Search found 279 matches

by zenpawn
Fri Aug 19, 2016 10:50 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: "moveerror" in Arena debug log
Replies: 2
Views: 517

"moveerror" in Arena debug log

Has anyone ever seen this error in the Arena 3.5 (build 2816) debug log?

*moveerror* start square<0 !...!

It appears among the thinking output and doesn't cause the game to be stopped. I'm using the Winboard protocol.

Thanks,
-Erin
by zenpawn
Fri Aug 19, 2016 10:43 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

Turns out some of the search tree explosion I always see (at least in the endgame) with check evasion extensions enabled was due to also having single-move extensions. If the latter extension is applied only when the former hasn't already extended the depth, the issue is largely mitigated. Thanks ag...
by zenpawn
Wed Aug 17, 2016 11:06 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

OK, I guess I've got this position on my mind, where a check evasion extension would give another ply and thus another chance for a check, which would cause another evasion extension and so on and so on. Ah, I think I just got the difference; the extra ply is immediately used up by the evader. Corr...
by zenpawn
Wed Aug 17, 2016 11:04 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

OK, I guess I've got this position on my mind, where a check evasion extension would give another ply and thus another chance for a check, which would cause another evasion extension and so on and so on.
by zenpawn
Wed Aug 17, 2016 9:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

In theory you would almost be right but that won't work in practice since it would result in an unmanageable tree explosion. It would search a much larger tree than with just check extension. The latter does not add checks and their subtrees, it just extends replies to checks which were already the...
by zenpawn
Wed Aug 17, 2016 8:49 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

Including checks in qsearch is a bit different, here you make the search wider by adding more moves to be searched (quiet checks), but you only do that during the first N plies of qsearch, typically N=1. This will basically extend the horizon at some leaf nodes. But the kind of extension is not the...
by zenpawn
Wed Aug 17, 2016 8:16 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

Thank you all for such a lively discussion, feedback, more test positions, and encouragement. You've definitely made me feel welcome. :)

Regarding check extensions, it basically accomplishes the same goal to include checks in qsearch, right?

-Erin
by zenpawn
Tue Aug 16, 2016 10:06 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

Re: perpetual check position

Thank you, Robert. It's an honor. I've experimented with check extensions, but am currently favoring just allowing them in q-search instead. Also, LMR is not allowed when checking or in check. I'm glad it's sufficiently long a variation to require 13 ply from Crafty (is that the mathematical minimum...
by zenpawn
Tue Aug 16, 2016 9:24 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: perpetual check position
Replies: 27
Views: 3411

perpetual check position

Hi all, This is my first post, having become hooked in late May to this addictive hobby. I now have a frustratingly-weak (~1800-1900 at 2+6 or 40/4 TC) chess engine all my own . :) I forget where I got this position. It was an example of perpetual check/three-fold repetition when white is to move, w...