template<typename Scalar_, int Options_>
class Eigen::Quaternion< Scalar_, Options_ >
The quaternion class used to represent 3D orientations and rotations. 
This is defined in the Geometry module. 
#include <Eigen/Geometry> 
- Template Parameters
 - 
  
    | Scalar_ | the scalar type, i.e., the type of the coefficients  | 
    | Options_ | controls the memory alignment of the coefficients. Can be # AutoAlign or # DontAlign. Default is AutoAlign. | 
  
   
This class represents a quaternion \( w+xi+yj+zk \) that is a convenient representation of orientations and rotations of objects in three dimensions. Compared to other representations like Euler angles or 3x3 matrices, quaternions offer the following advantages: 
- compact storage (4 scalars) 
 
- efficient to compose (28 flops), 
 
- stable spherical interpolation
 
The following two typedefs are provided for convenience: 
- Warning
 - Operations interpreting the quaternion as rotation have undefined behavior if the quaternion is not normalized.
 
- See also
 - class AngleAxis, class Transform 
 
 
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| template<typename Derived1, typename Derived2>  | 
| Quaternion< Scalar, Options >  | FromTwoVectors (const MatrixBase< Derived1 > &a, const MatrixBase< Derived2 > &b) | 
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| Quaternion< Scalar_, Options_ > &  | operator*= (const QuaternionBase< OtherDerived > &q) | 
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| Quaternion &  | operator= (Quaternion &&other) noexcept(std::is_nothrow_move_assignable< Scalar >::value) | 
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|   | Quaternion () | 
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|   | Quaternion (const AngleAxisType &aa) | 
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| template<typename Derived>  | 
|   | Quaternion (const MatrixBase< Derived > &other) | 
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| template<typename OtherScalar, int OtherOptions>  | 
|   | Quaternion (const Quaternion< OtherScalar, OtherOptions > &other) | 
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| template<class Derived>  | 
|   | Quaternion (const QuaternionBase< Derived > &other) | 
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| template<typename Derived>  | 
|   | Quaternion (const Scalar &w, const Eigen::MatrixBase< Derived > &vec) | 
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|   | Quaternion (const Scalar &w, const Scalar &x, const Scalar &y, const Scalar &z) | 
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|   | Quaternion (const Scalar *data) | 
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|   | Quaternion (Quaternion &&other) noexcept(std::is_nothrow_move_constructible< Scalar >::value) | 
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| Vector3  | _transformVector (const Vector3 &v) const | 
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| Vector3  | _transformVector (const Vector3 &v) const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Scalar  | angularDistance (const QuaternionBase< OtherDerived > &other) const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Scalar  | angularDistance (const QuaternionBase< OtherDerived > &other) const | 
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| internal::cast_return_type< Quaternion< Scalar_, Options_ >, Quaternion< NewScalarType > >::type  | cast () const | 
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| internal::cast_return_type< Quaternion< Scalar_, Options_ >, Quaternion< NewScalarType > >::type  | cast () const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients &  | coeffs () | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients &  | coeffs () | 
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| const internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients &  | coeffs () const | 
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| const internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients &  | coeffs () const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients  | coeffsScalarFirst () const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients  | coeffsScalarFirst () const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients  | coeffsScalarLast () const | 
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| internal::traits< Quaternion< Scalar_, Options_ > >::Coefficients  | coeffsScalarLast () const | 
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| Quaternion< Scalar >  | conjugate () const | 
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| Quaternion< Scalar >  | conjugate () const | 
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| Scalar  | dot (const QuaternionBase< OtherDerived > &other) const | 
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| Scalar  | dot (const QuaternionBase< OtherDerived > &other) const | 
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| Quaternion< Scalar >  | inverse () const | 
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| Quaternion< Scalar >  | inverse () const | 
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| bool  | isApprox (const QuaternionBase< OtherDerived > &other, const RealScalar &prec=NumTraits< Scalar >::dummy_precision()) const | 
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| bool  | isApprox (const QuaternionBase< OtherDerived > &other, const RealScalar &prec=NumTraits< Scalar >::dummy_precision()) const | 
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| Scalar  | norm () const | 
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| Scalar  | norm () const | 
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| void  | normalize () | 
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| void  | normalize () | 
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| Quaternion< Scalar >  | normalized () const | 
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| Quaternion< Scalar >  | normalized () const | 
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| bool  | operator!= (const QuaternionBase< OtherDerived > &other) const | 
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| bool  | operator!= (const QuaternionBase< OtherDerived > &other) const | 
