Build sum-to-zero contrasts

Creates sum-to-zero contrast matrices for a set of factors, suitable for use with effect-coded kernels.

Usage

sum_contrasts(Ls)

Arguments

Ls

Named integer vector specifying the number of levels per factor

Value

Named list of contrast matrices, each of dimension L x (L-1) where L is the number of levels for that factor. Each matrix has row sums of zero.

Examples

contrasts <- sum_contrasts(c(A=3, B=4))
print(dim(contrasts$A))  # 3 x 2
#> [1] 3 2
print(dim(contrasts$B))  # 4 x 3
#> [1] 4 3