Author: David Dory
Date: 13:52:43 01/27/02
Go up one level in this thread
On January 27, 2002 at 16:08:21, walter irvin wrote:
>what is depth of search worth in elo per ply ?????? i mean is the jump from 5
>ply to 6 ply worth the same as 14 ply to 15 ply ????? i wonder if there is a
>relationship between the different plys and the percentage of times that the
>computer changes its mind on the moves at diferent plys .i mean if the program
>only changes its mind .01 % of the time between 14 ply and 15 ply and it changes
>its mind 14 % between 5 ply and 6 ply then how can the gain in ply be worth the
>same elo gain ??? and if this indeed the case have we just about gotten all we
>are going to get out of hardware speed up ????????
In Levy & Newborn's book "How Computers Play Chess", they give this comparison
of program, depth of search, and rating:
Depth Program Rating
===============================
5 CHESS 3.5 1600
6 CHESS 4.0 1800
7 CHESS 4.7 2000
8 BELLE 2200
9 HITECH 2400
10 DEEP THOUGHT 2600
===============================
Hidden within this data is the obvious fact that other programming improvements
were also added to these programs besides the stated increase in depth search.
In my opinion, increases in search depth do no correlate to a straight line
improvement, but rather, as you suggest, as your program searches deeper and
deeper, the improvement becomes less and less. So as your work in the search is
increasing substantially, your benefit from that work decreases. Certainly a one
ply increase from 4 to 5 is worth more than an increase from 14 to 15 ply's.
I think we really have just started to reap the real benefit of the better
hardware we now have to use. In the future, as a result of knowing better ways
of using that hardware, we'll see program strength increase dramatically through
heretofore unused methods. (Which wouldn't have made sense to develop with
yesterday's hardware.)
Dave
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