An algorithm to detect positive cycles in a constraint graph for layout compaction

The problems of finding positive cycles and calculating the longest path lengths in a given constraint graph are considered. An O( b S(n,m)) time algorithm is proposed, where n, m, and b are the numbers of vertices, edges, and backward edges (corresponding to the user-defined design rules) in the graph, and S(n,m) is the time needed in the Dijkstra algorithm. Experimental results are shown