[Boost-users] Usage of iterator_facade and iterator_adaptor

Hi, I'm trying to use Boost.Iterator library. I understand that iterator_adaptor specialize some part of iterator_facade. However, I can not tell for what application I should use iterator_facade or iterator_adaptor. I think the manual should summarize this for the user. Can somebody give me some hint on which to use them and under what condition, if you have the experience? Thanks, Peng