R/discounted.csf.R

In antoanne/ifmFramework: Financial evaluation of Projects

#' The cash flows incomes/outcomes applying the Tax Rate to the present time.
#' @name discounted.csf
#'
#' @aliases discounted_csf discountedCsf
#'
#' @param cfs A vector with a series of cash flows.
#'
#' @param interest.rate A number that represents the nominal Interest Rate,
#' presented by year.
#'
#' @param begin.of.period A boolean that represents if the Tax Rate will be
#' applied at the begining of period. FALSE by default, the Tax Rate will be
#' applied to the second period.
#'
#' @export
#'
#' @return The vector of cash flows incomes/outcomes applying the Tax Rate to
#' the present time.
#'
#' @keywords cash flow series
#'
#' @family financial
#'
#' @examples
#'
#' ex.disc.csf <- discounted.csf(c(-350,100,200,150,75), 0.0619, FALSE)
#'
discounted.csf <- discounted_csf <- discountedCsf <-
function(cfs = c(-350,100,200,150,75),
         interest.rate = 0.0619,
         begin.of.period = FALSE)
{
  time.instance <- if(begin.of.period) {0:(length(cfs)-1)} else {1:(length(cfs))}
  tax.rate <- (1 / ((1 + (interest.rate)) ^ time.instance))
  return (cfs * tax.rate)
}