Author: Peter McKenzie
Date: 21:43:23 05/14/00
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On May 14, 2000 at 16:53:46, Brian Richardson wrote: >Tinker's q-search lazy eval (material - max_pos_score)> beta return (like >standing pat?), and (material + queen+pawn) <= alpha return (quasi-futility?) >was working fairly well, until a K vs KBN endgame. Since it was not getting to >the eval function, the special mating code was never used and Tinker ended up >with a 50 move draw...Now I check for opponent's pieces <= one minor and skip. > >This was discussed in ICCA Vol 21 # 2 (Extended Futility and Dark Thought). I >also have tried various regular futility, extended futility and razoring (as >outlined in the ICCA article), but they did not seem to help, at least given >Tinker's mix of searching algorithims. > >Anyone else getting "good" results with them? I use normal futility pruning, I think its pretty much a no-brainer although there are a few traps as you have discovered :-) I also use extended futility pruning, which is a little risky (but only a little) so not to everyone's taste. It is a definite win for my program though. I don't use any form of razoring, it just didn't appeal to me :-) I also have my own pruning scheme that extends Ernt's ideas somewhat, this is still under development. cheers, Peter
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