thanks. Ravi and Nash. I will read the new package and may use it after I am familiar with it. I may bother both of you when I have questions.thanks for that in advance.
Nan from Montreal Hi Nan, You can take a look at the "optimx" package on CRAN. John Nash and I wrote this package to help lay and sophisticated users alike. This package unifies various optimization algorithms in R for smooth, box-constrained optimization. It has features for checking objective function, gradient (and hessian) specifications. It checks for potential problems due to poor scaling; checks feasibility of starting values. It provides diagnostics (KKT conditions) on whether or not a local optimum has been located. It also allows the user to run various optimization algorithms in one simple call, which is essentially identical to "optim" call. This feature can be especially useful for developers to benchmark different algorithms and choose the best one for their class of problems. http://cran.r-project.org/web/packages/optimx/index.html Ravi. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.