R/getA.R

In effectFusion: Bayesian Effect Fusion for Categorical Predictors

getA <- function(levels) {
    
    A_list <- list()
    lev <- levels
    
    for (j in 1:length(lev)) {
        
        if (lev[j] > 1) {
            
            hd <- choose(lev[j], 2)
            k <- lev[j]
            Aresh <- matrix(0, hd, k)
            istrt <- 1
            
            for (i in 1:(k - 1)) {
                hi <- k - i
                iend <- istrt + hi - 1
                indx <- istrt:iend
                Aresh[indx, i] <- matrix(-1, hi, 1)
                Aresh[indx, i + (1:hi)] <- diag(hi)
                istrt <- iend + 1
            }
            
            if (hd == 1) {
                A <- cbind(Aresh, 1)
            } else {
                A <- cbind(Aresh, diag(rep(1, hd)))
            }
            
        } else {
            A <- as.matrix(0)
        }
        
        A_list$A <- A
        names(A_list) <- 1:j
        
    }
    
    A <- A_list
    
}