Author: Steve Maughan
Date: 19:31:52 07/24/03
Go up one level in this thread
Russell, >>With respect this is nonesense. There is no reason at all to clear the hash, >>killer or historytable just because you're under UCI. Monarch doesn't and I >>doubt Shredder, YACE or Sjeng do either. > >Perhaps I am just inexperienced compared to you when it comes to transposition >tables, but it seems like there would be a good reason to clear the >transposition table when you start a new game or start analyzing an unrelated >position. Correct me if I'm overlooking something important. No. Don't be confused by the "UCI says start a game every move comment". This is just UCI's way of setting up a board i.e. it's effectively its version of FEN >Let's say that I use a single table and I replace using the "depth preferred" >method. I let my engine analyze overnight on an endgame position, and my table >is now filled with entries of 20 ply or more. I wake up the next morning, note >the analysis results, and decide to analyze a complicated middlegame position, >in which it gets to only (say) 13 ply after another overnight analysis. Wouldn't >my transposition table be completely useless then, since not one single element >would get written to it? Even if you use two tables of "depth preferred" and >"always replace", you're wasting the depth preferred table. You can easily get round this by adding an "age" term to the hash record. I do this in Monarch and many other engines do the same. This works by always replacing if the age of the search is newer than hash record that may be overwritten. In normal play none of criticisms are valid - just don't clear the hash or reset the killer etc when you are sent a SETPOSITION command. The criticisms are really only valid if you're using the engine to analyze and want to replicate analysis again and again. Authors could even have a parameter in the UCI setup where the user can set whether or not the hash is cleared before a search. In summary UCI is not perfect but I'd recommend it over Winboard. Cheers, Steve
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.