R/duplicateHandling.R

In bartzbeielstein/SPOT: Sequential Parameter Optimization Toolbox

###################################################################################
#' Handle Duplicates and Replicates
#' 
#' This function deals with duplicates, that is, when a candidate solution (\code{xnew})
#' has already been evaluated (that is, \code{xnew} is element of \code{x}).
#' If \code{control$noise} is \code{TRUE} (objective is noisy), duplicates are allowed.
#' In that case, this function only makes sure that such duplicates do
#' do not receive additional replications (i.e., the duplicate is evaluated only once).
#' If the objective is not noisy, duplicates are replaced by randomly created solution
#' and a warning is given.
#'
#' @param xnew matrix of new candidate solution(s), one row for each solution.
#' @param x matrix of evaluated solutions.
#' @param lower vector for lower boundary of decision space
#' @param upper vector for upper boundary of decision space
#' @param control list of controls
#'
#' @return matrix \code{xnew}, with additional replicates for non-duplicates, or duplicates replaced by random solutions.
#'
#' @export
#' @keywords internal
###################################################################################
duplicateAndReplicateHandling <- function(xnew,x,lower,upper,control){
  if(control$noise){
    ##determine on the fly whether xnew is in x -> no "initialReplications" needed. else, assign initial replications.
    xtmp <- NULL
    for(i in 1:nrow(xnew)){
			#if solution has NOT been evaluated previously
			if(!any(apply(x,1,identical,xnew[i,]))){ #TODO this may conflict with parameter names... does x, xnew, xtmp  etc have parameter names?
					xtmp <- rbind(xtmp, xnew[rep(i,control$replicates-1),] )  #TODO this does not deal with duplicates in xnew itself. 
				}              
		}
		xnew <- rbind(xnew,xtmp)
	}else{
		## check for duplicates in case of noise==FALSE --> warning + return results or warning + replace with random solution
		for(i in 1:nrow(xnew)){
			#if solution has NOT been evaluated previously
			if(any(apply(x,1,identical,xnew[i,]))){ #TODO this may conflict with parameter names... does x, xnew  etc have parameter names?
				warning("SPOT created a duplicated solution. This can be due to early convergence or bad configuration. Duplicate is replaced by random solution.")
				control$designControl$replicates <- 1
				control$designControl$size <- 1
				xnew[i,] <- designUniformRandom(,lower,upper,control$designControl) #TODO what if result is also duplicate
			}              
		}
	}
	xnew
}
#TODO: needs testing