Senpai 2.0

[Xann]

Hi all,

After a few years in computer draughts, I am back to chess for a little while. I see too many draws at top level, and am afraid that it will be too late in a couple of years. Big hardware and large opening books are also not helping IMO.

So I'm here to announce Senpai 2.0. The code looks all different because I started from my draughts program, but it's actually still Senpai inside. I prefer having a consistent codebase for multiple games (also Shogi and Othello).

As a rewrite it's hard to list changes, but here is an attempt:
- Chess960 is baked in, not an add-on; Senpai 2 plays chess only as a special case!
- search: restricted singular extensions
- search: additional reduction/pruning of "losing" moves (SEE < 0)
- eval: tempo bonus (it seems I forgot in 1.0 ...)
- eval: "space" (glorified pawn-chain PST); this changes playing style a lot
- eval: scoring by logistic regression; this gives me more freedom for eval features
- board: copy/make (customary in games with fewer piece types than chess)
- board: optional PEXT bitboards (BMI2)

As I recall, no single change brought more than 10 Elo. So it's more a sum of small (IMO) things.

This release has been rushed a little, so it's still lacking UCI options and multi-PV; sorry about that.

Official website: http://www.amateurschach.de/main/_senpai.htm
Direct link: http://www.amateurschach.de/download/senpai_20.zip
Expected level: Texel/Protector (again)

Thanks to everybody who helped with this release:
- Graham Banks
- Michael Byrne
- Wilhelm Hudetz
- Daniel Jose
- Steve Maughan (https://www.chessprogramming.net)
- Frank Quisinsky (http://www.amateurschach.de)
- XXX (<- this line for people I forgot, sorry in advance).

That's all for now,

Fabien.

[Dann Corbit]

Fabulous news.

Perhaps it will be world champion soon

[BrendanJNorman]

Hi all,

After a few years in computer draughts, I am back to chess for a little while. I see too many draws at top level, and am afraid that it will be too late in a couple of years. Big hardware and large opening books are also not helping IMO.

So I'm here to announce Senpai 2.0. The code looks all different because I started from my draughts program, but it's actually still Senpai inside. I prefer having a consistent codebase for multiple games (also Shogi and Othello).

As a rewrite it's hard to list changes, but here is an attempt:
- Chess960 is baked in, not an add-on; Senpai 2 plays chess only as a special case!
- search: restricted singular extensions
- search: additional reduction/pruning of "losing" moves (SEE < 0)
- eval: tempo bonus (it seems I forgot in 1.0 ...)
- eval: "space" (glorified pawn-chain PST); this changes playing style a lot
- eval: scoring by logistic regression; this gives me more freedom for eval features
- board: copy/make (customary in games with fewer piece types than chess)
- board: optional PEXT bitboards (BMI2)

As I recall, no single change brought more than 10 Elo. So it's more a sum of small (IMO) things.

This release has been rushed a little, so it's still lacking UCI options and multi-PV; sorry about that.

Official website: http://www.amateurschach.de/main/_senpai.htm
Direct link: http://www.amateurschach.de/download/senpai_20.zip
Expected level: Texel/Protector (again)

Thanks to everybody who helped with this release:
- Graham Banks
- Michael Byrne
- Wilhelm Hudetz
- Daniel Jose
- Steve Maughan (https://www.chessprogramming.net)
- Frank Quisinsky (http://www.amateurschach.de)
- XXX (<- this line for people I forgot, sorry in advance).

That's all for now,

Fabien.

Great news from a computer chess legend.

Will test Senpai A.S.A.P.

*Hoping the playing style is lovely!*

[Frank Quisinsky]

Hi Brendan,

and on other legend made the graphics (Wilhelm Hudetz, Austria).

Both, Fabien & John on one site ...
A good day for computer chess in my humble opinion!

Of course, not important that it's the own site!

After a longer time slower downloads on www.amateurschach.de it's solved since yesterday. My provider found & fixed a defect patch cable.

Downloads now with full speed ...

Best
Frank

I had here again a lot of fun with Fabien ...
Fabien is really a very interesting person.

I wish me to have 0.1% from his programming knowledge only and I am an expert. But unfortunately ... maybe 0.001% ...

[MikeB]

Hi Brendan,

and on other legend made the graphics (Wilhelm Hudetz, Austria).

Both, Fabien & John on one site ...
A good day for computer chess!

Of course, not important that it's the own site!

After a longer time slower downloads on www.amateurschach.de it's solved since yesterday. My provider found & fixed a defect patch cable.

Downloads now with full power ...

Best
Frank

Good job Frank, you do nice work! &#128074;

[Evert]

The code looks all different because I started from my draughts program, but it's actually still Senpai inside. I prefer having a consistent codebase for multiple games (also Shogi and Othello).

Good man.

I have a (private) version of Senpai 1.0 that plays Makruk; as I recall the changes were not too hard to make, so hopefully I can port those over easily.

[Xann]

I have a (private) version of Senpai 1.0 that plays Makruk; as I recall the changes were not too hard to make, so hopefully I can port those over easily.

More painful, I guess, but doable. However reusing eval parts would be more difficult with this version, maybe much more. The weights are probably very specific.

And (say) with your own eval, switching to version 2.0 doesn't make much sense.

[Guenther]

Hi all,

After a few years in computer draughts, I am back to chess for a little while. I see too many draws at top level, and am afraid that it will be too late in a couple of years. Big hardware and large opening books are also not helping IMO.

So I'm here to announce Senpai 2.0.

...

Fabien.

Thanks a lot Fabien and all who helped with this release!

Guenther

[Evert]

I have a (private) version of Senpai 1.0 that plays Makruk; as I recall the changes were not too hard to make, so hopefully I can port those over easily.

More painful, I guess, but doable. However reusing eval parts would be more difficult with this version, maybe much more. The weights are probably very specific.

And (say) with your own eval, switching to version 2.0 doesn't make much sense.

Oh, I didn't tune the evaluation (apart from a few very specific things), I made it mainly to have a larger variety of opponents (and as a proof-of-concept that just modifying the move generator of a reasonably strong engine to play a different variant doesn't automatically give you a very strong engine without redoing the evaluation).
From what I remember, most of the work was converting from UCI to CECP (there is some de-facto standard for handling variants with UCI now, but there was nothing back then), which was pretty straightforward.

[Michel]

Thanks!