Author: Uri Blass
Date: 10:18:30 09/28/02
Go up one level in this thread
On September 28, 2002 at 13:04:17, Sune Fischer wrote: >On September 28, 2002 at 12:18:59, Uri Blass wrote: >>It is a common knowledge and Amir Ban explained in CCC some years ago that >>Junior almost always tries to finish the iteration that it is searching and only >>in cases when there is a danger of losing in time it does not stop >>in the end of the iteration. >> >>I also do it and my decision if to start a new iteration is based on my estimate >>of the time to finish the next iteration. > >hmm, chess programming is more complicated than I thought! > >>There are programs that do not do it but every good program that I know use more >>time after failing low to try to finish the iteration. >> >>I know it based on my experience in watching games of chess programs togrther >>with their evaluations. >> >>Hiarcs even extend time after finishing the iteration and it may be too >>dangerous but the idea is that if the position failed low the program probably >>does not understand it and it may be important to search another ply to avoid >>the horizon effect. >> >> >>I also know about other mistakes that they do in time management and movei today >>also does part of their stupid mistakes. >> >>Here is one small example: >> >>Suppose that your program is at move 41 and the time control is 40 moves for 40 >>minutes. >> >>Suppose that your program wants to play a move that force a draw by repetition >> >>A smart time management is not to play it but to try to find alternative that is >>clearly better and to play the drawing move only when there is danger of losing >>on time because you can lose nothing by delaying the decision. >> >>I prefer not to work on fixing it because the 1 elo that I may gain from it is >>not worth the danger of new bugs. > >How about giving it more time when the program can't make up it's mind, when the >pv keeps changing - keep searching! I am not sure if it is a good idea. > >Give it less time if it is a recapture or something easy like a constant score >and move on pv. I think to give it less time when the move is forced(of course I need to calculate the exact value of the next best move for it) but it is not in the top of my priorities. Of course I need not to use too much time to calculate the value of the next best move so the price is smaller than the gain that I get from that knowledge. I think that if you use 1/1000 of your time for finding exact score for the 2 best moves and continue to search in normal way except cases when the difference after 1/1000 of your time is high enough then it can be a clear win. Not that I do not say to stop search after 1/1000 of your time except cases that the second best move is mate against yourself but if the difference is more than 2 pawns then you can continue to search the 2 best moves and if the difference does not go down(it is going to happen often) then you can use less time when the exact time can be dependent on the difference. Uri
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