Author: Ed Schröder
Date: 00:46:01 07/25/05
Go up one level in this thread
On July 24, 2005 at 21:08:43, Eelco de Groot wrote:
>Hallo Ed,
Hi Eelco,
>Fruit 2.1 presents quite a difficult challenge I think for all the programmers
>to see if they are able to distill some of the strong characteristics of Fruit
>2.1 for their own programs. But great that the source is available from Fabien,
>that should make a difference, in due time!
>
>Any luck with Windows 2000 and compiling Pro Deo with GCC (or was it another Gnu
>compiler) Ed?
I have moved to Windows 2000 now and able to run MVS 2005, it compiles a lot
faster than my "Digital Mars" compiler.
>Also, I was wondering Ed do you have any idea if this (from
>http://www.talkchess.com/forums/1/message.html?437706) could be a position where
>Pro Deo 1.1 is doing a bit too much pruning? Or could it possibly be a history
>reduction thing?
>
>Pro Deo 1.1 default is doing better here than Vulcan {9k9i} but also wants to
>sac the knight at move 31 at first.
>
>[D]7r/1kpr1p2/1p4p1/p6n/3pPP1N/3P1K2/PP1R3P/6R1 w - - 2 1
>
>Pro Deo 1.1 default
>00:35:52.4 0,00 17 2840425533 f5 Nf6 Nxg6 fxg6 Rxg6 Re7 Rxf6 Rh4
>
>Vulcan {9k9n4}(={9k9i} with small end1 change) after 29..Rh8,
>
>I waited for the 18 ply result, finally it got in but unfortunately 30.f5 did
>not remain best choice... there was no fail-low high, so I think one of the
>extensions must have take so much time to get to 18 ply..
I don't remember the Vulcan settings by head but sacs like these can be easily
related to the following tweaks:
1) You have giving the piece-values a too low setting, if you use:
[Pawn value = 95]
[Knight value = 95]
then the engine will more easily sac a knight for 3 pawns as in this case.
2) A too high passed pawn evaluation, if you use:
[Passed Pawns = 111]
then the engine will sac a knight/bishop in exchange for the passed passed (as
in this case) more easily.
3) The use of a too high value of the [Attractiveness] parameter. The
[Attractiveness] parameter multiplies all positional components with the
corresponding value. Say you are using a value of 120 then realize that in this
specific position the 3 passed pawns created by the knight will receive an extra
bonus of 20% which easily might be too much in this specific case.
Last but not least, realize that all parameters are connected to each other. So
if you are using:
[Passed Pawns = 111]
[Attractiveness = 120]
then first the 3 passed pawns are upgraded with 11% and there after with 20%.
Hope this makes some sense!
Best,
Ed
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