c#-计算两个空间点形成的单位向量

/// <summary>
/// 计算单位向量
/// </summary>
/// <param name="fromPoint">起点</param>
/// <param name="toPoint">终点</param>
/// <returns></returns>
private double[] GetUnitVec(double[] fromPoint, double[] toPoint)
{
double dist = Math.Sqrt((fromPoint[0] - toPoint[0]) * (fromPoint[0] - toPoint[0]) +
(fromPoint[1] - toPoint[1]) * (fromPoint[1] - toPoint[1]) +
(fromPoint[2] - toPoint[2]) * (fromPoint[2] - toPoint[2]));
return new double[] { (toPoint[0] - fromPoint[0]) / dist, (toPoint[1] - fromPoint[1]) / dist, (toPoint[2] - fromPoint[2]) / dist };
}