Bug 214197 [Regression] Auto scale does not work correctly [13]
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/computation/withaxes/AutoScale.java
* 
	 * @return
	 */
	public final double getUnitSize( )
	{
		if ( atcTickCoordinates == null )
		{
			throw new RuntimeException( new ChartException( ChartEnginePlugin.ID,
					ChartException.COMPUTATION,
					"exception.unit.size.failure",  
					Messages.getResourceBundle( rtc.getULocale( ) ) ) );
		}
		return Math.abs( atcTickCoordinates.getStep( ) );
	}
	/**
	 * 
	 * @return
	 */
	public final Object getMinimum( )
	{
		return oMinimum;
	}
	/**
	 * @param o
	 */
	public final void setMinimum( Object o )
	{
		this.oMinimum = o;
	}
	/**