Author: Robert Hyatt
Date: 13:27:37 09/24/01
Go up one level in this thread
On September 24, 2001 at 15:24:53, José Carlos wrote: > First, the context: > > Last night I finished implementing pondering for the first time. As usual, I >chose the easyest way to begin with, until I make sure I understand everything. > So I did it this way: after moving, I guess the opponent move (second of the >pv), make it, and start thinking. When the opponent's move arrives, I unmake the >guessed move, make the real move, and start thinking normally. I expected the >program to get to the pondering depth due to the info in the hash table. > This worked fine most of the time, but when the ponder search failed low deep, >the research didn't go straight to that point. Instead, it chose another move at >the begginning (because it saw the bad move in the hash table) and went >deepening slowly. > I was very disapointed with this behavior, but when I started playing on ICC, >I saw a big rating increase. Actually, the explained behaviour turned out to >work really good, as usually the program made a good move even with less depth. > > Now the question: > > Has this been tried in _normal_ search? I mean, restarting from the begginning >after a deep fail low. > Is this it a mistake to do what I'm doing? If so, what are the drawbacks? > > Thanks in advance, > > José C. I don't do it this way. But there is a reasonable point for doing it that way. If you fail low, you can keep going to resolve the score and then try to improve it. Or you can start the search over, knowing that the deep fail low score will stick around, and force you to find a different move at the root and iterate down through the depths on it as well. If it fails low, you can continue this if you want. I simply remember the assumed move for pondering, and if the opponent makes this move, I just turn off the "pondering" flag, set the "start search time" to right _now_ and keep searching. I set this start time so that I can later figure out how much time to take off my clock and how much time to take off the opponent's clock. I use the total ponder + search time in the decision on when to stop the search due to time limit...
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