R/SpecialValues.R

In gamstransfer: A Data Interface Between 'GAMS' and R

#
# GAMS - General Algebraic Modeling System R API
#
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#' @title SpecialValues list object
#' @description This list contains GAMS special values and
#' helper functions to check if a given value is a GAMS
#' special value.
#' Please visit https://www.gams.com/latest/docs/API_R_GAMSTRANSFER.html 
#' for detailed documentation of this package.
#'
#' @examples
#' # check the value of GAMS special value NA
#' NA_val = SpecialValues[["NA"]]
#' # check the value of GAMS special value EPS
#' EPS_val = SpecialValues[["EPS"]]
#' # check if a value is GAMS special value `NA`
#' isNA_check = SpecialValues$isNA(0)
SpecialValues = list(
  "NA" = NA, # cannot be anything else
  "EPS" = -0.0,
  "UNDEF" = NaN,
  "POSINF" = Inf,
  "NEGINF" = -Inf,
  "isNA" = function(x) return(is.na(x) & !is.nan(x)),
  "isEps" = function(x) {
    isna = is.na(x)
    iseps_logical = ((x == 0) & (sign(1/x) == -1))
    iseps_logical[isna] = FALSE
    return(iseps_logical)
    },
  "isUndef" = function(x) return(is.nan(x)),
  "isPosInf" = function(x) return(is.infinite(x) & sign(x) == 1),
  "isNegInf" = function(x) return(is.infinite(x) & sign(x) == -1)
  )