Lc0 training.

 If you are new to Leela (Lc0) Chess and have begun contributing games either using Google Cloud or some other online service or your own home computer, you may be wondering where all those games go and how training of Leela happens.


Leela beats Fire promoting to Semi-Final of TCEC Cup!

 Leela in a classic drama style, promoted in TCEC Cup Semi-Finals and it will face Stockfish today!
While in CCCC blitz tournament she is still at 3rd place ahead of Komodo, Ethereal and Fire and behind Stockfish and Houdini.


CCCC Blitz is running.... Leela on top 3!

CCCC blitz tournament is running and till now Leela is having a good performance being steadily on the top 3.

Conditions for the tournament are:
33 engines play a 4x Round Robin tournament with each engine that will play each other 4 times(2 with black and 2 with white) in a total of 128 games per engine, with no opening books or predefined positions used.
This implies a problem though as an engine will play each other twice with white and twice with black so the question becomes: how variety of play will be assured to not have duplicate games? Obviously they will rely on the non determinism of multithreaded search(traditional engines that use more than 1 threads/cores are not deterministic, even Leela that uses more than 1 CPU threads it's not(Leela mainly uses GPU for its search, but uses also CPUs)). This is of course not that wise decision and they should use predefined positions for the second part of the Round Robin.

•Time control of 5 minutes per game plus 2 seconds added time per move.


Draw in Chess. Some odd cases.

Chess is a game where there are 3 distinct results. White wins or black wins or it is a draw and nobody wins.  Draw can achieved in many ways in Chess. These are:

•Stalemate position. A position where the player to move does not have a legal move to play and his King is not in check. Game immediately ends as a draw.


Understanding Training against Q as Knowledge Distillation.

Article by Cyanogenoid, member of Leela Chess Zero development team .

Recently, Oracle investigated training the value head against not the game outcome z, but against the accumulated value q for a position that is obtained after exploring some number of nodes with UCT [Lessons From AlphaZero: Improving the Training Target.]. In this post, we describe some of the experiments with Knowledge Distillation (KD) and relate them to training against q.


Knowledge Distillation (KD) [1 , 2] is a technique where there are two neural networks at play: a teacher network and a student network. The teacher network is usually a fixed, fully-trained network, perhaps of bigger size than the student network. Through KD, the goal is usually to produce a smaller student network than the teacher -- which allows for faster inference -- while still encoding the same "knowledge" within the network; the teacher teaches its knowledge to the student. When training the student network, instead of training with the dataset labels as targets (in our case this is the policy distribution and the value output), the student is trained to match the outputs of the teacher.


Leela promotes to round of 16 in TCEC Cup with 2 nice wins!

 Leela after 6 consecutive draws in the series of games against Laser(division 1 engine) she won last 2 games so she promoted to next round where she will face Ethereal(premier division engine) that beat Rodent(division 4 engine) easily with 5-0 and promoted too. The games against Ethereal will probably take place on this Sunday.

 Leela's performances generally seem very odd, since when she is playing top engines like Stockfish and getting countless draws with performances like around 40 Elo short of Stockfish(like it is on TCEC bonus games) you expect to crush weaker engines. But this doesn't really happen.
 It's a general observation that Leela underperforms against weaker engines and a good analysis of this can be found HERE where it was found that the usual Elo curve does not fit Leela's results well.


Achilles heel of Chess engines.... Neural net engines and Leela the only hope!

 When first Chess engines were born were very weak. First real Chess program(even though in 1912 there was a King Rook versus King solver and in 1951 Turing wrote only in paper a Chess program) was written in 1951 by Alan Turing's colleague, Dietrich Prinz, but it was not able to play a whole game but could only solve small "mate in 2" problems.
 The interest in computer Chess was growing and more and more researchers in artificial intelligence(AI) used Chess as a platform to showcase their progress on AI. As hardware has started to evolve more and more, many researchers started to be able to use the already known algorithm, that has proved to be the backbone for future Chess engines: the Minimax algorithm, that was invented many years before by the pioneer in so many fields, John Von Neumann.

