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Subject: Re: QSearch() as PVS() ?

Author: Tord Romstad

Date: 03:22:07 01/15/04

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On January 15, 2004 at 02:41:40, Uri Blass wrote:

>I see that you test old SOS.
>I am surprised to hear that SOS is often considered to be the strongest MTD
>engine.

According to the UEL list, it is at least clearly stronger than AnMon
and Gothmog.

>I thought that this title is of one of the commercial(Shredder showed stupid
>pv's so it may use MTD and I also remembered that the same happened with Fritz)

Stupid PVs are not the best thing to look at in order to recognize MTD(f)
engines.  Some people prefer to reconstruct the PV from the hash table
even if they use PVS or something similar.  I would probably do so myself;
it feels cleaner to use a separate function to build the PV than to clutter
my search with code for updating the PV.

The best way to recoginize a MTD(f) engine is to observe the search process.
If the engine searches all moves several times at the same iteration and
the score and PV tends to change very rapidly, it is likely that MTD(f)
or some similar algorithm is used.

I am not sure about Fritz (the latest version I have seen in action was
5.32), but I am almost 100% sure that Shredder does not use MTD(f).

>I do not know how did you get that PostModernist is one of the strongest MTD
>engines in the world.
>
>I do not know which engines use MTD and I simply mentioned the probably weaker
>engine out of the only 2 free engines that I knew to use MTD except
>Gothmog(PostModernist and Comet)

I didn't know about Comet.  AnMon uses it, and I suspect that Abrok does,
too.

>Gothmog may be also stronger than Comet.

It seems to be stronger than Comet at blitz, but I've seen it reported
that Comet is not a good blitz player.

Tord



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