问题:
调用lightgbm库,设置了早停轮次“early_stopping_rounds”参数和打印log间隔“verbose_eval”参数后出现UserWarning
示例代码如下:
import lightgbm
cv_results = lightgbm.cv(
params,
lgb_train,
seed=1,
nfold=5,
metrics='auc',
###
early_stopping_rounds=30,
verbose_eval=True
###
)
两个UserWarning如下:
UserWarning: 'early_stopping_rounds' argument is deprecated and will be removed in a future release of LightGBM. Pass 'early_stopping()' callback via 'callbacks' argument instead.
UserWarning: 'verbose_eval' argument is deprecated and will be removed in a future release of LightGBM. Pass 'log_evaluation()' callback via 'callbacks' argument instead.
原因:
'early_stopping_rounds' argument is deprecated and will be removed in a future release of LightGBM. Pass 'early_stopping()' callback via 'callbacks' argument instead. 的意思是参数'early_stopping_rounds' 已被弃用,将在LightGBM的未来版本中删除。改为通过“callbacks”参数传入“early_stopping()”。
由于LightGBM库在更新之后将老版本的函数进行了改动,导致需要传入的参数或传入参数的方式发生了改变。
解决方法:
将代码做如下修改
import lightgbm
###
from lightgbm import log_evaluation, early_stopping
callbacks = [log_evaluation(period=100), early_stopping(stopping_rounds=30)]
###
cv_results = lightgbm.cv(
params,
lgb_train,
seed=1,
nfold=5,
metrics='auc',
###
callbacks=callbacks
###
)
首先
from lightgbm import log_evaluation, early_stopping
之后用
callbacks = [log_evaluation(period=100), early_stopping(stopping_rounds=30)]
替换之前的'verbose_eval'以及'early_stopping_rounds'即可:)
其中period=100指每迭代100次打印一次log;stopping_rounds=30指如果验证集的误差在30次迭代内没有降低,则停止迭代。