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hand-motion-pipeline/third_party/vipe/csrc/lietorch_ext/so3.h
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/**
* This file includes code originally from the lietorch repository:
* https://github.com/princeton-vl/lietorch
* Licensed under the BSD-3 License. See THIRD_PARTY_LICENSES.md for details.
*/
#ifndef SO3_HEADER
#define SO3_HEADER
#include <cuda.h>
#include <stdio.h>
#include <eigen3/Eigen/Dense>
#include <eigen3/Eigen/Geometry>
#include "common.h"
template <typename Scalar>
class SO3 {
public:
const static int constexpr K = 3; // manifold dimension
const static int constexpr N = 4; // embedding dimension
using Vector3 = Eigen::Matrix<Scalar, 3, 1>;
using Vector4 = Eigen::Matrix<Scalar, 4, 1>;
using Matrix3 = Eigen::Matrix<Scalar, 3, 3>;
using Tangent = Eigen::Matrix<Scalar, K, 1>;
using Data = Eigen::Matrix<Scalar, N, 1>;
using Point = Eigen::Matrix<Scalar, 3, 1>;
using Point4 = Eigen::Matrix<Scalar, 4, 1>;
using Transformation = Eigen::Matrix<Scalar, 3, 3>;
using Adjoint = Eigen::Matrix<Scalar, K, K>;
using Quaternion = Eigen::Quaternion<Scalar>;
EIGEN_DEVICE_FUNC SO3(Quaternion const& q) : unit_quaternion(q) { unit_quaternion.normalize(); };
EIGEN_DEVICE_FUNC SO3(const Scalar* data) : unit_quaternion(data) { unit_quaternion.normalize(); };
EIGEN_DEVICE_FUNC SO3() { unit_quaternion = Quaternion::Identity(); }
EIGEN_DEVICE_FUNC SO3<Scalar> inv() { return SO3<Scalar>(unit_quaternion.conjugate()); }
EIGEN_DEVICE_FUNC Data data() const { return unit_quaternion.coeffs(); }
EIGEN_DEVICE_FUNC SO3<Scalar> operator*(SO3<Scalar> const& other) {
return SO3(unit_quaternion * other.unit_quaternion);
}
EIGEN_DEVICE_FUNC Point operator*(Point const& p) const {
const Quaternion& q = unit_quaternion;
Point uv = q.vec().cross(p);
uv += uv;
return p + q.w() * uv + q.vec().cross(uv);
}
EIGEN_DEVICE_FUNC Point4 act4(Point4 const& p) const {
Point4 p1;
p1 << this->operator*(p.template segment<3>(0)), p(3);
return p1;
}
EIGEN_DEVICE_FUNC Adjoint Adj() const { return unit_quaternion.toRotationMatrix(); }
EIGEN_DEVICE_FUNC Transformation Matrix() const { return unit_quaternion.toRotationMatrix(); }
EIGEN_DEVICE_FUNC Eigen::Matrix<Scalar, 4, 4> Matrix4x4() const {
Eigen::Matrix<Scalar, 4, 4> T = Eigen::Matrix<Scalar, 4, 4>::Identity();
T.template block<3, 3>(0, 0) = Matrix();
return T;
}
EIGEN_DEVICE_FUNC Eigen::Matrix<Scalar, 4, 4> orthogonal_projector() const {
// jacobian action on a point
Eigen::Matrix<Scalar, 4, 4> J = Eigen::Matrix<Scalar, 4, 4>::Zero();
J.template block<3, 3>(0, 0) =
0.5 * (unit_quaternion.w() * Matrix3::Identity() + SO3<Scalar>::hat(-unit_quaternion.vec()));
J.template block<1, 3>(3, 0) = 0.5 * (-unit_quaternion.vec());
return J;
}
EIGEN_DEVICE_FUNC Tangent Adj(Tangent const& a) const { return Adj() * a; }
EIGEN_DEVICE_FUNC Tangent AdjT(Tangent const& a) const { return Adj().transpose() * a; }
EIGEN_DEVICE_FUNC static Transformation hat(Tangent const& phi) {
Transformation Phi;
Phi << 0.0, -phi(2), phi(1), phi(2), 0.0, -phi(0), -phi(1), phi(0), 0.0;
return Phi;
}
EIGEN_DEVICE_FUNC static Adjoint adj(Tangent const& phi) { return SO3<Scalar>::hat(phi); }
EIGEN_DEVICE_FUNC Tangent Log() const {
using std::abs;
using std::atan;
using std::sqrt;
Scalar squared_n = unit_quaternion.vec().squaredNorm();
Scalar w = unit_quaternion.w();
Scalar two_atan_nbyw_by_n;
/// Atan-based log thanks to
///
/// C. Hertzberg et al.:
/// "Integrating Generic Sensor Fusion Algorithms with Sound State
/// Representation through Encapsulation of Manifolds"
/// Information Fusion, 2011
if (squared_n < EPS * EPS) {
// If quaternion is normalized and n=0, then w should be 1;
// w=0 should never happen here!
