简易kmeans-c++版本

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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mxnint 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;}

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