orb_slam3_details/Thirdparty/Sophus/sophus/rxso2.hpp

657 lines
22 KiB
C++

/// @file
/// Direct product R X SO(2) - rotation and scaling in 2d.
#ifndef SOPHUS_RXSO2_HPP
#define SOPHUS_RXSO2_HPP
#include "so2.hpp"
namespace Sophus {
template <class Scalar_, int Options = 0>
class RxSO2;
using RxSO2d = RxSO2<double>;
using RxSO2f = RxSO2<float>;
} // namespace Sophus
namespace Eigen {
namespace internal {
template <class Scalar_, int Options_>
struct traits<Sophus::RxSO2<Scalar_, Options_>> {
static constexpr int Options = Options_;
using Scalar = Scalar_;
using ComplexType = Sophus::Vector2<Scalar, Options>;
};
template <class Scalar_, int Options_>
struct traits<Map<Sophus::RxSO2<Scalar_>, Options_>>
: traits<Sophus::RxSO2<Scalar_, Options_>> {
static constexpr int Options = Options_;
using Scalar = Scalar_;
using ComplexType = Map<Sophus::Vector2<Scalar>, Options>;
};
template <class Scalar_, int Options_>
struct traits<Map<Sophus::RxSO2<Scalar_> const, Options_>>
: traits<Sophus::RxSO2<Scalar_, Options_> const> {
static constexpr int Options = Options_;
using Scalar = Scalar_;
using ComplexType = Map<Sophus::Vector2<Scalar> const, Options>;
};
} // namespace internal
} // namespace Eigen
namespace Sophus {
/// RxSO2 base type - implements RxSO2 class but is storage agnostic
///
/// This class implements the group ``R+ x SO(2)``, the direct product of the
/// group of positive scalar 2x2 matrices (= isomorph to the positive
/// real numbers) and the two-dimensional special orthogonal group SO(2).
/// Geometrically, it is the group of rotation and scaling in two dimensions.
/// As a matrix groups, R+ x SO(2) consists of matrices of the form ``s * R``
/// where ``R`` is an orthogonal matrix with ``det(R) = 1`` and ``s > 0``
/// being a positive real number. In particular, it has the following form:
///
/// | s * cos(theta) s * -sin(theta) |
/// | s * sin(theta) s * cos(theta) |
///
/// where ``theta`` being the rotation angle. Internally, it is represented by
/// the first column of the rotation matrix, or in other words by a non-zero
/// complex number.
///
/// R+ x SO(2) is not compact, but a commutative group. First it is not compact
/// since the scale factor is not bound. Second it is commutative since
/// ``sR(alpha, s1) * sR(beta, s2) = sR(beta, s2) * sR(alpha, s1)``, simply
/// because ``alpha + beta = beta + alpha`` and ``s1 * s2 = s2 * s1`` with
/// ``alpha`` and ``beta`` being rotation angles and ``s1``, ``s2`` being scale
/// factors.
///
/// This class has the explicit class invariant that the scale ``s`` is not
/// too close to zero. Strictly speaking, it must hold that:
///
/// ``complex().norm() >= Constants::epsilon()``.
///
/// In order to obey this condition, group multiplication is implemented with
/// saturation such that a product always has a scale which is equal or greater
/// this threshold.
template <class Derived>
class RxSO2Base {
public:
static constexpr int Options = Eigen::internal::traits<Derived>::Options;
using Scalar = typename Eigen::internal::traits<Derived>::Scalar;
using ComplexType = typename Eigen::internal::traits<Derived>::ComplexType;
using ComplexTemporaryType = Sophus::Vector2<Scalar, Options>;
/// Degrees of freedom of manifold, number of dimensions in tangent space
/// (one for rotation and one for scaling).
static int constexpr DoF = 2;
/// Number of internal parameters used (complex number is a tuple).
static int constexpr num_parameters = 2;
/// Group transformations are 2x2 matrices.
