QDist implements a sub-cubic algorithm for computing the quartet distance between general trees (i.e. the trees are not required to be binary).
The QDist package implements the O(n log2 n) time method for computing the quartet distance between unrooted evolutionary trees.
:: MORE INFORMATION
T. Mailund and C.N.S. Pedersen,
QDist—Quartet Distance Between Evolutionary Trees,
Bioinformatics, Vol. 20, No. 10, pp 1636-1637, 2004.