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Jungfraujoch/tests/LatticeReductionTest.cpp
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// SPDX-FileCopyrightText: 2024 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only
#include <catch2/catch_all.hpp>
#include <Eigen/Dense>
#include "../image_analysis/geom_refinement/LatticeReduction.h"
namespace {
Eigen::Vector3d to_eigen(const Coord& v) {
return {v[0], v[1], v[2]};
}
double angle_rad(const Eigen::Vector3d& a, const Eigen::Vector3d& b) {
const double na = a.norm();
const double nb = b.norm();
if (na == 0.0 || nb == 0.0)
return 0.0;
double c = a.dot(b) / (na * nb);
c = std::max(-1.0, std::min(1.0, c));
return std::acos(c);
}
// Compare two lattices up to a global rotation: compare Gram matrices G = L^T L (rotation-invariant).
Eigen::Matrix3d gram(const CrystalLattice& latt) {
const Eigen::Vector3d A = to_eigen(latt.Vec0());
const Eigen::Vector3d B = to_eigen(latt.Vec1());
const Eigen::Vector3d C = to_eigen(latt.Vec2());
Eigen::Matrix3d G;
G(0,0) = A.dot(A); G(0,1) = A.dot(B); G(0,2) = A.dot(C);
G(1,0) = B.dot(A); G(1,1) = B.dot(B); G(1,2) = B.dot(C);
G(2,0) = C.dot(A); G(2,1) = C.dot(B); G(2,2) = C.dot(C);
return G;
}
void check_gram_close(const CrystalLattice& a,
const CrystalLattice& b,
double abs_eps,
double rel_eps) {
const Eigen::Matrix3d Ga = gram(a);
const Eigen::Matrix3d Gb = gram(b);
for (int r = 0; r < 3; ++r) {
for (int c = 0; c < 3; ++c) {
const double va = Ga(r, c);
const double vb = Gb(r, c);
// Scale for relative error; avoid blowing up around zero.
const double scale = std::max({1.0, std::abs(va), std::abs(vb)});
const double tol = std::max(abs_eps, rel_eps * scale);
INFO("G(" << r << "," << c << ") va=" << va << " vb=" << vb
<< " scale=" << scale << " tol=" << tol);
CHECK(va == Catch::Approx(vb).margin(tol));
}
}
}
} // namespace
TEST_CASE("LatticeToRodrigues") {
double rod[3];
double lengths[3];
CrystalLattice latt_i(40,50,80,90,90,90);
LatticeToRodriguesAndLengths_GS(latt_i, rod, lengths);
CHECK(lengths[0] == Catch::Approx(40.0));
CHECK(lengths[1] == Catch::Approx(50.0));
CHECK(lengths[2] == Catch::Approx(80.0));
CHECK(fabs(rod[0]) < 0.001);
CHECK(fabs(rod[1]) < 0.001);
CHECK(fabs(rod[2]) < 0.001);
auto latt_o = AngleAxisAndCellToLattice(rod, lengths, M_PI/2, M_PI/2, M_PI/2);
CHECK(latt_o.Vec0().Length() == Catch::Approx(40.0));
CHECK(latt_o.Vec1().Length() == Catch::Approx(50.0));
CHECK(latt_o.Vec2().Length() == Catch::Approx(80.0));
}
TEST_CASE("LatticeToRodrigues_irregular") {
double rod[3];
double lengths[3];
CrystalLattice latt_i(Coord(40,0,0),
Coord(0, 50 / sqrt(2), -50 / sqrt(2)),
Coord(0, 80 / sqrt(2), 80 / sqrt(2)));
LatticeToRodriguesAndLengths_GS(latt_i, rod, lengths);
CHECK(lengths[0] == Catch::Approx(40.0));
CHECK(lengths[1] == Catch::Approx(50.0));
CHECK(lengths[2] == Catch::Approx(80.0));
auto latt_o = AngleAxisAndCellToLattice(rod, lengths, M_PI/2, M_PI/2, M_PI/2);
CHECK(latt_o.Vec0().Length() == Catch::Approx(40.0));
CHECK(latt_o.Vec1().Length() == Catch::Approx(50.0));
CHECK(latt_o.Vec2().Length() == Catch::Approx(80.0));
}
TEST_CASE("LatticeToRodrigues_Hex") {
double rod[3];
double lengths[3];
Coord a = Coord(40,0,0);
Coord b = Coord(40 / 2, 40 * sqrt(3)/ 2.0, 0);
Coord c = Coord(0, 0, 70);
RotMatrix R(1.0, Coord(0,1,1));
CrystalLattice latt_i(R*a,R*b,R*c);
LatticeToRodriguesAndLengths_Hex(latt_i, rod, lengths);
CHECK(lengths[0] == Catch::Approx(40.0));
CHECK(lengths[1] == Catch::Approx(40.0));
CHECK(lengths[2] == Catch::Approx(70.0));
auto latt_o = AngleAxisAndCellToLattice(rod, lengths,M_PI / 2.0, M_PI / 2.0, 2.0 * M_PI / 3.0);
auto uc_o = latt_o.GetUnitCell();
CHECK(uc_o.a == Catch::Approx(40.0));
CHECK(uc_o.b == Catch::Approx(40.0));
CHECK(uc_o.c == Catch::Approx(70.0));
CHECK(uc_o.alpha == Catch::Approx(90.0));
CHECK(uc_o.beta == Catch::Approx(90.0));
CHECK(uc_o.gamma == Catch::Approx(120.0));
}
TEST_CASE("LatticeReduction Lattice param roundtrip (GS) preserves Gram matrix") {
// Non-orthogonal, irregular basis, but still a valid lattice
CrystalLattice latt_i(Coord(40, 1, 2),
Coord( 3, 50, -4),
Coord(-5, 6, 80));
double rod[3]{}, lengths[3]{};
LatticeToRodriguesAndLengths_GS(latt_i, rod, lengths);
auto latt_o = AngleAxisAndCellToLattice(rod, lengths, M_PI/2, M_PI/2, M_PI/2);
// This parametrization only keeps "lengths + rotation", i.e. it cannot reproduce shear.
