multireader vs multisearcher

[John Wang]

Hi:

   What is the difference between using:

1) MultiReader reader=....; // create multi reader from different indexes
    IndexSearcher searcher=new IndexSearcher(reader);
    searcher.search();

vs.

2) IndexSearcher searcher1=...
    IndexSearcher searcher 2=..

    MultiSearcher searcher=new MultiSearcher(new
IndexSearcher[]{searcher1,searcher});

    searcher.search();


I understand there are some differences with idf fixing etc., but seems to
me the api is presenting two ways of solving a problem with slightly
different results.

Thanks

-John