Designing an A* Algorithm for Calculating Edit Distance between Rooted-Unordered Trees

Tree structures are useful for describing and analyzing biological objects and processes. Consequently, there is a need to design metrics and algorithms to compare trees. A natural comparison metric is the "Tree Edit Distance," the number of simple edit (insert/delete) operations needed to transform one tree into the other. Rooted-ordered trees, where the order between the siblings is significant, can be compared in polynomial time. Rooted-unordered trees are used to describe processes or objects where the topology, rather than the order or the identity of each node, is important. For example, in immunology, rooted-unordered trees describe the process of immunoglobulin (antibody) gene diversification in the germinal center over time. Comparing such trees has been proven to be a difficult computational problem that belongs to the set of NP-Complete problems. Comparing two trees can be viewed as a search problem in graphs. A is a search algorithm that explores the search space...

• Type: Journal
• Year: 2006
• Where: JCB
• Authors: Yair Horesh, Ramit Mehr, Ron Unger
• Keywords: Algorithm, JCB 2006, Rooted-unordered Trees, Tree Edit Distance