Problem position using Scorpio Egbbs

[Ross Boyd]

Greetings, it's many many years since I've posted here.

My hobby engine has a problem with this position using Scorpio egbb's. It scores a Black win for this position. It should be a draw.
[d]8/p7/8/1P4k1/7p/8/7K/8 w - -

probe_egbb_fen() also returns the same result.

The engine is 32 bit and uses egbbdll.dll - the most recent 4.1 version from Daniel Shawul's site.

I cross-checked using Deuterium and it also has the same error (using the same set of EGBB's) but with egbbdll64.dll (version 4.1).

The egbb's in use are the 6 man set d/led from Joshua Shriver's site. The MD5 checksums are all correct.

Could someone please test if they get the same result (using Scorpio egbbs)? Thanks!

[Ferdy]

Greetings, it's many many years since I've posted here.

My hobby engine has a problem with this position using Scorpio egbb's. It scores a Black win for this position. It should be a draw.
[d]8/p7/8/1P4k1/7p/8/7K/8 w - -

probe_egbb_fen() also returns the same result.

The engine is 32 bit and uses egbbdll.dll - the most recent 4.1 version from Daniel Shawul's site.

I cross-checked using Deuterium and it also has the same error (using the same set of EGBB's) but with egbbdll64.dll (version 4.1).

The egbb's in use are the 6 man set d/led from Joshua Shriver's site. The MD5 checksums are all correct.

Could someone please test if they get the same result (using Scorpio egbbs)? Thanks!

When using 5-men egbb, Deuterium scored this as a draw. I don't have 6-men at the moment.

[Ferdy]

Scorpio 2.7.9 using 5-men egbb also returns a draw score.

[Ross Boyd]

Thanks Ferdinand

If you evaluate the position without any search - just a straight probe, do you still get a draw score?
Are you running 64bit? And what version of egbbdll.dll?

I've downloaded the 5 man set (EGBB5N from Joshua's site) now and still getting the error. Strange...

[Ferdy]

Thanks Ferdinand

If you evaluate the position without any search - just a straight probe, do you still get a draw score?
Are you running 64bit? And what version of egbbdll.dll?

I've downloaded the 5 man set (EGBB5N from Joshua's site) now and still getting the error. Strange...

I revised Deuterium's current dev to return egbb score in eval, I am using 64bit dll. Now I got same result as yours
[d]8/p7/8/1P4k1/7p/8/7K/8 w - - 0 1

Code: Select all

setoption name UseScorpioBitBases value true
info string UseScorpioBitBases is set to true
setoption name ScorpioBitBasesPath value C:\myfiles\chess\egtb\egbb5N
info string ScorpioBitBasesPath is set to C:\myfiles\chess\egtb\egbb5N\
info string Deuterium said Please use egbbdll64.dll file
EgbbProbe 4.1 by Daniel Shawul
180 egbbs loaded !
position fen 8/p7/8/1P4k1/7p/8/7K/8 w - - 0 1
eval
info string eval egbb probing hit, value equals -5175cp
evalscore cp -5175

For other sample position, looks fine.
[d]8/3k4/3P4/3K4/8/6B1/2b5/8 w - - 0 1

Code: Select all

ucinewgame
position fen 8/3k4/3P4/3K4/8/6B1/2b5/8 w - - 0 1
eval
info string eval egbb probing hit, value equals 0cp
evalscore cp 0

[Ross Boyd]

Thank you for looking into it. It appears there is indeed a problem with either the egbbs or the probe dll - not sure yet.

I wonder if anyone else has the same issue - or can shed some light?

[pedrox]

I have tested the position with DanaSah and with different distributions of egbb (egbb6men, egbb5men, egbb4men).
All with dll version 4.1 32-bit
The result is a win for Black.

Gaviota Tablebases indicates draw.

With dll 3.1 and egbb4men danasah has draw.

[Ross Boyd]

Thanks Pedro. That confirms it.

I've contacted Daniel. Have to wait and see...

[Graham Banks]

My hobby engine......

Is there a new Trace in the pipeline?

[Ferdy]

I have tested the position with DanaSah and with different distributions of egbb (egbb6men, egbb5men, egbb4men).
All with dll version 4.1 32-bit
The result is a win for Black.

Gaviota Tablebases indicates draw.

With dll 3.1 and egbb4men danasah has draw.

I took some games from Frank's page, extract some 5-men (around 12k pos) run 5-men sy egtb and add c0 op code in epd based on sy. Here are the resulting epd where 5-men egbb is different.

Could you verify it also?

[d]8/8/8/4k3/7p/4K2P/6P1/8 w - - c0 "1/2-1/2"; fmvn 92; hmvc 0; egbb 4977;
[d]8/8/8/8/2p1P1k1/8/1P5K/8 b - - c0 "0-1"; fmvn 76; hmvc 0; egbb 0;
[d]8/8/8/1k6/p7/P3K3/1P6/8 b - - c0 "1/2-1/2"; fmvn 154; hmvc 0; egbb -5051;
[d]6k1/5p2/6p1/6P1/8/8/5K2/8 b - - c0 "1/2-1/2"; fmvn 80; hmvc 0; egbb 4968;
[d]8/7p/1Pk5/4K1P1/8/8/8/8 b - - c0 "1-0"; fmvn 69; hmvc 0; egbb 0;
[d]8/5p2/1k4p1/6P1/2K5/8/8/8 w - - c0 "1/2-1/2"; fmvn 61; hmvc 0; egbb -5022;
[d]8/1p6/p3k3/P1K5/8/8/8/8 b - - c0 "1/2-1/2"; fmvn 111; hmvc 0; egbb 4864;
[d]8/8/8/4k2K/6p1/8/5P1P/8 b - - c0 "1/2-1/2"; fmvn 70; hmvc 0; egbb -5057;
[d]6k1/5p2/8/3pPK2/8/8/8/8 b - - c0 "1/2-1/2"; fmvn 87; hmvc 0; egbb 4911;
[d]8/3kp3/5p2/3K1P2/8/8/8/8 b - - c0 "1/2-1/2"; fmvn 119; hmvc 0; egbb 4933;
[d]8/8/8/8/K5p1/5kP1/7P/8 b - - c0 "0-1"; fmvn 57; hmvc 0; egbb 0;
[d]8/1p6/p5k1/P7/3K4/8/8/8 b - - c0 "1/2-1/2"; fmvn 68; hmvc 0; egbb 4779;