R/makeSolver.R

In jakobbossek/salesperson: Computation of Instance Features and R Interface to the State-of-the-Art Exact and Inexact Solvers for the Traveling Salesperson Problem

#' @title
#' Generator for TSP solvers.
#'
#' @description
#' Construct a TSP solver object.
#'
#' @param solver [\code{character(1)}]\cr
#'   Solver Id.
#' @return [\code{TSPSolver}]
#' @export
makeSolver = function(solver) {
  constructor = getS3method("makeTSPSolver", solver)
  solver = do.call(constructor, list())
  if (isExternalSolver(solver)) {
    solver$bin = solverPaths()[[solver$cl]] #getSolverPath(solver$short.name)
  }
  return(solver)
}

# @title
# Internal generator for TSP solvers.
#
# @param cl [\code{character(1)}]\cr
#   Class name for the TSP solver.
# @param short.name [\code{character(1)}]\cr
#   Short name / identifier for the solver.
# @param name [\code{character(1)}]\cr
#   Long name of the solver.
# @param properties [\code{character}]\cr
#   Character vector of characterizing properties of the learner, e.g., \dQuote{external}
#   if the solver is called via an external script.
# @param packages [\code{character}]\cr
#   Character vector of package names of R packages which are necessary to
#   run the solver.
# @param description [\code{character(1)}]\cr
#   Optional description of the solver or solvers functioning principle.
# @return [\code{TSPSolver}]
makeTSPSolverInternal = function(cl, short.name, name,
  properties, packages = NULL, description = NULL) {
  makeS3Obj(
    cl = cl,
    short.name = short.name,
    name = name,
    description = description,
    properties = properties,
    packages = packages,
    classes = c(cl, "TSPSolver")
  )
}

#' Make TSP solver dispatcher.
#'
#' @return [\code{TSPSolver}]
#' @export
makeTSPSolver = function() {
  UseMethod("makeTSPSolver")
}

#' Check if solver is called via an external binary.
#'
#' @param solver [\code{TSPSolver}]
#' @return [\code{logical(1)}]
isExternalSolver = function(solver) {
  return(hasProperties(solver, "external"))
}

#' Check if learner has certain properties.
#'
#' @param solver [\code{TSPSolver}]\cr
#'   Solver object.
#' @param properties [\code{character}]\cr
#'   Vector of strings.
#' @return [\code{logical(1)}] \code{TRUE} if the solver has all properties, \code{FALSE} otherwise.
#' @export
hasProperties = function(solver, properties) {
  UseMethod("hasProperties")
}

hasProperties.TSPSolver = function(solver, properties) {
  return(isSubset(properties, getSolverProperties(solver)))
}

#' Get the properties/tags of the solver.
#'
#' @param solver [\code{TSPSolver}]\cr
#'   Solver object.
#' @return [\code{character}]
#' @export
getSolverProperties = function(solver) {
  UseMethod("getSolverProperties")
}

getSolverProperties.TSPSolver = function(solver) {
  return(solver$properties)
}

#' Run a TSP solver to solve a problem instance.
#'
#' @param solver [\code{TSPSolver}]\cr
#'   Solver object.
#' @param instance [\code{Network}]\cr
#'   TSP instance to solve.
#' @param ... [any]\cr
#'   Not used.
#' @return [\code{TSPSolverResult}]
#' @export
run = function(solver, instance, ...) {
  UseMethod("run")
}