I use Birch to cluster my data and my data is kind of time-series data. I don't know the actually cluster numbers and need to read large data(online learning), so I choose Birch rather than MiniKmeans. When I read it, I found the critical parameters might be branching_factor and threshold, and threshold will affect my cluster numbers obviously! Any way to estimate the suitable threshold of Birch? Any paper suggestion is ok. thx