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Comparative nodes per second
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Don Dailey



Joined: 29 Apr 2008
Posts: 4502
PostPost subject: Re: Comparative nodes per second    Posted: Sun Apr 15, 2012 3:26 pm Reply to topic Reply with quote
Uri Blass wrote:
Don wrote:
lucasart wrote:
Uri Blass wrote:
Here is another example for the huge positional score of chess programs(probably also includes IvanHoe that I did not install in my computer and at least it includes robbolito0.09w32 and houdini that gives more than +4 for white at depth 1 when the program cannot see the promotion by search because it is hidden by a lot of checks)

Toga1.2.1a gives 1.17 for black at depth 1 but toga is inferior old program
and I believe that all the programs that are at the playing strength of Rybka3 or higher give a big advantage for white when they search to depth 1 inspite of nominal 6 pawns advantage by black.

[D]7k/PP5p/2PP3p/7p/7p/7p/6r1/K7 b - - 0 1
   ::    ::    ::    BK
WP WP ::    ::    :: BP
   :: WP WP    ::    BP
::    ::    ::    :: BP
   ::    ::    ::    BP
::    ::    ::    :: BP
   ::    ::    :: BR ::
WK    ::    ::    ::    

???
it's black's turn to play in your fen, and it's very obvious that black has an unstoppable passed pawn on h3. the eval should already return a big score for black without even a search!


These positions only illustrate what is already well known, that humans don't evaluate positions the same way that computers do but instead reason about the position. I would remind you that in this case it usually involves not just evaluation but look-ahead - you are looking ahead here to know that there will be a checkmate in 2 moves. You didn't process this in your brain statically.

Computers use a version of the same process and it's called null move search. We will never (in my opinion) have computers match the human brain and it may not even be desirable to try - computers are much different and trying to force them to do things the same way is like trying to force a human to run on all fours because it works for Cheeta's.

In your example of course we know that a computers static evaluation function is not very good at sorting out what is most relevant. That can be improved incrementally with a more sophisticated evaluation function for specific cases but a general solution is probably going to make programs a lot weaker - simply because it will slow the program down enormously and only be useful once in a while. Even the position you show is not a problem for any chess program doing 1 or 2 more ply - although it's easily understood that you can compose arbitrarily more and more difficult cases.


I think that the evaluation function of top programs in this position is very good and they evaluate it even after searching to depth 1 when they cannot see the promotion of white(because black has many checks) as advantage for white.


Exactly. But of course this was a poorly designed position if it's purpose was to illustrate the concept of being able to reason about a position and focus on only the most relevant. There are positions that requires 40 or more moves to mate which humans can solve by reasoning about the position - one of those would be a good example of what computers DO NOT do well. The most practical examples are covered by good chess programs, positions like lone Knight vs King is a draw - it's a rule we all know, but it can be reasoned about, the knight can never mate the king, the lone king can never mater the other king, so it's a good example even though it happens to be so common we can make a rule that easy to apply to a chess program.

A really practical example is something that ALL programs handle very poorly and it's not a rare thing - completely locked pawn structure - super closed positions. You could have an extra queen or two and it's still a draw if you cannot get to the other side of the board. Even that could be detected and scored correctly in a program by reasoning about whether one of the opponent pawns could ever be attacked to open up the position, but what happens if there is one last hope but it's all easily covered? One open file, but all intrusion points of the superior side are covered in all cases? It's not easy to detect that case and so being up a knight might be meaningless advantage if the knight can get it but be taken and other intrusions are still just as impossible.