TCEC CUP running. Leela in danger of elimination from the 1st round against Laser! UPDATE: Leela won!

TCEC Cup continues and we already know 6 engines that have promoted to next round.
Leela right now has a big fight with Laser and after 4 games it is on 2-2 with 4 draws.

It would be a big surprise if Leela will not manage to promote but with just 8 games everything can happen. The peculiar strength adaption to the opponent of Leela is well known anyway, this means it can hold Stockfish to very close result but playing against much weaker engines she doesn't perform accordingly.

UPDATE:     After 6 draws in the first 6 games, Leela won the last 2 games to promote in the next round. In the game with black pieces she slowly outplayed Laser obtaining eventually a won position, while with white pieces, in a reversed opening from previous game, she managed to easily win heavily outplaying Laser in a French defense where Leela knew even sooner than Cfish(a clone of Stockfish that can run with 7 piece tablebases somewhat better than Stockfish) running on 88 cores, what is going on in the position!
Some analysis of the games will follow.....


TCEC Cup started! CCCC variants tournament continues....

The TCEC Cup has started and 2 match pairs will be played every day.
We remind that 32 engines will compete in a Knockout elimination tournament, and in each pair match, the best out of 8 games will promote to next round.
That means if an engine completes first, in the 8 games, 4.5 points will promote. As per their decision if an engine completes first 4.5 or 5 points, the match is stopped and the engine promotes to next round. So not all 8 games will be played if not necessary.
Also the tournament would not necessarily be continuous like normal TCEC, since only 2 pairs will be played every day even if there is time for more. The games will begin 12:30 UTC every day.

Till now Stockfish crushed Ivanhoe with a 5-0 score and promoted and Gull won 4.5-2.5 against Texel and will play Stockfish in next round.


Leela wins the match series against Komodo and wins a Pawn odds game against Stockfish!

 Leela won 16-14 against Komodo the 30 games match to determine 3rd position in CCCC1, while on the variants tournament she won a game against Stockfish while being handicapped having a Pawn less!!

 So the 3rd place Komodo-Leela match has ended with Leela winning 16-14, having 5 wins, 3 losses and 22 draws, so Leela had finished 3rd in the first CCCC tournament according to Chess.com changed rules.

Lc0 v0.18.1 has been released.

It turned out that the version v0.18.0, that was released a few days ago, had a bug that caused it to miss tablebase wins sometimes.

Because of that, v0.18.1 is released. You can download it here.

If you don't use tablebases, there is no need to update, v0.18.0 is fine.
Also version v0.18.1 is not necessary for training game contribution, version 0.18.0 is totally fine for that too.

CCCC season 2 will use v0.18.1.
TCEC cup uses v0.18.0 (probably).


Contributing to Leela Chess Zero. Creating the Caissa of Chess engines....

 Deepmind's latest paper release (Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm) on 5 December 2017, presented a method of reinforcement learning for convolutional neural networks that its result was fantastic as they created 3 engines, one for GO, one for Chess and one for Shogi that were beating easily the best available engines of the time.

 For Chess the known AlphaZero for Chess, beat Stockfish 8 easily, but in order AlphaZero to be created it required generating games and training for "only" 4 hours, having generated 44 million games! Then these games were used to make the engine learn observing these games and become stronger.
Generating games is the hard part of the whole process anyway. As it is the most time consuming thing. And one has to generate millions of games to start becoming really strong.

CCCC Leela-Komodo 3rd place match started and TCEC Cup is about to start.

TCEC Cup is about to start in a few days and Chessdom.com just announced the complete pairings up to the final.

Leela is on the Stockfish side and if she will promote from the first match against Laser she will probably face Ethereal in round of 16, so it will be a tough match already.
But first has to overcome Laser of course.
Leela in TCEC Cup will use the v18 of Lc0 and 11248 net of test10.

Here is the format of TCEC Cup: