keras用auc做metrics以及早停例項
阿新 • • 發佈:2020-07-03
我就廢話不多說了,大家還是直接看程式碼吧~
import tensorflow as tf from sklearn.metrics import roc_auc_score def auroc(y_true,y_pred): return tf.py_func(roc_auc_score,(y_true,y_pred),tf.double) # Build Model... model.compile(loss='categorical_crossentropy',optimizer='adam',metrics=['accuracy',auroc])
完整例子:
def auc(y_true,y_pred): auc = tf.metrics.auc(y_true,y_pred)[1] K.get_session().run(tf.local_variables_initializer()) return auc def create_model_nn(in_dim,layer_size=200): model = Sequential() model.add(Dense(layer_size,input_dim=in_dim,kernel_initializer='normal')) model.add(BatchNormalization()) model.add(Activation('relu')) model.add(Dropout(0.3)) for i in range(2): model.add(Dense(layer_size)) model.add(BatchNormalization()) model.add(Activation('relu')) model.add(Dropout(0.3)) model.add(Dense(1,activation='sigmoid')) adam = optimizers.Adam(lr=0.01) model.compile(optimizer=adam,loss='binary_crossentropy',metrics = [auc]) return model ####cv train folds = StratifiedKFold(n_splits=5,shuffle=False,random_state=15) oof = np.zeros(len(df_train)) predictions = np.zeros(len(df_test)) for fold_,(trn_idx,val_idx) in enumerate(folds.split(df_train.values,target2.values)): print("fold n°{}".format(fold_)) X_train = df_train.iloc[trn_idx][features] y_train = target2.iloc[trn_idx] X_valid = df_train.iloc[val_idx][features] y_valid = target2.iloc[val_idx] model_nn = create_model_nn(X_train.shape[1]) callback = EarlyStopping(monitor="val_auc",patience=50,verbose=0,mode='max') history = model_nn.fit(X_train,y_train,validation_data = (X_valid,y_valid),epochs=1000,batch_size=64,callbacks=[callback]) print('\n Validation Max score : {}'.format(np.max(history.history['val_auc']))) predictions += model_nn.predict(df_test[features]).ravel()/folds.n_splits
補充知識:Keras可使用的評價函式
1:binary_accuracy(對二分類問題,計算在所有預測值上的平均正確率)
binary_accuracy(y_true,y_pred)
2:categorical_accuracy(對多分類問題,計算在所有預測值上的平均正確率)
categorical_accuracy(y_true,y_pred)
3:sparse_categorical_accuracy(與categorical_accuracy相同,在對稀疏的目標值預測時有用 )
sparse_categorical_accuracy(y_true,y_pred)
4:top_k_categorical_accuracy(計算top-k正確率,當預測值的前k個值中存在目標類別即認為預測正確 )
top_k_categorical_accuracy(y_true,y_pred,k=5)
5:sparse_top_k_categorical_accuracy(與top_k_categorical_accracy作用相同,但適用於稀疏情況)
sparse_top_k_categorical_accuracy(y_true,k=5)
以上這篇keras用auc做metrics以及早停例項就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支援我們。