question: @ Override public Instance generateExample ( ) throws Exception { Instance result ; int centroid ; double [ ] atts ; double magnitude ; double desiredMag ; double scale ; int i ; double label ; Random rand ; result = null ; rand = getRandom ( ) ; if ( m_DatasetFormat == null ) { throw new Exception ( "Dataset format not defined." ) ; } centroid = chooseRandomIndexBasedOnProportions ( m_centroidWeights , rand ) ; label = m_centroidClasses [ centroid ] ; atts = new double [ getNumAttributes ( ) + 1 ] ; for ( i = 0 ; i < getNumAttributes ( ) ; i ++ ) { atts [ i ] = ( rand . nextDouble ( ) * 2.0 ) - 1.0 ; } atts [ atts . length - 1 ] = label ; magnitude = 0.0 ; for ( i = 0 ; i < getNumAttributes ( ) ; i ++ ) { magnitude += atts [ i ] * atts [ i ] ; } magnitude = Math . sqrt ( magnitude ) ; desiredMag = rand . nextGaussian ( ) * m_centroidStdDevs [ centroid ] ; scale = desiredMag / magnitude ; for ( i = 0 ; i < getNumAttributes ( ) ; i ++ ) { atts [ i ] *= scale ; atts [ i ] += m_centroids [ centroid ] [ i ] ; result = new DenseInstance ( 1.0 , atts ) ; } result . setDataset ( m_DatasetFormat ) ; return result ; }
target:  Generates one example of the dataset.