playing strength is not relevant here because I suggested comparing evaluation based on small depth searches when the small depth is based on similiar level to depth 1 of rybka(the closest that we can get)bob wrote:And since robo* seems to be testing at rybka + 70 elo or so, it is quite likely that in many positions they will be almost identical since they are so strong, while in a few others, they will be quite different due to that 70 elo difference. It is not so easy to compare that way. Pick the right positions and Crafty will appear to be a perfect clone of Rybka.Uri Blass wrote:Larry also said the following:bob wrote:The danger of "one was enough for me" is to compare rybka 1 beta table values to fruit's. More than one is enough there. BTW that has been done with direct disassembly of the piece/square table values. I don't remember the specifics now, but there is some material value difference between the two that requires some sort of multiplier. For example, stockfish uses P=256, so to convert to my pc/sq table values, one would need to multiply mine by 2.56 or divide the stockfish values by the same constant. But that doesn't make the values different, obviously, just duplicated and then scaled properly. I agree that duplicate tables would be a problem. But in both cases here (fruit/rybka 1 and robo/rybka3).lkaufman wrote:I can't even read RobboLito code myself, I'm not a programmer. I based my conclusion on an email from a reliable independent chess programmer (no connection to Don, me, or Rybka) who sent this king table he either found in or derived from an early Ippo version. He had no access to Rybka code himself, he just sent this info along. I compared it with my files of the values sent to Vas for R3, and the resemblance was startling. I didn't ask for other tables to compare, one was enough for me. It was also obvious to me that using Ippo (or later Robbo) for analysis generally produced evals extremely close to R3 in most situations, with rare exceptions. This should be equally obvious to anyone who compares them in analyzing many positions.
I could post the king table I submitted, but as I said I have no proof that it is actually in R3, I only know that Vas told me any time he made even the slightest changes to my terms or values, so I have no personal doubt on this point. So I'll leave it to others to post the relevant section from the R3 code if they wish to do so.
I don't claim that Robbo has taken the entire Rybka eval. Rather it seems that some parts may have been too difficult to decipher and were left out. So of course I won't post the whole eval even if I could prove it to be in R3.
"It was also obvious to me that using Ippo (or later Robbo) for analysis generally produced evals extremely close to R3 in most situations"
I think that it is possible to prove similiarity in this case
take(rybka,robbo,stockfish,Naum,Shredder,toga) and give them to analyze many random positions at small depth(rybka can get depth 1 when other programs get depth that they have similiar strength to rybka depth 1)
If the difference between Rybka and Robbo is significantly smaller than the difference between other pairs then it is going to be an evidence against robbo.
Uri
Uri