/***********************************
* Function: create_circle
* -----------------------
* Creates a circular distribution (radius 1) of POS and NEG values, with
* num_pos POS values inside a radius=1/2, and num_neg NEG values outside that
* radius
*/
TrainingData create_circle(int num_pos, int num_neg){
// create TrainingData object (circle, dimension 2)
TrainingData circle;
// create positive distribution within radius=1/2
vector <float> coord;
float radius, theta;
for (int i=0; i<num_pos; i++){
// get radius and angle
radius = sqrt((float)rand()/RAND_MAX)/2;
theta = 2*M_PI*(float)rand()/RAND_MAX;
// convert to x and y
coord.push_back(radius * cos(theta));
coord.push_back(radius * sin(theta));
coord.push_back(5.0f);
//coord.push_back(coord[0]*coord[0] + coord[1]*coord[1]);
FeatureVector fv(coord, POS);
circle.addFeature(fv);
coord.clear();
}
// create negative distribution for 1/2 <= radius <= 1
for (int i=num_pos; i<num_pos+num_neg; i++){
// get radius and angle
radius = sqrt(3*(float)rand()/RAND_MAX+1)/2;
theta = 2*M_PI*(float)rand()/RAND_MAX;
// convert to x and y
coord.push_back(radius * cos(theta));
coord.push_back(radius * sin(theta));
coord.push_back(1.5f);
//coord.push_back(coord[0]*coord[0] + coord[1]*coord[1]);
FeatureVector fv(coord, NEG);
circle.addFeature(fv);
coord.clear();
}
return circle;
}
