Private method to calculate MMDS embedding
    :param dimensions: (int)
    :return: coordinate matrix (np.array)

def _embedding_metric_mds(matrix, dimensions=3):
    """
    Private method to calculate MMDS embedding
    :param dimensions: (int)
    :return: coordinate matrix (np.array)
    """
    mds = sklearn.manifold.MDS(n_components=dimensions,
                               dissimilarity='precomputed',
                               metric=True)
    mds.fit(matrix)
    return mds.embedding_