采MC-UVE写一个光谱特征选择python函数,带注释
时间: 2023-03-31 20:03:09 浏览: 201
好的,我可以回答这个问题。以下是采用MC-UVE算法编写的光谱特征选择Python函数,带注释:
```python
import numpy as np
from sklearn.preprocessing import MinMaxScaler
def mc_uve(X, y, k=10, alpha=.5):
"""
MC-UVE算法:基于互信息的光谱特征选择方法
参数:
X: array-like, shape (n_samples, n_features)
输入数据,每行为一个样本,每列为一个特征
y: array-like, shape (n_samples,)
标签数据,每个元素为一个样本的类别标签
k: int, optional (default=10)
进行k折交叉验证的k值
alpha: float, optional (default=.5)
MC-UVE算法中的超参数,控制特征选择的严格程度
返回值:
selected_features: array-like, shape (n_selected_features,)
选择出的特征的下标
"""
# 数据归一化
scaler = MinMaxScaler()
X = scaler.fit_transform(X)
# 计算互信息
n_samples, n_features = X.shape
mi = np.zeros(n_features)
for i in range(n_features):
mi[i] = mutual_info(X[:, i], y)
# 计算特征权重
w = np.zeros(n_features)
for i in range(n_features):
w[i] = np.sum(mi) - mi[i]
# 进行k折交叉验证,选择特征
selected_features = []
for i in range(k):
# 将数据分成训练集和测试集
train_X, test_X, train_y, test_y = train_test_split(X, y, test_size=1/k, random_state=i)
# 计算训练集的互信息
train_mi = np.zeros(n_features)
for j in range(n_features):
train_mi[j] = mutual_info(train_X[:, j], train_y)
# 计算训练集的特征权重
train_w = np.zeros(n_features)
for j in range(n_features):
train_w[j] = np.sum(train_mi) - train_mi[j]
# 选择特征
selected = np.argsort(train_w)[-1]
for j in range(2, n_features+1):
if train_w[selected] - train_w[np.argsort(train_w)[-j]] > alpha * np.sum(train_w) / n_features:
selected = np.argsort(train_w)[-j]
else:
break
selected_features.append(selected)
# 返回选择出的特征的下标
return np.array(selected_features)
```
希望这个函数对您有所帮助。
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