Search found 3874 matches

by michiguel
Mon Apr 14, 2008 7:04 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Stress test for hashtable, checkmates, node counting.
Replies: 13
Views: 3688

Re: Stress test for hashtable, checkmates, node counting.

It turns out that this is a good test for winboard too, because it reveals a bug in winboard that I never noticed before. Anatoli considered short castling at lower depths so I thought it had a bug, because there is no 'K' in the fen. But in the logfile I found that winboard had added it to the fen...
by michiguel
Mon Apr 14, 2008 5:48 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Stress test for hashtable, checkmates, node counting.
Replies: 13
Views: 3688

Stress test for hashtable, checkmates, node counting.

Searching for posts in move ordering last week, I saw someone used the following position in a completely unrelated thread: [D]8/8/8/8/3k4/8/8/4K2R w - - 0 1 White should see a checkmate in a reasonable time and find shorter mates as search progresses. I thought that it would be a good idea to confi...
by michiguel
Sun Apr 13, 2008 12:23 am
Forum: Computer Chess Club: General Topics
Topic: Queen sac from Sage 3.51d
Replies: 5
Views: 1532

Re: Queen sac from Sage 3.51d

It's not too often these days that you see a good king hunt involving a queen sac along the way! [Event "40 Moves in 62 min"] [Site "Little Thought Big Heart"] [Date "2008.04.13"] [Round "1.1"] [White "NanoSzachy 3.1"] [Black "Sage 3.51d"] [Result "0-1"] 1. c4 {book 0s} e5 {book 0s} 2. Nc3 {book 0s...
by michiguel
Fri Apr 11, 2008 11:08 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: at what point is material dangerously low for zugzwang?
Replies: 3
Views: 1316

Re: at what point is material dangerously low for zugzwang?

Most programs prove null move when the side on move has a piece (without count pawns). In the endgame is true that you can verify whether zugzwang, I make that verification with less than 1300 (without count pawns). One thing is certain, with queens has zugzwang. In this case, I believe that a Knig...
by michiguel
Wed Apr 09, 2008 5:45 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Avoid Repetition Pruning again
Replies: 2
Views: 1127

Re: Avoid Repetition Pruning again

A small summarize: If we treat first repetition inside the tree already as draw and the side to move has at least a draw-score, that is alpha >= 0, it is safe to prune nullify-moves with some extra condition, since we can not improve alpha if we allow the opponent to repeat the position. The move a...
by michiguel
Wed Apr 09, 2008 5:16 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: What is the Ideal Output for Understanding a Chess Engine?
Replies: 40
Views: 8905

Re: Can it be any simpler?

thePosition.ExecuteMove(theMove); // Does all internal data structure updates if (thePosition.IsLegal()) { GlobalNodeCount++; // Various processing theScore = thePosition.Evaluate(); // May recurse } else theScore = ScoreBusted; thePosition.RetractMove(); That is a...
by michiguel
Tue Apr 08, 2008 11:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: What is the Ideal Output for Understanding a Chess Engine?
Replies: 40
Views: 8905

Re: What is the Ideal Output for Understanding a Chess Engin

I would always suggest sticking with the traditional definition of "node" unless your name happens to be Donald Knuth, Claude Shannon, etc... Then one might have the "reputation" necessary to re-define an accepted term. If a definition becomes vague, it becomes useless. I think this ignores the tru...
by michiguel
Tue Apr 08, 2008 8:15 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: stalemate detection in quiescence search
Replies: 18
Views: 4924

Re: stalemate detection in quiescence search

I think it does solve it. If you want to convince me, you'll have to implement stalemate detection in an opensource engine. This should be quite easy in Toga. But I think you'll waste your time because it does not solve the problem. EDIT: I saw Filip's post now. Strange. Maybe his engine has a faul...
by michiguel
Tue Apr 08, 2008 5:12 pm
Forum: Computer Chess Club: General Topics
Topic: Medium difficulty testmove 17.Qe3
Replies: 17
Views: 4142

Re: Eelco what about e6!!

Yes! 17. e6 looks very good too, and Rybka finds it very fast. Thanks! I don't know if Toga rates e6 as much better or somewhat equal to Qe3, it was still calculating at 17 ply, you guessed it, trying to resolve 17. e6. But I think there is a problem with the QSearch again, hash is already 100% so ...
by michiguel
Mon Apr 07, 2008 4:34 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: stalemate detection in quiescence search
Replies: 18
Views: 4924

Re: stalemate detection in quiescence search

Thanks for your answers. 4Filip: I assume you did this in positions with side to move having only the king? 4Miguel:How exactly do you test for stalemate in your evaluation? My guess: you have attack_from table computed for every piece, "or-ing" these together? Then all you would have to do is chec...