N1Spr()
calculates the number of trees one subtree prune-and-regraft
operation away from a binary input tree using the formula given by
Allen and Steel (2001)
;
IC1Spr()
calculates the information content of trees at this
distance: i.e. the entropy corresponding to the proportion of all possible
n-tip trees whose SPR distance is at most one from a specified tree.
N1Spr(n)
IC1Spr(n)
Integer vector specifying the number of tips in a tree.
N1Spr()
returns an integer vector denoting the number of trees one
SPR rearrangement away from the input tree..
IC1Spr()
returns an numeric vector giving the phylogenetic
information content of trees 0 or 1 SPR rearrangement from an n-leaf tree,
in bits.
Allen BL, Steel MA (2001). “Subtree transfer operations and their induced metrics on evolutionary trees.” Annals of Combinatorics, 5(1), 1--15. doi:10.1007/s00026-001-8006-8 .
N1Spr(4:6)
#> [1] 2 12 30
IC1Spr(5)
#> [1] 0.2064509