LightGBM regressor score function?

Question

I'm trying to find what is the score function for the LightGBM regressor. In their documentation page I could not find any information regarding the function used to calculate the score attribute...

Answer 1

The score function of the LGBMRegressor is the R-squared.

from lightgbm import LGBMRegressor
from sklearn.datasets import make_regression
from sklearn.metrics import r2_score

X, y = make_regression(random_state=42)

model = LGBMRegressor()
model.fit(X, y)
y_pred = model.predict(X)

print(model.score(X, y))
# 0.9863556751160256

print(r2_score(y, y_pred))
# 0.9863556751160256