Author: Steve Coladonato
Date: 11:55:28 05/23/00
Go up one level in this thread
On May 23, 2000 at 10:34:15, Jeremiah Penery wrote: >On May 23, 2000 at 08:00:53, Steve Coladonato wrote: > >>On May 23, 2000 at 00:05:36, Jeremiah Penery wrote: >> >><snip> >>>http://www.rebel.nl/db2.htm >> >>The following in an excerpt from the above link and I don't fully understand the >>evaluation. >> >> 13. Nc6-a5 >> Kasparov,G :11.00 -0.03 Nc6-a5 Bb3-c2 c7-c5 d4-d5 g7-g6 b2-b4 >> Rebel 8.0 :11.00 -0.03 Nc6-a5 Bb3-c2 c7-c5 d4-d5 g7-g6 b2-b4 >> 14. Bb3-c2 >> DEEP BLUE :11.00 0.13 Bb3-c2 c7-c5 b2-b3 Ra8-c8 Bc1-e3 g7-g6 >> Rebel 8.0 :11.00 0.13 Bb3-c2 c7-c5 b2-b3 Ra8-c8 Bc1-e3 g7-g6 >> 14. c7-c5 >> Kasparov,G :10.00 -0.05 c7-c5 b2-b3 Ra8-c8 Bc1-e3 g7-g6 d4xe5 >> Rebel 8.0 :10.00 -0.05 c7-c5 b2-b3 Ra8-c8 Bc1-e3 g7-g6 d4xe5 >> >>I am interpreting the evaluations to be relative and not absolute (for the 3 >>moves above, the white position is evaluated better in all cases) So, at move >>13, Rebel evaluated the position -0.03 at 11 ply. At move 14, the evaluation is >>now 0.13 at ply 11 again. This I can understand because the line has changed >>from d4-d5 to b2-b3 and move 14 has looked one ply deeper than move 13. >>However, on black's move 14 the ply count is now 10 which indicates that the >>depth reached in the analysis is the same as that for white's move 14 but the >>evaluation has changed from +0.13 to +0.05 (absolute) the line being identical >>except fot the inclusion of d4xe5 in the printout. My question is why would the >>program change its evaluation of the position if it searched to exactly the same >>depth? > >It looks just like a slight asymmetry in the evaluation function. When >evaluating the same position from the white side and black side, I think a lot >of the programs will get slightly different numbers, because of asymmetry. The >asymmetry can be useful when you want to, say, value your own king safety more >than the opponent's. This way, you can do more to prevent attacks on your own >king, but you won't be making silly attacks on the opponent. Jeremiah, Thanks. If I read between the lines, this answer and the one Ed provided are basically the same. Steve
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