R/T1perGroup.R

In TreeBUGS: Hierarchical Multinomial Processing Tree Modeling

# make index variables to compute T1 statistic by group
getGroupT1 <- function(covData, predType, T1group = NULL) {
  if (!is.null(T1group)) {
    if (!T1group %in% colnames(covData)) {
      stop("T1group not found in covData (matching by column names)")
    }
    if (is.null(covData) || is.null(T1group)) {
      return(NULL)
    }

    groupTab <- table(covData[, T1group])
    NgroupT1 <- as.vector(groupTab)
    groupNames <- names(groupTab)
    names(NgroupT1) <- groupNames
    N <- sum(NgroupT1)
    G <- length(NgroupT1)

    #### general index vector, stored in matrix
    groupMatT1 <- matrix(0, G, max(NgroupT1),
      dimnames = list(groupNames, NULL)
    )
    cnt <- rep(0, G)
    for (i in 1:N) {
      group <- covData[i, T1group]
      groupMatT1[group, cnt[group] <- cnt[group] + 1] <- i
    }
    list(
      groupMatT1 = groupMatT1,
      NgroupT1 = NgroupT1
    )
  } else {
    NULL
  }
}