5d81071953
Created from 2 distinct spsa tunes of the latest main net (nn-31337bea577c.nnue) and applying the params to the prior main net (nn-e8bac1c07a5a.nnue). This effectively reverts the modifications to output weights and biases in https://github.com/official-stockfish/Stockfish/pull/5509 SPSA: A: 6000, alpha: 0.602, gamma: 0.101 1st - 437 feature transformer biases where values are < 25 54k / 120k games at 180+1.8 https://tests.stockfishchess.org/tests/view/66af98ac4ff211be9d4edad0 nn-808259761cca.nnue 2nd - 208 L2 weights where values are zero 112k / 120k games at 180+1.8 https://tests.stockfishchess.org/tests/view/66b0c3074ff211be9d4edbe5 nn-a56cb8c3d477.nnue When creating the above 2 nets (nn-808259761cca.nnue, nn-a56cb8c3d477.nnue), spsa params were unintentionally applied to nn-e8bac1c07a5a.nnue rather than nn-31337bea577c.nnue due to an issue in a script that creates nets by applying spsa results to base nets. Since they both passed STC and were neutral or slightly positive at LTC, they were combined to see if the elo from each set of params was additive. The 2 nets can be merged on top of nn-e8bac1c07a5a.nnue with: https://github.com/linrock/nnue-tools/blob/90942d3/spsa/combine_nnue.py ``` python3 combine_nnue.py \ nn-e8bac1c07a5a.nnue \ nn-808259761cca.nnue \ nn-a56cb8c3d477.nnue ``` Merging yields nn-87caa003fc6a.nnue which was renamed to nn-1111cefa1111.nnue with an updated nnue-namer around 10x faster than before by: - using a prefix trie for efficient prefix matches - modifying 4 non-functional bytes near the end of the file instead of 2 https://github.com/linrock/nnue-namer Thanks to @MinetaS for pointing out in #nnue-dev what the non-functional bytes are: L3 is 32, 4 bytes for biases, 32 bytes for weights. (fc_2) So -38 and -37 are technically -2 and -1 of fc_1 (type AffineTransform<30, 32>) And since InputDimension is padded to 32 there are total 32 of 2 adjacent bytes padding. So yes, it's non-functional whatever values are there. It's possible to tweak bytes at -38 - 32 * N and -37 - 32 * N given N = 0 ... 31 The net renamed with the new method passed non-regression STC vs. the original net: https://tests.stockfishchess.org/tests/view/66c0f0a821503a509c13b332 To print the spsa params with nnue-pytorch: ``` import features from serialize import NNUEReader feature_set = features.get_feature_set_from_name("HalfKAv2_hm") with open("nn-31337bea577c.nnue", "rb") as f: model = NNUEReader(f, feature_set).model c_end = 16 for i,ft_bias in enumerate(model.input.bias.data[:3072]): value = int(ft_bias * 254) if abs(value) < 25: print(f"ftB[{i}],{value},-1024,1024,{c_end},0.0020") c_end = 6 for i in range(8): for j in range(32): for k in range(30): value = int(model.layer_stacks.l2.weight.data[32 * i + j, k] * 64) if value == 0: print(f"twoW[{i}][{j}][{k}],{value},-127,127,{c_end},0.0020") ``` New params found with the same method as: https://github.com/official-stockfish/Stockfish/pull/5459 Passed STC: https://tests.stockfishchess.org/tests/view/66b4d4464ff211be9d4edf6e LLR: 2.94 (-2.94,2.94) <0.00,2.00> Total: 136416 W: 35753 L: 35283 D: 65380 Ptnml(0-2): 510, 16159, 34416, 16597, 526 Passed LTC: https://tests.stockfishchess.org/tests/view/66b76e814ff211be9d4ee1cc LLR: 2.95 (-2.94,2.94) <0.50,2.50> Total: 159336 W: 40753 L: 40178 D: 78405 Ptnml(0-2): 126, 17497, 43864, 18038, 143 closes https://github.com/official-stockfish/Stockfish/pull/5534 bench 1613043 |
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Stockfish
A free and strong UCI chess engine.
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Overview
Stockfish is a free and strong UCI chess engine derived from Glaurung 2.1 that analyzes chess positions and computes the optimal moves.
Stockfish does not include a graphical user interface (GUI) that is required to display a chessboard and to make it easy to input moves. These GUIs are developed independently from Stockfish and are available online. Read the documentation for your GUI of choice for information about how to use Stockfish with it.
See also the Stockfish documentation for further usage help.
Files
This distribution of Stockfish consists of the following files:
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README.md, the file you are currently reading.
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Copying.txt, a text file containing the GNU General Public License version 3.
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AUTHORS, a text file with the list of authors for the project.
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src, a subdirectory containing the full source code, including a Makefile that can be used to compile Stockfish on Unix-like systems.
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a file with the .nnue extension, storing the neural network for the NNUE evaluation. Binary distributions will have this file embedded.
Contributing
See Contributing Guide.
Donating hardware
Improving Stockfish requires a massive amount of testing. You can donate your hardware resources by installing the Fishtest Worker and viewing the current tests on Fishtest.
Improving the code
In the chessprogramming wiki, many techniques used in Stockfish are explained with a lot of background information. The section on Stockfish describes many features and techniques used by Stockfish. However, it is generic rather than focused on Stockfish's precise implementation.
The engine testing is done on Fishtest. If you want to help improve Stockfish, please read this guideline first, where the basics of Stockfish development are explained.
Discussions about Stockfish take place these days mainly in the Stockfish Discord server. This is also the best place to ask questions about the codebase and how to improve it.
Compiling Stockfish
Stockfish has support for 32 or 64-bit CPUs, certain hardware instructions, big-endian machines such as Power PC, and other platforms.
On Unix-like systems, it should be easy to compile Stockfish directly from the
source code with the included Makefile in the folder src. In general, it is
recommended to run make help to see a list of make targets with corresponding
descriptions. An example suitable for most Intel and AMD chips:
cd src
make -j profile-build ARCH=x86-64-avx2
Detailed compilation instructions for all platforms can be found in our documentation. Our wiki also has information about the UCI commands supported by Stockfish.
Terms of use
Stockfish is free and distributed under the GNU General Public License version 3 (GPL v3). Essentially, this means you are free to do almost exactly what you want with the program, including distributing it among your friends, making it available for download from your website, selling it (either by itself or as part of some bigger software package), or using it as the starting point for a software project of your own.
The only real limitation is that whenever you distribute Stockfish in some way, you MUST always include the license and the full source code (or a pointer to where the source code can be found) to generate the exact binary you are distributing. If you make any changes to the source code, these changes must also be made available under GPL v3.