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ConformalLabpp/code/include/hyper_ideal_utility.hpp
Tarik Moussa 62b02f88b9
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docs(doxygen): 100% public-API coverage (228 → 0 undocumented)
Completes the work begun in the previous commit on this branch.  Every
public symbol under code/include/ now carries a brief Doxygen comment
(0 undocumented per scripts/doxygen-coverage.sh, with the `detail::`
implementation namespaces excluded as before).

Trajectory on this branch:
  start (after Doxyfile fix):  24.0 %  (165 / 437 in the no-detail set
                                       was 105 / 437 when detail counted)
  after PR #17 base commit  :  42.4 %  (165 / 396)
  this commit               : 100.0 %  (396 / 396)

Files touched (all .hpp / .h headers under code/include/):
  * cgal/Conformal_map_traits.h
  * clausen.hpp, conformal_mesh.hpp, constants.hpp (already docd)
  * cp_euclidean_functional.hpp, cut_graph.hpp, discrete_elliptic_utility.hpp
  * euclidean_functional.hpp, euclidean_geometry.hpp, euclidean_hessian.hpp
  * fundamental_domain.hpp, gauss_bonnet.hpp
  * hyper_ideal_{functional,geometry,hessian,utility,visualization_utility}.hpp
  * inversive_distance_functional.hpp, layout.hpp
  * matrix_utility.hpp, mesh_builder.hpp, mesh_io.hpp
  * newton_solver.hpp, p2_utility.hpp, period_matrix.hpp, projective_math.hpp
  * serialization.hpp, spherical_functional.hpp, spherical_geometry.hpp
  * spherical_hessian.hpp, viewer_utils.h

CI:
.gitea/workflows/doxygen-pages.yml now enforces
`scripts/doxygen-coverage.sh --threshold 100`, so any future regression
(a new public function landed without a `///` brief) fails the build
before the Doxygen HTML is published to Codeberg Pages.

Doxygen warnings remain at 0.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-24 04:22:49 +02:00

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#pragma once
// Hyperbolic tetrahedron volume formulas.
// Ported from de.varylab.discreteconformal.functional.HyperIdealUtility (Java).
#include "clausen.hpp"
#include "constants.hpp"
#include <Eigen/Dense>
#include <cmath>
#include <complex>
namespace conformallab {
/// Volume of a generalized hyperbolic tetrahedron with dihedral
/// angles `A,…,F` via the Meyerhoff / Ushijima 2006 formula.
/// Same as Java `HyperIdealUtility.calculateTetrahedronVolume()`.
inline double calculateTetrahedronVolume(double A, double B, double C,
double D, double E, double F) {
// PI from constants.hpp (conformallab::PI)
// Degenerate if any angle equals pi.
if (A == PI || B == PI || C == PI || D == PI || E == PI || F == PI)
return 0.0;
const double sA = std::sin(A), sB = std::sin(B), sC = std::sin(C);
const double sD = std::sin(D), sE = std::sin(E), sF = std::sin(F);
const double cA = std::cos(A), cB = std::cos(B), cC = std::cos(C);
const double cD = std::cos(D), cE = std::cos(E), cF = std::cos(F);
// Unit complex numbers e^(i*angle).
using Cx = std::complex<double>;
auto polar = [](double angle) { return std::polar(1.0, angle); };
Cx ad = polar(A + D), be = polar(B + E), cf = polar(C + F);
Cx abc = polar(A + B + C), abf = polar(A + B + F);
Cx ace = polar(A + C + E), aef = polar(A + E + F);
Cx bcd = polar(B + C + D), bdf = polar(B + D + F);
Cx def = polar(D + E + F), cde = polar(C + D + E);
Cx abde = ad * be, acdf = ad * cf, bcef = be * cf;
Cx abcdef = abc * def;
Cx z = ad + be + cf + abf + ace + bcd + def + abcdef;
// Gram matrix of the tetrahedron.
Eigen::Matrix4d G;
G << 1.0, -cA, -cB, -cF,
-cA, 1.0, -cC, -cE,
-cB, -cC, 1.0, -cD,
-cF, -cE, -cD, 1.0;
Cx sqrtG = std::sqrt(Cx(G.determinant(), 0.0));
Cx f = Cx(sA*sD + sB*sE + sC*sF, 0.0);
Cx f1 = f - sqrtG;
Cx f2 = f + sqrtG;
Cx z1 = -2.0 * f1 / z;
Cx z2 = -2.0 * f2 / z;
auto U = [&](Cx zi) {
return 0.5 * (
+ ImLi2(zi)
+ ImLi2(abde * zi)
+ ImLi2(acdf * zi)
+ ImLi2(bcef * zi)
- ImLi2(-abc * zi)
- ImLi2(-aef * zi)
- ImLi2(-bdf * zi)
- ImLi2(-cde * zi)
);
};
return (U(z1) - U(z2)) / 2.0;
}
/// Volume of a hyperideal tetrahedron with one ideal vertex at γ via
/// the Kolpakov-Mednykh formula (arxiv math/0603097). Same as Java
/// `HyperIdealUtility.calculateTetrahedronVolumeWithIdealVertexAtGamma()`.
inline double calculateTetrahedronVolumeWithIdealVertexAtGamma(
double gamma1, double gamma2, double gamma3,
double alpha23, double alpha31, double alpha12)
{
// PI from constants.hpp (conformallab::PI)
auto L = [](double x) { return Lobachevsky(x); };
double result = L(gamma1) + L(gamma2) + L(gamma3);
result += L((PI + alpha31 - alpha12 - gamma1) / 2.0);
result += L((PI + alpha12 - alpha23 - gamma2) / 2.0);
result += L((PI + alpha23 - alpha31 - gamma3) / 2.0);
result += L((PI - alpha31 + alpha12 - gamma1) / 2.0);
result += L((PI - alpha12 + alpha23 - gamma2) / 2.0);
result += L((PI - alpha23 + alpha31 - gamma3) / 2.0);
result += L((PI + alpha31 + alpha12 - gamma1) / 2.0);
result += L((PI + alpha12 + alpha23 - gamma2) / 2.0);
result += L((PI + alpha23 + alpha31 - gamma3) / 2.0);
result += L((PI - alpha31 - alpha12 - gamma1) / 2.0);
result += L((PI - alpha12 - alpha23 - gamma2) / 2.0);
result += L((PI - alpha23 - alpha31 - gamma3) / 2.0);
return result / 2.0;
}
} // namespace conformallab