private void graphPicture_MouseClick(object sender, MouseEventArgs e)
        {
            float      x          = (float)e.X;
            float      y          = (float)e.Y;
            PictureBox pictureBox = sender as PictureBox;

            if (pictureBox.Image == null)
            {
                return;
            }

            double[] testData = new double[] {
                x / graphDrawer.getFactorX(),
                y / graphDrawer.getFactorY()
            };
            if (irisSet.normalized)             //Normalize testData if data set is.
            {
                testData = irisSet.norm(testData, features);
            }

            int newClass = (int)machine.classify(testData);

            int brushIndex = Array.IndexOf(target, newClass);

            SolidBrush[] brushes = new SolidBrush[] {
                irisBrushes[(int)numClassOne.Value - 1],
                irisBrushes[(int)numClassTwo.Value - 1],
            };

            graphDrawer.drawPoint(x, y, brushes[brushIndex]);
        }