Author: chandler yergin
Date: 06:26:45 02/06/06
Go up one level in this thread
On February 05, 2006 at 22:25:49, Robert Hyatt wrote:
>On February 05, 2006 at 15:46:39, chandler yergin wrote:
>
>>On February 04, 2006 at 22:12:34, Robert Hyatt wrote:
>>
>>>On February 04, 2006 at 13:53:28, chandler yergin wrote:
>>>
>>>>On February 04, 2006 at 12:19:33, dhanial wrote:
>>>>
>>>>>What is the best hash table settings for rybka for 10 to 15 min games and for 1
>>>>>to 3 min games.
>>>>Default Value
>>>>as true for any engine.
>>>
>>>
>>>This is not true. At least not for Crafty. The longer the time control, the
>>>bigger hash should be, as larger hash provides better search times (not NPS
>>>times). The default for Crafty is simply small so that it won't cause problems
>>>on machines with very small memory sizes.
>>
>>How soon we forget..
>>http://www.rebel.nl/ches2010.htm
>
>I didn't forget a thing. No idea what your link was supposed to prove, but I've
>run the test many times. Bigger hash means faster search speeds, until you
>reach some magic point where the entire tree you are searching can be stored
>without losing information to table overwrites. But the minute you increase the
>time control, hash once again gets overwritten, and the search slows down
>compared to the speed with optimal hash.
>
>I'm not sure why you want to argue this point. It is trivial to test and prove
>exactly what I said is the case for Crafty.
For Crafty perhaps...
I prefer other opinions...
and it's not an argument..
Refute it!
The game tree consists of all possible moves for the current players starting at
the root and all possible moves for the next player as the children of these
nodes, and so forth, as far into the future of the game as desired. The leaves
of the game tree represent terminal positions as one where the outcome of the
game is clear (a win, a loss, a draw, a payoff). Each terminal position has a
score. High scores are good. For example, we may associate 1 with a win, 0 with
a draw and -1 with a loss.
Bounded Lookahead in Large Tree
In large trees, it is quite impossible to search all the nodes. The next best
thing is to trim the tree to a few levels and pretend that it is a good
approximation of the (unknown) minimax tree by assigning scores to its leaves.
The difference now is that the scores are no longer exact, but only educated
guesses. The scores obtained in this manner are said to be calculated with the
aid of an evaluation function. Evaluation functions are constructed by the user
based upon insight and experience. We may still employ the minimax algorithm to
compute all the scores:
http://www.seanet.com/~brucemo/topics/minmax.htm
Quoting:
A game of chess can be considered as a (usually) large n-ary tree ("n-ary"
means that from each node in the tree, there are some arbitrary number of
branches leading to other nodes). The position that is on the board now is the
root position or root node. Positions that can be reached in one move from the
root position are reached by branches from the root position. These positions
are called successor positions or successor nodes, Each of these successor
positions has a series of branches emanating from it, each of which represents a
legal move from that position.
http://www.rebel.nl/ches2010.htm
Recent Computer Chess developments
Especially the last years ideas based on the BERLINER experiment have been
practiced in chess programs with extremely good results in the computer-computer
area. Chess programmers discovered that by a new approach that looks illogical
at first sight their programs became a lot stronger in the computer-computer
area.
Computer chess development of the last years:
Make the program as fast as possible.
Even remove existing chess knowledge to ensure a fast chess program.
Add lots of tactics to out-search the opponent.
Add only the very basic chess knowledge (Berliner concept)
Make the program aggressive to ensure tactics in games.
Schröder about this new trend:
It's my opinion it all seem to work in the comp-comp area.
Now for comp-comp lovers this is great news but what about the people who use a
chess program for analysis, study and playing games?
10 days ago I released Rebel10.0c as an engine update for Rebel10.
In 10c I removed some chess knowledge which made Rebel 30% faster, next this 30%
speed gain was used to add new tactics. As a result 10c is a better comp-comp
player now but a lower positional player than the original Rebel10.
This is actually what is happening the last years and I want to report it in all
its details in the hope it will be understood.
There are advantages and disadvantages. The advantages are for the comp-comp
lovers. The disadvantages are for people who use a chess program for analysis,
study and playing games as the positional understanding of chess programs will
drop and no progress is made.
My personal opinion is that the disadvantages are bigger than the advantages
because the vast majority of people that use a chess program use it for playing
games, analysis and study.
It's my wish the computer chess press will pick up the subject, explain and
judge.
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