Extension - Reductions and threats

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Re: Extension - Reductions and threats

Postby diepeveen » 21 May 2006, 21:17

mjlef wrote:OK,

This is a germ of an idea which I am testing now. Looking at huge trees my program often generates after extensions, and how it hurts search depth, this idea popped into my head:

After any extension involving a threat, reduce the depth the same amount once the threat is over. Example, if you extend on soem passed pawn push, once that pawn promotes or is captured, reduce the depth the same amount you extended it. Doing this seems to let me do more passed pawn move extensions without a huge blowup. The idea could be extended to mate threats, extensions for tactical threats, etc. Does anyone do this and what have been your results?

I will post my results once I get a lot more games in (specific limits seem critical).

Mark


Diep plays basically with only check escape extension turned on.

Apart from that extension, i basically have kicked out all other extensions.

i would love to do a mate threat in search, but it's just too expensive for the branching factor. I lose 1 to 2 ply to already very lobotomized mate threat extensions in several positions where nothing is wrong. (so as a result of that the mate threat extensions is turned OFF in diep, i am throwing dices always that its kingsafety is good enough to withstand such a minor problem).

So your idea is quite good idea, yet i don't see how to implement it for a mate threat extension.

The real idea of such a mate threat extension is to get the line longer, in order to be less vulnerable to a horizon effect.
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Re: Extension - Reductions and threats

Postby Stan Arts » 26 May 2006, 09:23

Sorry, I didn't have internetacces for two weeks. (hospital)

Any users of Free Pascal around? I really need to compile NOW for newer processors and I am having some problems with it.


I'm a big fan, and know a thing or two about Free Pascal.

What sort of problems are you having?

greets
Stan
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Stan Arts
 
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Re: Extension - Reductions and threats

Postby mjlef » 26 May 2006, 14:09

Stan Arts wrote:Sorry, I didn't have internetacces for two weeks. (hospital)

Any users of Free Pascal around? I really need to compile NOW for newer processors and I am having some problems with it.


I'm a big fan, and know a thing or two about Free Pascal.

What sort of problems are you having?

greets
Stan


Some compile errors, but they are vague and tell me next to nothing. I can email you on the side for some suggestions, and to not fill this board with boring stuff. Mark
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