public OnLineStatistics getOnlineDenseStats()
    {
        OnLineStatistics stats = new OnLineStatistics();
        double N = getNumNumericalVars();
        for(int i = 0; i < size(); i++)
            stats.add(getDataPoint(i).getNumericalValues().nnz()/N);
        return stats;
    }
public OnLineStatistics getOnlineDenseStats ( ) { OnLineStatistics stats = new OnLineStatistics ( ) ; double N = getNumNumericalVars ( ) ; for ( int i = 0 ; i < size ( ) ; i ++ ) stats . add ( getDataPoint ( i ) . getNumericalValues ( ) . nnz ( ) / N ) ; return stats ; }
Returns an {@link OnLineStatistics } object that is built by observing
what proportion of each data point contains non zero numerical values.
A mean of 1 indicates all values were fully dense, and a mean of 0
indicates all values were completely sparse (all zeros).

@return statistics on the percent sparseness of each data point