Author: Ricardo Gibert
Date: 16:27:18 08/03/99
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On August 03, 1999 at 19:09:29, KarinsDad wrote: >On August 03, 1999 at 18:45:49, Ricardo Gibert wrote: > >[snip] >> >>Yes, this is workable, but how could it be better? There can be a lot of leaf >>nodes that could hit the EGTB and the extra time spent taking care of the 50 >>move rule could be better spent some where else. Some of the EGTB hits will >>return mate in over 50. The program has to go further down the line to make sure >>a pawn move or capture takes place before 50 moves are played. For example: mate >>in 110 will require the program to find more than one pawn move or capture. Why >>bother when you don't have to? > >If you are in a mate in 110 situation (probably extremely rare), it would >probably behoove you to do your own searching for capture/push moves that lead >to positions that maintain the win since you will probably find them relatively >close to the main line anyway. Compared to searching even something as simple as >an 8 ply alpha-beta, searching for those moves would take VERY little time. The >reason this works out so well is that you do not have to search outside the >tablebase once you are in it (or once you are close enough to it to force your >way into it). In many pawnless EGs a "good" capture can be hard to come by. 8 ply would not do it in that case. > >From what I have been told, 5 piece tablebases take about a month to generate on >a 500 Mhz system (more or less). In order to regenerate the work done so far on >6 piece tablebases would be a great deal of work. > >Yes, you could improve upon the tablebases by doing what you suggest, however, I >would expect that it would significantly increase the time required to generate >the table, possibly by a factor of x2 or more. I realize that this would not be >a great amount of time for 3, 4, and 5 piece tablebases, but for those people >currently generating 6 piece tablebases, it's probably a significant amount of >time (even if they were to find a way to keep the data they already have and >just add to it). I'm not sure if it would take longer, but if so, I can understand the trade off of allowing draws in winning positions, since they are extremely rare. This is a good point you make. > >So, all in all, it seems that you could improve upon them, but there probably >isn't a need when it can be handled in real time within the program for those >few instances when it would be needed. JMO. > >KarinsDad :)
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