Author: Bernd Nürnberger
Date: 00:21:12 02/04/06
Hello, I have a question concerning the rate of beta cuts. My program prunes the tree by doing a beta cut at about 5-10% of all nodes. This seems rather low to me. Thus most moves that were generated are actually made. Nethertheless I am getting rather low node counts and a mediocre first cut rate: for WAC (pos 1-300) at depth 8, my program searches about 69 M nodes with a first cut rate of 88%. Now to the question: is a cut rate of 5..10% common?? I often heard that most moves generated are nether done because of beta cuts. That's not the case in my program. For WAC (depth 8) 88 M nodes are generated and 69 M nodes are done ! Configuration: - Hash Table (1 M entries, deep/new two-level replacement) - Razoring/(Extended) Futility Pruning - Null Move (rather aggressive) - Move Ordering: x hash move (IID) x winning + equals caps (by SEE, only x-rays capturer) x killer 1 / killer 2 x non-caps (history heuristics) x losing caps - PVS / aspiration search - QS (prunes rather aggresively using SEE) - plain vanilla eval (mat + pc-sq + boni/penality for castlings) Any comments appreciated :-) Bernd
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