The mxFactor() function was introduced in the 0.3.0 release. In the source code repository, it has been updated to accept multiple columns of a data frame. Here is an example of the new functionality:
nthresh1 <- 1 nthresh2 <- 12 data <- read.table("data/mddndzf.dat", na.string=".", col.names=c("t1neur1", "t1mddd4l", "t2neur1", "t2mddd4l")) data[,c(1,3)] <- mxFactor(data[,c(1,3)], c(0 : nthresh2)) data[,c(2,4)] <- mxFactor(data[,c(2,4)], c(0 : nthresh1))
This will be included in the next binary release.