Abstract :
This paperpresentsanewalgorithmforderivative-freeoptimizationofexpensiveblack-boxobjective
functionssubjecttoexpensiveblack-boxinequalityconstraints.Theproposedalgorithm,called
ConstrLMSRBF,usesradialbasisfunction(RBF)surrogatemodelsandisanextensionoftheLocalMetric
StochasticRBF(LMSRBF)algorithmbyRegisandShoemaker(2007a) [1] that canhandleblack-box
inequalityconstraints.Previousalgorithmsfortheoptimizationofexpensivefunctionsusingsurrogate
modelshavemostlydealtwithboundconstrainedproblemswhereonlytheobjectivefunctionis
expensive,andso,thesurrogatemodelsareusedtoapproximatetheobjectivefunctiononly.In
contrast,ConstrLMSRBFbuildsRBFsurrogatemodelsfortheobjectivefunctionandalsoforallthe
constraintfunctionsineachiteration,andusestheseRBFmodelstoguidetheselectionofthenextpoint
wheretheobjectiveandconstraintfunctionswillbeevaluated.Computationalresultsindicatethat
ConstrLMSRBFisbetterthanalternativemethodson9outof14testproblemsandontheMOPTA08
problemfromtheautomotiveindustry(Jones,2008 [2]). TheMOPTA08problemhas124decision
variablesand68inequalityconstraintsandisconsideredalarge-scaleproblemintheareaofexpensive
black-boxoptimization.ThealternativemethodsincludeaMeshAdaptiveDirectSearch(MADS)
algorithm(AbramsonandAudet,2006 [3]; AudetandDennis,2006 [4]) thatusesakriging-based
surrogatemodel,theMultistartLMSRBFalgorithmbyRegisandShoemaker(2007a) [1] modifiedto
handle black-boxconstraintsviaapenaltyapproach,ageneticalgorithm,apatternsearchalgorithm,a
sequentialquadraticprogrammingalgorithm,andCOBYLA(Powell,1994 [5]), whichisaderivative-free
trust-regionalgorithm.Basedontheresultsofthisstudy,theresultsinJones(2008) [2] and other
approachespresentedattheISMP2009conference,ConstrLMSRBFappearstobeamongthebest,ifnot
the best,knownalgorithmfortheMOPTA08probleminthesenseofprovidingthemostimprovement
from aninitialfeasiblesolutionwithinaverylimitednumberofobjectiveandconstraintfunction
evaluations.
Keywords :
Expensive function , radial basis function , Derivative-free optimization , Surrogate model , Constrained optimization , Large-scale optimization , Stochastic algorithm