relGV.multi {vcvComp}

Ratio of generalized variances

Description

Computes the (log-transformed) ratios of the generalized variances of a set of covariance matrices

Usage

relGV.multi(Sm, logGV = TRUE)

Arguments

Sm

a (p x p x m) array of covariance matrices, where p is the number of variables and m the number of groups.

logGV

a logical argument to indicate if the ratios should be log-transformed

Value

The matrix of the (log-transformed) ratios of the generalized variances. For each row, the ratio corrresponds to the group of the row relative to the group of a column.

Examples

# Data matrix of 2D landmark coordinates
data("Tropheus.IK.coord")
coords <- which(names(Tropheus.IK.coord) == "X1"):which(names(Tropheus.IK.coord) == "Y19")
proc.coord <- as.matrix(Tropheus.IK.coord[coords])

# Data reduction
phen.pca <- prcomp(proc.coord, rank. = 5, tol = sqrt(.Machine$double.eps))
pc.scores <- phen.pca$x

# Covariance matrix of each population
S.phen.pop <- cov.group(pc.scores, groups = Tropheus.IK.coord$POP.ID)

# Ratio of the generalized variances of 2 populations (IKA1 and IKS5)
relGV.multi(S.phen.pop[, , c("IKA1", "IKS5")], logGV = FALSE)