K均值聚类(C++)

  1 #include<math.h>
  2 #include<stdio.h>
  3 #include<stdlib.h>
  4 #include<iostream>
  5 using namespace std;
  6 void kmeans(int n, float* xy, int k, float* cxy)
  7 {
  8     int i,j;
  9     for(i=0;i<k;i++)
 10     {
 11         cxy[2*i]=xy[2*i];
 12         cxy[2*i+1]=xy[2*i+1];
 13     }
 14 
 15     int* mindis=(int*)malloc(n*sizeof(int));
 16     int* premindis=(int*)malloc(n*sizeof(int));
 17     for(i=0;i<n;i++)
 18     {
 19         mindis[i]=-1;
 20     }
 21     int change=1;
 22     
 23     while(change)
 24     {
 25         for(i=0;i<n;i++)
 26         {
 27             premindis[i]=mindis[i];
 28         }
 29         for(i=0;i<n;i++)
 30         {
 31             float min=9999;
 32             for(j=0;j<k;j++)
 33             {
 34                 double s=sqrt((xy[2*i]-cxy[2*j])*(xy[2*i]-cxy[2*j])+(xy[2*i+1]-cxy[2*j+1])*(xy[2*i+1]-cxy[2*j+1]));
 35                 if(s<min)
 36                 {
 37                     min=s;
 38                     mindis[i]=j;
 39                 }
 40             }
 41         }
 42         
 43         /*
 44         for(i=0;i<2;i++)
 45         {
 46             printf("%.3f ",cxy[2*i]);
 47             printf("%.3f\n",cxy[2*i+1]);
 48         }
 49         */
 50         
 51         for(i=0;i<k;i++)
 52         {
 53             int num=0;
 54             float s0=0.0;
 55             float s1=0.0;
 56             //cout<<i<<":";
 57             for(j=0;j<n;j++)
 58             {
 59                 if(mindis[j]==i)
 60                 {
 61                     num++;
 62                     //cout<<j<<" ";
 63                     s0+=xy[2*j];
 64                     s1+=xy[2*j+1];
 65                 }
 66             }
 67             if(num)
 68             {
 69                 cxy[2*i]=s0/num;
 70                 cxy[2*i+1]=s1/num;
 71             }
 72             //cout<<endl;
 73         }
 74         int flag=0;
 75         for(i=0;i<n;i++)
 76         {
 77             if(mindis[i]!=premindis[i])
 78             {
 79                 flag=1;
 80                 break;
 81             }
 82         }
 83         if(flag==0)
 84             change=0;
 85     }
 86 
 87     
 88 }
 89 int main()
 90 {
 91     float xy[12]={1.0, 1.0, 2.0, 1.0, 1.0, 2.0, 4.0, 5.0, 5.0, 4.0, 4.0, 4.0};
 92     float cxy[4]={0.0, 0.0, 0.0, 0.0};
 93     kmeans(6,xy,2,cxy);
 94     int i;
 95     for(i=0;i<2;i++)
 96     {
 97         printf("%.3f ",cxy[2*i]);
 98         printf("%.3f\n",cxy[2*i+1]);
 99     }
100     return 0;
101 }