R/ambiguity-methods.R

In FuzzyNumbers: Tools to deal with fuzzy numbers in R

## This file is part of the FuzzyNumbers library.
##
## Copyright 2012 Marek Gagolewski
##
##
## FuzzyNumbers is free software: you can redistribute it and/or modify
## it under the terms of the GNU Lesser General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## FuzzyNumbers is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
## GNU Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public License
## along with FuzzyNumbers. If not, see <http://www.gnu.org/licenses/>.



setGeneric("ambiguity",
           function(object, ...) standardGeneric("ambiguity"))



#' Calculate the ambiguity of a fuzzy number
#' 
#' The ambiguity is a measure of nonspecificity of a fuzzy number.
#' It is defined as
#' \eqn{amb(A) := \int_0^1 \alpha\left(A_U(\alpha)-A_L(\alpha)\right)\,d\alpha}{val(A) := int_0^1 \alpha(A_U(\alpha) - A_L(\alpha))d\alpha}.
#'
#' @section Methods:
#' \describe{
#'      \item{\code{signature(object = "FuzzyNumber")}}{}
#' }
#' @exportMethod ambiguity
#' @name ambiguity
#' @aliases ambiguity,FuzzyNumber-method
#' @rdname ambiguity-methods
#' @docType methods
#' @seealso \code{\link{alphaInterval}} on which the method is based
#' @family FuzzyNumber-method
#' @references
#' Delgado M., Vila M.A., Voxman W. (1998), On a canonical representation of a fuzzy number,
#' Fuzzy Sets and Systems 93, pp. 125-135.\cr
setMethod(
   f="ambiguity",
   signature(object="FuzzyNumber"),
   definition=function(object, ...)
   {
      return(diff(alphaInterval(object, ...)))
   }
)