Quaternion

This class represents a general quaternion, i.e. a quaternion that may not have $\left\lVert \mathbf{Q} \right\rVert = 1$ . It’s not used in NEML natively, just as a base class to the unit quaternion orientation class.

class Quaternion

A generic quaternion, stored as [s v1 v2 v3].

Subclassed by neml::Orientation

Public Functions

Quaternion(): Default constructor (manage own memory)

Quaternion(const std::vector<double> v): Construct from vector (manage own memory)

Quaternion(double *v): Construct from raw pointer (don’t manage memory)

Quaternion(const Quaternion &other): Copy constructor.

Quaternion(const Quaternion &&other): Move constructor.

virtual ~Quaternion()

Quaternion &operator=(const Quaternion &rhs): Copy.

Quaternion &operator=(const Quaternion &&rhs): Move.

bool store() const: Do you store your own data?

const double *quat() const: Raw quaternion as a const pointer.

double *data(): Raw quaternion as a nonconst pointer.

virtual double norm() const: Quaternion norm.

Quaternion opposite() const: Opposite.

Quaternion operator-() const: C++ operator opposite.

Quaternion conj() const: Conjugation.

Quaternion flip() const: Opposite scalar.

Quaternion inverse() const: Inversion.

Quaternion exp() const: Exponential map.

Quaternion log() const: Inverse exponential map.

Quaternion &operator*=(const Quaternion &rhs): Quaternion multiplication.

Quaternion &operator*=(double scalar): Scalar multiplication.

Quaternion &operator/=(const Quaternion &rhs): Quaternion division.

Quaternion &operator/=(double scalar): Scalar division.

Quaternion pow(double w) const: Power.

double dot(const Quaternion &other) const: Dot product, useful for various distances.

size_t hash() const: Hash function for quick comparisons.

void to_product_matrix(double *M) const: Product matrix for quaternion composition.