简易kmeans-c++版本

typedef double dtype;
主要接口：
void Kmeans(const vector<vector<dtype> > &d,int k,string distype,vector<vector<int> > &kset,map<int,int> &category,vector<vector<dtype> > &kcenter)

参数：
vector<vector<dtype> > &d： 数据矩阵mxn
int k：聚类类别数目
string distype：距离类别,"sqeuclidean"表示欧式距离，"cosine"表示余弦距离，"hamming"表示海明距
vector<vector<int> > &kset：初始化K个中心
map<int,int> &category：返回的类别号
vector<vector<dtype> > &kcenter：返回的类别中心

double SSE(const vector<vector<dtype> > &matrix,const vector<vector<dtype> > &kcenter,map<int,int> &category,string distype,map<int,double> &EverySSE)
返回总的误差平方和，map<int,double> &EverySSE返回每个类的误差平方和

#include<iostream>
#include<vector>
#include<map>
#include<algorithm>
#include<cmath>
#include<fstream>
#include<string>
#include<assert.h>
#include<stdlib.h>
#include<time.h>
int const N = 1000;
int const eps = 1e-3;
using namespace std;
typedef double dtype;
typedef vector<int>::size_type vt;
double disfun(const vector<dtype> &a,const vector<dtype> &b,string distype)
{
    double dis_sum=0;
    if(distype=="sqeuclidean")
    {
        for(vt i=0;i<a.size();++i)
            dis_sum+=pow(a[i]-b[i],2);
    }
    if(distype=="cosine")
    {
        double len_a=0,len_b=0,in_product=0;
        for(vt i=0;i<a.size();++i)
        {
            len_a+=pow(a[i],2);
            len_b+=pow(b[i],2);
            in_product+=a[i]*b[i];
        }
        dis_sum = 1-in_product*1.0/(sqrt(len_a)*sqrt(len_b));
    }
    if(distype=="hamming")
    {
        int count=0;
        for(vt i=0;i<a.size();++i)
        {
            if(a[i]!=b[i])count++;
        }
        dis_sum = count*1.0/a.size();
    }
    return dis_sum;
}
vector<int> random_chooseK(const int n,int k)
{
    map<int,int> mvis;
    vector<int> vec;
    int i=0;
    cout<<"n:"<<n<<"k:"<<k<<endl;
    cout<<"random choose K ok"<<endl;
    srand((unsigned)time(NULL));
    while(i<k)
    {
        int tmp=rand()%(n);
        if(!mvis.count(tmp)){
            mvis[tmp]=1;
            vec.push_back(tmp);
            i++;
        }
    }
    for(int &i:vec)cout<<i<<"->";
    cout<<"random choose K over"<<endl;
    return vec;
}
bool nochange(const vector<vector<dtype> > &kcenter,const vector<vector<dtype> > &prekcenter)
{
    for(int i=0;i<kcenter.size();++i)
    {
        string st("sqeuclidean");
        if(disfun(kcenter[i],prekcenter[i],st)>eps)return false;
    }
    return true;
}
vector<dtype> sum_vector(const vector<dtype> &a,const vector<dtype> &b)
{
    vector<dtype> avec;
    assert(a.size()==b.size());
    for(int i=0;i<a.size();++i)
    {
        avec.push_back(a[i]+b[i]);
    }
    return avec;
}
void setZero(vector<dtype> &vec)
{
    for(int i=0;i<vec.size();++i)
    {
        vec[i]=0;
    }
}
void AlterKcenter(const vector<vector<dtype> > &d,vector<vector<dtype> > &kcenter,const vector<vector<int> > &kset,string distype)
{
    for(int i=0;i<kcenter.size();++i)
    {
        setZero(kcenter[i]);
        cout<<i<<":"<<kset[i].size()<<endl;
        for(int j=0;j<kset[i].size();++j)
        {
            kcenter[i] = sum_vector(d[kset[i][j]],kcenter[i]);
        }
        for(int p=0;p<kcenter[i].size();++p)
        {
            if(distype=="hamming")
                kcenter[i][p]=int(kcenter[i][p]*1.0/kset[i].size()+0.5);
            else kcenter[i][p]=kcenter[i][p]*1.0/kset[i].size();
        }
    }
}
void Kmeans(const vector<vector<dtype> > &d,int k,string distype,vector<vector<int> > &kset,map<int,int> &category,vector<vector<dtype> > &kcenter)
{
    vector<int> kgram=random_chooseK(d.size(),k);