So closed positions in general are still a serious problem for chess programs and knowing who has the advantage and what must be done to make progress is a hard problem. A few more ply will help only a little, we need better positional heuristics.
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Subject Author Date/Time
Comparative nodes per second Larry Kaufman Tue Apr 10, 2012 7:49 pm
      Re: Comparative nodes per second Vincent Diepeveen Tue Apr 10, 2012 8:16 pm
      Re: Comparative nodes per second Marco Costalba Tue Apr 10, 2012 8:41 pm
            Re: Comparative nodes per second Larry Kaufman Tue Apr 10, 2012 9:02 pm
                  Re: Comparative nodes per second Thomas Petzke Tue Apr 10, 2012 9:30 pm
            Re: Comparative nodes per second Richard Vida Tue Apr 10, 2012 10:15 pm
                  Re: Comparative nodes per second Larry Kaufman Tue Apr 10, 2012 10:18 pm
                        Re: Comparative nodes per second Sam Hamilton Tue Apr 10, 2012 10:54 pm
                        Re: Comparative nodes per second Richard Vida Tue Apr 10, 2012 11:28 pm
                              Re: Comparative nodes per second Larry Kaufman Wed Apr 11, 2012 4:52 am
            Re: Comparative nodes per second Don Dailey Wed Apr 11, 2012 11:23 pm
                  Re: Comparative nodes per second Don Dailey Wed Apr 11, 2012 11:50 pm
                        Re: Comparative nodes per second Sam Hamilton Thu Apr 12, 2012 12:07 am
      Re: Comparative nodes per second Robert Hyatt Tue Apr 10, 2012 9:31 pm
            Re: Comparative nodes per second Larry Kaufman Tue Apr 10, 2012 9:35 pm
                  Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 1:10 am
      Re: Comparative nodes per second Daniel Shawul Tue Apr 10, 2012 11:41 pm
            Re: Comparative nodes per second Larry Kaufman Wed Apr 11, 2012 5:05 am
                  Re: Comparative nodes per second Sam Hamilton Wed Apr 11, 2012 5:28 am
                        Re: Comparative nodes per second Marco Costalba Wed Apr 11, 2012 5:58 am
                              Re: Comparative nodes per second Larry Kaufman Wed Apr 11, 2012 1:04 pm
                  Re: Comparative nodes per second Daniel Shawul Wed Apr 11, 2012 12:27 pm
      Re: Comparative nodes per second Jon Dart Wed Apr 11, 2012 1:59 pm
            Re: Comparative nodes per second Sam Hamilton Wed Apr 11, 2012 2:25 pm
                  Re: Comparative nodes per second Larry Kaufman Wed Apr 11, 2012 2:36 pm
                        Re: Comparative nodes per second Jon Dart Wed Apr 11, 2012 3:06 pm
            Re: Comparative nodes per second Larry Kaufman Wed Apr 11, 2012 2:28 pm
                  Re: Comparative nodes per second Jon Dart Wed Apr 11, 2012 3:10 pm
                        Re: Comparative nodes per second Larry Kaufman Wed Apr 11, 2012 3:59 pm
                              Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 1:19 am
                  Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 1:15 am
                        Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 1:35 am
                              Re: Comparative nodes per second Sam Hamilton Thu Apr 12, 2012 2:32 am
                                    Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 2:50 am
                                          Re: Comparative nodes per second Sam Hamilton Thu Apr 12, 2012 3:10 am
                                                Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 3:35 am
                              Re: Comparative nodes per second Jon Dart Thu Apr 12, 2012 2:37 pm
                                    Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 3:24 pm
                                          Re: Comparative nodes per second Jon Dart Thu Apr 12, 2012 4:25 pm
                                                Re: Comparative nodes per second Don Dailey Thu Apr 12, 2012 4:33 pm
                                                      Re: Comparative nodes per second Jon Dart Thu Apr 12, 2012 4:41 pm
                                                      Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 8:13 pm
                                                            Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 9:00 pm
                                                            Re: Comparative nodes per second Daniel Homan Thu Apr 12, 2012 9:52 pm
                                                                  Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 11:26 pm
                                                                        Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 11:40 pm
                                                                              Re: Comparative nodes per second Sam Hamilton Thu Apr 12, 2012 11:51 pm
                                                                              Re: Comparative nodes per second Robert Hyatt Sat Apr 14, 2012 4:23 am
                                                                        Re: Comparative nodes per second Uri Blass Sat Apr 14, 2012 5:05 pm
                                                                              Re: Comparative nodes per second Robert Hyatt Sat Apr 14, 2012 6:46 pm
                                                                                    Re: Comparative nodes per second Don Dailey Sat Apr 14, 2012 6:56 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Sun Apr 15, 2012 4:31 am
