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Subject: Re: Fruit 1.5 parameter test extended

Author: Stuart Cracraft

Date: 15:30:10 08/27/04

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>Fruit v1.5nmalways: nullmove search is tried always (instead of in the fail-high case only)

It seems this is the big result, and I don't understand it.

In my program, nullmove search is always done except if there
is an immediate previous nullmove done the "move" before, and
are not endgame, not in check, and either verify null
move set (null verification search) or depth > 1. Those are my
conditions.

There is no search prior to the null move to fail high to serve as
another condition of whether null move is done or not so I don't
understand your point.

Maybe I am missing something in terms of my understanding or
don't have all the conditions necessary for null move to be
successful or have too many conditions?

What do you think?

Stuart

>Fruit v1.5noetc: ETC disabled
>Fruit v1.5ppushext: pawn push extension (7th rank) enabled
>Fruit v1.5nosinglerep: single reply extension disabled
>Fruit v1.5noqchecks: quiescence search does not include checking moves
>Fruit v1.5nmR2: nullmove reduction set to 2 instead of the default 3
>Fruit v1.5qchknm: quiescence search considers checking moves only after a
>nullmove
>Fruit v1.5matvjr: alternative settings for piece values by J. Rang
>Fruit v1.5comb1: combination of nullmove always, ETC disabled and pawn push
>extensions enabled; the three parameter settings that each have resulted in a
>higher result than the default settings (albeit in some cases only by a very
>tiny margin)
>
>plus 13 other engines as reference opponents.
>
>
>
>Results:
>========
>
>    Program                     Elo    +   -   Games   Score   Av.Op.  Draws
>
>  1 Ruffian v1.01             : 2698   24  38   440    70.7 %   2545   21.8 %
>  2 List v5.12                : 2664   26  35   440    66.2 %   2547   23.0 %
>  3 El Chinito v3.25          : 2648   26  33   440    64.1 %   2548   24.1 %
>  4 Gothmog v0.4.8            : 2604   29  31   440    57.7 %   2550   18.6 %
>  5 Fruit v1.5nmalways        : 2598   30  29   440    56.8 %   2550   22.3 %
>  6 Fruit v1.5noetc           : 2577   31  28   440    53.8 %   2551   21.1 %
>  7 Fruit v1.5comb1           : 2576   31  28   440    53.6 %   2551   21.8 %
>  8 Fruit v1.5ppushext        : 2573   32  27   440    53.1 %   2551   24.3 %
>  9 Fruit v1.5def             : 2568   32  28   440    52.4 %   2551   21.6 %
> 10 Fruit v1.5qchknm          : 2560   33  27   440    51.1 %   2552   21.8 %
> 11 Fruit v1.5matvjr          : 2557   33  26   440    50.8 %   2552   23.4 %
> 12 Fruit v1.5noqchecks       : 2557   33  28   440    50.7 %   2552   19.5 %
> 13 Fruit v1.5nosinglerep     : 2554   33  25   440    50.3 %   2552   27.5 %
> 14 AnMon v5.21               : 2550   26  33   440    49.7 %   2552   24.3 %
> 15 SoS4                      : 2543   26  32   440    48.6 %   2553   24.5 %
> 16 Ktulu v5.0                : 2541   25  32   440    48.3 %   2553   29.8 %
> 17 Fruit v1.5nmR2            : 2534   27  32   440    47.3 %   2553   25.0 %
> 18 Amyan v1.592              : 2533   28  32   440    47.2 %   2553   21.6 %
> 19 Yace Paderborn            : 2513   30  30   440    44.1 %   2554   19.1 %
> 20 Ufim v5.00                : 2465   33  27   440    37.2 %   2556   22.5 %
> 21 Frenzee v1.59             : 2441   36  26   440    33.9 %   2557   19.5 %
> 22 Patzer v3.61              : 2427   38  25   440    32.0 %   2558   19.5 %
> 23 Sjeng v12.13              : 2415   39  25   440    30.5 %   2558   19.5 %
>
>
>
>Essentially all these parameters have pretty much no impact on Fruit´s playing
>strength with the probable exceptions of:
>- Enabling "nullmove always" probably increases playing strength
>- Setting nullmove reduction to 2 probably decreases playing strength
>
>Interestingly the combined setting (comb1) scored lower than the pure nmalways
>setting, but maybe this can be blamed on statistics.
>
>
>
>Conclusion:
>===========
>
>Generally the impact of the different UCI parameter settings on Fruit´s playing
>strength is comparatively small, in the end all results still fall within the
>error margins of ~30.
>
>I personnally am a bit surprised that enabling/disabling the extensions makes
>pretty much no difference, and would be interested in views as to why this would
>be the case.
>
>I would have also expected a bigger impact of the modified piece value settings
>and of disabling/enabling checks in the quiescence search.
>
>Robert



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