def _symmetrize_correlograms(correlograms):
    """Return the symmetrized version of the CCG arrays."""

    n_clusters, _, n_bins = correlograms.shape
    assert n_clusters == _

    # We symmetrize c[i, j, 0].
    # This is necessary because the algorithm in correlograms()
    # is sensitive to the order of identical spikes.
    correlograms[..., 0] = np.maximum(correlograms[..., 0],
                                      correlograms[..., 0].T)

    sym = correlograms[..., 1:][..., ::-1]
    sym = np.transpose(sym, (1, 0, 2))

    return np.dstack((sym, correlograms))
Return the symmetrized version of the CCG arrays.