// So we *do not* compare Gram matrices here.
// Instead, sanity-check: reconstructed vectors have the requested lengths.
CHECK(latt_o.Vec0().Length() == Catch::Approx(lengths[0]).margin(1e-9));
CHECK(latt_o.Vec1().Length() == Catch::Approx(lengths[1]).margin(1e-9));
CHECK(latt_o.Vec2().Length() == Catch::Approx(lengths[2]).margin(1e-9));
}
TEST_CASE("LatticeReduction Lattice param roundtrip (Hex) preserves unit cell") {
Coord a = Coord(40, 0, 0);
Coord b = Coord(40 / 2.0, 40 * std::sqrt(3) / 2.0, 0);
Coord c = Coord(0, 0, 70);
// Apply an arbitrary rotation to ensure the rod extraction is meaningful
RotMatrix R(1.0, Coord(0, 1, 1));
CrystalLattice latt_i(R * a, R * b, R * c);
double rod[3]{}, ac[3]{};
LatticeToRodriguesAndLengths_Hex(latt_i, rod, ac);
auto latt_o = AngleAxisAndCellToLattice(rod, ac, M_PI/2, M_PI/2, 2*M_PI/3);
auto uc_o = latt_o.GetUnitCell();
CHECK(uc_o.a == Catch::Approx(40.0).margin(1e-6));
CHECK(uc_o.b == Catch::Approx(40.0).margin(1e-6));
CHECK(uc_o.c == Catch::Approx(70.0).margin(1e-6));
CHECK(uc_o.alpha == Catch::Approx(90.0).margin(1e-6));
CHECK(uc_o.beta == Catch::Approx(90.0).margin(1e-6));
CHECK(uc_o.gamma == Catch::Approx(120.0).margin(1e-6));
}
TEST_CASE("LatticeReduction Monoclinic param roundtrip") {
struct Case { double beta_deg; };
const std::vector<Case> cases = {
{60.0}, {75.0}, {115.0}, {130.0}
};
for (const auto& cs : cases) {
INFO("beta_deg=" << cs.beta_deg);
// Start from a clean monoclinic cell in its conventional setting (unique axis b).
CrystalLattice latt0(50, 60, 70, 90, cs.beta_deg, 90);
// Now apply a TRUE global rotation: rotate each basis vector (left-multiply).
RotMatrix R(0.7, Coord(0.3, 0.9, 0.1));
CrystalLattice latt_i(R * latt0.Vec0(),
R * latt0.Vec1(),
R * latt0.Vec2());
double rod[3]{}, lengths[3]{}, beta_rad = 0.0;
LatticeToRodriguesLengthsBeta_Mono(latt_i, rod, lengths, beta_rad);
// Basic sanity
CHECK(lengths[0] == Catch::Approx(50.0).margin(1e-6));
CHECK(lengths[1] == Catch::Approx(60.0).margin(1e-6));
CHECK(lengths[2] == Catch::Approx(70.0).margin(1e-6));
CHECK(beta_rad * 180.0 / M_PI == Catch::Approx(cs.beta_deg).margin(1e-6));
auto latt_o = AngleAxisAndCellToLattice(rod, lengths, M_PI/2, beta_rad, M_PI/2);
// Rotation-invariant check: Gram matrices match.
check_gram_close(latt_i, latt_o, /*abs_eps=*/5e-4, /*rel_eps=*/1e-10);
// Also check the unit-cell angles we expect for monoclinic(unique b).
auto uc_o = latt_o.GetUnitCell();
CHECK(uc_o.alpha == Catch::Approx(90.0).margin(1e-4));
CHECK(uc_o.gamma == Catch::Approx(90.0).margin(1e-4));
CHECK(uc_o.beta == Catch::Approx(cs.beta_deg).margin(1e-4));
}
}
TEST_CASE("LatticeReduction monoclinic") {
// This isolates only the beta definition, independent of other choices.
CrystalLattice latt_i(50, 60, 70, 90, 130, 90);
const Eigen::Vector3d A = to_eigen(latt_i.Vec0());
const Eigen::Vector3d C = to_eigen(latt_i.Vec2());
const double beta_geom = angle_rad(A, C);
double rod[3]{}, lengths[3]{}, beta_rad = 0.0;
LatticeToRodriguesLengthsBeta_Mono(latt_i, rod, lengths, beta_rad);
CHECK(beta_rad == Catch::Approx(beta_geom).margin(1e-12));
}