Author: Dann Corbit
Date: 11:55:12 05/05/03
Go up one level in this thread
On May 03, 2003 at 06:03:04, Geoff wrote: >Hi Dan > >Thanks a lot for the tips > >>1. Hash table >The later version of TSCP has got code in for hash key generation for reps >checking so that is a good start to get me going with this mod. I haven't really >thought too much about how hashing works yet though. I guess the actual key must >be stored in the indexed position to make sure you avoid the case where >different board positions (and different keys) get stored in the same slot ? Look at Zobrist hashing code. You really, really want to be able to do incremental hashing, since the savings is very large. It really is not that much more complicated than rehashing everything from the start. >>2. Move ordering (based primarily on hashing, so do step 1 first) >I think I need to try and improve the way the whole move ordering is working and >improve my understanding at the same time hopefully ! From the average case move ordering (random move selection) to best case move ordering (choosing the best move) your nodes examined will go from N to sqrt(N). As you can well imagine, this results in an enormous speedup. > >>3. Null move. (make/unmake is the tricky part) >The whole idea sounds tricky at the moment, this is at the back of my list of >mods till I get the other stuff sorted Seems that some people have no trouble with it. The idea is really pretty simple. If a move makes you worse off than not making the move, don't bother with it (unless we are Zugzwang).
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