R/validity_funs.R

In permutations: The Symmetric Group: Permutations of a Finite Set

singleword_valid <- function(w){  # takes an integer vector
    if(length(w)==0){return(TRUE)}
    if(identical(unname(seq_len(max(w))),unname(sort(w)))){
      return(TRUE)
    } else {
      warning("invalid word")
      return(FALSE)
    }
}

cyclist_valid <- function(x){   # takes a cyclist and checks it for validity
    if(length(unlist(x))==0){return(TRUE)}
    x <- c(x,recursive=TRUE)
    if(any(x<0)){
      warning("negative elements")
      return(FALSE)
    } else if (any(x==0)){
      warning("zero element")
      return(FALSE)
    } else if (any(abs(x-round(x))>0.1)) {
      warning('non-integer entries')
      return(FALSE)
    } else if (any(table(x)>1)){
      warning("repeated value")
      return(FALSE)
    } else {
      return(TRUE)
    }
}