# WFMath_Quaternion man page

WFMath::Quaternion — A normalized quaterion.

## Synopsis

#include <quaternion.h>

### Public Member Functions

Quaternion ()
Construct a Quatertion.
Quaternion (CoordType w_in, CoordType x_in, CoordType y_in, CoordType z_in)
Construct a Quaternion from (w, x, y, z) components.
Quaternion (int axis, CoordType angle)
Construct a Quaternion giving a rotation around axis by angle.
Quaternion (const Vector< 3 > &axis, CoordType angle)
Construct a Quaternion giving a rotation around the Vector axis by angle.
Quaternion (const Vector< 3 > &axis)
Construct a Quaternion giving a rotation around the Vector axis.
Quaternion (const Quaternion &p)
Construct a copy of a Quaternion.
Quaternion (const AtlasInType &a)
Construct a Quaternion from an Atlas::Message::Object.
AtlasOutType toAtlas () const
Create an Atlas object from the Quaternion.
void fromAtlas (const AtlasInType &a)
Set the Quaternion's value to that given by an Atlas object.
Quaternion & identity ()
Set the Quaternion to the identity rotation.
bool fromRotMatrix (const RotMatrix< 3 > &m)
set a Quaternion's value from a RotMatrix
Quaternion inverse () const
returns the inverse of the Quaternion
Quaternion & rotate (const RotMatrix< 3 > &)
Rotate quaternion using the matrix.
Quaternion & rotate (const Quaternion &q)
rotate the quaternion using another quaternion
Quaternion & rotation (int axis, CoordType angle)
sets the Quaternion to a rotation by angle around axis
Quaternion & rotation (const Vector< 3 > &axis, CoordType angle)
sets the Quaternion to a rotation by angle around the Vector axis
Quaternion & rotation (const Vector< 3 > &axis)
sets the Quaternion to a rotation around the Vector axis
Quaternion & rotation (const Vector< 3 > &from, const Vector< 3 > &to)
sets the Quaternion to rotate 'from' to be parallel to 'to'
CoordType scalar () const
returns the scalar (w) part of the Quaternion
const Vector< 3 > & vector () const
returns the Vector (x, y, z) part of the quaternion
void normalize ()
normalize to remove accumulated round-off error
unsigned age () const
current round-off age

## Detailed Description

A normalized quaterion.

## Constructor & Destructor Documentation

### WFMath::Quaternion::Quaternion (CoordType w_in, CoordType x_in, CoordType y_in, CoordType z_in)

Construct a Quaternion from (w, x, y, z) components. This normalizes the components so the sum of their squares is one.

### WFMath::Quaternion::Quaternion (const Vector< 3 > & axis) [inline], [explicit]

Construct a Quaternion giving a rotation around the Vector axis. The angle of rotating is equal to the magnitude of the Vector

References rotation().

## Member Function Documentation

### bool WFMath::Quaternion::fromRotMatrix (const RotMatrix< 3 > & m)

set a Quaternion's value from a RotMatrix Since a Quaternion can only represent an even-parity RotMatrix, this function returns false if the parity of m is odd. In this case, the quaternion is set to the value of m multiplied by a fixed parity-odd RotMatrix, so the full RotMatrix can be recovered by passing the Quaternion and the value of 'not_flip' returned by this function to RotMatrix::fromQuaternion().

### Quaternion& WFMath::Quaternion::rotation (const Vector< 3 > & axis)

sets the Quaternion to a rotation around the Vector axis The rotation angle is given by the magnitude of the Vector

## Author

Generated automatically by Doxygen for WFMath from the source code.

## Info

Sat Feb 10 2018 Version 1.0.2 WFMath