我正在使用Keras模型上的sklearn执行超参数调优优化任务 . 我正在尝试优化管道中的KerasClassifiers ...代码如下:
import numpy as np
import pandas as pd
from keras.models import Sequential
from keras.layers import Dense
from keras.wrappers.scikit_learn import KerasClassifier
from sklearn.model_selection import cross_val_score, StratifiedKFold,RandomizedSearchCV
from sklearn.preprocessing import LabelEncoder, StandardScaler
from sklearn.pipeline import Pipeline
my_seed=7
dataframe = pd.read_csv("z:/sonar.all-data.txt", header=None)
dataset = dataframe.values
# split into input and output variables
X = dataset[:,:60].astype(float)
Y = dataset[:,60]
encoder = LabelEncoder()
Y_encoded=encoder.fit_transform(Y)
myScaler = StandardScaler()
X_scaled = myScaler.fit_transform(X)
def create_keras_model(hidden=60):
model = Sequential()
model.add(Dense(units=hidden, input_dim=60, kernel_initializer="normal", activation="relu"))
model.add(Dense(1, kernel_initializer="normal", activation="sigmoid"))
#compile model
model.compile(loss="binary_crossentropy", optimizer="adam", metrics=["accuracy"])
return model
def create_pipeline(hidden=60):
steps = []
steps.append(('scaler', StandardScaler()))
steps.append(('dl', KerasClassifier(build_fn=create_keras_model,hidden=hidden, verbose=0)))
pipeline = Pipeline(steps)
return pipeline
my_neurons = [15, 30, 60]
my_epochs= [50, 100, 150]
my_batch_size = [5,10]
my_param_grid = dict(hidden=my_neurons, epochs=my_epochs, batch_size=my_batch_size)
model2Tune = KerasClassifier(build_fn=create_keras_model, verbose=0)
model2Tune2 = create_pipeline()
griglia = RandomizedSearchCV(estimator=model2Tune, param_distributions = my_param_grid, n_iter=8 )
griglia.fit(X_scaled, Y_encoded) #this works
griglia2 = RandomizedSearchCV(estimator=create_pipeline, param_distributions = my_param_grid, n_iter=8 )
griglia2.fit(X, Y_encoded) #this does not
我们看到 RandomizedSearchCV
与griglia一起工作,而它不适用于griglia2,返回
“TypeError:estimator应该是一个实现'fit'方法的估算器,被传递了” .
是否可以修改代码以使其在Pipeline对象下运行?
提前致谢
1 回答
估计器参数需要一个对象,而不是一个指针 . 目前,您正在传递一个指向生成管道对象的方法的指针 . 尝试添加
()
来解决这个问题:griglia2 = RandomizedSearchCV(estimator=create_pipeline(), param_distributions = my_param_grid, n_iter=8 )
现在关于无效参数错误的第二条评论 . 您需要将创建管道时定义的名称附加到实际参数,以便可以成功传递它们 .
请查看Pipeline usage here的说明 .
用这个:
注意
dl__
(带有两个下划线) . 当您想要调整管道内多个对象的参数时,这非常有用 .例如,假设与上述参数一起,您还要调整或指定StandardScaler的参数 .
然后您的参数网格变为:
希望这能清除事情 .