Author: Uri Blass
Date: 10:28:02 10/26/03
Go up one level in this thread
On October 26, 2003 at 13:11:26, Christophe Theron wrote: >On October 26, 2003 at 12:12:33, Uri Blass wrote: > >>On October 26, 2003 at 11:10:14, Peter Berger wrote: >> >>>Maybe I should have posted this in WinBoard forum, but the diagram feature is so >>>much nicer here :) >>> >>>This is the first match in (planned at least ;) ) a little series between modern >>>middle-class amateur engines and old professionals. >>> >>>Genius 2 played on a PIV2.2GHz, 32MB Hash, tournament.bok used. >>>Movei (17.10.03) played on a PIV1.8GHz, 16MB Hash. It used the book of the >>>public version and the s parameter. >> >>How much hardware advantage does it give for Genius? >> >>can you compare nodes per seconds for Genius and movei? >> >>> >>>Time control was game in half an hour. >>> >>>It was a surprisingly one-sided match where Movei was without any real chances. >> >>From looking at few game it seems that movei had chances but blundered. >> >>In game 1 movei could draw by tablebases >>but blundered with 42...Kf6(it did not know that KQ vs KP is a draw when the >>pawn is in the 7th and when it played 42...Kf6 it could not search deep enough >>to see the promotion of white). >> >>In game 2 movei also blundered in an endgame that is not clear(Fritz8 says that >>white is better before 39.Ne5 but movei needs too much time to avoid that move). >> >>Movei could play 39.Re7 h3 40.Re2 Rg2 41.Re1 f6 42.gxf6 gxf6 43.Rh1 h2 44.Nd4 >> >>and yace could learn from that line almost a draw score for white. >> >>I still did not look at the rest of the games but from the positions that you >>posted in game 7 and 8 it is clear that movei also had chances in these games >>and maybe time control of x minutes/y moves could be better for it but I need to >>check if it can avoid the mistakes in case of searching one ply deeper. >> >>> >>>A few comments: >>> >>>Genius 2 was the first chessprogram I bought. At this time I had a mighty >>>386SX20, and its play impressed me much, kind of a first love. >>>I just loved its passive and accurate play, and the endgame looked very strong >>>to me. >>> >>>a.) While later Genius version were stronger in the past I am not sure if this >>>will also turn out to be the truth on current hardware. >>>The branching factor of Genius 2 looks much better than what I am used to with >>>later versions (untested impression). It was only mildly outsearched by >>>movei (1-2 ply), in the endgame it actually searched deeper than its opponent >>>most of the time. >>> >>>b.) Movei suffered some in the opening. The opening book used for it wasn't too >>>impressive. Still its one victory was clearly a book win in fact :), when Genius >>>couldn't find the right moves in time to justify the good opening line it had >>>chosen ( Round 6). >>> >>>c.) Movei's time management is unconventional. While it plays a little too fast >>>in general, it doesn't seem to have an upper limit (or it is very high) for the >>>time to finish a ply. >> >>The upper limit is half of the time that it has in the clock to finish the game >>or the time control. >> >>>This made it think on 14. O-O in game 6 for _several_ minutes for example, >>>because it was so eager to finish ply 12. Maybe this could be improved. >> >>I learned this from Amir Ban who said that it is a bad idea to finish search in >>the middle of the iteration. >> >>Uri > > > >I don't agree with Amir here. > >I think it is important to finish the first move of the iteration you have >started, so at least you know if there is something wrong about this move. > >If it is the case (the score drops significantly from the previous iteration), >extend the time. Let it search very long if needed, so it either finds a better >move or finishes the iteration. > >If the score of the first move is better or does not drop much (from the >previous iteration) and you have exceeded your target time, stop the search and >play that move. > > > > Christophe You may be right but I am not sure about it. I agree that it is more important to finish the iteration when the score drops (after fail low) relative to the case when the score does not drop much but I still believe that there is an advantage in finishing at the end of the iteration. The point is that I am not sure if it is a good idea to waste time to search the first move when in most cases the score does not drop significantly only to find a case when the scores drops significantly. Maybe I should have a combination of both methods. The idea is that I may decide to stop to search if I finish the iteration in more than 20 seconds and also stop to search in case that the score did not drop and I already used more than 50 seconds. Uri
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