actapia / dnted

Python library for computing a normalized tree edit distance metric

dnted

dnted is a small Python library for computing a normalized edit distance metric between ordered labeled trees using the method presented in Li and Chenguang.

dnted uses the zss module to compute absolute edit distances between ordered trees before normalizing and is desgined to be easy to use for those who have already used zss. In fact, the two most useful functions in dnted�normalized_simple_distance and normalized_distance�are modelled after the coresponding simple_dsitance and distance functions provided by zss, respectively, and should be compatible with their arguments.

The most important difference between the normalized functions in dnted and those in zss is the presence of two additional arguments in dnted�alpha and get_tree_size. The former, alpha, is expected to be a number representing the maximum cost of adding or deleting a node. The latter, get_tree_size, is expected to be a function that gets the size of a given tree.

References

• Yujian Li and Zhang Chenguang. 2011. A metric normalization of tree edit distance. Front. Comput. Sci China 5, 1 (March 2011), 119-125. DOI=http://dx.doi.org/10.1007/s11704-011-9336-2.