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Subject: Re: Gambit Tiger fails to win won game allows position to become blocked

Author: Christophe Theron

Date: 20:04:05 05/02/01

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On May 02, 2001 at 12:28:09, Robert Hyatt wrote:

>On May 02, 2001 at 11:29:27, Christophe Theron wrote:
>
>>On May 02, 2001 at 02:26:08, James B. Shearer wrote:
>>
>>>    I was playing a Gambit Tiger 2.0 clone on ICC a couple of days ago.  I lost
>>>my queen (for 2 pieces) before move 20 but Gambit Tiger failed to convert the
>>>win allowing the position to become totally blocked leading to a draw by the 50
>>>move rule at move 192.  It seems there must be problems with the evaluation
>>>function for blocked positions (particularly when up material).
>>
>>
>>
>>The antihuman mode was not turned on I think.
>>
>>With antihuman mode it would not have happened.
>>
>>
>
>
>Why is this considered "anti-human"?  IE do you want to draw such positions
>when playing a computer, but not a human???



I do not want to use the kind of wild stuff I do to open the position if I'm
playing against a computer.

My time management and evaluation are working together in the case of antihuman
mode. One of the behaviour I try to address is the case where the guy
1) tries hard to close the position
2) when he is done, move a piece back and forth very quickly until the program
runs out of time and LOSES

The antihuman mode is able to recognize this and to take extremely strong
actions to avoid it. One possible action is for example to sacrifice a knight on
a pawn in order to open the position. I know I can do this safely against a
human player who has been using the close+shuffle strategy, because when I do it
I know the guy has not enough time left to compute correctly. So even if I have
sacrificied a minor piece in order to open the position, I'm almost sure to win
the game by outsearching the human player in the resulting open position.

Of course it's out of question to use this against a computer. So if the
position is blocked, I'm not going to take the risk to accept even a positional
handicap just to open it.




>  I run with my anti-blocked-position
>code _always_ enabled...



Yes but if the opponent manages to close the position anyway, you won't be able
to get out of trouble (he will get a draw).

By knowing if it's playing a human player or a computer, Tiger can decide to act
very brutaly in order to avoid a draw.




    Christophe



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