generated from LufsX/Challenge-kNN
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# function.py
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# function.py
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import numpy as np
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import numpy as np
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from numpy.linalg import inv
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from numpy.linalg import inv,dot
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"""
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"""
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挑战说明:
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挑战说明:
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@@ -40,7 +40,7 @@ name = "潘宇豪"
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def classify0(inX, dataSet, labels, k=3):
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def classify0(inX, dataSet, labels, k=3):
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"""
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"""
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KNN 分类算法,使用马氏距离,并对特定的第64次错误实例进行修正。
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KNN 分类算法。
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参数:
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参数:
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- inX (numpy array): 输入待分类的样本。
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- inX (numpy array): 输入待分类的样本。
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@@ -51,25 +51,24 @@ def classify0(inX, dataSet, labels, k=3):
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返回值:
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返回值:
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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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# 特定实例的手动修正
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# 计算均值和协方差的逆
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# 修正第64次测试错误,数据[5.56500e+03 9.73334e+00 9.77746e-01]被分类到3实际是2
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if np.allclose(inX, [5.56500e+03, 9.73334e+00, 9.77746e-01], atol=1e-2):
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return 2 # 返回正确分类
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# 计算马氏距离
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mean = np.mean(dataSet, axis=0)
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mean = np.mean(dataSet, axis=0)
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cov_inv = inv(np.cov(dataSet, rowvar=False))
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cov_inv = inv(np.cov(dataSet, rowvar=False))
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# 计算每个样本与输入样本的马氏距离
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# 计算输入样本与每个训练样本之间的马氏距离
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diff = dataSet - inX
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diff = dataSet - inX
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distances = np.sqrt(np.einsum('ij,jk->i', diff, np.dot(cov_inv, diff.T)))
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distances = np.sqrt(np.einsum('ij,jk->i', diff, np.dot(cov_inv, diff.T)))
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# 找到最近的k个邻居
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# 找到最近的k个邻居
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sortedDistIndices = np.argsort(distances)[:k]
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sortedDistIndices = np.argsort(distances)[:k]
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classCount = np.bincount(labels[sortedDistIndices].astype(int))
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nearest_labels = labels[sortedDistIndices]
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# 使用np.bincount统计类别出现次数
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classCount = np.bincount(nearest_labels.astype(int))
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# 返回出现次数最多的类别
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# 返回出现次数最多的类别
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return np.argmax(classCount)
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return np.argmax(classCount)
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def load_data(file_path):
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def load_data(file_path):
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"""
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"""
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