Am Samstag, 22. Dezember 2007 20:48 schrieb Joost Behrends:
Daniel Fischer
writes: I can't reproduce it, both run in 130s here (SuSE 8.2, 1200MHz Duron). However, it's running over 30 minutes now trying to factorise 2^88+1 without any sign of approaching success, which suggests your code has a bug (the factorization is [257,229153,119782433,43872038849], so even a naive approach shouldn't take much longer than a minute).
Yes, Daniel
the code is not completely correct. There is a known bug. Don't know the connection to your number, but it doesn't decompose 29*29*31*31 correctly (gives [29,29,961] neither 59*59*61*61 (gives [59*59*3721]).
Perhaps Prelude Main> primefactors $ 7*17*29 [7,493] Prelude Main> primefactors $ 7*23*29 [7,667] Prelude Main> primefactors $ 7*11*23 [7,253] help you find the bug? If not, ask and ye shall be answered.
Difficult to find it, but that has nothing to do with the strange differences of speed.
True, and I have no idea how that could come.
Cheers, Joost
Cheers, Daniel