library(ltm)
library(nFactors)
library(psych)

gen.test <- function()
{
  test <- lapply(1:10, function(u) rep(NA,5))
  
  b.min <- seq(-2,2,length=10)
  a <- rnorm(10,1.25,0.07)
  
  for(i in 1:10)
  {
    test[[i]] <- c(
      b.min[i],
      b.min[i] + sort(runif(3,0,0.1)),
      a[i]
    )
  }
  
  # return #
  test
}

test <- gen.test()
responses <- rmvordlogis(200,test,IRT=FALSE,z.vals=traits$theta1)
grm <- grm(responses,constrained=FALSE,IRT.param=TRUE,start.val = "random")
scores <- ltm::factor.scores(grm,resp.patterns = responses)$score.dat$z1