generated from LufsX/Challenge-kNN
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-16
@@ -39,20 +39,14 @@ name = "陈垣豪"
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- int: 预测的分类标签。
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- int: 预测的分类标签。
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"""
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"""
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def classify0(inX, dataSet, labels, k=3):
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def classify0(inX, 数据集, 标签, k=3):
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# Normalize the dataset
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dataSet_mean = np.mean(dataSet, axis=0)
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dataSet_std = np.std(dataSet, axis=0)
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normalized_dataSet = (dataSet - dataSet_mean) / dataSet_std
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normalized_inX = (inX - dataSet_mean) / dataSet_std
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# 计算协方差矩阵并求其逆矩阵
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# 计算协方差矩阵并求其逆矩阵
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cov_matrix = np.cov(normalized_dataSet, rowvar=False)
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cov_matrix = np.cov(数据集,rowvar=False)
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inv_cov_matrix = np.linalg.inv(cov_matrix)
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inv_cov_matrix = np.linalg.inv(cov_matrix)
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# 计算马氏距离
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# 计算马氏距离
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diff = normalized_dataSet - normalized_inX
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diff = dataSet - inX
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distances = np.einsum('ij,jk->i', diff, inv_cov_matrix @ diff.T) # 使用 einsum 简化计算
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distances = np.sum(diff @ inv_cov_matrix * diff, axis=1)
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# 获取距离最小的 k 个样本的索引
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# 获取距离最小的 k 个样本的索引
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sorted_indices = np.argsort(distances)[:k]
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sorted_indices = np.argsort(distances)[:k]
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@@ -62,15 +56,13 @@ def classify0(inX, dataSet, labels, k=3):
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# 统计 k 个最近邻中每个类别的出现次数
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# 统计 k 个最近邻中每个类别的出现次数
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label_count = {}
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label_count = {}
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weights = 1 / (distances[sorted_indices] + 1e-10) # Avoid division by zero
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for label in nearest_labels:
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for i, label in enumerate(nearest_labels):
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if label in label_count:
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if label in label_count:
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label_count[label] += weights[i]
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label_count[label] += 1
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else:
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else:
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label_count[label] = weights[i]
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label_count[label] = 1
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# 找到出现次数最多的标签
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# 找到出现次数最多的标签
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predicted_label = max(label_count, key=label_count.get)
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predicted_label = max(label_count, key=label_count.get)
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return predicted_label
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return predicted_label提高准确率
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