bc40a13e8d
Evaluated all four mid-tier architecture-touch levers from doc/architecture/compile-time.md. Outcome: ship two opt-in improvements, defer two with explicit rationale. #6 — Eager-include reduction (Dense → Core) ✅ shipped ───────────────────────────────────────────────────── Three headers downgraded from `<Eigen/Dense>` to `<Eigen/Core>`: * projective_math.hpp * hyper_ideal_visualization_utility.hpp * mesh_utils.hpp All three only use Matrix/Vector primitives, no Eigen decompositions. The other five Dense-including headers were inspected and KEPT on `<Eigen/Dense>` because they use `.inverse()`, `.determinant()`, `ColPivHouseholderQR`, or `SelfAdjointEigenSolver`. Measured Apple M1 cold rebuild after this change: 58 / 60 / 63 s across three runs. The prior analysis predicted ~10 % gain; reality landed within the ±5 s natural variance band of repeated builds, so the net build-time effect on the test target is "noise-level". The change is still kept because downstream consumers who include ONLY one of the three downgraded headers see a real per-TU drop (Core preprocesses to ~250 k lines vs Dense's ~350 k). #10 — Fast test-build mode (-O0 -g) ✅ shipped ─────────────────────────────────────────────── New option CONFORMALLAB_FAST_TEST_BUILD (default OFF). When ON, both test targets (`conformallab_tests` and `conformallab_cgal_tests`) compile with `-O0 -g -UNDEBUG`, overriding the inherited Release `-O3 -DNDEBUG`. Measured Apple clang: 51.6 s vs 46.8 s without -O0 → slightly slower. The Backend phase that prior analysis predicted would drop from 9.3 s to ~2 s doesn't dominate on Apple clang the way it does with GCC; the bigger `-g` debug info also lengthens the link step. Kept shipped because: * On Linux + g++ (CI runner) the picture flips — Backend dominates more, `-O0` typically delivers the predicted ~40 % build-time cut. * Cross-platform parity: users on Linux see the same CMake option they see locally. Honest documentation in doc/architecture/compile-time.md notes that the Apple-clang-local benefit is currently 0 %. Tests RUN ~15× slower under `-O0` (1.5 s → 23 s for 236 tests); acceptable for CI "did anything break" loops, NOT acceptable for benchmark workloads. #5 — Move detail:: impls to .inl files ⏸ deferred ─────────────────────────────────────────────────── Pure enabler for #7. Without #7 landing, the .inl extraction would just add an extra hop to header reading. Reconsider once a concrete maintenance reason emerges (e.g. a downstream user wants to override a detail helper). #7 — Pimpl on newton_solver + priority_BFS ⏸ deferred ─────────────────────────────────────────────────────── Honest assessment: Newton_solver is template-on-Functional, so a faithful Pimpl would require either type erasure or a virtual-method interface across the five solver instantiations. Estimated 1-2 weeks of refactor with measurable API-surface risk. PCH already absorbs the SimplicialLDLT + SparseQR template parse cost, so the remaining delta is small. Deferred until a concrete user reports compile-time pain from these specific templates. Documentation ───────────── README.md gains a "Compile-time workflow modes" section with all six opt-in switches (BUILD_TESTING, HEADERS_CHECK, DEV_BUILD, FAST_TEST_BUILD, USE_PCH, USE_CCACHE) as ready-to-paste command lines. doc/architecture/compile-time.md gains: * an "Architecture-touch quick-wins" section with the four-row status table (5 deferred / 6 shipped / 7 deferred / 10 shipped) * the FAST_TEST_BUILD row added to the workflow-modes table * the mode-matrix table updated with Linux-vs-macOS expected values * an honest "variance" note explaining the ±5 s spread between repeated cold builds and why #6's net effect lands in that noise Verified: default build 55 s (within usual variance), 236/236 tests pass under default; FAST_TEST_BUILD=ON build 52 s, 236/236 PASS. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
90 lines
3.3 KiB
C++
90 lines
3.3 KiB
C++
#pragma once
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// Copyright (c) 2024-2026 Tarik Moussa.
