def rav2xf(rot, av):
    """
    This routine determines a state transformation matrix
    from a rotation matrix and the angular velocity of the
    rotation.

    http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/rav2xf_c.html

    :param rot: Rotation matrix.
    :type rot: 3x3-Element Array of floats
    :param av: Angular velocity vector.
    :type av: 3-Element Array of floats
    :return: State transformation associated with rot and av.
    :rtype: 6x6-Element Array of floats
    """
    rot = stypes.toDoubleMatrix(rot)
    av = stypes.toDoubleVector(av)
    xform = stypes.emptyDoubleMatrix(x=6, y=6)
    libspice.rav2xf_c(rot, av, xform)
    return stypes.cMatrixToNumpy(xform)