Author: Sune Fischer
Date: 11:21:26 07/28/04
Go up one level in this thread
On July 28, 2004 at 11:02:36, Robert Hyatt wrote: >On July 28, 2004 at 03:18:52, Sune Fischer wrote: > >>On July 27, 2004 at 18:26:16, Robert Hyatt wrote: >> >>>Aha. And exactly how many times do you do the N+1 iteration and get the _same_ >>>best move? For crafty that is about 85% of the time. So I should cut the >>>search off one ply early? Or is that 15% critical? >> >>I don't understand the question. > >you said I wasted time by starting the next search which won't fail low most of >the time. I said you waste time by doing iteration N+1 that doesn't change the >best move most of the time. See the fallacy in the argument? I _know_ going to >depth N+1 won't change the best move most of the time. But it will likely >change the best move when it is important to do so... No. It's going to depend on how much time you have left. If you need 5 seconds to fail-low and you have 4 seconds left, you won't see it. >I never said "win-win". I said it works better for me after testing. And I >have done _lots_ of testing with various approaches. That's how I settled on >the current approach. I'm not much for tea leaves and Tarot cards. That interesting, because I was beginning to wonder how you could have such strong opinions on something you _haven't_ tested. :) >>I too would like to know if there is a big fail-low at the next ply, I just >>don't see your way as the most efficient way of doing it though. > >That's ok. All engines are different in some respect. I base my decisions on >what to do on testing. That's all I can say. Nothing says that what works for >my program will work for yours or vice-versa. But what I do works for mine >pretty well... Sure, but perhaps you are closing your eyes to something that might work even better. You should test it first, then say how much it sucks :) Unless of course you can come up with some super logical argument why it's not going to work. >>To see the next ply you have to extend time, which you won't be able to do if >>you run out of time before the search returns. > >I don't have to extend the time. You proposed the 15% rule. It breaks above >and I'd stop 2 plies too soon, even though I could finish _both_. Where does it break? Please show me some analysis output where ply N+1 takes less than 15% of ply N. You definitely won't find many of those, and even if you manage to find one it will be insignificantly rare. >>..and then bite the dust when the fail-low doesn't have time to return or the >>time is simply wasted :) > >Again, I use aspiration search in addition to PVS. My fail lows happen _very_ >quickly in 99% of the cases. Ok, so in 99% of the cases you have some idea how long it will take to fail-low, anything longer means it's not going to FL and it's trying to resolve the score. Somewhere inbetween you can abort if you are not interested in the score. > And with my approach I have no special-case "last >iteration" stuff to deal with. I just search until the search returns "time up" >and go with what I have. > >That's the KISS part of this. It's just very random, I prefer something more harmonious. -S.
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