Author: José Carlos
Date: 07:28:03 08/10/01
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On August 10, 2001 at 09:51:39, Robert Hyatt wrote: >On August 10, 2001 at 04:30:20, José Carlos wrote: > >> After completely rewriting my chess program (Averno), I've run into the >>null-move world, which I haddn't in old versions. >> In old Averno I had: >> >> -Reasonably good move ordering (hash move; good captures; killers; ...) >> -Transposition table >> -2 killers >> -Lazy eval >> -Check and recapture extension >> -Some out-of-check stuff in qsearch >> >> With that, I was searching 6-7 plies in blitz (in midgame) and 7-9 in >>standard. [Athlon 550] >> >> I've read some open source programs to get a clue on how to search deeper, and >>now I have: >> >> -Nullmove (tried R=3 and R=2, not yet R=2/3) >> -Futility pruning >> -Same move ordering as before >> -Same hashing scheme >> -Same 2 killers >> -Same Lazy eval >> -Check and null-threat extension >> -No out-of-check stuff in qsearch >> >> And now, I search 7-8 plies in blitz and 8-10 in standard (and the worst thing >>is that the program looks weaker than the old one!) >> That looks like a poor search depth, isn't it? So what am I missing to get, as >>most null-movers, 12-13 in standard? >> SEE? History heuristic for move ordering? ETC? Razoring? > >Are you sure you have implemented null-move correctly? IE R=2 everywhere, >trying null-moves _everywhere_ (except for not allowing two consecutive null- >moves in a row)? Allowing multiple null-moves in a single path with the above >restriction? > >You should be going deeper. Significantly deeper. That's what I expected to hear... :( Yes, I'm trying null moves everywhere, except two consecutive and when inCheck. I must be doing something wrong. I'll check my move ordering and null move implementation, but the look fine, at first sight. Anyway, thanks for your help. José C.
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