__init__.py 文件源码

def polar3d(x):
    """
    Polar coordinate representation of a three-dimensional vector.

    @param x: vector (i.e. rank one array)
    @return: polar coordinates (radius and polar angles)
    """

    if x.shape != (3,):
        raise ValueError(x)

    r = norm(x)
    theta = numpy.arccos(x[2] / r)
    phi = numpy.arctan2(x[1], x[0])

    return numpy.array([r, theta, phi])