Author: Robert Hyatt
Date: 06:50:29 10/18/99
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On October 17, 1999 at 18:35:56, Heiko Mikala wrote: >On October 16, 1999 at 12:49:29, Frank Phillips wrote: > >>I have been experimenting with DarkThought type pre-pre-frontier and >>pre-frontier pruning with mixed results and wondered what other?s experience is >>of this type of forward pruning. Unless I missed it, I noticed Crafty does no >>forward pruning (except null move) and no longer even razors the last ply. > >Hi Frank! > >I tested DarkThought's so called Extended Futility Pruning (I'll call it EFT >from now on) with mixed results too. The first results were very bad, but my >experience is, that you need speed and search depth to make it work. Like Andrew >said, this can be a killer in blitz games, especially if your program is slow >and/or you're using a slow computer. And my results in test suites like BS or >LCTII have been a bit worse than withouht EFT. >Nevertheless, my program is very slow (around 20-30k NPS on a Cyrix MII 300) but >I have been using all three stages of DT's EFT for some months now, and it >worked fine. It let's you miss some things, but it also makes you search a lot >deeper which seems to help more, than the missing of a few things seems to hurt. >I have also tried Crafties razoring technique (which mentions "Kent et. al." as >the original authors), but my experience with DT's combined pruning/razoring >scheme has been far better. Maybe my implementation of Crafties technique is >wrong, or my EFT implementation is too conservative, because I think in general >Crafties scheme should be much safer, but my program makes more tactical >mistakes with Crafties scheme than with DT's EFT. > >But, to be honest, I'm not really 100% happy with it. It's a bit too selective >for my taste, and I'll continue to search for better things. > > >Greetings, > >Heiko. In crafty, 'razoring' is gone... I didn't like it overall and finally took it out forever...
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