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optimal aspiration window for stockfish question
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Robert Hyatt



Joined: 27 Feb 2006
Posts: 15818
Location: Birmingham, AL
PostPost subject: Re: optimal aspiration window for stockfish question    Posted: Sat Mar 17, 2012 4:11 pm Reply to topic Reply with quote
diep wrote:
bob wrote:
mcostalba wrote:
bob wrote:
Absolutely no change, either up or down.


Have you tested at longer TC ? It would be interesting to know how scales at longer TC, with your cluster should be feasible to test say at 1' TC.


I thought I had said that I tested up to 1 minute + 1 second. I did not go beyond that, and found absolutely no difference, which was surprising. The only thing I didnt like was the excessive re-searches to reach a mate. But at that point, it doesn't affect the game result at all of course...

When we first started doing this in Cray Blitz, we tried lots of ideas. Our aspiration window was roughly 1/3 of a pawn, so we relaxed alpha/beta to +1.0, then +3.0, then +9.0 and then all the way to infinite. In Crafty, I eliminated that +3.0 and have been using +1, +9 and +infinite for the longest...

I am also running a test (since I was not testing anything else) on various aspiration window widths as well. I'll post those results when they finish...


Cray Blitz still alive?

In diep i'm starting search with (-inf,+inf) for a simple reason: hashtable will directly give back a great bound anyway and you nullwindow around that.

Only when your PV is a total mess i assume that aspiration search is a great idea, shouldn't happen for a proper YBW search.

Maybe that's why crafty doesn't suffer from the same problem there.


Depends on what you mean by "alive". The last 3 years of Cray Blitz development was lost. I have a 1991 or so version that is on the net and compiles/runs just fine (no parallel search however as the Cray "task common" is not a standard fortran feature.

I'm beginning to think that the +/- infinity idea is just as good as aspiration search. Most likely because we all use PVS (null-window, not null-move) anyway. I did not go all the way to infinity in my test results I posted here, but I will try it to see if it makes any difference. (I suspect there will be no change at all).
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Subject Author Date/Time
optimal aspiration window for stockfish question Uri Blass Mon Mar 12, 2012 11:14 am
      Re: optimal aspiration window for stockfish question Ed Schroder Mon Mar 12, 2012 12:55 pm
            Re: optimal aspiration window for stockfish question Marco Costalba Mon Mar 12, 2012 6:47 pm
                  Re: optimal aspiration window for stockfish question Don Dailey Mon Mar 12, 2012 9:41 pm
                        Re: optimal aspiration window for stockfish question Robert Hyatt Wed Mar 14, 2012 10:18 pm
                              Re: optimal aspiration window for stockfish question Marco Costalba Thu Mar 15, 2012 6:15 am
                                    Re: optimal aspiration window for stockfish question Robert Hyatt Thu Mar 15, 2012 2:06 pm
                                          Re: optimal aspiration window for stockfish question Robert Hyatt Thu Mar 15, 2012 5:30 pm
                                                Re: optimal aspiration window for stockfish question Robert Hyatt Thu Mar 15, 2012 8:11 pm
                                                      Re: optimal aspiration window for stockfish question (update Robert Hyatt Thu Mar 15, 2012 9:55 pm
                                                            Re: optimal aspiration window for stockfish question (update Miguel A. Ballicora Thu Mar 15, 2012 10:23 pm
                                                                  Re: optimal aspiration window for stockfish question (update Robert Hyatt Fri Mar 16, 2012 3:29 am
                                                                        Re: test results Robert Hyatt Fri Mar 16, 2012 3:41 am
                                                                              Re: test results Rémi Coulom Fri Mar 16, 2012 8:38 am
                                                                                    Re: test results Robert Hyatt Fri Mar 16, 2012 5:20 pm
                                                                              Re: test results Karlo Bala Jr. Fri Mar 16, 2012 11:30 am
                                                                                    Re: test results Robert Hyatt Fri Mar 16, 2012 5:26 pm
                                                                                          Re: test results Ed Schroder Fri Mar 16, 2012 6:31 pm
                                                                                          Re: test results Robert Hyatt Fri Mar 16, 2012 7:16 pm
                                          Re: optimal aspiration window for stockfish question Vincent Diepeveen Sat Mar 17, 2012 1:44 pm
                                                Re: optimal aspiration window for stockfish question Robert Hyatt Sat Mar 17, 2012 4:11 pm
                                                      Re: optimal aspiration window for stockfish question Marco Costalba Sat Mar 17, 2012 5:28 pm
                                                            Re: optimal aspiration window for stockfish question Robert Hyatt Sun Mar 18, 2012 3:28 am
                                                                  Re: optimal aspiration window for stockfish question Lucas Braesch Sun Mar 18, 2012 5:55 am
                                                                        Re: optimal aspiration window for stockfish question Joona Kiiski Sun Mar 18, 2012 9:02 am
                  Re: optimal aspiration window for stockfish question Robert Houdart Mon Mar 12, 2012 10:44 pm
                        Re: optimal aspiration window for stockfish question Robert Houdart Tue Mar 13, 2012 9:18 am
                              Re: optimal aspiration window for stockfish question Uri Blass Tue Mar 13, 2012 10:12 am
                                    Re: optimal aspiration window for stockfish question Karlo Bala Jr. Wed Mar 14, 2012 7:46 pm
                                          Re: optimal aspiration window for stockfish question Robert Hyatt Thu Mar 15, 2012 9:49 pm
                  Re: optimal aspiration window for stockfish question Lucas Braesch Wed Mar 14, 2012 4:10 pm
                        Re: optimal aspiration window for stockfish question Eelco de Groot Wed Mar 14, 2012 7:30 pm
                              Re: optimal aspiration window for stockfish question Lucas Braesch Thu Mar 15, 2012 2:03 am
                                    Re: optimal aspiration window for stockfish question Marco Costalba Thu Mar 15, 2012 6:13 am
      Re: optimal aspiration window for stockfish question Eelco de Groot Tue Mar 13, 2012 10:20 am
            Re: optimal aspiration window for stockfish question Uri Blass Tue Mar 13, 2012 12:57 pm
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