def quaternion_about_axis(angle, axis):
    """Return quaternion for rotation about axis.

    >>> q = quaternion_about_axis(0.123, [1, 0, 0])
    >>> numpy.allclose(q, [0.99810947, 0.06146124, 0, 0])
    True

    """
    q = numpy.array([0.0, axis[0], axis[1], axis[2]])
    qlen = vector_norm(q)
    if qlen > _EPS:
        q *= math.sin(angle / 2.0) / qlen
    q[0] = math.cos(angle / 2.0)
    return q
Return quaternion for rotation about axis.

    >>> q = quaternion_about_axis(0.123, [1, 0, 0])
    >>> numpy.allclose(q, [0.99810947, 0.06146124, 0, 0])
    True

    
deploy/helpers/transformations.py