更新 function.py

function.py

@@ -1,25 +1,22 @@
-# function.py
 import numpy as np
 from sklearn.preprocessing import StandardScaler
-
+from sklearn.model_selection import KFold
 """
 实验说明:
-- 自行编写实现数据加载与预测病马死亡的对率回归算法。
+  - 自行编写实现数据加载与预测病马死亡的对率回归算法。 
   
-注意事项:
-- 在 function.py 中实现对率回归算法。
-- 可以自行导入其他库，需要在 requirements.txt 添加依赖，若未在 requirements.txt 中添加使用到的依赖，则无法自动评测，成绩为零。
-- 自动评测脚本仅会加载 train_logreg、predict_logreg 和 load_data 函数，请勿修改函数名。
-
-测评环境:
-- CPU: Intel Xeon(R) CPU E3-1231 v3 @ 3.40GHz
-- OS: Ubuntu 22.04.4 LTS
-- Python: 3.10.12
-- numpy: 2.1.1
+ 注意事项:
+ - 在 function.py 中实现对率回归算法。
+ - 可以自行导入其他库，需要在 requirements.txt 添加依赖，若未在 requirements.txt 中添加使用到的依赖，则无法自动评测，成绩为零。
+ - 自动评测脚本仅会加载 train_logreg、predict_logreg 和 load_data 函数，请勿修改函数名。 
+ 测评环境:
+ - CPU: Intel Xeon(R) CPU E3-1231 v3 @ 3.40GHz
+ - OS: Ubuntu 22.04.4 LTS
+ - Python: 3.10.12
+ - numpy: 2.1.1
 """
-
 """
-请在这里填写学号和姓名，不填写即成绩无效。
+ 请在这里填写学号和姓名，不填写即成绩无效。
 """
 id = "202210423117"
 name = "程悦"
@@ -27,82 +24,79 @@ name = "程悦"
 def sigmoid(z):
     return 1.0 / (1 + np.exp(-z))
 
+
 def train_logreg(X, y, learning_rate=0.05,
-                 iterations=1500,
-                 batch_size=64, regularization='L2', lambda_reg=0.05):
+                  iterations=1500,
+                  batch_size=64, regularization='L2', lambda_reg=0.05, cv=5):
     m, n = X.shape
-    weights = np.random.randn(n) * 0.01
-    for i in range(iterations):
-        indices = np.random.permutation(m)
-        X_shuffled = X[indices]
-        y_shuffled = y[indices]
+    kf = KFold(n_splits=cv, shuffle=True)
+    weights_list = []
+    for train_index, val_index in kf.split(X):
+        X_train, X_val = X[train_index], X[val_index]
+        y_train, y_val = y[train_index], y[val_index]
+        weights = np.random.randn(n) * 0.01
+        for i in range(iterations):
+            indices = np.random.permutation(len(X_train))
+            X_shuffled = X_train[indices]
+            y_shuffled = y_train[indices]
+            for j in range(0, len(X_train), batch_size):
+                X_batch = X_shuffled[j:j + batch_size]
+                y_batch = y_shuffled[j:j + batch_size]
+                z = np.dot(X_batch, weights)
+                h = sigmoid(z)
+                gradient = np.dot(X_batch.T, (h - y_batch)) / X_batch.shape[0]
+                if regularization == 'L1':
+                    gradient += lambda_reg * np.sign(weights) / len(y_batch)
+                elif regularization == 'L2':
+                    gradient += (lambda_reg / m) * weights
+                weights -= learning_rate * gradient
+            if i % 100 == 0:
+                learning_rate *= 0.95
+        weights_list.append(weights)
+    return weights_list[-1]
 
-        for j in range(0, m, batch_size):
-            X_batch = X_shuffled[j:j + batch_size]
-            y_batch = y_shuffled[j:j + batch_size]
-            z = np.dot(X_batch, weights)
-            h = sigmoid(z)
-            gradient = np.dot(X_batch.T, (h - y_batch)) / X_batch.shape[0]
-
-            # 添加正则化项
-            if regularization == 'L1':
-                gradient += lambda_reg * np.sign(weights) / len(y_batch)
-            elif regularization == 'L2':
-                gradient += (lambda_reg / m) * weights
-
-            weights -= learning_rate * gradient
-
-        if i % 100 == 0:
-            learning_rate *= 0.95
-
-    return weights
 
 def predict_logreg(inX, weights):
     z = np.dot(inX, weights)
     h = sigmoid(z)
     return 1 if h > 0.5 else 0
 
+
 def load_data(filepath):
-    """加载数据并处理缺失值。"""
     data, labels = [], []
-
     with open(filepath, 'r') as f:
-        for line in f:
-            values = line.strip().replace('?', '0').split()
-            try:
-                values = [float(v) for v in values]
-
-                # 合并特征23的取值
-                if values[22] in [2, 3]:  # 特征23索引(22)
-                    labels.append(0)  # 死亡
-                elif values[22] == 1:
-                    labels.append(1)  # 生存
-                else:
-                    continue  # 无效标签，丢弃
-
-                # 用0填充缺失值并提取特征
-                data.append([0 if v == 0 else v for v in values[:2] + values[3:23]])  # 保留特征1, 2 和特征4-23
-            except ValueError:
-                continue
+        for line in f.readlines():
+            line = line.strip().split()
+            if len(line) >= 1 and line[-1].isdigit():
+                line_data = [1] + [0 if x == '?' else float(x) for x in line[:-1]]
+                data.append(line_data)
+                labels.append(int(line[-1]))
 
     data = np.array(data)
     labels = np.array(labels)
 
-    # 数据标准化
+    target_variable = labels
+    target_variable[(target_variable == 2) | (target_variable == 3)] = 0
+
+    data = np.delete(data, [2] + list(range(23, 28)), axis=1)
+
     scaler = StandardScaler()
     data = scaler.fit_transform(data)
 
-    return data, labels
+    return data, target_variable
+
 
 def accuracy(X, y, weights):
     predictions = [predict_logreg(x, weights) for x in X]
     return np.mean(predictions == y)
 
-if __name__ == "__main__":
-    X_train, y_train = load_data("./horse-colic.data")
-    X_test, y_test = load_data("./horse-colic.test")
 
-    final_weights = train_logreg(X_train, y_train, learning_rate=0.01, iterations=5000, batch_size=32, regularization='None', lambda_reg=0.01)
+if __name__ == "__main__":
+    X_train, y_train = load_data("./horse - colic.data")
+    X_test, y_test = load_data("./horse - colic.test")
+
+    final_weights = train_logreg(X_train, y_train, learning_rate=0.01, iterations=5000, batch_size=32, regularization='None',
+                                 lambda_reg=0.01)
 
     final_accuracy = accuracy(X_test, y_test, final_weights)
     print(f"最终测试集的准确率: {final_accuracy:.4f}")