[PATCH 0/3] Add Lc0

This patch series adds Lc0 “Leela Chess Zero” (a chess engine), alongside a few other optional dependencies that help improve its runtime performance.

zamfofex (3):

gnu: Add ISPC. * gnu/packages/c.scm (ispc): New variable.

gnu: Add oneDNN. * gnu/packages/machine-learning.scm (oneapi-dnnl):

New variable.

gnu: Add Lc0. * gnu/packages/games.scm (lc0): New variable.

gnu/packages/c.scm | 63 +++++++++++++++++++++++++++++++

gnu/packages/games.scm | 60 ++++++++++++++++++++++++++++-

gnu/packages/machine-learning.scm | 21 +++++++++++

3 files changed, 143 insertions(+), 1 deletion(-)

base-commit: 380faf265b0c3b231ab8b69597d161be5e704e18

--

2.39.2

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gnu/packages/c.scm | 63 ++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 63 insertions(+)

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gnu/packages/machine-learning.scm | 21 +++++++++++++++++++++

1 file changed, 21 insertions(+)

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gnu/packages/games.scm | 60 +++++++++++++++++++++++++++++++++++++++++-

1 file changed, 59 insertions(+), 1 deletion(-)

Hello, I have pushed ispc and oneapi-dnnl, thank you!

zamfofex <zamfofex@twdb.moe> writes:

Will we able to train a model from source? And how much will it cost?

As far as I know, guix haven't decided to accept pre-trained models:

I don’t think it is feasible. Lc0’s approach is based on self?play reinforcement?learning, which in effect means that training starts with no knowledge about chess except for its rules (playing seemingly random moves), and going from there to learn increasingly more about it. So, in practice, this means it would take multiple months or at least several weeks to attain a neural network model that is anywhere close to as effective as the ones provided and pre?trained. Besides, I believe training requires a (reasonably decent) GPU.

But the network isn’t prohibitively large and its license is not proprietary. I’ll also note that Stockfish (packaged immediately above my Lc0 package) *does* itself include a provided pre?trained network and no?one has really complained about it, so I think it should be fine here too.

Hi,

On Thu, 11 May 2023 at 18:25, zamfofex <zamfofex@twdb.moe> wrote:

I concur.

I will try to dedicate some time for reviewing this patch set.

Cheers,

simon

Lc0 recently released version 0.30.0, so here is a patch with the updates version (in case the issue regarding the network’s inclusion is ever resolved).

Also, I wanted to say: Is it reasonable to include Lc0 without the networks in? People can still download and use them, they just wouldn’t be included in Guix itself.

Note that, unlike Stockfish, Lc0 does run without the neural networks, so it would be necessary for the user to download or otherwise acquire one by themself in order to use Lc0. The user can choose an appropriate network in their chess GUI program when configuring Lc0 in it.

If this is more desireable, I can submit a patch without the trained neural network, which would allow the user to choose whichever one they might want.

Thanks in advance!

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gnu/packages/games.scm | 58 ++++++++++++++++++++++++++++++++++++++++++

1 file changed, 58 insertions(+)

Sorry, I meant to say “Lc0 does *not* run without the neural networks”. (“Not” is a fairly important word to have forgotten!)

Am Donnerstag, dem 27.07.2023 um 20:34 -0300 schrieb zamfofex:

This sentence looks semantically incorrect.

Providing a default, if it can be bootstrapped, but allowing the user

to choose would be the best option.

I think the postfix "based", which typically requires a dash is not

easily applied here. Simply write "Chess engine using neural networks"

or something like that.

Not a full sentence without period

Cheers

Yes, sorry! I guess you didn’t receive my correction email. (I’m still bad at sending emails properly, it seems.) See: https://issues.guix.gnu.org/63088#8 I had meant “Lc0 does *not* run without the neural networks”.

I don’t think a default can be easily bootstrapped. When I first submitted the patch, I talked with some of the Lc0 developers, and they said it might be possible to bootstrap one by using Stockfish in several minutes, but there is no code that does that currrently (it would have to be written and is nontrivial). And it wouldn’t be as effective as the existing networks, because Stockfish’s evaluation provides less information than Lc0’s is able to use.

