标准化vs非标准化

from sklearn.datasets import load_iris
from sklearn.neural_network import MLPClassifier
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import StandardScaler
from sklearn.metrics import accuracy_score
iris = load_iris()
X_train, X_test, y_train, y_test = train_test_split(iris.data, iris.target, test_size=0.2, random_state=42)
clf1 = MLPClassifier(hidden_layer_sizes=(10,), max_iter=500, random_state=42)
clf1.fit(X_train, y_train)
acc1 = accuracy_score(y_test, clf1.predict(X_test))
scaler = StandardScaler()
X_train_s = scaler.fit_transform(X_train)
X_test_s = scaler.transform(X_test)
clf2 = MLPClassifier(hidden_layer_sizes=(10,), max_iter=500, random_state=42)
clf2.fit(X_train_s, y_train)
acc2 = accuracy_score(y_test, clf2.predict(X_test_s))
print(f'非标准化: {acc1:.4f}')
print(f'标准化: {acc2:.4f}')