Re: Programmers Open Letter to ICGA on Rybka/Fruit
Posted: Sat Mar 12, 2011 10:11 am
Does it contain parts of Fruit?BB+ wrote:(this assumes Rybka 2.3.2a is the last one that contains any significant parts from Fruit).
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Does it contain parts of Fruit?BB+ wrote:(this assumes Rybka 2.3.2a is the last one that contains any significant parts from Fruit).
IMO, yes, the evaluation function from Rybka 2.3.2a is sufficiently similar to that for Rybka 1.0 Beta that I would still say it is "non-original". See this post for a brief summary, and the attached disassembly therein (to compare to the disassembly for Rybka 1.0 Beta). If this becomes an item for dispute, I will be more thorough and quantify this more.Does it contain parts of Fruit?(this assumes Rybka 2.3.2a is the last one that contains any significant parts from Fruit).
Another minor point that I just noted is that the criterion for a 7th rank rook bonus in Rybka 2.3.2a is to have an opposing king/pawn on the 7th/8th, while in Rybka 1.0 Beta it requires the opposing king on the 8th or a pawn on the 7th. Similarly with queens. Also, the "can-castle" criterion with pawn shelter/storm is no longer in the main eval, but it conceivably could be in pawn hash (especially if this was really "king location plus pawn hash" by this point). As I say, I will have to check to be sure.See this post for a brief summary
BB+ wrote:Another minor point that I just noted is that the criterion for a 7th rank rook bonus in Rybka 2.3.2a is to have an opposing king/pawn on the 7th/8th, while in Rybka 1.0 Beta it requires the opposing king on the 8th or a pawn on the 7th. Similarly with queens. Also, the "can-castle" criterion with pawn shelter/storm is no longer in the main eval, but it conceivably could be in pawn hash (especially if this was really "king location plus pawn hash" by this point). As I say, I will have to check to be sure.See this post for a brief summary
Code: Select all
if (Rank(square)==RANK7 && (BlackKingSQ>H7 ||
BlackPawns&rank_mask[RANK7])) {
score+=ROOK_ON_7TH;
if (tree->pawn_score.passed_w && BlackKingSQ>H7 &&
!(BlackPieces&mask_abs7_w)) score+=ROOK_ABSOLUTE_7TH;
if (AttacksRank(square)&(WhiteRooks|WhiteQueens))
score+=ROOK_CONNECTED_7TH_RANK;
}
I haven't gone over there, but I would hope that the owner of the Rybka site would respond to a post on his own site indicating clear evidence of code copying. Surely he has responded at length, explaining how Bob and others are completely mistaken. Surely. You know ... being his website, his forum ...hyatt wrote:I think that "the cat is out of the bag" now. Deleting posts probably seems worse than letting them stand...
I'm not sure Rajlich actually owns the site/forum. It could be Convekta (for instance). Dadi Jonsson administers the forum, and Felix Kling the website AFAIK.You know ... being his website, his forum ...