Suicide chess tablebases (stalemated player wins)

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niklasf
Posts: 42
Joined: Sat May 16, 2015 9:41 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by niklasf » Sat Dec 10, 2016 5:22 pm

Since I had only 5 piece tables (with pawns) anyway I somewhat wastefully regenerated all DTZ tables. The new md5sums (https://syzygy-tables.info/suicide/2-3- ... s.stbz.md5 ) differ for 66 tables. My probing code and the stats now agree on everything except the 4 positions you pointed out :)

Now trying to find that mistake ... WDLs match the expected result in all of the root positions.

niklasf
Posts: 42
Joined: Sat May 16, 2015 9:41 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by niklasf » Sat Dec 10, 2016 5:55 pm

Alright, found it. My probe_ab was reporting a "threat" when a capture could be forced, even if the position was still losing then. And then probe_dtz just returned 2/102.

All stats in agreement now.

syzygy
Posts: 4476
Joined: Tue Feb 28, 2012 10:56 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by syzygy » Sat Dec 10, 2016 10:26 pm

niklasf wrote:Since I had only 5 piece tables (with pawns) anyway I somewhat wastefully regenerated all DTZ tables. The new md5sums (https://syzygy-tables.info/suicide/2-3- ... s.stbz.md5 ) differ for 66 tables. My probing code and the stats now agree on everything except the 4 positions you pointed out :)
Did you not yet generate any 6-piece tables with pawns for giveaway? Then the damage remains small.

If you did generate a substantial number of 6-piece tables with pawns, then let me know so that I will create a small program to check whether they need to be regenerated. (I will probably make such a thing for personal use anyway.)

niklasf
Posts: 42
Joined: Sat May 16, 2015 9:41 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by niklasf » Sat Dec 10, 2016 11:59 pm

I started generating pawnless 6 piece tables first, and that's not even complete. So I am in luck, here.

syzygy
Posts: 4476
Joined: Tue Feb 28, 2012 10:56 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by syzygy » Sun Dec 11, 2016 2:44 am

niklasf wrote:I started generating pawnless 6 piece tables first, and that's not even complete. So I am in luck, here.
Now let's hope there are no further hidden problems :-)

I have been able to reduce the number of potentially problematic DTZ tables to 595 now. Some are false positives (e.g. 90 tables with 2-5 pieces compared to the 66 you found), but regenerating 595 tables is a lot better than regenerating all 4830 tables with pawns.

niklasf
Posts: 42
Joined: Sat May 16, 2015 9:41 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by niklasf » Fri Dec 16, 2016 11:10 am

Status update from me:

- The 2310 pawnless 6 piece tables are now complete. As always I uploaded them to https://syzygy-tables.info/suicide/ including checksums.
- I've ported giveaway table probing to Daniel Dugovic's variant-playing Stockfish: https://github.com/ddugovic/Stockfish

Next:

- Generate 6 piece giveaway tables with pawns
- Online lookup

Henk
Posts: 6048
Joined: Mon May 27, 2013 8:31 am

Re: Suicide chess tablebases (stalemated player wins)

Post by Henk » Fri Dec 16, 2016 1:24 pm

What a bad name for a game. No need to advertise psychic diseases. It may even be contagious. Don't mention the war.

syzygy
Posts: 4476
Joined: Tue Feb 28, 2012 10:56 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by syzygy » Thu Dec 22, 2016 1:51 am

niklasf wrote:Status update from me:

- The 2310 pawnless 6 piece tables are now complete. As always I uploaded them to https://syzygy-tables.info/suicide/ including checksums.
All checksums are identical to mine.

In the meantime I have regenerated the 4/5/6-piece suicide DTZ tables with pawns that were potentially affected by the cursed win bug. Surprisingly, their total size is now 13952 bytes less. This seems to be caused mainly by KKPPvQP.stbz, which went from 5655440 bytes to 5627344 bytes. I suspect the slight changes in the uncompressed data caused the generator to pick a different permutation for that table which just happened to compress a bit better.

Good luck generating 6-piece pawnful giveaway tables :-)

niklasf
Posts: 42
Joined: Sat May 16, 2015 9:41 pm

Re: Suicide chess tablebases (stalemated player wins)

Post by niklasf » Thu Jan 19, 2017 1:42 am

After round about 4 years of CPU time the 6 piece giveaway tables are finally complete.
The 2310 pawnless and 3444 giveaway tables together occupy 317G WDL + 68G DTZ = 384G total (and then additional 10G for the 2646 tables with less pieces).

Stats, checksums and downloads can be found at https://syzygy-tables.info/suicide/.

Online lookup based on a modified version of Daniel Dugovic's variant playing Stockfish is hosted by (the free software chess website) lichess.org as a public HTTP API.

An online user interface for analysing antichess games is also available: https://lichess.org/analysis/antichess#opening. FENs can be pasted below. Tablebases will be shown in the lower right corner. (Btw. Watkins antichess proof trees can also be selected as an opening book in the lower right corner. Syzygy tables will be used once the position reaches tablebase land.)

For offline usage Daniel Dugovic's Stockfish and my library python-chess support probing variant Syzygy bases.

I have not yet decided if I will also compute the pawnful tables with FICS rules.

Thanks again, Ronald de Man, for the amazing generator and your help with the probing code. This was a fun project :)

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George Tsavdaris
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Re: Suicide chess tablebases (stalemated player wins)

Post by George Tsavdaris » Tue Dec 24, 2019 8:37 am

syzygy wrote:
Sun Nov 06, 2016 12:28 pm
I have also added a generator for atomic chess just in case someone is interested.
Hi, does the TB generator here https://github.com/syzygy1/tb for Atomic Chess support 7 men generation for Atomic Chess?
I would like to generate certain 7 men TBS if possible so i wonder if it supports them.
Also how the command line to generate Atomic Chess TBs works anyway? Any info?

BTW is this (https://github.com/syzygy1/tb) able to generate the 7 men Chess TBs? Because the info on the page talks only about 6 men Chess EGTBs. So is just the info on the page just outdated?
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