Author: Mogens Larsen
Date: 09:47:00 11/28/00
Go up one level in this thread
On November 28, 2000 at 12:12:12, Mogens Larsen wrote: >On November 28, 2000 at 11:50:12, Dann Corbit wrote: > >>On November 28, 2000 at 10:30:00, Robert Hyatt wrote: >>[snip] >>To add a bit, here is an output from a chess engine for one of the WAC >>positions: >> >>Middlegame phase. >> 2 -173 4 525 e5c6 d6c6 >> 2 -173 4 1232 e5c6 d6c6 >> 3 -188 5 1569 e5c6 d6c6 f6h5 >> 3 -187 6 4205 g3g6 ! >> 3 -123 6 4577 g3g6 >> 3 -122 7 6316 f6h5 ! >> 3 -101 7 7444 f6e8 ! >> 3 -17 7 7746 f6e8 d6e5 d4e5 d8e8 >> 4 -17 7 8247 f6e8 d6e5 d4e5 d8e8 >> 4 -17 8 10898 f6e8 d6e5 d4e5 d8e8 >> 5 -12 8 11626 f6e8 d6e5 d4e5 d8e8 a1d1 >> 5 -11 11 22518 g3g6 ! >> 5 383 14 33800 g3g6 !! >> 5 999996 14 34042 g3g6 d6e5 >> 5 999996 15 34369 g3g6 d6e5 >>Learning score: 999996 best: 36 depth:5 hash: F45FB3C8 >> >>Notice that it 'found' g6 at ply 3. Was it 'solved'? Obviously not. Why not? >>Because it had no idea how good the position was. Because of this, the choice >>was easily abandoned at later ply. Given enough time, it found the right move >>for the right reason and stuck to it. That is an obvious case but you're oversimplifying the question at hand. First of all it found the move at ply 5 for the same reasons as at ply 3, ie. better evaluation than other possibilities. You conclude that it found the right move because the evaluation is improving (rapidly), because you know that it should. The fact that the score explodes is irrelevant as it depends on the position, eg. finding a mating sequence or finding a slightly better move. So going from -167 to 11 slowly as an example is just as valid as -11 to 383 rapidly. It depends on the nature of the position and the depth of the correct variation. Guessing the correct first move in a long variation with a high score is even more suspicious IMO. The evaluation score isn't a right reason by itself. My interpretation of right reason is an improvement in score as the PV approaches the "correct" variation. The Gandalf case doesn't justify this "right reason" conclusively, but it's very close. I find my interpretation easy to understand, independent of position type and free of suspicious speculation. Mogens.
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