Chess engine: Stockfish 23020906 NNUE for Windows and Linux (+1.55)

Stockfish 23020906 - UCI chess engine, compiled by Linmiao Xu
Rating CEDR=3708

Timestamp: 1675925427

Update default net to nn-1337b1adec5b.nnue

Created by retraining the master net on a dataset composed of:

* Most of the previous best dataset filtered to remove positions likely having only one good move

* Adding training data from Leela T77 dec2021 rescored with 16tb of 7-piece tablebases

Trained with end lambda 0.7 and max epoch 900. Positions with ply <= 28 were removed from most of the previous best dataset before training began. A new nnue-pytorch trainer param for skipping early plies was used to skip plies <= 24 in the unfiltered and additional Leela T77 parts of the dataset.

```

python easy_train.py \

--experiment-name leela96-dfrc99-T80octnovT79aprmayT60novdec-eval-filt-v2-T78augsep-12tb-T77dec-16tb-lambda7-sk24 \

--training-dataset /data/leela96-dfrc99-T80octnovT79aprmayT60novdec-eval-filt-v2-T78augsep-12tb-T77dec-16tb.binpack \

--nnue-pytorch-branch linrock/nnue-pytorch/easy-train-early-fen-skipping \

--early-fen-skipping 24 \

--gpus "0," \

--start-from-engine-test-net True \

--start-lambda 1.0 \

--end-lambda 0.7 \

--gamma 0.995 \

--lr 4.375e-4 \

--tui False \

--seed $RANDOM \

--max_epoch 900

```

The depth6 multipv2 search filtering method is the same as the one used for filtering recent best datasets, with a lower eval difference threshold to remove slightly more positions than before. These parts of the dataset were filtered:

* 96% of T60T70wIsRightFarseerT60T74T75T76.binpack

* 99% of dfrc_n5000.binpack

* T80 oct + nov 2022 data, no positions with castling flags, rescored with ~600gb 7p tablebases

* T79 apr + may 2022 data, rescored with 12tb 7p tablebases

* T60 nov + dec 2021 data, rescored with 12tb 7p tablebases

These parts of the dataset were not filtered. Positions with ply <= 24 were skipped during training:

* T78 aug + sep 2022 data, rescored with 12tb 7p tablebases

* 84% of T77 dec 2021 data, rescored with 16tb 7p tablebases

The code and exact evaluation thresholds used for data filtering can be found at:

https://github.com/linrock/Stockfish/tree/tools-filter-multipv2-eval-diff-t2/src/filter

The exact training data used can be found at:

https://robotmoon.com/nnue-training-data/

Local elo at 25k nodes per move:

nn-epoch859.nnue : 3.5 +/ 1.2

Passed STC:

LLR: 2.95 (-2.94,2.94) <0.00,2.00>

https://tests.stockfishchess.org/tests/view/63dfeefc73223e7f52ad769f

Total: 219744 W: 58572 L: 58002 D: 103170 Elo +0.90

Ptnml(0-2): 609, 24446, 59284, 24832, 701

Passed LTC:

https://tests.stockfishchess.org/tests/view/63e268fc73223e7f52ade7b6

LLR: 2.94 (-2.94,2.94) <0.50,2.50>

Total: 91256 W: 24528 L: 24121 D: 42607 Elo +1.55

Ptnml(0-2): 48, 8863, 27390, 9288, 39

closes https://github.com/official-stockfish/Stockfish/pull/4387

bench 3841998

Download:

Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
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