Generates orthonormal (orthogonal and normalized) contrasts. Each row is the vertex of an N-dimensional simplex. The only exception are contrasts for the 2-level case, which return 1 and -1.
Usage
contr.simplex(n, size = NULL)
Arguments
- n
The number of levels in the catagorical variable. If this is a factor or character vector, `n` will be `length(n)`
- size
Default `1`. The length of the simplex vector.
Value
A matrix of Orthonormal contrasts.
Examples
contr.simplex(4)
#> [,1] [,2] [,3]
#> [1,] 1.7320508 0.0000000 0.000000
#> [2,] -0.5773503 1.6329932 0.000000
#> [3,] -0.5773503 -0.8164966 1.414214
#> [4,] -0.5773503 -0.8164966 -1.414214