Method getHalfCircles

JSAT/test/jsat/FixedProblems.java:222–238

(int dataSetSize, Random rand, double... radi )

    }
    
    public static ClassificationDataSet getHalfCircles(int dataSetSize, Random rand, double... radi )
    {
        ClassificationDataSet train = new ClassificationDataSet(2, new CategoricalData[0], new CategoricalData(radi.length));
        
        int n = dataSetSize/2 ;

        for(int r_i = 0; r_i < radi.length; r_i++)
            for (int i = 0; i < n; i++)
            {
                double t = 2 * Math.PI * (i/2) / n;
                double x = radi[r_i] * Math.cos(t) + (rand.nextDouble() - 0.5) / 5;
                double y = radi[r_i] * Math.sin(t) + (rand.nextDouble() - 0.5) / 5;
                train.addDataPoint(DenseVector.toDenseVec(x, y), new int[0], r_i);
            }

        return train;
    }
}