Pawn-ending extension

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Full name: H G Muller

Pawn-ending extension

Post by hgm » Wed May 29, 2019 8:50 pm

I just implemented an extension of 50% of the remaining depth for moves that convert to a Pawn ending in KingSlayer. This to prevent it from converting to such a lost end-game by unnecessarily trading its last piece because it lacks the depth to recognize it as lost. While it could have added that depth with negligible impact on the total tree size, as the branching ratio in Pawn endings is very low. So that is what it does now.

The results are a bit funny, though. When it now is ahead one-to-nothing in pieces, it often just gives away the piece for free, to get the extension. Because only with the extension the promotion is within the horizon. This has no effect on the result, of course; it wins those games anyway. But it looks a bit silly...

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Re: Pawn-ending extension

Post by JVMerlino » Wed May 29, 2019 9:16 pm

hgm wrote:
Wed May 29, 2019 8:50 pm
But it looks a bit silly...
No sillier than some endgames (or even conversion to endgames) from engines using endgame tablebases....

Volker Annuss
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Re: Pawn-ending extension

Post by Volker Annuss » Wed Jun 05, 2019 4:17 am

That's easy to avoid when you extend recaptures only.

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