry-central comparison** — shared core, demarcation, adoption candidates, scientific added value | [doc/architecture/geometry-central-comparison.md](doc/architecture/geometry-central-comparison.md) |
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| **Design decisions** — key architectural choices + rationale | [doc/architecture/design-decisions.md](doc/architecture/design-decisions.md) |
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| **Project structure** — directory tree + build targets | [doc/architecture/project-structure.md](doc/architecture/project-structure.md) |
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| **Discrete conformal theory** — mathematical background for collaborators | [doc/math/discrete-conformal-theory.md](doc/math/discrete-conformal-theory.md) |
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| **Validation** — known analytic results + how to verify them | [doc/math/validation.md](doc/math/validation.md) |
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| **Validation protocol** — concrete commands with expected outputs | [doc/math/validation-protocol.md](doc/math/validation-protocol.md) |
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| **Tutorial: add a new functional** — step-by-step Inversive-Distance port | [doc/tutorials/add-inversive-distance.md](doc/tutorials/add-inversive-distance.md) |
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| **Declarative YAML pipeline** — concept, token vocabulary, 5 examples | [doc/concepts/declarative-pipeline.md](doc/concepts/declarative-pipeline.md) |
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| **Geometry modes** — Euclidean / Spherical / HyperIdeal comparison | [doc/math/geometry-modes.md](doc/math/geometry-modes.md) |
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| **References** — all papers by module | [doc/math/references.md](doc/math/references.md) |
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| **Software landscape** — how conformallab++ relates to libigl, CGAL, geometry-central | [doc/math/software-landscape.md](doc/math/software-landscape.md) |
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| **Novelty statement** — unique features, target audience, what this is not | [doc/math/novelty-statement.md](doc/math/novelty-statement.md) |
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| **Complexity & scalability** — O() analysis, measured timings on real meshes, HyperIdeal bottleneck | [doc/math/complexity.md](doc/math/complexity.md) |
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| **Roadmap** — Phases 1–10 | [doc/roadmap/phases.md](doc/roadmap/phases.md) |
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| **Java parity table** — what is ported, what is planned | [doc/roadmap/java-parity.md](doc/roadmap/java-parity.md) |
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| **Contributing** — language policy, test standards, release flow | [doc/contributing.md](doc/contributing.md) |
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| **Claude Code context** | [CLAUDE.md](CLAUDE.md) |
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---
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## Citing
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If you use conformallab++ in your research, please cite it using the metadata
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in [`CITATION.cff`](CITATION.cff). GitHub and Codeberg show a "Cite this repository"
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button that generates BibTeX and APA automatically.
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The primary algorithmic source is:
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> Stefan Sechelmann — *Variational Methods for Discrete Surface Parameterization:
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> Applications and Implementation*, TU Berlin 2016.
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> DOI: [10.14279/depositonce-5415](https://depositonce.tu-berlin.de/items/8e2988b2-d991-45b5-aad5-9fb7988f3b2f)
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---
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## Bugs & questions
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- **Bug reports / feature requests:** [Gitea Issues](https://git.eulernest.eu/conformallab/ConformalLabpp/issues)
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- **Code mirror (read-only):** [Codeberg](https://codeberg.org/TMoussa/ConformalLabpp)
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- **Contact:** Tarik Moussa · Tarik.moussa95@gmail.com
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---
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## License
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conformallab++ is released under the MIT License (see [LICENSE](LICENSE)).
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Copyright © 2024–2026 Tarik Moussa.
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The dissertation (Sechelmann 2016) is CC BY-SA 4.0.
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