n.四个一组；四人一组；四元数
The norm of a quaternion is similar to that of a vector. 四元数的平均值与矢量的有点相似。
This paper studies comparatively dual Euler method and quaternion method which are used for the solution of the singularity of the Euler equation. 对解决欧拉方程奇异性的双欧法和四元数法进行了对比研究。
