Author: Robert Hyatt
Date: 17:42:59 12/24/98
Go up one level in this thread
On December 23, 1998 at 08:29:49, Amir Ban wrote: >On December 23, 1998 at 04:30:13, Harald Faber wrote: > >>On December 23, 1998 at 04:27:03, Ralph E. Carter wrote: >> >>>>>>>Do you know that engines under Fritz and Junior have their hashtables cleared >>>>>>>before every move? And that this has a disproportionate effect on those engines >>>>>>>that intelligently save information between moves, like hiarcs and crafty? >>>>>> >>>>>>I do not know but if it is the case then it is a bug in Fritz/Junior. >>>>>> >>>>>>Uri >>>>> >>>>>What do you mean "it is a bug in Fritz/Junior"? >>>>>Just because the results of automated tournaments in Fritz will not be reliable, >>>>>is this a bug? >>>> >>>>Everything not working correctly and/or making your system crash is a bug. >>>>Check your topic again, you wrote s.th. of CM6k but the bug obviously is in >>>>Fritz and/or Junior. >>> >>>Well, if there is an obvious bug in Fritz, I think that is more important, and >>>we should change the title. You are right. >>> >>>Maybe some of our programmers can tell us if this hashtable issue has a >>>disproportionate effect on the engines that save information between moves in >>>the hash table. >> >>AFAIR it is "an engine's problem". Fritz sends kind of "new" signal which makes >>some engines clear their hash tables what harms their strength. >>Bob, Amir, short summary? > >AFAIK: Before each move the engine gets the position in the form of move history >from the initial position. That's the way it was in Fritz5, and it didn't change >in Junior5 and other 32-bit front-ends. There is no command to clear the hash >table. This is an internal engine consideration. > >This is not a bug, it's as it's intended to work. It certainly doesn't force the >engine to do anything it would rather not do, and since anyone who's written an >engine for ChessBase was aware of how it works, I assume he would take care not >to clear the hashtable if he thought that important. > >I don't know about Winboard engines, but since they were written to work in a >different environment, it's quite possible that the way Fritz5 handles them is >an unpleasant surprise, so for Winboard engines the term "bug" is more >justified. > >Amir This appears to be what is happening to me. Because I'm not used to getting a "new" and batch of moves stuffed into crafty for each move. "new" resets nearly everything, but then reading in the moves causes crafty to go from "opening" to "middlegame" to "endgame" and at each change a flag is set that clears the hash tables, since some scoring things are turned on/off. It would be a serious change to stop doing this.... and continuing to do it is a real problem the way this stuff is working at present. IE I'm not sure exactly how to "win" here... And as I've said before, this "new" business wipes out other things that are important as well, like move ordering stuff, previous PV, etc...
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