Function generate_data

examples/multiclass_classification_ex.cpp:185–245

// ----------------------------------------------------------------------------------------

void generate_data (
    std::vector<sample_type>& samples,
    std::vector<double>& labels
)
{
    const long num = 50;

    sample_type m;

    dlib::rand rnd;


    // make some samples near the origin
    double radius = 0.5;
    for (long i = 0; i < num+10; ++i)
    {
        double sign = 1;
        if (rnd.get_random_double() < 0.5)
            sign = -1;
        m(0) = 2*radius*rnd.get_random_double()-radius;
        m(1) = sign*sqrt(radius*radius - m(0)*m(0));

        // add this sample to our set of training samples 
        samples.push_back(m);
        labels.push_back(1);
    }

    // make some samples in a circle around the origin but far away
    radius = 10.0;
    for (long i = 0; i < num+20; ++i)
    {
        double sign = 1;
        if (rnd.get_random_double() < 0.5)
            sign = -1;
        m(0) = 2*radius*rnd.get_random_double()-radius;
        m(1) = sign*sqrt(radius*radius - m(0)*m(0));

        // add this sample to our set of training samples 
        samples.push_back(m);
        labels.push_back(2);
    }

    // make some samples in a circle around the point (25,25) 
    radius = 4.0;
    for (long i = 0; i < num+30; ++i)
    {
        double sign = 1;
        if (rnd.get_random_double() < 0.5)
            sign = -1;
        m(0) = 2*radius*rnd.get_random_double()-radius;
        m(1) = sign*sqrt(radius*radius - m(0)*m(0));

        // translate this point away from the origin
        m(0) += 25;
        m(1) += 25;

        // add this sample to our set of training samples 
        samples.push_back(m);