Calculates the maximum width, this is calculated by first collecting the depth of each node and tip across the entire tree, where the depth represents the distance (in nodes) to the root. Then, the width represents the number of occurrences of each possible depth. The maximal width then returns the maximum number of such occurences.
max_width(phy, normalization = "none")
maximum width
phylogeny or ltable
"none" or "tips", in which case the resulting statistic is divided by the number of tips in the tree.
C. Colijn and J. Gardy. Phylogenetic tree shapes resolve disease transmission patterns. Evolution, Medicine, and Public Health, 2014(1):96-108, 2014. ISSN 2050-6201. doi: 10.1093/emph/eou018.