class SubMatrix implements Cloneable {

    @NewObject
    public DataBlock columnSum() {
        return columns().sum();
    }

    public  SubMatrix(final double[] data, final int nrows, final int ncols);
    public  SubMatrix(final double[] data, final int start, final int nrows,
            final int ncols, final int rowinc, final int colinc);
    public  SubMatrix(final SubMatrix m);

}