static int constexpr N = 2;
using Transformation = Matrix<Scalar, N, N>;
using Point = Vector2<Scalar>;
using HomogeneousPoint = Vector3<Scalar>;
using Line = ParametrizedLine2<Scalar>;
using Tangent = Vector<Scalar, DoF>;
using Adjoint = Matrix<Scalar, DoF, DoF>;
/// For binary operations the return type is determined with the
/// ScalarBinaryOpTraits feature of Eigen. This allows mixing concrete and Map
/// types, as well as other compatible scalar types such as Ceres::Jet and
/// double scalars with RxSO2 operations.
template <typename OtherDerived>
using ReturnScalar = typename Eigen::ScalarBinaryOpTraits<
Scalar, typename OtherDerived::Scalar>::ReturnType;
template <typename OtherDerived>
using RxSO2Product = RxSO2<ReturnScalar<OtherDerived>>;
template <typename PointDerived>
using PointProduct = Vector2<ReturnScalar<PointDerived>>;
template <typename HPointDerived>
using HomogeneousPointProduct = Vector3<ReturnScalar<HPointDerived>>;
/// Adjoint transformation
///
/// This function return the adjoint transformation ``Ad`` of the group
/// element ``A`` such that for all ``x`` it holds that
/// ``hat(Ad_A * x) = A * hat(x) A^{-1}``. See hat-operator below.
///
/// For RxSO(2), it simply returns the identity matrix.
///
SOPHUS_FUNC Adjoint Adj() const { return Adjoint::Identity(); }
/// Returns rotation angle.
///
SOPHUS_FUNC Scalar angle() const { return SO2<Scalar>(complex()).log(); }
/// Returns copy of instance casted to NewScalarType.
///
template <class NewScalarType>
SOPHUS_FUNC RxSO2<NewScalarType> cast() const {
return RxSO2<NewScalarType>(complex().template cast<NewScalarType>());
}
/// This provides unsafe read/write access to internal data. RxSO(2) is
/// represented by a complex number (two parameters). When using direct
/// write access, the user needs to take care of that the complex number is
/// not set close to zero.
///
/// Note: The first parameter represents the real part, while the
/// second parameter represent the imaginary part.
///
SOPHUS_FUNC Scalar* data() { return complex_nonconst().data(); }
/// Const version of data() above.
///
SOPHUS_FUNC Scalar const* data() const { return complex().data(); }
/// Returns group inverse.
///
SOPHUS_FUNC RxSO2<Scalar> inverse() const {
Scalar squared_scale = complex().squaredNorm();
return RxSO2<Scalar>(complex().x() / squared_scale,
-complex().y() / squared_scale);
}
/// Logarithmic map
///
/// Computes the logarithm, the inverse of the group exponential which maps
/// element of the group (scaled rotation matrices) to elements of the tangent
/// space (rotation-vector plus logarithm of scale factor).
///
/// To be specific, this function computes ``vee(logmat(.))`` with
/// ``logmat(.)`` being the matrix logarithm and ``vee(.)`` the vee-operator
/// of RxSO2.
///
SOPHUS_FUNC Tangent log() const {
using std::log;
Tangent theta_sigma;
theta_sigma[1] = log(scale());
theta_sigma[0] = SO2<Scalar>(complex()).log();
return theta_sigma;
}
/// Returns 2x2 matrix representation of the instance.
///
/// For RxSO2, the matrix representation is an scaled orthogonal matrix ``sR``
/// with ``det(R)=s^2``, thus a scaled rotation matrix ``R`` with scale
/// ``s``.
///
SOPHUS_FUNC Transformation matrix() const {
Transformation sR;
// clang-format off
sR << complex()[0], -complex()[1],
complex()[1], complex()[0];
// clang-format on
return sR;
}
/// Assignment-like operator from OtherDerived.
///
template <class OtherDerived>
SOPHUS_FUNC RxSO2Base<Derived>& operator=(
RxSO2Base<OtherDerived> const& other) {
complex_nonconst() = other.complex();
return *this;
}
/// Group multiplication, which is rotation concatenation and scale
/// multiplication.
