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Subject: Re: King's Out : move ordering questions

Author: Bernd Nürnberger

Date: 07:06:10 04/02/04

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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





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