                                                                                    Re: Comparative nodes per second Larry Kaufman Sat Apr 14, 2012 7:47 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Sun Apr 15, 2012 4:36 am
                                                                                          Re: Comparative nodes per second Larry Kaufman Sun Apr 15, 2012 4:47 am
                                                                                          Re: Comparative nodes per second Robert Hyatt Mon Apr 16, 2012 7:14 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Tue Apr 17, 2012 3:02 pm
                                          Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 6:50 pm
                                                Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 8:12 pm
                                                      Re: Comparative nodes per second Robert Hyatt Sat Apr 14, 2012 4:28 am
                                                            Re: Comparative nodes per second Larry Kaufman Sat Apr 14, 2012 4:45 am
                                                                  Re: Comparative nodes per second Robert Hyatt Sat Apr 14, 2012 4:46 pm
                                                                        Re: Comparative nodes per second Larry Kaufman Sat Apr 14, 2012 5:10 pm
                                                                              Re: Comparative nodes per second Sam Hamilton Sat Apr 14, 2012 5:35 pm
                                                                              Re: Comparative nodes per second Robert Hyatt Sun Apr 15, 2012 4:38 am
                                                                                    Re: Comparative nodes per second Larry Kaufman Sun Apr 15, 2012 4:51 am
                                                                                          Re: Comparative nodes per second Robert Hyatt Mon Apr 16, 2012 7:20 pm
                                                                                    Re: Comparative nodes per second Don Dailey Sun Apr 15, 2012 12:14 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Mon Apr 16, 2012 7:21 pm
                                                                  Re: Comparative nodes per second Uri Blass Sat Apr 14, 2012 5:17 pm
                                                                        Re: Comparative nodes per second Larry Kaufman Sat Apr 14, 2012 5:22 pm
                                                                              Re: Comparative nodes per second Uri Blass Sat Apr 14, 2012 5:36 pm
                                                                                    Re: Comparative nodes per second Larry Kaufman Sat Apr 14, 2012 5:47 pm
                                    Re: Comparative nodes per second Sam Hamilton Thu Apr 12, 2012 4:49 pm
                                          Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 5:14 pm
                                                Re: Comparative nodes per second Jon Dart Thu Apr 12, 2012 6:00 pm
                                                      Re: Comparative nodes per second Uri Blass Thu Apr 12, 2012 6:37 pm
                                                            Re: Comparative nodes per second Jon Dart Thu Apr 12, 2012 6:50 pm
                                                            Re: Comparative nodes per second Uri Blass Thu Apr 12, 2012 6:53 pm
                                                                  Re: Comparative nodes per second Lucas Braesch Sun Apr 15, 2012 4:56 am
                                                                        Re: Comparative nodes per second Uri Blass Sun Apr 15, 2012 5:16 am
                                                                              Re: Comparative nodes per second Lucas Braesch Sun Apr 15, 2012 7:58 am
                                                                        Re: Comparative nodes per second Don Dailey Sun Apr 15, 2012 1:10 pm
                                                                              Re: Comparative nodes per second Uri Blass Sun Apr 15, 2012 2:48 pm
                                                                                    Re: Comparative nodes per second Don Dailey Sun Apr 15, 2012 3:26 pm
                                                                                    Re: Comparative nodes per second Robert Hyatt Tue Apr 17, 2012 5:17 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Tue Apr 17, 2012 6:05 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Tue Apr 17, 2012 7:11 pm
                                                                                          Re: Comparative nodes per second Don Dailey Tue Apr 17, 2012 6:06 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Tue Apr 17, 2012 6:16 pm
                                                                                          Re: Comparative nodes per second Don Dailey Tue Apr 17, 2012 6:45 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Tue Apr 17, 2012 6:55 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Tue Apr 17, 2012 7:16 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Tue Apr 17, 2012 7:25 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Tue Apr 17, 2012 7:59 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Tue Apr 17, 2012 8:14 pm
