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Subject: Re: UCI in practice

Author: Fabien Letouzey

Date: 07:33:12 03/04/04

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Hello Tord,

On March 04, 2004 at 09:12:38, Tord Romstad wrote:

>On March 03, 2004 at 09:31:22, Matthias Gemuh wrote:

>>xx depth without extensions
>>yy includes extensions in main search, not quiescence

>I don't think the standard specifies what the "seldepth" is supposed to mean,
>and I don't think xx and yy have the above meaning in all UCI engines.

My post was indeed about holes in the UCI document and other non-standard
features, hence the title "in practice".
I think UCI engine authors can agree about "common non-standard" features :)

>In Gothmog, I use them in approximately the way you describe.  xx is the
>iteration number (which in my engine is not quite the same as "depth
>without extensions", because my search is not even close to fixed-depth),
>while yy is the longest line searched in the main search.

Do you use a probability-based "depth decrement" if I may ask?
One that estimates a probability distribution of moves at every node, and
decreases the "remaining depth" by the log or something similar?
This is anyway only a generalisation of SEX/fractional-ply algorithms.
It also includes singular extensions as a special case.

Sounds really slow, but I think worth a try.
One could switch to normal ply-counting near the leaves anyway.

You can answer by just yes or no :)

About "yy", can you confirm that you never include quiescence plies in it?
I don't really understand why stopping there, quiescence search is also a
selective search ...

By the way, I believe Gothmog has a *very* bright future; good luck :)

Fabien.




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