public static PlotCanvas plot(double[][] data, int k, Color[] palette) {
        return plot(data, k, false, palette);
    }
public static PlotCanvas plot ( double [ ] [ ] data , int k , Color [ ] palette ) { return plot ( data , k , false , palette ) ; }
Create a plot canvas with the histogram plot of given data.
@param data a sample set.
@param k the number of bins.
@param palette the color palette.