FWIW one concern I have about using fixed depth searches in general is that in actual games engines don't do that. Some positions require deeper searches and each engine makes their own assessment of how much time they can afford to spend (and hence how deep the search) on determining which move to make, using the remaining time as a guide and who knows what else. And, once you make time a criteria then the hardware that you are running the engine on becomes a factor since the more powerful the hardware, the deeper the engine can search in the same amount of time. So under game conditions an engine may be capable of making better moves than if fixed search depth is used.

The reason behind analysts picking such low depths or time per move, is pragmatic - they want results to get publicized rather quickly, it has nothing to do with a belief that engine at a particular depth would be good enough in al positions or absolutely perfect. It's pointless to criticize various researches on those grounds.

Please don't. This is 3 pages of completely 'off topic' already. Use a computer forum instead. -

I have asked <chessgames.com> to create a page for these type of general chess engine discussions since there doesn't seem to be any. There are several pages for specific chess engines (Rybka, Houdini, Stockfish, Komodo, etc.) but these kinds of general chess engine discussion would seem to me to be equally off-topic in one of those specific chess engine pages also.

<Topalov (8/11)> - +5 was pretty sensational. The 5 wins were exceptionally well played games, where Topalov completely outplayed his opponents in complex positions. He even entertained us with 3 consecutive exchange sacs (his trademark) in rounds 2, 3 and 4. This was a dominating performance, winning by 1.5 points and a spectacular 2924 TPR! That's 2 Grand Prix wins out of 2 and looks an odds on favourite to win a place in the next candidates.

<Nakamura (6.5/11)> - Never a dull moment watching Nakamura. He deserved his second place, only losing to the in form Topalov. He was no where near as clinical as Topalov though. In fact Nakamura's worst game of the tournament was the game against Morozevich, which by some miracle Nakamura won. Nakamura played with his usual fighting spirit. He made Karjakin suffer for over a hundred moves in round 1, he tortured Giri for 70 moves in round 2, and put Ponomariov under sustained pressure throughout the game in round 8, but only achieved 3 draws against them. All in all a good performance by Nakamura without setting the world alight,

<Ponomariov (6/11)> - Made a great start to the tournament with 2 wins and 5 draws, including a nice win against Caruana. Ponomariov was also the only player to push Topalov into a worst endgame which he eventually saved. Ponomariov eventually faded in the last 4 rounds. He was under severe pressure from Nakamura, but got a draw, then lost to Radjabov, and finished with 2 uneventful draws. Seemed to run out of steam at the end, but not a bad tournament.

<Caruana (6/11)> - More of a rollercoaster ride for young Fabio, with 3 wins and 2 losses. 3 nice wins against Radjabov, Kasimjanov and Kamsky, but outplayed against Ponomariov and Topalov. Round 6 saw the crazy game against Karjakin which neither player seemed to want to win. First Caruana had a winning position, then Karjakin got a winning position, but in the end a draw was probably the best result as neither deserved to win. Still, joint 3rd is a nice performance and lots to learn from the tournament.

<Morozevich (5.5/11)> - Got off to a flying start with 4/6. Disaster then struck with 3 losses in a row, not made any easier for Moro when he had a completely won position against Nakamura in round 9, he didn't find the winning moves, and finally blundered and lost. Morozevich was lost for words at the press conference. He eased his shattered confidence with a win in round 10 against Radjabov, and a draw in the last round. A tale of two halves. Impressive in the first, disaster in the second.

<Kamsky (5.5/11)> - How to describe Kamsky's tournament? The general theme was unstable. He was falling into sequences of draw, loss, draw, draw, win, loss, win, draw, loss, win, draw. He even refused a three-fold repetition in the middle game to continue pursuing the full point, and lost. 2 of his draws he could have lost, especially against Topalov who missed a win. So, not a terrible tournament, but his play wasn't what he probaly desired.

<Leko (5/11)> -(+0 -1 =10) Dare I say it - Drawko. There's definitely some mojo missing in Leko's games. Another poor result in a Grand Prix tournament which means he has already lost any chance of a candidates place. Back to the drawing board for Peter (excuse the pun)

<Mamedyarov (4.5/11)> - Not a good score for Shak, but I think he played better than his score suggests. He was unfortunate to fall into Karjakins home prep with the positional sacrifice 16 Nxh6+! He played a game to forget against Nakamura, his only bad game, which was really bad. Other than that his 9 draws were well fought, and he even had a few chances in those draws. Perhaps nothing too much to be concerned about, except it has damaged his Grand Prix points tally Big time! Just needs to recover his killer instinct.

<Kasimdzhanov (4.5/11)> - The Grand Prix series is showing that Kasimjanov is not quite up to the level of some of these players. He has had trouble in games where the position was very complex. He needs to improve this to beat players at this level.

I was about to say that it's nice that this <KWregan> fellow is joining the discussion since he seems to know what he's talking about ... and then I just realized who he is! .... It's of course professor Kennneth Regan whose papers I've been pouring over these last few weeks in spite of having to dodge the various mathematics I no longer understand (my calculus days being long long behind me!) ...

I'm curious ... what kind of volunteer help do you need?

;) Well, I actually told you that a while back e.g.:

I think it didn't register at the time because I was not fully clued in who professor Regan was; I don't think I had yet struggled through his papers yet!

It is also a common knowledge that despite of its impressive strength in practical play, Rybka’s evaluations, especially if calculating in short horizon, can be often utterly misleading. Any decent correspondence chess player knows quite well that to let the engine to play alone with no human intervention in a CC tournament is a sure recipe for disaster, no matter how deeply the engine is allowed to calculate. I can provide you also a lot of practical examples from real games where Rybka running for many hours and reaching the depth much over 20 plies gives wrong evaluation and bad continuation, which can be easily recognized by a human chess player. For example, quite well-known positional blunder made by Bobby Fischer in the second game of his candidate match against Mark Taimanov (see Fischer vs Taimanov, 1971), i.e. 50.c5??, which throws away the decisive advantage instead of forced win after 50.Ra6! Kc7 51.c5 bxc5+ 52.bxc5 Ne8 53.Rg6! (discovery of Yuri Balashov), is something, what passes by completely undetected by Rybka or Houdini, because they don’t understand that after this move black can build a simple blockade with objectively drawn position. Of course, to find Balashov’s fairly simple forcing line leading to technically easily won ending, they are unable as well. It is also funny how Rybka evaluates the last move 41.Qb7+ in our game against Arno Nickel (The World vs A Nickel, 2006), which forces transition into easily won Rook ending, and what it recommends to play instead of it. Of course, human assistance to engine and more qualitative approach instead of mechanical grinding of centipawns can be quite helpful here.

In a paper (http://www.cse.buffalo.edu/~regan/p...) written by you, Bartek Macieja and Guy Haworth, there are also some quite interesting details, which seem to be a bit in contradiction with your rather categorical conclusions. For example, Intrinsic Performance Rating calculated by you for 1979 Montreal tournament (mere 15th category of FIDE with average elo 2622 – even Czech championship could be stronger today) was 2588, that is significantly higher than IPR of 18th cat. Linares 1993 (elo=2676, IPR=2522) or Linares 1994 (elo=2685, IPR=2517). Another quite interesting point apparent from figure 3 was the fact that tournaments in period 1971-1984 and in lesser extent tournaments from 1985-1999 had far lower values of average error in later phases of play after move forty (adjournments apparently mattered) despite the lower average ratings of tournaments then played in comparison to 2000-2009 and 2010+. So much for superiority of current players over their predecessors from 1970s and 1980s.:-D