1. A method comprising: performing collected components processing, wherein performing collected components processing includes: maintaining a relabeling data structure comprising labels; and labeling vertices of a graph based upon labeling rules; and detecting a merge condition when a selected vertex has two intersecting arcs connecting the selected vertex to two labeled vertices labeled with conflicting labels; accessing the relabeling data structure based upon the merge condition; and propagating a label from one of the labeled vertices to the selected vertex.