I am trying to figure out how parameters are defined in a function that is used by DEOptim. That is, when I set upper and lower bounds for DEOptim how does it know which element of the function to apply those bounds to? For example, in DEOptim call below, when DEOptim goes into "optimfxn" how does it know what element of "optimfxn" to apply the upper and lower bounds to? optimization<-DEoptim( fn=optimfxn, lower=c(1.01000, 0.98000), upper=c(1.20000, 4.44000) optimfxn<- function (x) { _________________________________________________________________ The New Busy is not the old busy. Search, chat and e-mail from your inbox. N:WL:en-US:WM_HMP:042010_3 [[alternative HTML version deleted]]