下面这段代码用了哪种数学建模方法fold = 5 for model_seed in range(num_model_seed): print(seeds[model_seed],"--------------------------------------------------------------------------------------------") oof_cat = np.zeros(X_train.shape[0]) prediction_cat = np.zeros(X_test.shape[0]) skf = StratifiedKFold(n_splits=fold, random_state=seeds[model_seed], shuffle=True) for index, (train_index, test_index) in enumerate(skf.split(X_train, y)): train_x, test_x, train_y, test_y = X_train[feature_name].iloc[train_index], X_train[feature_name].iloc[test_index], y.iloc[train_index], y.iloc[test_index] dtrain = lgb.Dataset(train_x, label=train_y) dval = lgb.Dataset(test_x, label=test_y) lgb_model = lgb.train( parameters, dtrain, num_boost_round=10000, valid_sets=[dval], early_stopping_rounds=100, verbose_eval=100, ) oof_cat[test_index] += lgb_model.predict(test_x,num_iteration=lgb_model.best_iteration) prediction_cat += lgb_model.predict(X_test,num_iteration=lgb_model.best_iteration) / fold feat_imp_df['imp'] += lgb_model.feature_importance() del train_x del test_x del train_y del test_y del lgb_model oof += oof_cat / num_model_seed prediction += prediction_cat / num_model_seed gc.collect()
时间: 2024-04-02 14:37:12 浏览: 56
lvq.rar_5-fold_The Fold_k fold_k fold cross_lvq
这段代码使用了交叉验证的方法(StratifiedKFold)来评估LightGBM模型的性能,并且使用了平均化的方法(num_model_seed)来减少模型的方差。其中,变量fold表示交叉验证折数,num_model_seed表示重复训练模型的次数。在每次交叉验证中,将训练数据(train_x)和测试数据(test_x)分别作为模型的训练集和验证集,使用LightGBM模型进行训练,并在验证集上进行早停策略(early_stopping_rounds),以避免模型过拟合。在训练过程中,记录并累加训练集和测试集的预测结果(oof_cat和prediction_cat),并计算特征重要性(feat_imp_df['imp'])。最后,使用平均化的方式计算oof和prediction,并释放不再使用的内存(gc.collect())。
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