Returns local parameters for an oligomeric assembly.

    Parameters
    ----------
    pitch : float
        Pitch of assembly
    radius : float
        Radius of assembly
    oligo : int
        Oligomeric state of assembly

    Returns
    -------
    pitchloc : float
        Local pitch of assembly (between 2 adjacent component helices)
    rloc : float
        Local radius of assembly
    alphaloc : float
        Local pitch-angle of assembly

def cc_to_local_params(pitch, radius, oligo):
    """Returns local parameters for an oligomeric assembly.

    Parameters
    ----------
    pitch : float
        Pitch of assembly
    radius : float
        Radius of assembly
    oligo : int
        Oligomeric state of assembly

    Returns
    -------
    pitchloc : float
        Local pitch of assembly (between 2 adjacent component helices)
    rloc : float
        Local radius of assembly
    alphaloc : float
        Local pitch-angle of assembly
    """
    rloc = numpy.sin(numpy.pi / oligo) * radius
    alpha = numpy.arctan((2 * numpy.pi * radius) / pitch)
    alphaloc = numpy.cos((numpy.pi / 2) - ((numpy.pi) / oligo)) * alpha
    pitchloc = (2 * numpy.pi * rloc) / numpy.tan(alphaloc)
    return pitchloc, rloc, numpy.rad2deg(alphaloc)