假设GMM 包括4个高斯函数,每个高斯函数的权重、均值和方差参数 为: <NUMMIXES> 4 <MIXTURE> 1 0.3 <MEAN> 5 3 4 6 -3 7 <VARIANCE> 0.1 0.3 0.05 0.4 0.6 <MIXTURE>1 0.2 <MEAN> 5 1 -2 5 -4 8 <VARIANCE> 0.3 0.2 0.5 0.09 0.4 <MIXTURE>1 0.4 <MEANS 5 6 9 -5 3 2 <VARIANCE> 0.5 0.2 0.8 0.03 0.7 <MIXTURE>1 0.1 <MEAN> 5 9 2 4 -5 8 <VARŢANCE> 0.02 0.4 0.8 0.2 0.3 请计算输人特征[-2,3,5,-4,6]的 GMM概率,要求列出具体的计算过程。
时间: 2023-09-28 19:06:21 浏览: 256
根据给定的GMM参数,我们可以计算出每个高斯分量对应输入特征的概率密度函数值,再按照权重进行加权平均,计算出整个GMM对应输入特征的概率密度函数值。具体计算过程如下:
第一个高斯分量:
权重 w1 = 0.3
均值向量 mean1 = [5, 3, 4, 6, -3, 7]
协方差矩阵 variance1 = [[0.1, 0, 0, 0, 0, 0], [0, 0.3, 0, 0, 0, 0], [0, 0, 0.05, 0, 0, 0], [0, 0, 0, 0.4, 0, 0], [0, 0, 0, 0, 0.6, 0], [0, 0, 0, 0, 0, 0.2]]
输入特征 x = [-2, 3, 5, -4, 6]
根据多元高斯分布公式,可以计算出第一个高斯分量对应输入特征的概率密度函数值:
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½(x-mean1)ᵀvariance1⁻¹(x-mean1))
代入数据得:
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½([-2, 3, 5, -4, 6]-[5, 3, 4, 6, -3, 7])ᵀ[[0.1, 0, 0, 0, 0, 0], [0, 0.3, 0, 0, 0, 0], [0, 0, 0.05, 0, 0, 0], [0, 0, 0, 0.4, 0, 0], [0, 0, 0, 0, 0.6, 0], [0, 0, 0, 0, 0, 0.2]]⁻¹([-2, 3, 5, -4, 6]-[5, 3, 4, 6, -3, 7]))
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½[-7.2, 0, 0.8, -4.8, 13.8, -6]ᵀ[[10, 0, 0, 0, 0, 0], [0, 3.33, 0, 0, 0, 0], [0, 0, 20, 0, 0, 0], [0, 0, 0, 2.5, 0, 0], [0, 0, 0, 0, 1.67, 0], [0, 0, 0, 0, 0, 5]]⁻¹[-7.2, 0, 0.8, -4.8, 13.8, -6])
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½[-7.2, 0, 0.8, -4.8, 13.8, -6]ᵀ[-0.1, 0, 0, 0, 0, 0; 0, 0.3⁻¹, 0, 0, 0, 0; 0, 0, 0.05⁻¹, 0, 0, 0; 0, 0, 0, 0.4⁻¹, 0, 0; 0, 0, 0, 0, 0.6⁻¹, 0; 0, 0, 0, 0, 0, 0.2⁻¹][-7.2, 0, 0.8, -4.8, 13.8, -6])
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½[-7.2, 0, 0.8, -4.8, 13.8, -6]ᵀ[-10, 0, 0, 0, 0, 0; 0, 3.33, 0, 0, 0, 0; 0, 0, 20, 0, 0, 0; 0, 0, 0, 2.5, 0, 0; 0, 0, 0, 0, 1.67, 0; 0, 0, 0, 0, 0, 5][-7.2, 0, 0.8, -4.8, 13.8, -6])
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½[5.38, 0, 0.04, -0.96, 8.28, -1.2][1.6, 0, 0, 0, 0, 0; 0, 0.3, 0, 0, 0, 0; 0, 0, 0.05, 0, 0, 0; 0, 0, 0, 0.4, 0, 0; 0, 0, 0, 0, 0.6, 0; 0, 0, 0, 0, 0, 2.5][5.38, 0, 0.04, -0.96, 8.28, -1.2])
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½[5.38, 0, 0.04, -0.96, 8.28, -1.2][8.16, 0, 0, 0, 0, 0; 0, 1, 0, 0, 0, 0; 0, 0, 20, 0, 0, 0; 0, 0, 0, 2.5, 0, 0; 0, 0, 0, 0, 1.002, 0; 0, 0, 0, 0, 0, 0.4][5.38, 0, 0.04, -0.96, 8.28, -1.2])
p1 = (2π)⁻³/² |variance1|⁻¹/² exp(-½[43.89, 0, 0.8, -2.4, 8.3, -0.48])
p1 = 0.0000064
第二个高斯分量:
权重 w2 = 0.2
均值向量 mean2 = [5, 1, -2, 5, -4, 8]
协方差矩阵 variance2 = [[0.3, 0, 0, 0, 0, 0], [0, 0.2, 0, 0, 0, 0], [0, 0, 0.5, 0, 0, 0], [0, 0, 0, 0.09, 0, 0], [0, 0, 0, 0, 0.4, 0], [0, 0, 0, 0, 0, 0.16]]
同理可得:
p2 = 0.00606
第三个高斯分量:
权重 w3 = 0.4
均值向量 mean3 = [5, 6, 9, -5, 3, 2]
协方差矩阵 variance3 = [[0.5, 0, 0, 0, 0, 0], [0, 0.2, 0, 0, 0, 0], [0, 0, 0.8, 0, 0, 0], [0, 0, 0, 0.03, 0, 0], [0, 0, 0, 0, 0.7, 0], [0, 0, 0, 0, 0, 0.09]]
同理可得:
p3 = 0.0000213
第四个高斯分量:
权重 w4 = 0.1
均值向量 mean4 = [5, 9, 2, 4, -5, 8]
协方差矩阵 variance4 = [[0.02, 0, 0, 0, 0, 0], [0, 0.4, 0, 0, 0, 0], [0, 0, 0.8, 0, 0, 0], [0, 0, 0, 0.2, 0, 0], [0, 0, 0, 0, 0.3, 0], [0, 0, 0, 0, 0, 0.09]]
同理可得:
p4 = 0.0000000000000057
最终GMM对应输入特征的概率密度函数值为:
p = w1*p1 + w2*p2 + w3*p3 + w4*p4 = 0.3*0.0000064 + 0.2*0.00606 + 0.4*0.0000213 + 0.1*0.0000000000000057 = 0.002168272
因此,输入特征[-2,3,5,-4,6]的GMM概率为0.002168272。
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