k均值聚类

结果和中心的初始有关

#include<stdio.h>
#include<MATH.H>

#define DGREE 2 //维度
#define SAMPLENUM 10 //样本数量
#define K 3 //分类个数

typedef struct
{
	int v[DGREE]; //向量
	int classify; //分类
}sample;
//欧式距离
double getDis(const sample *a,double *center)
{
	int i=0;
	double dis=0;
	for (i=0;i<DGREE;++i)
	{
		dis = pow((a->v[i] - center[i]),2);
	}
	return pow(dis,0.5);
}
//获取最小值下标
int getMinTip(double *dis)
{
	int i=0,j=0;
	double temp = dis[0];
	for (i=0;i<K;++i)
	{
		if (dis[i]<=temp)
		{
			temp = dis[i];
			j=i;
		}
	}
	return j;
}
//计算聚类中心
void getClassCenter(const sample *s,double center[K][DGREE])
{
	int i=0,j=0,k=0,count=0,sum[DGREE]={0};
	for (i=0;i<K;++i)
	{
		count=0;
		for (j=0;j<DGREE;++j) sum[j]=0;
		for (k=0;k<SAMPLENUM;++k)
		{
			if (s[k].classify == i)
			{
				count++;
				for (j=0;j<DGREE;++j)
				{
					sum[j] += s[k].v[j];
				}
			}
		}
		for (j=0;j<DGREE;++j)
		{
			if (count == 0)
			{
				center[i][j] = 0.0;
			}
			else{
				center[i][j] = (double)sum[j]/(double)count;
			}
		}
	}
}

int isClassOk(double center[K][DGREE],double oldCenter[K][DGREE])
{
	int i,j;
	for (i=0;i<K;++i)
	{
		for (j=0;j<DGREE;++j)
		{
			if (fabs(center[i][j]-oldCenter[i][j]) >0.000000001)
			{
				return 0;
			}
		}
	}
	return 1;
}

void printResult(const sample *s,double center[K][DGREE])
{
	int i,j,k;
	for (i=0;i<K;++i)
	{
		printf("class-------%d\n",i);
		printf("center------: ");
		for (j=0;j<DGREE;++j) printf("%f ",center[i][j]);
		printf("\n");
		for (k=0;k<SAMPLENUM;++k)
		{
			if (s[k].classify == i)
			{
				printf("(");
				for (j=0;j<DGREE;++j) printf("%d ",s[k].v[j]);
				printf(")\t");
			}
		}
		printf("\n\n");
	}
}

//分类
void getClass(sample *s,double center[K][DGREE])
{
	double dis[K] = {0};
	double  tempCenter[K][DGREE] = {0};
	int i,j,k;//test=0;

	while (!isClassOk(center,tempCenter))
	{
		for (k=0;k<SAMPLENUM;++k)
		{
			for (i=0;i<K;++i)
			{
				dis[i] = getDis(&s[k],center[i]);
			}
			s[k].classify = getMinTip(dis);
		}
		for (i=0;i<K;++i) 
		{
			for (j=0;j<DGREE;++j)
			{
				tempCenter[i][j] = center[i][j];
			}
		}
		getClassCenter(s,center);
		//printf("%d\n",test++);
	//	printResult(s,center);
	}
}

int main(int argc, char* argv[])
{
	sample s[SAMPLENUM] ={{{0,0},0},{{1,1},0},{{2,1},0},{{4,3},0},{{5,3},0},{{5,4},0},{{6,5},0},{{1,4},0},{{1,5},0},{{1,6},0}};
	double center[K][DGREE] = {{0,0},{1,5},{5,4}};
	getClass(s,center);
	printResult(s,center);
	return 0;
}