/// <summary>
///
/// </summary>
public static double Angle(double[] v0, double[] v1, int count)
{
var d = Dot(v0, v0, count) * Dot(v1, v1, count);
return(d > 0.0 ? SlurMath.AcosSafe(Dot(v0, v1) / Math.Sqrt(d)) : 0.0);
}