Hello! I have a very large experimental design space (all possible combinations of all possible levels of several factors). For example, 'allcand' below has 1,875,000 possible combinations of 9 factors. allcand<-expand.grid(a1=as.factor(1:5),a2=as.factor(1:5),a3=as.factor(1:5),a4=as.factor(1:5), a5=as.factor(1:5),a6=as.factor(1:3),a7=as.factor(1:5),a8=as.factor(1:5),a9=as.factor(1:8)) dim(allcand) My ultimate goal is to grab a subset of 10,000 out of those 1.875 million candidates, such that the resulting 10,000 are as orthogonal as possible. Usually, I use package "AlgDesign" for such tasks. However, my design space is so large that it is taking too long even to grab 100 out 1,875,000 - like that: library(AlgDesign) system.time(mydes<-optFederov(~.,data=allcand,nTrials=100)) # It took me on my machine 38 min. Is there a package that could do something like this faster? Thank you very much! -- Dimitri Liakhovitski [[alternative HTML version deleted]]