Tablebase config

[Thomas Kaas]

Hi

Can anyone tell me how to create a Lc0.config file in the Lc0 directory for use of tablebases ?

Thank you in advance.

regards 

[pwa128]

Assuming you are using Windows open Notepad and type in syzygy-paths=pathname   where pathname is the path to your syzygy tablebases (e.g. c:\docments\syzygy).   Using the File menu do a Save As and pick the Lc0 folder.   In the file name put in Lc0.config and in the drop down box below that change txt file to all file types.   The hit the Save button to save.

[Thomas Kaas]

Thank you. But iam not sure I got this right. Should i save to folder where all my lc0 engines are, or save in each specific enginefolder? And do I need to change any engine parameters ?

I tried in specific engine folder. Then it stop analysing.

[pwa128]

You need to put it in the specific folder where the lc0 v0.17 engine is.    Default engine parameters work fine for me.   I can only suggest that you double check that you have a valid syzygy path in the config file.

[Thomas Kaas]

Engine wont load when i put Lc0.config into folder where lc0.exe is. No path needed in engine configuration for config file ? My bases look like this     c:/tablebases/5/5   I created a config file in windows note containing that line.

mandag den 20. august 2018 kl. 09.04.53 UTC+2 skrev Thomas Kaas:

[pwa128]

Assuming you are using Windows you need the slashes going the other way  c:\tablebases\5\5\

[Thomas Kaas]

Ok, did that now. But its strange, engine will not load when i add the Lc0.config to folder containing Lc0.exe. If I remove it, it works fine.

mandag den 20. august 2018 kl. 09.04.53 UTC+2 skrev Thomas Kaas:

[Thomas Kaas]

I am using arena 3.51 if that means something.

mandag den 20. august 2018 kl. 09.04.53 UTC+2 skrev Thomas Kaas:

[Galaga]

With arena you don't need a config file.

The installation folder contains a file called ArenaENG.cfg

Look for the entry of your leela, e.g.   

[lc0 cudnn]

...

List of Syzygy tablebase directories=C:\syzygy

..

That's it!

[Thomas Kaas]

Ahh cool. Thank you guys very much for your time. Really appreciate. Thank you !! 

mandag den 20. august 2018 kl. 09.04.53 UTC+2 skrev Thomas Kaas:

[Rudolf Posch]

Lc0 lost many end games after good play in TCEC-S13 because of missing  ETB support and in the TCEC forum many users urged an implementation. Now I was surprised that the new lc0 version V17.0 RC already supports syzygy table bases. Very fast response!  :=).

 So I copied today the new  V17 release candidate RC1 lc0.exe  in my Windows Leela folder.

Lczero.exe  has been supporting syzygy endgame table bases all the time and I had created therefore already some months ago  a 150 GB syzygy folder with the name syzygy inside the Leela folder (with the merged 3-4-5  and 6 men WDL DTM, DTZ  tables).  So today I  only created with an editor a new lc0.config file with the only line syzygy-paths= syzygy.

I tested the RC1 l0.exe with a position with 4 men and as you see in the screenshot below the tbhits count is nonzero and counting  :=)

One thing I do not understand, at the loading of the syzygy tables there are found 510 WDL, 0 DTM and 510 DTZ tablebase files. 

The release note says     "Only WDL probe for now, e.g. the engine only probes for positions after pawn moves and captures."  (what means this exactly?)

Seemingly there are now only the 510 WDL files used.  But why are nill DTM files found?? I have thoroughly copied all syzygy files together in my syzygy folder with 150 GB.

[Frank Müller]

Rudolf, AFAIK DTM don't exist for syzygy.

You can read it even here from that known download site - DTZ and WDL in brackets.

(GaviotaBases would be needed for DTM plus implementation of course)

http://oics.olympuschess.com/tracker/index.php

[Rudolf Posch]

@Frank Thanks for the info!

Am Mittwoch, 22. August 2018 12:58:34 UTC+2 schrieb Frank Müller:

Rudolf, AFAIK DTM don't exist for syzygy.

You can read it even here from that known download site - DTZ and WDL in brackets.

(GaviotaBases would be needed for DTM plus implementation of course)

http://oics.olympuschess.com/tracker/index.php    ....

[pwa128]

Adding to Franks post...

Syzygy has DTZ which gives the distance to a pawn move or a piece capture.   This is normally sufficient to help an engine to find the win but does not always lead the engine to the shortest mate.   I am sure I saw some examples posted on Talkchess a couple of years back of engines failing to win some of the harder 6 man endgames when using syzygy, though it is rare and I doubt it affects the top engines.

Houdini has the best of both worlds.   It uses syzygy WDL in the search and then Nalimovs for the shortest mate once it has reached a TB position on the board.