规范化四元数

数

Versor \Ver"sor\, n. [NL., fr. L. vertere, versus, to turn. See
{Version}.] (Geom.)
The turning factor of a quaternion.

Note: The change of one vector into another is considered in
quaternions as made up of two operations; 1st, the
rotation of the first vector so that it shall be
parallel to the second; 2d, the change of length so
that the first vector shall be equal to the second.
That which expresses in amount and kind the first
operation is a versor, and is denoted geometrically by
a line at right angles to the plane in which the
rotation takes place, the length of this line being
proportioned to the amount of rotation. That which
expresses the second operation is a tensor. The product
of the versor and tensor expresses the total operation,
and is called a quaternion. See {Quaternion}.

{Quadrantal versor}. See under {Quadrantal}.