create_comparison_matrix function

Creates row-wise perturbations of compositions from the mean composition

create_comparison_matrix(comparisons, comps, mean_comps)

Arguments

• comparisons: currently two choices: "one-v-one" or "prop-realloc" (default).
• comps: the names (character vector) of the compositional variables
• mean_comps: the mean composition of comps

Details

comparisons = "one-v-one" creates a matrix with length(comps) columns and length(comps) * (length(comps) - 1) rows. The rows contain all pairs of variables with 1 and -1 values.

comparisons = "prop-realloc" creates a matrix with length(comps) columns and length(comps) rows. Each rows contains a 1 value for a compositional variable and the remaining values sum to -1 proportional to the mean_comps value for those variables.

Note that for both comparisons options the net change is 0 (each row sums to 0).