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python - 带有 Keras 分类器的“ValueError：激活不是合法参数”

问题描述

我一直在玩 Tensorflow 和 Keras，最终在尝试超参数调整时遇到以下错误：“ValueError：激活不是合法参数”

关键是我想在我的模型中尝试不同的激活函数，看看哪一个效果最好。我有以下代码：

import pandas as pd 
import tensorflow as tf 
from keras.wrappers.scikit_learn import KerasClassifier
from sklearn.model_selection import GridSearchCV
import numpy as np

ds = pd.read_csv(
    "https://storage.googleapis.com/download.tensorflow.org/data/abalone_train.csv",
    names=["Length", "Diameter", "Height", "Whole weight", "Shucked weight",
           "Viscera weight", "Shell weight", "Age"])
print(ds)

x_train = ds.copy()
y_train = x_train.pop('Age')
x_train = np.array(x_train)

def create_model(layers, activations):
    model = tf.keras.Sequential()
    for i, nodes in enumerate(layers):
        if i == 0:
            model.add(tf.keras.layers.Dense(nodes, input_dim=x_train.shape[1]))
            model.add(layers.Activation(activations))
            model.add(Dropout(0.3))
        else:
            model.add(tf.keras.layers.Dense(nodes))
            model.add(layers.Activation(activations))
            model.add(Dropout(0.3))

    model.add(tf.keras.layers.Dense(units=1, kernel_initializer='glorot_uniform'))
    model.add(layers.Activation('sigmoid'))
    model.compile(optimizer='adam', loss='binary_crossentropy', metrics=['accuracy'])
    return model

model = KerasClassifier(build_fn=create_model, verbose=0)

layers = [[20], [40,20], [45, 30, 15]]
activations = ['sigmoid', 'relu']
param_grid = dict(layers=layers, activation=activations, batch_size = [128, 256], epochs=[30])
grid = GridSearchCV(estimator=model, param_grid=param_grid, cv=5)

grid_result = grid.fit(x_train, y_train)

print(grid_result.best_score_,grid_reslult.best_params_)

pred_y = grid.predict(x_test)
y_pred = (pred_y > 0.5)

cm=confusion_matrix(y_pred, y_test)
score=accuracy_score(y_pred, y_test) 

model.fit(x_train, y_train, epochs=30, callbacks=[cp_callback])
#steps_per_epoch
model.evaluate(x_test, y_test, verbose=2)

probability_model = tf.keras.Sequential([
    model,
    tf.keras.layers.Softmax()
]) 

probability_model(x_test[:100])

标签： pythontensorflowkerasscikit-learn

解决方案

如果您在此处看到，则必须将激活指定为：

from tensorflow.keras import activations layers.Activation(activations.relu)

现在，你有：

activations = ['sigmoid', 'relu']

所以，这就是价值错误的原因。

你应该把你的代码改成这样：

model.add(tf.keras.layers.Dense(nodes, activation=activations[i], input_dim=x_train.shape[1]))

因此，删除激活层：model.add(layers.Activation(activations))而是在每个层内使用激活。

例子：

def create_model(layers, activations):
    model = tf.keras.Sequential()
    for i in range(2):
        if i == 0:
            model.add(tf.keras.layers.Dense(2, activation=activations[i], input_dim=x_train.shape[1]))
            model.add(tf.keras.layers.Dropout(0.3))
        else:
            model.add(tf.keras.layers.Dense(2, activation=activations[i]))
            model.add(tf.keras.layers.Dropout(0.3))

    model.add(tf.keras.layers.Dense(units=1, activation='sigmoid', kernel_initializer='glorot_uniform'))
    model.compile(optimizer='adam', loss='binary_crossentropy', metrics=['accuracy'])
    return model

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