更快的numpy笛卡尔到球面坐标转换？

I have an array of 3 million data points from a 3-axiz accellerometer (XYZ), and I want to add 3 columns to the array containing the equivalent spherical coordinates (r, theta, phi). The following code works, but seems way too slow. How can I do better?I have an array of 3 million data points from a