code: protected void setToRootNodeNewID( GrowQueue_I32 regionMemberCount ) {
  
  		tmpMemberCount.reset();
  
  		for( int i = 0; i < mergeList.size; i++ ) {
  			int p = mergeList.data[i];
  
  			if( p == i ) {
  				mergeList.data[i] = rootID.data[i];
  				tmpMemberCount.add( regionMemberCount.data[i] );
  			} else {
  				mergeList.data[i] = rootID.data[mergeList.data[i]];
  			}
  		}
  
  		regionMemberCount.reset();
  		regionMemberCount.addAll(tmpMemberCount);
  	}
docs: Does much of the work needed to remove the redundant segments that are being merged into their root node.
  The list of member count is updated.  mergeList is updated with the new segment IDs.