"By far the best ICCF analysis tool for Leela." — jhorthos
Nibbler is a real-time analysis GUI for Leela Chess Zero (Lc0), which runs Leela in the background and constantly displays opinions about the current position. You can also compel the engine to evaluate one or more specific moves. Nibbler is loosely inspired by Lizzie.
For prebuilt binary releases, see the Releases section. For help, the Discord may be your best bet, or open an issue here.
- Display Leela's top choices graphically.
- Choice of winrate, node %, or policy display.
- Optionally shows Leela statistics N, P, Q, U, and/or Q+U for each move.
- UCI
searchmovesfunctionality. - PGN loading via menu, clipboard, or drag-and-drop.
- Supports PGN variations of arbitrary depth.
- FEN loading.
- Versus Mode - where Leela only analyses one side.
Some Windows and Linux standalone releases are uploaded to the Releases section from time to time. Mac builds are harder to make but @twoplan is experimenting with it in this repo.
Running Nibbler from source requires Electron, but has no other dependencies. If you have Electron installed (e.g. npm install -g electron) you can likely enter the Nibbler directory, then do electron . to run it. This is mostly tested with Electron 5, but older and newer versions may work too.
As well as the menu options, various aesthetic adjustments are possible in the config.json file, which can be found via the App menu. For example, board colour can be changed.
If you like a different piece set, you can create a folder of .png or .svg files with the right names and point the override_piece_directory config option to it.
All Leela's UCI engine options can be set in two ways: in the options part of Nibbler's own config.json file (which you can find via the App menu) or in a file called lc0.config in the same folder as Leela - for info about how to use that, see here.
See also this list of UCI options supported by Leela.
An option to enable the UCI searchmoves feature is available in the Analysis menu. Once enabled, one or more moves can be specified as moves to focus on; Leela will ignore other moves. This is useful when you think Leela isn't giving a certain move enough attention.
Leela forgets much of the evaluation if the position changes. To mitigate this, an option in the Analysis menu allows you to hover over a PV (on the right) and see it play out on the board, without changing the position we're actually analysing. You might prefer to halt Leela while doing this, so that the PVs don't change while you're looking at them.
Leela running out of RAM can be a problem if searches go on too long. You might like to use the UCI option RamLimitMb (see advanced engine options, above).
Note that other UCI engines should run OK if they support Chess960 castling format, but the results will be poor because we use MultiPV, which cripples traditional A/B engines.
Thanks to everyone in Discord and GitHub who's offered advice and suggestions; and thanks to all Lc0 devs and GPU-hours contributors!
The pieces are from Lichess.