@@ -749,6 +749,9 @@ def predict(Theta1,Theta2,X):
749749 ![ enter description here] [ 35 ]
750750 - 最后` 10 ` 步之后的聚类中心
751751 ![ enter description here] [ 36 ]
752+
753+ -
754+
752755- 计算每条数据到哪个中心最近实现代码:
753756```
754757# 找到每条数据距离哪个类中心最近
@@ -785,11 +788,8 @@ def computerCentroids(X,idx,K):
785788### 2、目标函数
786789- 也叫做** 失真代价函数**
787790- ![ J({c^{(1)}}, \cdots ,{c^{(m)}},{u_1}, \cdots ,{u_k}) = \frac{1}{m}\sum\limits_ {i = 1}^m {||{x^{(i)}} - {u_ {{c^{(i)}}}}|{|^2}} ] ( http://chart.apis.google.com/chart?cht=tx&chs=1x0&chf=bg,s,FFFFFF00&chco=000000&chl=J%28%7Bc%5E%7B%281%29%7D%7D%2C%20%5Ccdots%20%2C%7Bc%5E%7B%28m%29%7D%7D%2C%7Bu_1%7D%2C%20%5Ccdots%20%2C%7Bu_k%7D%29%20%3D%20%5Cfrac%7B1%7D%7Bm%7D%5Csum%5Climits_%7Bi%20%3D%201%7D%5Em%20%7B%7C%7C%7Bx%5E%7B%28i%29%7D%7D%20-%20%7Bu_%7B%7Bc%5E%7B%28i%29%7D%7D%7D%7D%7C%7B%7C%5E2%7D%7D%20 )
788- - 最后我们想得到:
789- ![ \mathop {\min }\limits_ \begin{subarray}{l}
790- {c^{(1)}}, \cdots ,{c^{(m)}} \\
791- {u_1}, \cdots ,{u_k}
792- \end{subarray} J({c^{(1)}}, \cdots ,{c^{(m)}},{u_1}, \cdots ,{u_k})] ( http://chart.apis.google.com/chart?cht=tx&chs=1x0&chf=bg,s,FFFFFF00&chco=000000&chl=%5Cmathop%20%7B%5Cmin%20%7D%5Climits_%5Cbegin%7Bsubarray%7D%7Bl%7D%20%0A%20%20%7Bc%5E%7B%281%29%7D%7D%2C%20%5Ccdots%20%2C%7Bc%5E%7B%28m%29%7D%7D%20%5C%5C%20%0A%20%20%7Bu_1%7D%2C%20%5Ccdots%20%2C%7Bu_k%7D%20%0A%5Cend%7Bsubarray%7D%20%20J%28%7Bc%5E%7B%281%29%7D%7D%2C%20%5Ccdots%20%2C%7Bc%5E%7B%28m%29%7D%7D%2C%7Bu_1%7D%2C%20%5Ccdots%20%2C%7Bu_k%7D%29 )
791+ - 最后我们想得到:
792+ ![ enter description here] [ 37 ]
793793- 其中![ {c^{(i)}}] ( http://chart.apis.google.com/chart?cht=tx&chs=1x0&chf=bg,s,FFFFFF00&chco=000000&chl=%7Bc%5E%7B%28i%29%7D%7D ) 表示第` i ` 条数据距离哪个类中心最近,
794794- 其中![ {u_i}] ( http://chart.apis.google.com/chart?cht=tx&chs=1x0&chf=bg,s,FFFFFF00&chco=000000&chl=%7Bu_i%7D ) 即为聚类的中心
795795
@@ -813,7 +813,7 @@ def kMeansInitCentroids(X,K):
813813- 聚类是不知道y的label的,所以不知道真正的聚类个数
814814- 肘部法则(Elbow method)
815815 - 作代价函数` J ` 和` K ` 的图,若是出现一个拐点,如下图所示,` K ` 就取拐点处的值,下图此时` K=3 `
816- ![ enter description here] [ 37 ]
816+ ![ enter description here] [ 38 ]
817817 - 若是很平滑就不明确,人为选择。
818818- 第二种就是人为观察选择
819819
@@ -858,19 +858,16 @@ def runKMeans(X,initial_centroids,max_iters,plot_process):
858858
859859### 7、运行结果
860860- 二维数据类中心的移动
861- ![ enter description here] [ 38 ]
862- - 图片压缩
863861![ enter description here] [ 39 ]
862+ - 图片压缩
863+ ![ enter description here] [ 40 ]
864864
865865
866866----------------------
867867
868868六、主成分分析(降维)
869869
870870
871-
872-
873-
874871 [ 1 ] : ./images/LinearRegression_01.png " LinearRegression_01.png "
875872 [ 2 ] : ./images/LogisticRegression_01.png " LogisticRegression_01.png "
876873 [ 3 ] : ./images/LogisticRegression_02.png " LogisticRegression_02.png "
@@ -907,6 +904,7 @@ def runKMeans(X,initial_centroids,max_iters,plot_process):
907904 [ 34 ] : ./images/K-Means_01.png " K-Means_01.png "
908905 [ 35 ] : ./images/K-Means_02.png " K-Means_02.png "
909906 [ 36 ] : ./images/K-Means_03.png " K-Means_03.png "
910- [ 37 ] : ./images/K-Means_04.png " K-Means_04.png "
911- [ 38 ] : ./images/K-Means_05.png " K-Means_05.png "
912- [ 39 ] : ./images/K-Means_06.png " K-Means_06.png "
907+ [ 37 ] : ./images/K-Means_07.png " K-Means_07.png "
908+ [ 38 ] : ./images/K-Means_04.png " K-Means_04.png "
909+ [ 39 ] : ./images/K-Means_05.png " K-Means_05.png "
910+ [ 40 ] : ./images/K-Means_06.png " K-Means_06.png "
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