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#######################################################################
# TSP - Traveling Salesperson Problem
# Copyrigth (C) 2011 Michael Hahsler and Kurt Hornik
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
TOUR <- function(x, method=NA, tsp=NULL){
if(inherits(x, "TOUR")) return(x)
x <- as.TOUR(x)
attr(x, "method") <- as.character(method)
if(!is.null(tsp)){
attr(x, "tour_length") <- tour_length(x, tsp)
names(x) <- labels(tsp)[x]
}
x
}
## coercion
as.TOUR <- function(object) UseMethod("as.TOUR")
as.TOUR.numeric <- function(object){
l <- labels(object) ### preserve lables
object <- as.integer(object)
names(object) <- l
as.TOUR(object)
}
as.TOUR.integer <- function(object){
## check tour
if(any(object < 1) || any(object > length(object)) || any(is.na(object)))
stop("tour contains illegal elements.")
if(any(duplicated(object))) stop("tour indices are not unique.")
class(object) <- c("TOUR", class(object))
object
}
## helper for tour
print.TOUR <- function(x, ...){
cat("object of class", sQuote(class(x)[1]), "\n")
cat("result of method", sQuote(attr(x, "method")), "for",
length(x), "cities\n")
if(!is.null(attr(x, "tour_length")))
cat("tour length:", attr(x, "tour_length"), "\n")
else
cat("tour length: unknown\n")
}
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