///
/// Note: This function performs saturation for products close to zero in
/// order to ensure the class invariant.
///
template <typename OtherDerived>
SOPHUS_FUNC RxSO2Product<OtherDerived> operator*(
RxSO2Base<OtherDerived> const& other) const {
using ResultT = ReturnScalar<OtherDerived>;
Scalar lhs_real = complex().x();
Scalar lhs_imag = complex().y();
typename OtherDerived::Scalar const& rhs_real = other.complex().x();
typename OtherDerived::Scalar const& rhs_imag = other.complex().y();
/// complex multiplication
typename RxSO2Product<OtherDerived>::ComplexType result_complex(
lhs_real * rhs_real - lhs_imag * rhs_imag,
lhs_real * rhs_imag + lhs_imag * rhs_real);
const ResultT squared_scale = result_complex.squaredNorm();
if (squared_scale <
Constants<ResultT>::epsilon() * Constants<ResultT>::epsilon()) {
/// Saturation to ensure class invariant.
result_complex.normalize();
result_complex *= Constants<ResultT>::epsilon();
}
return RxSO2Product<OtherDerived>(result_complex);
}
/// Group action on 2-points.
///
/// This function rotates a 2 dimensional point ``p`` by the SO2 element
/// ``bar_R_foo`` (= rotation matrix) and scales it by the scale factor ``s``:
///
/// ``p_bar = s * (bar_R_foo * p_foo)``.
///
template <typename PointDerived,
typename = typename std::enable_if<
IsFixedSizeVector<PointDerived, 2>::value>::type>
SOPHUS_FUNC PointProduct<PointDerived> operator*(
Eigen::MatrixBase<PointDerived> const& p) const {
return matrix() * p;
}
/// Group action on homogeneous 2-points. See above for more details.
///
template <typename HPointDerived,
typename = typename std::enable_if<
IsFixedSizeVector<HPointDerived, 3>::value>::type>
SOPHUS_FUNC HomogeneousPointProduct<HPointDerived> operator*(
Eigen::MatrixBase<HPointDerived> const& p) const {
const auto rsp = *this * p.template head<2>();
return HomogeneousPointProduct<HPointDerived>(rsp(0), rsp(1), p(2));
}
/// Group action on lines.
///
/// This function rotates a parameterized line ``l(t) = o + t * d`` by the SO2
/// element and scales it by the scale factor
///
/// Origin ``o`` is rotated and scaled
/// Direction ``d`` is rotated (preserving it's norm)
///
SOPHUS_FUNC Line operator*(Line const& l) const {
return Line((*this) * l.origin(), (*this) * l.direction() / scale());
}
/// In-place group multiplication. This method is only valid if the return
/// type of the multiplication is compatible with this SO2's Scalar type.
///
/// Note: This function performs saturation for products close to zero in
/// order to ensure the class invariant.
///
template <typename OtherDerived,
typename = typename std::enable_if<
std::is_same<Scalar, ReturnScalar<OtherDerived>>::value>::type>
SOPHUS_FUNC RxSO2Base<Derived>& operator*=(
RxSO2Base<OtherDerived> const& other) {
*static_cast<Derived*>(this) = *this * other;
return *this;
}
/// Returns internal parameters of RxSO(2).
///
/// It returns (c[0], c[1]), with c being the complex number.
///
SOPHUS_FUNC Sophus::Vector<Scalar, num_parameters> params() const {
return complex();
}
/// Sets non-zero complex
///
/// Precondition: ``z`` must not be close to zero.
SOPHUS_FUNC void setComplex(Vector2<Scalar> const& z) {
SOPHUS_ENSURE(z.squaredNorm() > Constants<Scalar>::epsilon() *
Constants<Scalar>::epsilon(),
"Scale factor must be greater-equal epsilon.");
static_cast<Derived*>(this)->complex_nonconst() = z;
}
/// Accessor of complex.
///
SOPHUS_FUNC ComplexType const& complex() const {
return static_cast<Derived const*>(this)->complex();
}
/// Returns rotation matrix.
