df['cluster'] = -1

for clusterIndex, points in tqdm(clusterMembers.items(), total=len(boundaries)):
    for point in tqdm(points, leave=False):
        lzRef, sqrtjRRef = point
        # Find the index of the point in the DataFrame
        mask = (df['lz_ref'] == lzRef) & (df['sqrtjR_ref'] == sqrtjRRef)
        df.loc[mask, 'cluster'] = clusterIndex