question: public DefaultHeatMapDataset ( int xSamples , int ySamples , double minX , double maxX , double minY , double maxY ) { if ( xSamples < 1 ) { throw new IllegalArgumentException ( "Requires 'xSamples' > 0" ) ; } if ( ySamples < 1 ) { throw new IllegalArgumentException ( "Requires 'ySamples' > 0" ) ; } if ( Double . isInfinite ( minX ) || Double . isNaN ( minX ) ) { throw new IllegalArgumentException ( "'minX' cannot be INF or NaN." ) ; } if ( Double . isInfinite ( maxX ) || Double . isNaN ( maxX ) ) { throw new IllegalArgumentException ( "'maxX' cannot be INF or NaN." ) ; } if ( Double . isInfinite ( minY ) || Double . isNaN ( minY ) ) { throw new IllegalArgumentException ( "'minY' cannot be INF or NaN." ) ; } if ( Double . isInfinite ( maxY ) || Double . isNaN ( maxY ) ) { throw new IllegalArgumentException ( "'maxY' cannot be INF or NaN." ) ; } this . xSamples = xSamples ; this . ySamples = ySamples ; this . minX = minX ; this . maxX = maxX ; this . minY = minY ; this . maxY = maxY ; this . zValues = new double [ xSamples ] [ ] ; for ( int x = 0 ; x < xSamples ; x ++ ) { this . zValues [ x ] = new double [ ySamples ] ; } }
target:  Creates a new dataset where all the z-values are initially 0.  This is a fixed size array of z-values.