I'm writing a <FwdIt1, FwdIt2> search(FwdIt1 _1b, FwdIt1 _1e, FwdIt2 _2b, FwdIt2 _2e) for stxxl and I'm trying to find the correct way to copy over the prefetch code in bits/algo/scan.h so that simultaneous increment on both [_1b, _1e) and [_2b, _2e). Porting over the binary predicate is trivial - all I have to do is modify 1 line of code in my copypaste of scan.h :)
Also, how should nbufers guessing be based on [_2b, _2e) so that find works more efficiently?
First of all, where does the data reside. Are both external or does the pattern fit into internal memory? Are you implementing some sophisticated algorithm with preprocessing (such as Knuth-Morris-Pratt or Boyer-Moore) or the trivial one?