SCID on Linux - using Polyglot and not using Polyglot...

[royb]

I've discovered that when using SCID to analyze with Rybka 2.3.2a that the moves selected by the engine differ depending on whether or not you configured the engine to use polyglot or not.

If I use polyglot explicitly, Rybka selects the same moves as when Rybka runs under Shredder9-UCI or ChessBase GUIs. However, there is now an option to not have to use Polyglot under SCID. I've configured Rybka to run in that way also. However, when doing so, it selects different moves in some situations (using infinite analysis in all cases).

An example: begin at the starting position. Start Rybka thinking with 256 MB of hash (yes, I have lots of RAM and paging/swapping is not happening). I'm also running under Linux which frees up tons of RAM for use by applications such as chess engines.

With Polyglot, the PVs from Rybka show 1. Nc3 as its best move for many ply up to 16 when I stop it.

Without Polyglot, the PVs from Rybka show 1. Nf3 as its best move for many ply up to 16 when I stop it.

There seems to be something that SCID without polyglot is doing to affect Rybka in some way. Anyone have any idea what?

Thanks,

Roy

[Mr. H.]

How do you get Rybka running in SCID without polyglot?

[royb]

Create a new engine via Tools -> Analysis Engine

Then, configure it like this:

Name: Rybka-2.3.2a
Command: wine
Parameters: /home/roy/chess/rybka-2.3.2a/Rybkav2.3.2a.w32.exe
Directory: /home/roy/chess/rybka-2.3.2a
URL:
Elo: 2950 (this is optional and a guess on my part of course)

Then click on the UCI checkbox (no checkmark may appear, on my screen, it's "pushed in" -- depends on your GUI and other Linux settings. Regardless, make sure "UCI" is enabled.

Then, click on the "Configure UCI engine" button. set hash table size (and any other parameters you like) and then click the "Save" button at the bottom of the parameters window.

Then, click OK button to save the new engine. Now, Go to Tools -> Analysis Engine and select Rybka-2.3.2a as your analysis engine.

However, it seems to affect the engine's move selection somehow (not sure yet how or why). Still, you have Rybka running without Polyglot being explicitly configured.

Oh yes, you should get the latest SCID (3.6.22) first.

Roy