                                                                                          Re: Comparative nodes per second Miguel A. Ballicora Tue Apr 17, 2012 10:33 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Tue Apr 17, 2012 10:51 pm
                                                                                          Re: Comparative nodes per second Vincent Diepeveen Wed Apr 18, 2012 12:12 am
                                                                                          Re: Comparative nodes per second Sam Hamilton Wed Apr 18, 2012 12:28 am
                                                                                          Re: Comparative nodes per second Miguel A. Ballicora Wed Apr 18, 2012 2:28 am
                                                                                          Re: Comparative nodes per second Sam Hamilton Wed Apr 18, 2012 4:32 am
                                                                                          Re: Comparative nodes per second Miguel A. Ballicora Wed Apr 18, 2012 4:44 am
                                                                                          Re: Comparative nodes per second Miguel A. Ballicora Tue Apr 17, 2012 10:28 pm
                                                                              Re: Comparative nodes per second José C. Martínez Galán Wed Apr 18, 2012 6:16 am
                                                                                    Re: Comparative nodes per second Robert Hyatt Thu Apr 19, 2012 9:53 pm
                                                                                    Re: Comparative nodes per second Don Dailey Thu Apr 19, 2012 10:22 pm
                                                                                          Re: Comparative nodes per second José C. Martínez Galán Thu Apr 19, 2012 10:49 pm
                                                                                          Re: Comparative nodes per second Robert Hyatt Thu Apr 19, 2012 11:21 pm
                                                                                          Re: Comparative nodes per second Marco Costalba Fri Apr 20, 2012 5:18 am
                                                                                          Re: Comparative nodes per second Michel Van den Bergh Fri Apr 20, 2012 6:10 am
                                                                                          Re: Comparative nodes per second Miguel A. Ballicora Fri Apr 20, 2012 11:35 am
                                                                                          Re: Comparative nodes per second Don Dailey Fri Apr 20, 2012 10:57 am
                                                                                          Re: Comparative nodes per second Marco Costalba Fri Apr 20, 2012 1:58 pm
                                                                                          Re: Comparative nodes per second Sam Hamilton Fri Apr 20, 2012 2:19 pm
                                                                                          Re: Comparative nodes per second Miguel A. Ballicora Fri Apr 20, 2012 2:29 pm
                                                                                          Re: Comparative nodes per second Don Dailey Fri Apr 20, 2012 3:13 pm
                                                                                          Re: Comparative nodes per second Don Dailey Fri Apr 20, 2012 4:52 pm
                                                                                          Re: Comparative nodes per second Uri Blass Sat Apr 21, 2012 6:03 am
                                                                                          Re: Comparative nodes per second Marco Costalba Sat Apr 21, 2012 8:14 am
                                                                                          Re: Comparative nodes per second Ed Schroder Sat Apr 21, 2012 10:50 am
                                                                                          Re: Comparative nodes per second Marco Costalba Sat Apr 21, 2012 11:13 am
                                                                                          Re: Comparative nodes per second Don Dailey Fri Apr 20, 2012 12:31 pm
                                                                                          Re: Comparative nodes per second Dan Andersson Fri Apr 20, 2012 4:14 pm
                                                                                          Re: Comparative nodes per second Don Dailey Fri Apr 20, 2012 4:38 pm
                                                            Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 7:10 pm
                                                Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 6:55 pm
                                                      Re: Comparative nodes per second (early results) Robert Hyatt Thu Apr 12, 2012 7:36 pm
                              Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 7:13 pm
                                    Re: Comparative nodes per second Larry Kaufman Thu Apr 12, 2012 8:18 pm
                                          Re: Comparative nodes per second Robert Hyatt Thu Apr 12, 2012 8:55 pm
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