Schooner Version 1.4

[D Sceviour]

Here is another chess program:

Schooner1.4_64.exe

- WinBoard compatible
- 64 bit
- SSE Popcnt support
- Default hash size 128Mb - adjustable
- 1 CPU - no threading
- No pondering allowed
- Resident personality book
- Also supports polyglot style book - named "book.bin" in the same directory as the engine.
- No endgame table base support

https://github.com/schooner64-chess/Schooner-Chess.git

[Graham Banks]

Roughly how strong?

[D Sceviour]

Hello Graham,

Maybe 2300-2400 depending on the resources allowed. Wait for someone else’s opinion to be sure.

[Graham Banks]

Hello Graham,

Maybe 2300-2400 depending on the resources allowed. Wait for someone else’s opinion to be sure.

Sounds like my Amateur Division 6 tournament might be about right for it.
That will start this weekend.

[ThatsIt]

[...snip...]
How deep is the internal book? Can it be disabled?
[...snip...]

Just delete or rename the book file to disable it.

Best wishes,
G.S.
(CEGT member)

[D Sceviour]

Hello Gabor,

You are asking important questions. Schooner does not support an initialization file, but that will be put on the to-do list for the future if the standard interfaces cannot setup the engine properly.

The resident book is about four half moves deep. It selects a random opening based on a binomial distribution. This is more interesting than watching it play the same opening blunder every time. This can reasonably be considered a personal characteristic of the engine, and a part of the move selection process.

All books can be disabled using "Book 0" or "Book off". Gerhard Sonnabend is correct; the polyglot book can be disabled by either deleting or renaming.

I thought Arena had external initialization support that will send custom messages to every engine including book usage and hash size, but looking at it a second time it only does that for uci engines and not Winboard! Needs re-testing and suggestions.

[D Sceviour]

Gabor, thank you. It did not take long to find a way to get the engine to crash. Apparently, the interface takes the following WARNING ERR very seriously and aborts the process:

2015-08-20 15:36:24,624<--1:#Polyglot Book "book.bin" not found - WARNING ERR # 2

Deleting the WARNING ERR line from the code seems to make the interface ignore any further problems.

As to the protocol rules, is the engine required to accept or reject another name and directory besides "book.bin"? Your code sent "ShortLines.abk" suffix for its external books which is not tested or used by Schooner. It seems to play anyway. Is this a problem?

Let’s hear some more ways to make the thing crash before an update is posted.

[D Sceviour]

OK, ShortLines.abk uses the force command to send a sequence of moves. Since there were three moves, the side to move was supposed to change.

2015-08-20 15:36:24,644-->1:force
2015-08-20 15:36:24,852-->1:c2c4
2015-08-20 15:36:24,852-->1:e7e5
2015-08-20 15:36:24,852-->1:c4c5

Unfortunately Schooner does not use the force command yet for move sequences. The main reason for this is that the interface also sends the force command to stop thinking and the xboard documentation stated the stop command could be ignored. [Also, if this is intended to force a move then there must be a new move entered in the buffer to makemove. But if it also wants to stop thinking then what does xboard want to do with the search move in the existing buffer waiting for makemove? However, that question can be postponed for another time.]

The force command will be put on the agenda for changes.

[Graham Banks]

[...snip...]
How deep is the internal book? Can it be disabled?
[...snip...]

Just delete or rename the book file to disable it.

Best wishes,
G.S.
(CEGT member)

Hi Gerhard,

Even if there is no book file Schooner uses its internal book, at least I saw it make one move immediately when book 1 was selected, and it started to think immediately when book 0 was selected.

I will see what happens with an 8 move deep ChessGUI opening book, as it starts from the exit point of the book line.

[D Sceviour]

Graham,
The program works as promised from the initial post providing no changes are made. However, the current version 1.4 requires a polyglot "book.bin" to be installed in the same directory or the engine will crash. There is a fix for this and will be updated along with some improvements to the xboard force command in version 1.4.1.

Do you have any other suggestions for improvements beforehand?