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Fabien Letouzey (CPW)
Fruit (CPW)
Senpai (CPW)


UCI Engine Senpai
by Fabien Letouzey, France
... current available version: 2.0
back to Frank's Chess Page

® Copyright: Fabien Letouzey
Last changes: April 03rd, 2018, 03:00

Logo by Wilhelm Hudetz (Austria), the new Senpai logo collection: senpai-logos = 2.631Mb


November 07th, 2017 (start point): In the past I had different contacts to Fabien. I learned a lot from him and participate from his comments to computer chess. A chess programmer with a clear vision of his own way of thinking and intentions, creativity. In my humble opinion one of the programming geniuses in computer chess history with an impressive reputation. Sure, that many programmers learned from Fabien's open sources. So wonderful and easy can be chess programming ... such comments we read in the past from amateur & professional programmers again and again. I must say that I dealt with a very pleasant, polite person, who was very friendly, more human and very professional. To read from him is an event for me, to add his work on my page a honour. Messages by Fabien in green ...

Fabien wrote me im March 2014 that I should added the flag from Japan to Senpai on my link selection. So, I am thinking at this time that a pride programmer honors a pride country and Japanese people and his mentality. Wilhelm had an issue / theme for a wonderful new logo! 

Note: Information to Senpai will be collected here!
Senpai (先輩, "earlier colleague") and kōhai (後輩, "later colleague") ...
WIKI (english)



February 24th, 2018 / March 20th, 2018 / March 22nd, 2018 / April 03rd, 2018:

After the Senpai FEOBOS analysis I have to test the new FEOBOS v20.1 Contempt 3 opening book.
I will test the book with 40 moves in 40 minutes repeatedly tourneys with 22 participants.

For sure with Senpai 2.0 BMI2 x64 as one of the 22 participants!

FEOBOS v20.1 with Contempt = 3,
40 moves in 40 minutes repeatedly, ponder = off, resign / offer draw = on, 512Mb for hash, 4-pieces endgame bases,
1 core on Intel Core i7-5930k / i7-4770k, 4.3Ghz, Windows 10 / 7 Prof., 4 rounds = 924 games!

Test-1, 2926 Elo after 84 games.

Test-2, 2916 Elo after 84 games.
Test-3, 2952 Elo after 84 games.

Performance for 252 games = ~ 2928 Elo (Elostat 1.3)

Statistics and games: feobos_v20.1_test-1-3_contempt-3.zip (4.633Mb).

Significanthy lesser fast lost games for Senpai 2.0 if we compare with Senpai 1.0.
Fabien solved the biggest criticism with his last changes.
Great are the stats to the perfect running FEOBOS v20.1 opening book with "Contempt = 3".



December 28th, 2017:

Senpai 2.0 BMI2 x64 will be analyzed now th 41.614 FEOBOS positions with 2 minutes per move and 4 cores. This need two months.
120 sec. per position,, 4.096 for hash tables, 4 cores / 4 threads (no HT), Intell Core i7-4770k, 4.0Ghz, Windows 7 Prof.



November 17th, 2017:

A) ~ +85 for Senpai 2.0
B) 32bit version!
C) Senpai a B01 expert?

Since days I try to win with my favorite Scandinavian line vs. Senpai. It's not possible for me. Vs. other engines I made some points here because I know the line and all the important variants. Playing the line since many years. Senpai is playing here very positional chess.

1. e4 d5, 2. exd5 Qxd5, 3. Nc3 Qa5, 4. d4 Nf6, 5.Nf3 c6, 6. Bd2 Qc7

In background isn't the eval to see ... much more easy a "clock" only :-)
Many possibilites for me as black player with moves like g6 or later b6 and strong bishops.
Castling to the other site with attacking moves on white's king size, many chess programs have problems here.
Black have many time to make the position from move to move better.
Try it out vs. Senpai. Senpai is playing allways the right moves.

Good news to Senpai from Wolfgang Batting (CEGT team):

~ +85 Elo to the predecessor Senpai 1.0!!

A 32bit version can be found in TalkChess under:



November 10th, 2017:

Senpai 2.0
by Fabien Letouzey is available!

senpai_20.zip = 1.304Mb (sources, mac & windows compiles, logo / graphics)

Fabien wrote:
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.

Expected level: Texel/Protector (again)

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

That's all for now,



November 10th, 2017:

It should be clear that Senpai 2.0 will be added as one of the 10 standard analyze engine for FEOBOS project. It's with Wasp an engine, available on my site and the FEOBOS book files should be optimised for Senpai. The Engine with the hightest draw score will be killed from the group of 10 FEOBOS standard engines (at the moment the famos Stockfish).

Stockfish with 15.062% draws ...

I discussed with my FEOBOS partner / Excel programmer Klaus Wlotzka about it.
Klaus have the same opinion.

Senpai is strong in positional and strategic game. A playing style = must have for FEOBOS.

We will do it end of January 2018.
I checked in beta test phase of Senpai 2.0 the compatiblity for Shredder Classic GUI.
Senpai 2.0 BMI2 x64 works fine (*.epd analysis) and is on start position on FEOBOS runway 21 and clear for take-off.



November 10th, 2017:

Helping persons for Senpai 2.0 compiles:
Listed below persons gave great helps for computer chess community and are computer chess experts.

1. Daniel José Queraltó, chess program Andscacs, windows compiles!
2. Michael (Mike) Byrne, variety of activities, mac compiles!

Mike wrote:
Two flavors attached - macOS_popcnt and macOS_bmi2 .  The bmi2 version was about 5% faster than the popcnt version on a bmi2 mac ( mostly recent macs).  A pseudo bench on the iMac ( go depth 20) was about 1.430 Mnps, the popcnt version on a 2010 Mac Pro 0.990 Mnps. 

For SMP :
2010 Mac Pro - 12 real cores w/popcnt, go depth 26
info depth 26 seldepth 39 nodes 375724239 time 43386 nps 8659951

2015 iMac I7, 4 real cores w/ bmi2, go depth 26
info depth 26 seldepth 38 nodes 173250055 time 34896 nps 4964778

Thanks Daniel / Mike!
And thanks again to Gerd Isenberg and the other authors for CPW (Chess Programming Wiki)

... my symbolic long time Award for Gerd!



November 07th, 2017 / November 08th, 2017:

I asked Wilhelm Hudetz for a new Senpai logo.
Wilhelm started directly the work and sent wonderful logos.

Fabien's art of chess programming should have a comparable logo with an artistic design.
Fabien gave directly green light for the new logo versions!

Thanks Wilhelm!


November 07th, 2017:

Senpai 1.0
by Fabien Letouzey

If you like you can download here the older senpai 1.0.zip = 1.26Mb (sources, mac, windows, android & linux compiles)



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