Author: Heiner Marxen
Date: 07:45:52 04/02/04
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On April 02, 2004 at 10:06:10, Bernd Nürnberger wrote: >On April 02, 2004 at 09:10:06, Heiner Marxen wrote: > >>On April 01, 2004 at 07:57:27, Bernd Nürnberger wrote: >> >>>On March 31, 2004 at 12:35:21, Renze Steenhuisen wrote: >>> >>>>>(1) >>>>>I recognized that a different move ordering delivers very alternating >>>>>results in my alpha beta search. (I implemented null move, pv search, >>>>>mvv/lva, some history moves, transposition table, quiescence search ...) >>>>>Is this a bug or is this a normal behaviour? >>>>>For example, with 3 history moves (on initial position) i get: >>>>>[...] >>>>> 8. 0:01.12 993512 0.00 Nc3 Nf6 d4 d5 Nf3 Bf5 Ne5 Ne4 >>-------------------------------^^^^ >>>>>... and with just one more history move (4): >>>>>[...] >>>>> 8. 0:01.28 1088694 0.00 e4 Nc6 Nf3 e5 d4 Nxd4 Nxd4 h6 >>-------------------------------^^^^ >>>> >>>>Seems reasonable. >>> >>>Mmmh, that still is not very reasonably to me to get much different results >>>for different move orderings. >>>The score of the moves itself should not be affected ?! >>>Do you have an explanation? >> >>But the score _is_not_ changed... see above. >> >>Cheers, >>Heiner > > >That's just a coincidence, another example from another position: > >10. 0:00.57 459625 0.22 Rxf4 Kg3 Rf7 Kxg2 Kb4 c5 Kb3 c4 > >... and with a slightly different move ordering: > >10. 0:01.78 1694656 0.01 e3 Kg3 exf4 Rf5 Rb2 Kxf4 Ka4 Rg5 > >That still seems somewhat strange to me ?! > >These are not made up strange examples. A different move ordering >changes everything very much in my engine and I am not glad about >this fact, whether it's natural or not, because I still cannot >understand it .. > >Greetings, Bernd Without transposition table that is a bug, IMHO. With TT anything can happen. Cheers, Heiner
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