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Pawn-ending extension

Posted: Wed May 29, 2019 10:50 pm
by hgm
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...

Re: Pawn-ending extension

Posted: Wed May 29, 2019 11:16 pm
by JVMerlino
hgm wrote: Wed May 29, 2019 10:50 pm But it looks a bit silly...
No sillier than some endgames (or even conversion to endgames) from engines using endgame tablebases....

Re: Pawn-ending extension

Posted: Wed Jun 05, 2019 6:17 am
by Volker Annuss
That's easy to avoid when you extend recaptures only.