calculate.blw: Calculate Branch Length Weightings for ILR Coordinates

In philr: Phylogenetic partitioning based ILR transform for metagenomics data

Description

Calculates the weightings for ILR coordinates based on branch lenghts of a phylogenetic tree via a few different methods (see details).

Usage

calculate.blw(tree, method = "sum.children")

Arguments

tree	a phylo class tree object that is binary (see multi2di)
method	options include: (default) 'sum.children' and 'mean.descendants' see details for more information.

Details

ILR balances built from a binary partition of a phylogenetic tree can be imbued with branch length information. This function is helpful in calculating those weightings.

There are a number of methods for calculating these weightings, the default 'sum.children' calculates the weighting for a given balance as the sum of its two direct children's branch length. An alternative that has been as yet less studied is 'mean.descendants' to calculate the weighting for a given balance as the sum of its two direct children's branch lengths PLUS for each child the average distance from it to its descendant tips.

Note: That some trees contain tips with branch lengths of zero length. This can result in that tip being unreasonably downweighted, as such this function automatically adds a small pseudocount to those tips with zero length (equal to the smallest non-zero) branch length on the tree.

Value

vector of weightings for ILR coordinates produced via specified method.

Author(s)

Justin Silverman

See Also

philr

Examples

tr <- named_rtree(50)
calculate.blw(tr, method='sum.children')[1:10]
calculate.blw(tr, method='mean.descendants')[1:10]

philr documentation built on Nov. 8, 2020, 5:38 p.m.