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| internal::rotation_base_generic_product_selector< Quaternion< Scalar_, Options_ >, OtherDerived, OtherDerived::IsVectorAtCompileTime >::ReturnType  | operator* (const EigenBase< OtherDerived > &e) const | 
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| Quaternion< typename internal::traits< Quaternion< Scalar_, Options_ > >::Scalar >  | operator* (const QuaternionBase< OtherDerived > &other) const | 
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| Quaternion< typename internal::traits< Quaternion< Scalar_, Options_ > >::Scalar >  | operator* (const QuaternionBase< OtherDerived > &other) const | 
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| Transform< Scalar, Dim, Mode >  | operator* (const Transform< Scalar, Dim, Mode, Options > &t) const | 
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| Transform< Scalar, Dim, Isometry >  | operator* (const Translation< Scalar, Dim > &t) const | 
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| RotationMatrixType  | operator* (const UniformScaling< Scalar > &s) const | 
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| Quaternion< Scalar_, Options_ > &  | operator*= (const QuaternionBase< OtherDerived > &q) | 
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| Quaternion< Scalar_, Options_ > &  | operator= (const AngleAxisType &aa) | 
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| Quaternion< Scalar_, Options_ > &  | operator= (const MatrixBase< MatrixDerived > &xpr) | 
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| Quaternion< Scalar_, Options_ > &  | operator= (const MatrixBase< MatrixDerived > &xpr) | 
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| bool  | operator== (const QuaternionBase< OtherDerived > &other) const | 
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| bool  | operator== (const QuaternionBase< OtherDerived > &other) const | 
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| Quaternion< Scalar_, Options_ > &  | setFromTwoVectors (const MatrixBase< Derived1 > &a, const MatrixBase< Derived2 > &b) | 
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| Quaternion< Scalar_, Options_ > &  | setFromTwoVectors (const MatrixBase< Derived1 > &a, const MatrixBase< Derived2 > &b) | 
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| QuaternionBase &  | setIdentity () | 
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| QuaternionBase &  | setIdentity () | 
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| Quaternion< typename internal::traits< Quaternion< Scalar_, Options_ > >::Scalar >  | slerp (const Scalar &t, const QuaternionBase< OtherDerived > &other) const | 
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| Quaternion< typename internal::traits< Quaternion< Scalar_, Options_ > >::Scalar >  | slerp (const Scalar &t, const QuaternionBase< OtherDerived > &other) const | 
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| Scalar  | squaredNorm () const | 
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| Scalar  | squaredNorm () const | 
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| Matrix3  | toRotationMatrix () const | 
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| Matrix3  | toRotationMatrix () const | 
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| VectorBlock< Coefficients, 3 >  | vec () | 
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| VectorBlock< Coefficients, 3 >  | vec () | 
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| const VectorBlock< const Coefficients, 3 >  | vec () const | 
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| const VectorBlock< const Coefficients, 3 >  | vec () const | 
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| constexpr NonConstCoeffReturnType  | w () | 
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| constexpr NonConstCoeffReturnType  | w () | 
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| constexpr CoeffReturnType  | w () const | 
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| constexpr CoeffReturnType  | w () const | 
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| constexpr NonConstCoeffReturnType  | x () | 
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| constexpr NonConstCoeffReturnType  | x () | 
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| constexpr CoeffReturnType  | x () const | 
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| constexpr CoeffReturnType  | x () const | 
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| constexpr NonConstCoeffReturnType  | y () | 
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| constexpr NonConstCoeffReturnType  | y () | 
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| constexpr CoeffReturnType  | y () const | 
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| constexpr CoeffReturnType  | y () const | 
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| constexpr NonConstCoeffReturnType  | z () | 
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| constexpr NonConstCoeffReturnType  | z () | 
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| constexpr CoeffReturnType  | z () const | 
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| constexpr CoeffReturnType  | z () const | 
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| Derived  | inverse () const | 
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| RotationMatrixType  | matrix () const | 
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| template<typename OtherDerived>  | 
| internal::rotation_base_generic_product_selector< Derived, OtherDerived, OtherDerived::IsVectorAtCompileTime >::ReturnType  | operator* (const EigenBase< OtherDerived > &e) const | 
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| template<int Mode, int Options>  | 
| Transform< Scalar, Dim, Mode >  | operator* (const Transform< Scalar, Dim, Mode, Options > &t) const | 
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| Transform< Scalar, Dim, Isometry >  | operator* (const Translation< Scalar, Dim > &t) const | 
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| RotationMatrixType  | operator* (const UniformScaling< Scalar > &s) const | 
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| RotationMatrixType  | toRotationMatrix () const | 
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