Scalar squared_w = w * w;
two_atan_nbyw_by_n = Scalar(2) / w - Scalar(2.0 / 3.0) * (squared_n) / (w * squared_w);
} else {
Scalar n = sqrt(squared_n);
if (abs(w) < EPS) {
if (w > Scalar(0)) {
two_atan_nbyw_by_n = Scalar(PI) / n;
} else {
two_atan_nbyw_by_n = -Scalar(PI) / n;
}
} else {
two_atan_nbyw_by_n = Scalar(2) * atan(n / w) / n;
}
}
return two_atan_nbyw_by_n * unit_quaternion.vec();
}
EIGEN_DEVICE_FUNC static SO3<Scalar> Exp(Tangent const& phi) {
Scalar theta2 = phi.squaredNorm();
Scalar theta = sqrt(theta2);
Scalar imag_factor;
Scalar real_factor;
if (theta < EPS) {
Scalar theta4 = theta2 * theta2;
imag_factor = Scalar(0.5) - Scalar(1.0 / 48.0) * theta2 + Scalar(1.0 / 3840.0) * theta4;
real_factor = Scalar(1) - Scalar(1.0 / 8.0) * theta2 + Scalar(1.0 / 384.0) * theta4;
} else {
imag_factor = sin(.5 * theta) / theta;
real_factor = cos(.5 * theta);
}
Quaternion q(real_factor, imag_factor * phi.x(), imag_factor * phi.y(), imag_factor * phi.z());
return SO3<Scalar>(q);
}
EIGEN_DEVICE_FUNC static Adjoint left_jacobian(Tangent const& phi) {
// left jacobian
Matrix3 I = Matrix3::Identity();
Matrix3 Phi = SO3<Scalar>::hat(phi);
Matrix3 Phi2 = Phi * Phi;
Scalar theta2 = phi.squaredNorm();
Scalar theta = sqrt(theta2);
Scalar coef1 = (theta < EPS) ? Scalar(1.0 / 2.0) - Scalar(1.0 / 24.0) * theta2 : (1.0 - cos(theta)) / theta2;
Scalar coef2 =
(theta < EPS) ? Scalar(1.0 / 6.0) - Scalar(1.0 / 120.0) * theta2 : (theta - sin(theta)) / (theta2 * theta);
return I + coef1 * Phi + coef2 * Phi2;
}
EIGEN_DEVICE_FUNC static Adjoint left_jacobian_inverse(Tangent const& phi) {
// left jacobian inverse
Matrix3 I = Matrix3::Identity();
Matrix3 Phi = SO3<Scalar>::hat(phi);
Matrix3 Phi2 = Phi * Phi;
Scalar theta2 = phi.squaredNorm();
Scalar theta = sqrt(theta2);
Scalar half_theta = Scalar(.5) * theta;
Scalar coef2 = (theta < EPS)
? Scalar(1.0 / 12.0)
: (Scalar(1) - theta * cos(half_theta) / (Scalar(2) * sin(half_theta))) / (theta * theta);
return I + Scalar(-0.5) * Phi + coef2 * Phi2;
}
EIGEN_DEVICE_FUNC static Eigen::Matrix<Scalar, 3, 3> act_jacobian(Point const& p) {
// jacobian action on a point
return SO3<Scalar>::hat(-p);
}
EIGEN_DEVICE_FUNC static Eigen::Matrix<Scalar, 4, 3> act4_jacobian(Point4 const& p) {
// jacobian action on a point
Eigen::Matrix<Scalar, 4, 3> J = Eigen::Matrix<Scalar, 4, 3>::Zero();
J.template block<3, 3>(0, 0) = SO3<Scalar>::hat(-p.template segment<3>(0));
return J;
}
private:
Quaternion unit_quaternion;
};
#endif