Hallo zusammen,

das fantastische Stockfishprojekt zieht immer mehr Leute in seinen Bann. Jetzt hat sich selbst die lebende Legende Ed Schröder, der das beste 8-bitter Schachprogramm aller Zeiten programmiert hat (Milano, Polgar) und Autor von Rebel/Prodeo ist, im Stockfish-Chat zu Wort gemeldet und einige Ideen dort gepostet, die er für interessant hält. Und er kündigt weitere Postings mit Input für Stockfish an.
Ich hänge das Posting von Ed Schröder hier mal an.

Stefan

Marco,

I like to contribute a couple of EVAL ideas that I have tested about a year ago and surprisingly still did well after my departure in 2003 long before hardware made it possible to play zillion of games.

Without much knowledge of Stockfish, so on the risk you already have something similar here goes.

1. Consider the game 1.e4 e6 2. Bc4 d5

2..d5 attacks both the bishop on c4 as well the pawn on e4 a double attack.

My SEE routine notices the double attack and will give a bonus for the lowest attacked piece, in this the pawn op e4. Following the classic 1|3|3|5|9 rule the bonus will be:

score += table [SEE result];        // 0-9

int table [ ] = { 0, 0.25, 0.50, 0.75, 1.00, 1.00 ......... 1.00 };

It was surprising this aggressive approach still works on nowadays deep depths. My test showed 20-25 elo.

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2. Consider a position WBg2 vs BRd5 and BRa8 (or BQa8)

In situations like these (I call it an 1½ attack) I add 0.75 to score.

Estimated elo 0-5.

==================

3. Bishop pair observation - It's at least true for my engine that the bonus for the bishop pair is related to the number of own pawns. As such I have this code.

if (bishop_pair_white) score += table [number_of_white_pawns];
                       1 pawn                                    8 pawns
int table [ ] = { 0.50, 0.50, 0.50, 0.50, 0.37, 0.25, 0.12, 0.07, 0.05 };

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Another Bishop pair feature - when white has the bishop pair and black has no knights and bishops I add an extra bonus of 0.25. In situations like these the bishop pair is practically untouchable. It's likely this bonus should be increased to 0.50 or even 1.00 but real game situations are rare and with my limited hardware (and lacking interest) this is untestable.

I have some more but it's already late here on this part of the planet.

Good luck with SF.