kmeans_example.cpp

#include <ctime>
#include <cstddef>
#include <algorithm>
#include <iostream>
#include "kmeans.hpp"

static const std::size_t nPoints = 50000;
static const std::size_t nClusters = 100;

struct Point
{
    typedef float field_type;

    float m_x, m_y, m_z;

    Point& operator=(const Point& point)
    {
        m_x = point.m_x;
        m_y = point.m_y;
        m_z = point.m_z;

        return *this;
    }

    Point& operator+=(const Point& point)
    {
        m_x += point.m_x;
        m_y += point.m_y;
        m_z += point.m_z;

        return *this;
    }

    Point& operator/=(float k)
    {
        m_x /= k;
        m_y /= k;
        m_z /= k;

        return *this;
    }
};

struct Distance
{
    typedef float return_type;
    typedef Point argument_type;

    float operator()(const Point& lhs, const Point& rhs)
    {
        return (lhs.m_x - rhs.m_x) * (lhs.m_x - rhs.m_x) +
               (lhs.m_y - rhs.m_y) * (lhs.m_y - rhs.m_y) +
               (lhs.m_z - rhs.m_z) * (lhs.m_z - rhs.m_z);
    }
};

struct Hasher
{
    std::size_t operator()(const Point& point)
    {
        return ((reinterpret_cast<const char&>(point.m_x)) <<  0) +
               ((reinterpret_cast<const char&>(point.m_y)) <<  8) +
               ((reinterpret_cast<const char&>(point.m_z)) << 16);
    }
};

struct RandomPointGenerator
{
    RandomPointGenerator()
    {
        srand(time(NULL));
    }
    
    Point operator()()
    {
        Point p;
        p.m_x = rand() / static_cast<float>(RAND_MAX);
        p.m_y = rand() / static_cast<float>(RAND_MAX);
        p.m_z = rand() / static_cast<float>(RAND_MAX);

        return p;
    }
};

int main()
{
    typedef kmeans::Algorithm<Distance, Hasher> KMeansAlgorithm;

    std::vector<Point> pointSet(nPoints);
    KMeansAlgorithm kmeansAlgorithm;

    std::generate(pointSet.begin(), pointSet.end(), RandomPointGenerator());
    kmeansAlgorithm(pointSet.begin(), pointSet.end(), nClusters);

    for (KMeansAlgorithm::clusters_iterator it = kmeansAlgorithm.m_clusters.begin();
                                            it != kmeansAlgorithm.m_clusters.end();
                                            it++)
    {
        std::cout << it->m_x << ", "
                  << it->m_y << ", "
                  << it->m_z << std::endl;
    }
    std::cout << std::getchar();

    return 0;
}