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Subject: Re: Rook Sacrifice and a deadly fail low

Author: Dann Corbit

Date: 17:14:30 03/06/04

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On March 06, 2004 at 20:02:13, GeoffW wrote:

>Hi Dan
>
>Thanks for the extensive analysis, that was a lot of output so I summarised the
>times to avoid the obvious Bishop takes rook
>
>
>Amy-net-087............00:16
>Aristarch 4.41.........00:02
>DeepSjeng..............00:04
>Delfi-440..............00:13
>Dragon_45..............01:23
>ELChinito 3.25.........00:06
>Glc300.................00:05
>Gothmog................01:31
>Kke-253................00:08
>Ktulu..................00:23
>List512................00:04
>Patzer 3.61.......... >00:35 not resolved
>Quark-232-net..........00:53
>Ruffian_202............00:03
>Ruffian_210........... 00:04
>Smarthink-017a.........00:10
>Yace...................01:06
>Shredder 7.04..........00:03
>
>
>This is seemingly a good test position to separate the elite programs from the
>merely good ones, the real top programs can see and resolve this threat in less
>than 5 seconds.
>
>I have only got to improve my program by a factor of 300 to get there, Arrrrrgh
>!
>
>It looks as though my program is the only one that really suffers from a nodes
>explosion though.
>
>I will do some experimenting on this tomorrow, maybe put some output in to try
>and see what extensions are adding lots of nodes. I will try a few tests with
>different features switched off to see if that makes a difference too ?
>
>>Interesting position.  I would like to be white here, for sure.  Great space
>>advantage and extremely dangerous king attack possibilities.
>>
>>Most top engines seem to go through similar ideas about the position as yours
>>does.
>>
>>What sort of hardware were you using?
>
>P4 1.6 Ghz running at 2.4 Ghz  512 Meg Ram (64Meg Hash table)
>Yes, chess programs do make it get a tad overheated !!
>
>
>>
>>What sort of techniques are used in your chess engine?
>>
>judging from this test position, not eough of the correct or intelligent
>techniques I would say :-)
>
>Joking apart, my program is TSCP + some code optimisations + 0x88 board + Null
>Moves + Hash table + killer moves + some rudimentary extensions and pruning
>
>Pretty standard stuff, it is quite surprising how much stronger TSCP can be made
>just from the above additions but with almost the same evaluation function.

Do you use internal iterative deepening?
It is very simple to implement, and helps a great deal in move ordering.  It
takes just 3 or 4 lines of code.
In case you don't, for a good example that is easy to understand, see Olithink
4.1.3.

If you have any loops with the number 64 in them, then you need a piece list.
It will make your program 3 times faster with a full board and many times faster
when the board is sparse.



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