question: public static String computeSimpsonReciprocal ( ViewerBase viewer , ProgressListener progressListener ) throws IOException , CanceledException { if ( viewer instanceof MainViewer ) return toString ( computeSimpsonReciprocal ( ( MainViewer ) viewer , progressListener ) ) ; else if ( viewer instanceof ClassificationViewer ) return toString ( computeSimpsonReciprocal ( ( ClassificationViewer ) viewer , progressListener ) ) ; else return null ; }
target:  compute the Shannon-Weaver diversity index in bits