Author: Dezhi Zhao
Date: 03:53:00 09/11/99
Posted by Robert Hyatt on September 10, 1999 at 00:19:37: [snip] >If you recall the discussion here a couple of weeks ago, I reported that I store >absolute mate scores (EXACT scores) in the hash table, and that I adjust them >so that they are always stored as "mate in N from the current position". This >has always worked flawlessly for me, and still does. >For bounds, I once tried adjusting the bounds as well, but found quirks, and >left them alone. Wrong answer. To fix this mate in 4 problem, I decided to >adjust the bounds as well, but I now set any bound value that is larger than >MATE-300, by reducing it to exactly MATE-300, but still using the "LOWER" >flag to say that this is the lowest value this position could have. For bound >values < -MATE+300, I set them to exactly -MATE+300 and leave the flag as is. Hi! If I understand correctly, you relax the bound mate scores to safe values, so that these bounds will not produce cutoffs when compared with other mate scores (esp. of EXACT type), but the bound will still generate cutoffs when compared with non-mate scores. I used to adjust the bound mate scores and the exact mate scores in the same way, and have not found any problems so far. Therefore, my question is: Why the adjusted bounds should not be compared with other mate scores and thus produce cutoffs? It seemed to me that the relaxed bounds would produce less cutoffs than the adjusted ones which are tighter. However, when I tried out your relaxed bounds on some mate positions, I found that your relaxed bounds save a lot (~ 12%)! Thanks to Dr. Hyatt! Any explainations? Can we find a even better way of using mate bounds? Dezhi Zhao
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