Merge branch '18-add-pole-pair-identification-function-to-modal' into 'master'

        out[..., c] = vals[..., clusters == c].mean(axis=-1)

    return out

def find_pole_pairs(pole_inds, mode_indices):

    """Find pole pairs within a subset of the poles. Useful for recombining

    poles into pairs after model-reduction or thresholding.

    """

    # Make sure that we track the modes as pairs of poles where necessary

    thresh_modes = []

    thresh_modes_extracted = []

    seen_inds = []

    idx = 0

    for pole in pole_inds:

        if pole in seen_inds:

            continue

        foundmode = None

        for mode in mode_indices:

            if pole in mode:

                foundmode = mode

                break

        if foundmode is None:

            raise Exception("Could not find pole")

        for pole in foundmode:

            seen_inds.append(pole)

            thresh_modes_extracted.append(idx)

            idx += 1

        thresh_modes.append(foundmode)

    return thresh_modes