date the IM with the contribution for this component.
 A component only contributes if it has a labelling for both parent geometries
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../com/vividsolutions/jts/geomgraph/GraphComponent.html#computeIM(com.vividsolutions.jts.geom.IntersectionMatrix)">computeIM</A></CODE> in class <CODE><A HREF="../../../../com/vividsolutions/jts/geomgraph/GraphComponent.html" title="class in com.vividsolutions.jts.geomgraph">GraphComponent</A></CODE></DL>
</D