R/scalar-term.R

In term: Create, Manipulate and Query Parameter Terms

#' Scalar Term
#'
#' Test whether each term is a scalar.
#'
#' @inheritParams params
#' @return A logical vector indicating whether the term is a scalar.
#' @export
#'
#' @examples
#' scalar_term(term("alpha[1]", "alpha[3]", "beta[1]", "sigma[3]"))
#' scalar_term(term("alpha[1]", NA_term_, "beta[1]", "beta[3]"))
scalar_term <- function(x) {
  if(!vld_s3_class(x, "term") && !vld_s3_class(x, "term_rcrd")) {
    chkor_vld(vld_s3_class(x, "term"), vld_s3_class(x, "term_rcrd"))
  }
  x <- as_term_rcrd(x)
  dim1 <- vapply(field(x, "dim"), function(x) identical(x, 1L), TRUE)
  pars_terms <- field(x, "par")
  scalar_term <- dim1 & !pars_terms %in% unique(pars_terms[!dim1])
  scalar_term[is.na(pars_terms)] <- NA
  scalar_term
}