///
SOPHUS_FUNC Transformation rotationMatrix() const {
ComplexTemporaryType norm_quad = complex();
norm_quad.normalize();
return SO2<Scalar>(norm_quad).matrix();
}
/// Returns scale.
///
SOPHUS_FUNC
Scalar scale() const { return complex().norm(); }
/// Setter of rotation angle, leaves scale as is.
///
SOPHUS_FUNC void setAngle(Scalar const& theta) { setSO2(SO2<Scalar>(theta)); }
/// Setter of complex using rotation matrix ``R``, leaves scale as is.
///
/// Precondition: ``R`` must be orthogonal with determinant of one.
///
SOPHUS_FUNC void setRotationMatrix(Transformation const& R) {
setSO2(SO2<Scalar>(R));
}
/// Sets scale and leaves rotation as is.
///
SOPHUS_FUNC void setScale(Scalar const& scale) {
using std::sqrt;
complex_nonconst().normalize();
complex_nonconst() *= scale;
}
/// Setter of complex number using scaled rotation matrix ``sR``.
///
/// Precondition: The 2x2 matrix must be "scaled orthogonal"
/// and have a positive determinant.
///
SOPHUS_FUNC void setScaledRotationMatrix(Transformation const& sR) {
SOPHUS_ENSURE(isScaledOrthogonalAndPositive(sR),
"sR must be scaled orthogonal:\n %", sR);
complex_nonconst() = sR.col(0);
}
/// Setter of SO(2) rotations, leaves scale as is.
///
SOPHUS_FUNC void setSO2(SO2<Scalar> const& so2) {
using std::sqrt;
Scalar saved_scale = scale();
complex_nonconst() = so2.unit_complex();
complex_nonconst() *= saved_scale;
}
SOPHUS_FUNC SO2<Scalar> so2() const { return SO2<Scalar>(complex()); }
private:
/// Mutator of complex is private to ensure class invariant.
///
SOPHUS_FUNC ComplexType& complex_nonconst() {
return static_cast<Derived*>(this)->complex_nonconst();
}
};
/// RxSO2 using storage; derived from RxSO2Base.
template <class Scalar_, int Options>
class RxSO2 : public RxSO2Base<RxSO2<Scalar_, Options>> {
public:
using Base = RxSO2Base<RxSO2<Scalar_, Options>>;
using Scalar = Scalar_;
using Transformation = typename Base::Transformation;
using Point = typename Base::Point;
using HomogeneousPoint = typename Base::HomogeneousPoint;
using Tangent = typename Base::Tangent;
using Adjoint = typename Base::Adjoint;
using ComplexMember = Eigen::Matrix<Scalar, 2, 1, Options>;
/// ``Base`` is friend so complex_nonconst can be accessed from ``Base``.
friend class RxSO2Base<RxSO2<Scalar_, Options>>;
using Base::operator=;
EIGEN_MAKE_ALIGNED_OPERATOR_NEW
/// Default constructor initializes complex number to identity rotation and
/// scale to 1.
///
SOPHUS_FUNC RxSO2() : complex_(Scalar(1), Scalar(0)) {}
/// Copy constructor
///
SOPHUS_FUNC RxSO2(RxSO2 const& other) = default;
/// Copy-like constructor from OtherDerived.
///
template <class OtherDerived>
SOPHUS_FUNC RxSO2(RxSO2Base<OtherDerived> const& other)
: complex_(other.complex()) {}
/// Constructor from scaled rotation matrix
///
/// Precondition: rotation matrix need to be scaled orthogonal with
/// determinant of ``s^2``.
///
SOPHUS_FUNC explicit RxSO2(Transformation const& sR) {
this->setScaledRotationMatrix(sR);
}
/// Constructor from scale factor and rotation matrix ``R``.
///
/// Precondition: Rotation matrix ``R`` must to be orthogonal with determinant
/// of 1 and ``scale`` must to be close to zero.
