chess_inator/nnue/s3_train_neural_net.py

76 lines
1.8 KiB
Python
Executable File

#!/usr/bin/env python
"""Train the NNUE weights."""
import torch
import pandas as pd
import numpy as np
from torch.utils.data import Dataset, DataLoader
from pathlib import Path
from dataclasses import dataclass
################################
################################
## Data loading / parsing
################################
################################
@dataclass
class Position:
"""Single board position."""
fen: str
"""Normal board representation."""
board: torch.Tensor
"""Multi-hot board representation."""
cp_eval: np.double
"""Centipawn evaluation (white perspective)."""
expected_points: np.double
"""
Points expected to be gained for white from the game, based on centipawn evaluation.
- 0: black win
- 0.5: draw
- 1: white win
"""
def sigmoid(x):
"""Calculate sigmoid of `x`, using scaling constant `K`."""
K = 150
return 1 / (1 + np.exp(-K * x / 400))
class ChessPositionDataset(Dataset):
def __init__(self, data_file: Path):
self.data = pd.read_csv(data_file, delimiter="\t")
def __len__(self):
return len(self.data)
def __getitem__(self, idx):
row = self.data.iloc[idx]
eval = np.double(row.iloc[2])
return Position(
fen=row.iloc[0],
board=torch.as_tensor([1 if c == "1" else 0 for c in row.iloc[1]]),
cp_eval=eval,
expected_points=sigmoid(eval/100),
)
if __name__ == "__main__":
full_dataset = ChessPositionDataset(Path("combined_training.tsv.gz"))
train_dataset, test_dataset = torch.utils.data.random_split(full_dataset, [0.8, 0.2])
train_dataloader = DataLoader(train_dataset, batch_size=64, shuffle=True)
test_dataloader = DataLoader(test_dataset, batch_size=64, shuffle=True)