Author: Dann Corbit
Date: 18:30:26 05/23/00
Go up one level in this thread
On May 23, 2000 at 18:24:21, Mark Young wrote: [snip] >Lets be generous and say a ply is worth 100 rating points, and we can take Fritz >6a for an example. Now you said it does not matter if it’s the 1st going to 2 or >14 ply going to 15 ply. Its pretty much the same, if I understand you >correctly. Lets assume Fritz 6a plays at a 2500 rating +/- 100 rating points, >with a average middle games search depth of 15 plies. > >15ply X 100 rating points = 1500 rating. Where are the extra 1000 rating points >coming from? Is Fritz really rated 1500, or are some plies worth much more the >others. > >It is clear that the early plies are worth much more the later plies, and if you >plot it out it’s a curve. I don't know of one program that does not exhibit a >curve. That is well established, as both Dr. Hyatt's and Dr. Heinz's experiments showed. However, as the depths increased, two very surprising things surfaced. At extreme depths, a linear model fits just as well as an exponential one. Hence, there may (or may not be) additional loss in the value of additional plies. Far more surprisingly (to me at least) is that the number of fresh ideas do not drop off. IOW, if the program liked one move at ply 10, and another at ply 11, and yet another completely different one at ply 12, they can just keep coming up with new moves that have not been considered best at deeper plies. This one is (to me at least) both astonishing and counter-intuitive. Obviously, it can't possibly find more fresh ideas than the number of possible moves! To say the least, it deserves further study. If you have not bought a copy of E. Heinz's book, it is highly recommended.
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