commons.math

    /**
     * Returns the entries in column number <code>col</code> as an array.
     * <p>
     * Column indices start at 0.  A <code>MatrixIndexException</code> is thrown
     * unless <code>0 <= column < columnDimension.</code></p>
     *
     * @param column the column to be fetched
     * @return array of entries in the column
     * @throws MatrixIndexException if the specified column index is not valid
     */
    double[] getColumn(int column) throws MatrixIndexException;