In any case, that feels entirely redundant, because Stockfish’s NNUE networks were trained on Lc0’s anyway, so it seems to be only adding a layer of complexity for no seemingly good reason.

If this concern can be addressed somehow, I can submit a followup patch. (Either just fixing the wording, or also removing the networks.)

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gnu/packages/games.scm | 59 ++++++++++++++++++++++++++++++++++++++++++

1 file changed, 59 insertions(+)

Am Donnerstag, dem 07.09.2023 um 18:23 +0800 schrieb iyzsong@envs.net:

Missing the entry for lc0-neural-network.

recursive? #t is meh ._.

Can we work around that?

Use new-style inputs.

Can we use search-input-file or the like here?

Is Lc0 = Leela Chess Zero? What's the connection?

Cheers

Yes, presumably easily, but I don’t think it would be a good idea in this case, because it isn’t used to build bundled software, but rather just for a small project?specific pair of source files (that are in a separate repo just because they are used by other repos of the project too).

Probably. Though would it be reasonable to package the network separately instead? Note that Lc0 is able to load various networks, and there is no canonical network, so maybe it would be useful to have it in a different package so that more can be potentially added in the future.

Then people could use them with something like ‘guix shell lc0 lc0-NETWORK_NAME’.

“Lc0”, “Leela Chess Zero”, “LCZero”, and sometimes just “Leela Chess” can be used roughly interchangeably to refer to the project as a whole. Though, occasionally, people will use the term “Lc0” (sometimes capitalised as “lc0”) to refer specifically to the ‘lc0’ executable, which can use the networks from the Leela Chess Zero project, but networks created by other people too, including those of e.g. the Maia project, see https://github.com/CSSLab/maia-chess and https://maiachess.com

At some point (very early on), the code for the executable was rewritten or otherwise largely refactored, and at the same time renamed from ‘lczero’ to the current ‘lc0’, so sometimes (very rarely nowadays), people will use the term “lc0” (or “Lc0”) to refer specifically to this new executable and code base, contrasting with the former ‘lczero’ executable and its code base.

Honestly, this all feels convoluted to me, so I usually like to use the terms interchangeably, and I don’t think using them differently in the package description is a good choice.

- - - - -

Hopefully this helps clarify things well enough! If there is interest, I can submit another patch with the requested changes and the appropriate path taken regarding the packaging for the networks.

Am Montag, dem 11.09.2023 um 07:22 -0300 schrieb zamfofex:

In that case, a comment explaining this in 1-2 lines would probably be

fine.

Sounds reasonable to me. Do add a phrase or two about this to the lc0

description though if it doesn't even ship a basic network.

In that case, for the description we should probably go with "Leela

Chess Zero" or "@acronym{lc0, Leela Chess Zero}"

Cheers

---

gnu/local.mk | 2 ++

gnu/packages/lc0.scm | 71 ++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 73 insertions(+)

create mode 100644 gnu/packages/lc0.scm

(lc0-611246, lc0-791556, lc0-815383): New variables.

---

gnu/packages/lc0.scm | 76 ++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 76 insertions(+)

(lc0-maia-1400, lc0-maia-1500, lc0-maia-1600, lc0-maia-1700)

(lc0-maia-1800, lc0-maia-1900): New variables.

---

gnu/packages/lc0.scm | 55 ++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 55 insertions(+)

Am Dienstag, dem 12.09.2023 um 08:58 -0300 schrieb zamfofex:

You might want to search for ways to shorten these urls. E.g. Define a

procedure (lc0-network "short-name")

Cheers

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gnu/local.mk | 2 ++

gnu/packages/lc0.scm | 71 ++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 73 insertions(+)

create mode 100644 gnu/packages/lc0.scm

(make-lc0-contrib-net): New procedures.

(lc0-611246, lc0-791556, lc0-815383): New variables.

---

gnu/packages/lc0.scm | 84 ++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 84 insertions(+)

(lc0-maia-1400, lc0-maia-1500, lc0-maia-1600, lc0-maia-1700)

(lc0-maia-1800, lc0-maia-1900): New variables.

---

gnu/packages/lc0.scm | 55 ++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 55 insertions(+)