///
SOPHUS_FUNC RxSO2(Scalar const& scale, Transformation const& R)
: RxSO2((scale * SO2<Scalar>(R).unit_complex()).eval()) {}
/// Constructor from scale factor and SO2
///
/// Precondition: ``scale`` must be close to zero.
///
SOPHUS_FUNC RxSO2(Scalar const& scale, SO2<Scalar> const& so2)
: RxSO2((scale * so2.unit_complex()).eval()) {}
/// Constructor from complex number.
///
/// Precondition: complex number must not be close to zero.
///
SOPHUS_FUNC explicit RxSO2(Vector2<Scalar> const& z) : complex_(z) {
SOPHUS_ENSURE(complex_.squaredNorm() >= Constants<Scalar>::epsilon() *
Constants<Scalar>::epsilon(),
"Scale factor must be greater-equal epsilon: % vs %",
complex_.squaredNorm(),
Constants<Scalar>::epsilon() * Constants<Scalar>::epsilon());
}
/// Constructor from complex number.
///
/// Precondition: complex number must not be close to zero.
///
SOPHUS_FUNC explicit RxSO2(Scalar const& real, Scalar const& imag)
: RxSO2(Vector2<Scalar>(real, imag)) {}
/// Accessor of complex.
///
SOPHUS_FUNC ComplexMember const& complex() const { return complex_; }
/// Returns derivative of exp(x).matrix() wrt. ``x_i at x=0``.
///
SOPHUS_FUNC static Transformation Dxi_exp_x_matrix_at_0(int i) {
return generator(i);
}
/// Group exponential
///
/// This functions takes in an element of tangent space (= rotation angle
/// plus logarithm of scale) and returns the corresponding element of the
/// group RxSO2.
///
/// To be more specific, this function computes ``expmat(hat(theta))``
/// with ``expmat(.)`` being the matrix exponential and ``hat(.)`` being the
/// hat()-operator of RSO2.
///
SOPHUS_FUNC static RxSO2<Scalar> exp(Tangent const& a) {
using std::exp;
Scalar const theta = a[0];
Scalar const sigma = a[1];
Scalar s = exp(sigma);
Vector2<Scalar> z = SO2<Scalar>::exp(theta).unit_complex();
z *= s;
return RxSO2<Scalar>(z);
}
/// Returns the ith infinitesimal generators of ``R+ x SO(2)``.
///
/// The infinitesimal generators of RxSO2 are:
///
/// ```
/// | 0 -1 |
/// G_0 = | 1 0 |
///
/// | 1 0 |
/// G_1 = | 0 1 |
/// ```
///
/// Precondition: ``i`` must be 0, or 1.
///
SOPHUS_FUNC static Transformation generator(int i) {
SOPHUS_ENSURE(i >= 0 && i <= 1, "i should be 0 or 1.");
Tangent e;
e.setZero();
e[i] = Scalar(1);
return hat(e);
}
/// hat-operator
///
/// It takes in the 2-vector representation ``a`` (= rotation angle plus
/// logarithm of scale) and returns the corresponding matrix representation
/// of Lie algebra element.
///
/// Formally, the hat()-operator of RxSO2 is defined as
///
/// ``hat(.): R^2 -> R^{2x2}, hat(a) = sum_i a_i * G_i`` (for i=0,1,2)
///
/// with ``G_i`` being the ith infinitesimal generator of RxSO2.
///
/// The corresponding inverse is the vee()-operator, see below.
///
SOPHUS_FUNC static Transformation hat(Tangent const& a) {
Transformation A;
// clang-format off
A << a(1), -a(0),
a(0), a(1);
// clang-format on
return A;
}
/// Lie bracket
///
/// It computes the Lie bracket of RxSO(2). To be more specific, it computes
///
/// ``[omega_1, omega_2]_rxso2 := vee([hat(omega_1), hat(omega_2)])``
///
/// with ``[A,B] := AB-BA`` being the matrix commutator, ``hat(.)`` the
/// hat()-operator and ``vee(.)`` the vee()-operator of RxSO2.
///
SOPHUS_FUNC static Tangent lieBracket(Tangent const&, Tangent const&) {
Vector2<Scalar> res;
res.setZero();
return res;
}
/// Draw uniform sample from RxSO(2) manifold.
///
/// The scale factor is drawn uniformly in log2-space from [-1, 1],
/// hence the scale is in [0.5, 2)].
///
template <class UniformRandomBitGenerator>
static RxSO2 sampleUniform(UniformRandomBitGenerator& generator) {
std::uniform_real_distribution<Scalar> uniform(Scalar(-1), Scalar(1));
using std::exp2;
return RxSO2(exp2(uniform(generator)),
SO2<Scalar>::sampleUniform(generator));
}
/// vee-operator
///
/// It takes the 2x2-matrix representation ``Omega`` and maps it to the
/// corresponding vector representation of Lie algebra.
///
/// This is the inverse of the hat()-operator, see above.
///
/// Precondition: ``Omega`` must have the following structure:
///
/// | d -x |
/// | x d |
///
SOPHUS_FUNC static Tangent vee(Transformation const& Omega) {
using std::abs;
return Tangent(Omega(1, 0), Omega(0, 0));
}
protected:
SOPHUS_FUNC ComplexMember& complex_nonconst() { return complex_; }
ComplexMember complex_;
};
} // namespace Sophus
namespace Eigen {
/// Specialization of Eigen::Map for ``RxSO2``; derived from RxSO2Base.
///
/// Allows us to wrap RxSO2 objects around POD array (e.g. external z style
/// complex).
template <class Scalar_, int Options>
class Map<Sophus::RxSO2<Scalar_>, Options>
: public Sophus::RxSO2Base<Map<Sophus::RxSO2<Scalar_>, Options>> {
using Base = Sophus::RxSO2Base<Map<Sophus::RxSO2<Scalar_>, Options>>;
public:
using Scalar = Scalar_;
using Transformation = typename Base::Transformation;
using Point = typename Base::Point;
using HomogeneousPoint = typename Base::HomogeneousPoint;
using Tangent = typename Base::Tangent;
using Adjoint = typename Base::Adjoint;
/// ``Base`` is friend so complex_nonconst can be accessed from ``Base``.
friend class Sophus::RxSO2Base<Map<Sophus::RxSO2<Scalar_>, Options>>;
using Base::operator=;
using Base::operator*=;
using Base::operator*;
SOPHUS_FUNC Map(Scalar* coeffs) : complex_(coeffs) {}
/// Accessor of complex.
///
SOPHUS_FUNC
Map<Sophus::Vector2<Scalar>, Options> const& complex() const {
return complex_;
}
protected:
SOPHUS_FUNC Map<Sophus::Vector2<Scalar>, Options>& complex_nonconst() {
return complex_;
}
Map<Sophus::Vector2<Scalar>, Options> complex_;
};
/// Specialization of Eigen::Map for ``RxSO2 const``; derived from RxSO2Base.
///
/// Allows us to wrap RxSO2 objects around POD array (e.g. external z style
/// complex).
template <class Scalar_, int Options>
class Map<Sophus::RxSO2<Scalar_> const, Options>
: public Sophus::RxSO2Base<Map<Sophus::RxSO2<Scalar_> const, Options>> {
public:
using Base = Sophus::RxSO2Base<Map<Sophus::RxSO2<Scalar_> const, Options>>;
using Scalar = Scalar_;
using Transformation = typename Base::Transformation;
using Point = typename Base::Point;
using HomogeneousPoint = typename Base::HomogeneousPoint;
using Tangent = typename Base::Tangent;
using Adjoint = typename Base::Adjoint;
using Base::operator*=;
using Base::operator*;
SOPHUS_FUNC
Map(Scalar const* coeffs) : complex_(coeffs) {}
/// Accessor of complex.
///
SOPHUS_FUNC
Map<Sophus::Vector2<Scalar> const, Options> const& complex() const {
return complex_;
}
protected:
Map<Sophus::Vector2<Scalar> const, Options> const complex_;
};
} // namespace Eigen
#endif /// SOPHUS_RXSO2_HPP