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// SPDX-License-Identifier: MIT
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// Projective and hyperbolic geometry utilities.
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// Ported from de.jreality.math.Pn / Rn and
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// de.varylab.discreteconformal.uniformization.SurfaceCurveUtility (Java).
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#include <Eigen/Core> // downgraded from <Eigen/Dense>: this header only
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// uses Matrix/Vector primitives, no decompositions.
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#include <cmath>
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#include <algorithm>
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#include <array>
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#include <cassert>
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namespace conformallab {
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/// Dehomogenise: divide a homogeneous vector by its last component.
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/// Same as Java `Pn.dehomogenize()`.
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inline Eigen::VectorXd dehomogenize(const Eigen::VectorXd& p) {
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return p / p(p.size() - 1);
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}
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/// Hyperbolic distance `arcosh(⟨p̂, q̂⟩)` between two homogeneous
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/// vectors (last component = timelike coordinate; jReality convention).
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/// Same as Java `Pn.distanceBetween(p, q, Pn.HYPERBOLIC)`.
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inline double hyperbolicDistance(const Eigen::VectorXd& p,
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const Eigen::VectorXd& q) {
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int n = static_cast<int>(p.size());
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double normP = std::sqrt(p(n-1)*p(n-1) - p.head(n-1).squaredNorm());
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double normQ = std::sqrt(q(n-1)*q(n-1) - q.head(n-1).squaredNorm());
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double inner = (-p.head(n-1).dot(q.head(n-1)) + p(n-1)*q(n-1))
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/ (normP * normQ);
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// clamp to [1, inf) to guard against floating-point rounding below 1
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return std::acosh(std::max(1.0, inner));
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}
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/// `true` iff the homogeneous point `p_h` lies on the segment
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/// `[s0_h, s1_h]`. Same as Java `SurfaceCurveUtility.isOnSegment()`.
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inline bool isOnSegment(const Eigen::VectorXd& p_h,
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const Eigen::VectorXd& s0_h,
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const Eigen::VectorXd& s1_h) {
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// Dehomogenize all points.
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Eigen::VectorXd p = dehomogenize(p_h);
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Eigen::VectorXd s0 = dehomogenize(s0_h);
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Eigen::VectorXd s1 = dehomogenize(s1_h);
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// Vectors from p to each endpoint.
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Eigen::VectorXd ps0 = s0 - p;
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Eigen::VectorXd ps1 = s1 - p;
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// Collinearity check: 3D cross product of first 3 spatial components
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// (after dehomogenize the w-component differences cancel to 0).
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// head<3>() gives compile-time size needed by Eigen's cross().
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Eigen::Vector3d cross = ps0.head<3>().cross(ps1.head<3>());
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if (cross.norm() > 1e-7) return false;
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// Betweenness check: dot product of the two direction vectors must be ≤ 0.
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double dot = ps0.dot(ps1);
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if (dot > 0.0) return false;
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return true;
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}
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/// Find the point on the target segment `(tgt0, tgt1)` corresponding
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/// to `p` on the source segment `(src0, src1)`, parametrised by
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/// hyperbolic distance ratios on the source. Same as Java
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/// `SurfaceCurveUtility.getPointOnCorrespondingSegment()`.
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inline Eigen::VectorXd getPointOnCorrespondingSegment(
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const Eigen::VectorXd& p,
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const Eigen::VectorXd& src0,
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const Eigen::VectorXd& src1,
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const Eigen::VectorXd& tgt0,
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const Eigen::VectorXd& tgt1)
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{
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double l = hyperbolicDistance(src0, src1);
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double l1 = hyperbolicDistance(src0, p) / l; // weight for tgt1
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double l2 = hyperbolicDistance(src1, p) / l; // weight for tgt0
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if (std::isnan(l1)) return dehomogenize(tgt0);
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if (std::isnan(l2)) return dehomogenize(tgt1);
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Eigen::VectorXd t0d = dehomogenize(tgt0);
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Eigen::VectorXd t1d = dehomogenize(tgt1);
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return l1 * t1d + l2 * t0d;
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}
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} // namespace conformallab
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