    vector<vector<dtype> > prekcenter;
    //vector<vector<int> > kset;
    for(int i=0;i<k;++i){
        vector<int> vitmp;
        kset.push_back(vitmp);
    }
    cout<<"kset"<<endl;
    for(vt i=0;i<kgram.size();++i)kcenter.push_back(d[kgram[i]]);
    cout<<"kset over"<<endl;
    bool flag =false;
    int count=0;
    while(!flag)
    {
        for(int x=0;x<k;++x)kset[x].clear();
        for(int j=0;j<d.size();++j)
        {
            double min_dis= 1e308;
            int index = -1;
            for(int m =0;m <k;++m)
            {
                double dis=disfun(d[j],kcenter[m],distype);
                if(dis<min_dis)
                {
                    min_dis=dis;
                    index = m;
                }
            }
            kset[index].push_back(j);
            category[j]=index;
        }
        prekcenter = kcenter;
        count++;
        cout<<"alterkcenter begin"<<endl;
        AlterKcenter(d,kcenter,kset,distype);
        cout<<"alterkcenter finished"<<endl;
        flag = nochange(kcenter,prekcenter);
        cout<<"µÚ"<<count<<"´Îµü´ú"<<endl;
    }
}
void printmatrix(const vector<vector<dtype> > &matrix)
{
    for(int i=0;i<matrix.size();++i)
    {
        for(int j=0;j<matrix[i].size();++j)
            cout<<matrix[i][j]<<"  ";
        cout<<endl;
    }
}
double SSE(const vector<vector<dtype> > &matrix,const vector<vector<dtype> > &kcenter,map<int,int> &category,string distype,map<int,double> &EverySSE)
{
    double TotalSSE=0;
    //map<int,double> EverySSE;
    for(int i=0;i<matrix.size();++i)
    {
        double tmpsse=0;
        tmpsse=disfun(matrix[i],kcenter[category[i]],distype);
        if(EverySSE.count(category[i]))
            EverySSE[category[i]]+=tmpsse;
        else EverySSE[category[i]]=tmpsse;
        TotalSSE+=tmpsse;
    }
    return TotalSSE;
}
void saveresult(const vector<vector<dtype> > &matrix,vector<vector<int> > &kset)
{
    fstream f("result.txt",ios::out);
    map<int,int> category;
    cout<<"kset size:"<<kset.size()<<endl;
    f<<"total:"<<endl;
    for(int i=0;i<kset.size();++i){
        f<<"µÚ"<<i<<"Àà:"<<kset[i].size()<<endl;
    }
    for(int i=0;i<kset.size();++i)
    {
        cout<<kset[i].size()<<endl;
        for(int j=0;j<kset[i].size();++j)
            category[kset[i][j]]=i;
    }
    for(int i=0;i<matrix.size();++i)
    {
        f<<i<<": "<<category[i]<<endl;
    }
    for(int i=0;i<matrix.size();++i)
    {
        f<<"----------------------------------"<<category[i]<<"---------------------------------"<<endl;
        for(int j=0;j<matrix[i].size();++j)
            f<<matrix[i][j]<<"  ";
        f<<endl;
    }
    f.close();

}
int main()
{
    vector<vector<dtype> > matrix;
    int all=0;
    srand((unsigned)time(0));
    while(all<600)
    {
        vector<dtype> row;
        for(int n=1;n<=600;++n)
        {
            int tmp=rand()%(2);
            if(rand()/double(RAND_MAX)>0.6)tmp=0;
            //cout<<tmp<<endl;
            row.push_back(tmp);
        }
        matrix.push_back(row);
        all++;
    }
    //printmatrix(matrix);
    vector<vector<int> > kset;
    vector<vector<dtype> > kcenter;
    map<int,int> category;
    string st("hamming");
    Kmeans(matrix,30,st,kset,category,kcenter);
    saveresult(matrix,kset);
    map<int,double> EverySSE;
    cout<<SSE(matrix,kcenter,category,st,EverySSE)<<endl;
    map<int,double>:: const_iterator it=EverySSE.begin();
    while(it!=EverySSE.end()){
        cout<<it->first<<":"<<it->second<<endl;
        it++;
    }
    system("pause");
    return 0;
}