segment.normalize();
	public void addFragment( long[] leftEdges, long[] rightEdges )	{		Fragment leftEdge = this;		for ( int i = 0; i < leftEdges.length; i++ )		{			leftEdge.segment.startSegment( leftEdges[i] );			// search the insert point in the edge tree			leftEdge = addFragment( leftEdge, leftEdges[i] );		}		//add it into left		leftEdge.segment.startSegment( Long.MIN_VALUE );				Fragment rightEdge  = this;		for ( int i = 0; i < rightEdges.length; i++ )		{			rightEdge.segment.endSegment( rightEdges[i] );			// search the insert point in the edge tree			rightEdge = addFragment( rightEdge, rightEdges[i] );		}		//add it into right		rightEdge.segment.endSegment( Long.MIN_VALUE );	}